Epiligrin, an epithelial ligand for integrins

1. FIELD OF THE INVENTION
The invention relates generally to epithelial cell receptors and ligands which are useful for adhering epithelial cells to a substratum.
2. BACKGROUND OF THE INVENTION
The invention is predicated upon a basic understanding of epithelial cells and tissues studied. Such epithelia, which cover free surfaces and line body cavities and ducts, have been studied microscopically for at least three centuries. Recently the biochemistry and molecular biology of epithelial cells and tissues have been extensively investigated. However, the seemingly simple question of how the cells in epithelial tissues are driven to become specialized has remained unanswered. The present invention provides reagents that allow us for the first time to unravel the inter- and intracellular signals that direct epithelial cell differentiation. More fundamentally, the subject reagents permit one to finally decipher what has been a tangled web of suspected interactions involving a wide variety of cell types, some of them non-epithelial, in order to understand and modulate at a molecular level how the cells are driven to differentiate to fulfill specialized functions in the body. Pertinent background information concerning these heretofore disparate systems follows.
2.1 Abbreviations
By way of introduction, the following abbreviations are used in this disclosure: BPA, bullous pemphigoid antigen; CD3, cellular determinant #3, a lymphocyte surface antigen marker; CP, cicatrical pemphigoid, an autoimmune dermatological disease; EBA, epidermolysis bullosa acquisita, an autoimmune dermatological disease; ECM, extracellular matrix; FAs, focal adhesions; HD-BSA, heat denatured bovine serum albumin; HFK(s), human foreskin keratinocyte(s); HFK-ECM, human foreskin keratinocyte-extracellular matrix; kDa, kilodaltons of molecular mass as determined by SDS-PAGE; MAbs, monoclonal antibodies; Mr, molecular radius by SDS-PAGE, approximating molecular mass; SACs, stable anchoring contacts; and SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
E200, E170, E145, E135, E100, and E36 refer to the constituent and associated glycoproteins of the subject epithelial ligand complex epiligrin, having apparent molecular weights of 200.+-.20 kDa, 170.+-.20 kDa, 145.+-.20 kDa, 135.+-.15 kDa, 100.+-.10 kDa, and 36.+-.5 kDa, respectively.
Ep-1, 1-1, and 8-6 refer to the disclosed cDNA clones deposited under ATCC accession numbers 75540, 75539, and 75538, respectively.
Throughout the specification, the notation "(#)" is used to refer to the documents listed in the appended Citations section.
2.2 Epithelial Cells
The invention is predicated upon a basic understanding of epithelial cells and tissues studied. Such epithelia, which cover free surfaces and line body cavities and ducts, have been studied microscopically for at least three centuries. Recently the biochemistry and molecular biology of epithelial cells and tissues have been extensively investigated. However, the seemingly simple question of how the cells in epithelial tissues are driven to become specialized has remained unanswered. The present invention provides reagents that allow us for the first time to unravel the inter- and intracellular signals that direct epithelial cell differentiation. More fundamentally, the subject reagents permit one to finally decipher what has been a tangled web of suspected interactions involving a wide variety of cell types, some of them nonepithelial, in order to understand and modulate at a molecular level how these cells are driven to differentiate to fulfill their specialized functions in the body. Pertinent background information concerning these heretofore disparate systems follows.
The significance of epithelial tissues as a protective barrier is readily apparent in the body as the lining of body cavities, blood vessels, digestive tract, mammary glands, urogenital, endocrine, reticuloendothelial systems, respiratory surfaces, placenta, and surrounding the nerves and brain. The epithelia also forms the basis for the epidermis, cornea, and conjunctiva.
2.3 Epithelial tissues are rather unique in their ability for continuous regulated self-renewal, and in their ability to polarize and control cellular division and the subsequent differentiation of the daughter cells. In attempting to explain how epithelial cells may decide how and when to differentiate, it has been suggested that perhaps gradients of growth factors or interactions with extracellular matrix (ECM) may influence the cells. However, the biochemical mechanisms remain largely unknown.
2.4 The epithelial basement membrane is a common histological feature of columnar, stratified, and squamous epithelia. Another prominent feature is a proliferative basal (stem) cell layer resting on a basement membrane. When viewed through the light microscope, an epithelial basement membrane may include lucent and dense regions termed, respectively, the Lamina lucida and Lamina densa, which are sandwiched between an overlying cellular stroma (stroma), made up of basal stem cells and fibroblasts, and an underlying collagenous matrix. Basement membranes are thin but continuous sheets that separate epithelium from stroma and surround nerves, muscle fibers, smooth muscle cells, and fat cells (1-4). The molecular composition of the basement membrane varies with specialized cellular functions and with the developmental stages, shape, structure, and architecture of different epithelia (5). In the simplest model, basement membranes contain at least type IV collagen (1, 6-8), laminin (7-8), entactin (9), and heparin sulfate proteoglycans (10-11). When co-electrophoresed in SDS-PAGE (12) under reducing conditions, purified EHS tumor laminin was reported to have apparent molecular sizes of 400 kDa and 200 kDa, entactin was 158 kDa, and nidogen was 100 kDa (Kleinman et al., Biochemistry 25:312-318 (1986)).
2.5 The human skin, for example, is an epithelial tissue composed of the epidermis and the dermis. The dermis is relatively acellular and composed of secreted cell products, e.g., collagens and heparin-sulfate- and chondroitin-sulfate-proteoglycans. In contrast, the epidermis is essentially cellular, containing a layer of cells resting on a basement membrane, termed the basal (stem) cells that are covered by a layer of cornified cells, termed the stratum corneum. Central questions in skin biology have been, (1) how do the cells in the basal layer commit to become cornified, and (2) how do cells decide which daughter cells will become cornified, and which will remain in the basal layer to provide the germinal basis for future generations of cells? Histological examination provides little insight. The viable inner malpighian layers of the skin, from which the cornified cells arise, are composed of the basal cell layer, the stratum spinosum and the stratum granulosum. The cell types in these areas include at least keratinocytes, melanocytes, Merkel cells, Langerhans cells, and migratory immune cells. Cell division in the basal (stem) cell layer forms the basis for the continuous self-renewal of the skin, and it is thought that decisions on the fate of the daughter cells are made in this layer.
2.6 Two types of daughter cells appear to be created by cell division in the basal (stem) cell layers of the skin. The first daughter cell, which will continue to divide; and the second daughter cell, which will differentiate and ultimately become cornified. Distinctive cellular features that may define stages in the differentiation of the second daughter cell include at least the acquisition first, of a flattened cell shape with cytoplasmic keratohyalin granules, ivolucrin, and cytokeratin filaments (characteristics of cells in the stratum spinosum); second, of greater amounts of cytoplasmic keratin and a submembranous envelope formed of proteins cross-linked by epidermal transglutaminase (characteristics of cells in the stratum granulosum); and third, the acquisition of distinguishing features associated with cornified anuclear cells such as extensively cross-linked dense submembranous envelopes (i.e., characteristics of cells in the stratum corneum). The molecular mechanisms determining "first daughter" and "second daughter" status, as well as the mechanisms which control epidermal cell differentiation into cornified anuclear cells, are largely unknown, but these mechanisms appear to be coordinated; i.e., cells enter and leave the malpighian layer at approximately the same rate; they appear to be polarized, i.e., from the basal (stem) cell layer to the apical cornified layers; and they appear to be self-regulating, i.e., processes by which the cornified layers are renewed can effectively compensate for variation in the rate of mechanical sloughing of cells from the surface in different parts of the body. The molecular processes by which this remarkable coordination of cells is achieved in skin or other epithelial tissues are largely unknown, at present.
2.7 The attachment of proliferating, basal (stem) cells to the basement membrane occurs at limited points of cellular contact. Contact of epithelial cells, in general, with the basement membrane has been thought to have potential functional significance for maintaining cellular polarization necessary for asymmetric cell division, e.g., to give rise to the distinctively different types of daughter cells, as well as for sustaining the continuous morphogenetic process through which progeny of stem cells differentiate into cornified epithelial cells in skin or into Schwann cells and cells of the spinous strata surrounding nerves. However, there has been (and is currently) a lack of detailed knowledge regarding the cellular biology and molecular biochemistry involved in these postulated polarization and morphogenetic processes. Thus, the mechanisms controlling proliferation of stem cells and commitment of the daughter cells to differentiation are largely unknown.
2.8 The ultrastructure of the attachment points where basal cells are in contact with the basement membrane exhibits characteristic features that are identifiable in appropriately fixed and stained tissues (and cultures). The ultrastructural features have been termed hemidesmosomes (14-16), focal adhesions (17, 18), and hemidesmosome-like stable anchoring contacts (SACs) (19). Focal adhesions and SAC/hemidesmosomes are structurally and functionally distinct adhesion structures (19, 20). Focal adhesions have been observed in motile cells in association with actin-containing stress fibers (20, 21), while SACs appear to be distinguished as a structural component of stationary cells which only form in vitro after cells stop migrating. The function of SACs and focal adhesions is currently not clear, either with respect to their possible role in motility or to other possible roles in the cell biology of the epidermis. However, it has been observed that the lamina densa may be connected to stroma through anchoring fibrils (22), such as those observed in cells which appear to be linked to hemidesmosomes (23-25). SAC/hemidesmosome structures have also been observed to be associated with cytoplasmic intermediate filaments (26, 27) which have a bullous pemphigoid antigen (BPA) identifiable by indirect immunofluorescence.
2.9 Studies of basal cell interactions with basement membranes have been complicated by lack of suitable in vitro model systems as well as by changes occurring in the structure, shape, and composition of basement membranes during development and acquisition of specialized cellular functions (5). There has been a near total lack of in vitro models by which basal (stem) cells might be studied. Keratinocytes are one in vitro epithelial model system. These cells are not basal (stem) cells, but they do represent a major cellular constituent of epidermis. Human keratinocytes have been isolated and cultured from stratified or squamous epithelia in vitro under controlled conditions either using fibroblast feeder layers and conditioned medium (28-30); medium containing at least epidermal growth factor (31); keratinocyte growth medium (KGM) containing at least hydrocortisone, low-calcium, insulin, and insulin-like growth factor-1 (32, 33) serum-free (34, 35) or supplemented MCDB 153 basal nutrient medium (36). One recent study has suggested that 85-90% of keratinocyte clones, derived from growing and cloning normal human skin keratinocytes, may be derived from the basal (stem) cell layer and 10-15% from the suprabasal layers of the epidermis (36). The presumptive "suprabasal" keratinocytes expressed markers of terminal differentiation (i.e., ivolucrin) but still possessed the ability to synthesize DNA. These findings suggested to the investigators that some "suprabasal" keratinocytes may exist in an altered state of "non-terminal" differentiation wherein they are still capable of cell division (36). Others have termed possibly related strains of keratinocytes "nondifferentiating keratinocytes" (37). Ivolucrin is one marker for keratinocyte differentiation in vitro. It is a cytosolic protein of human keratinocytes with a reported apparent Mr of 140 kDa on SDS-PAGE (38); the gene has recently been reportedly cloned (39) and its regulation studied in cells in vitro (40). Ivolucrin is useful as a marker for an early stage in the terminal differentiation of keratinocytes since it is synthesized shortly after keratinocytes leave the basal (stem) cell layer, at a time when cellular enlargement has begun, but before onset of envelope cross-linking (41, 42). Ivolucrin has been reported to have undergone a relatively rapid evolution with the possibility of 3 alleles in monkeys (43, 44). Cytokeratins are a second useful marker for keratinocyte differentiation in vitro. There are at least five cytokeratins which may be expressed by keratinocytes in vitro using Western immunoblot analysis and commercially available monoclonal antibodies AE1 and AE3: these include cytokeratins No. 5 (58 kDa), No. 6 (56 kDa); No. 14/15 (50 kDa); No. 16 (48 kDa); and No. 17 (46 kDa) (45).
Keratinocyte differentiation can be induced in vitro, at least to the extent that the cells change morphology into cells resembling cornified epithelia. This process can be induced in tissue culture with calcium or with ionophores (46, 47). When such keratinocyte differentiation is induced in tissue culture, epidermal transglutaminase can become activated in the cells with coincident development of a cross-linked submembranous protein envelope. During cross-linking, cytosolic ivolucrin becomes associated with the submembranous protein envelope as do two other proteins which are reportedly found in keratinocytes but not in fibroblasts. These two proteins have reported apparent molecular sizes on SDS-PAGE of 210 kDa and 195 kDa (48). In an in vitro reconstituted system it was suggested that addition of ivolucrin promoted cross-linking of proteins (49). Thus, while keratinocytes are useful as an in vitro model for some molecular processes involved in epithelial differentiation, they are not basal (stem) cells and are clearly distinguished from them with at least ivolucrin as a marker. In addition, the past studies of keratinocytes has not approached at a molecular level the possible interactions which may occur between receptors in basal (stem) cells and ligands in the basement membrane.
2.10 Ligands which mediate the binding of basal (stem) cells to the epithelial basement membrane are largely unknown. The known basement membrane components in the lamina lucida layer of the epithelium include at least laminin, nidogen, and heparin sulfate proteoglycan, and in the lamina densa they include types IV and VII collagen (5, 50, 51). The possible cellular receptors which may bind to these ligands include at least the integrin adhesion receptors (for reviews see 52-55).
2.11 Integrins are a family of receptor glycoproteins with two noncovalently associated polypeptide chains of different molecular sizes (the larger termed the a chain and the smaller the b), forming a structure termed a heterodimer. The respective chains have amino acid sequence homology, and the integrins serve a similar function at least as receptors for cellular adhesion to extracellular matrix glycoproteins. Six a chains and at least four b chains have recently been identified, giving at least 24 different theoretical heterodimers which could act as receptors for cellular adhesion. An alignment of the .alpha.6 chain amino acid sequence with the .alpha..sub.3 chain reportedly showed approximately 37% identity (#56). The molecular events and mechanisms governing control of the biosynthesis and assembly of the different a and b chains in different cells and tissues are largely unknown, as is the possible existence of several of the theoretical integrin structures. In T-lymphocytes, as opposed to epithelial cells, the activation of cells with interleukin-2 is correlated with induction of expression of the .alpha..sub.3 .beta..sub.1 integrin on the cell surface (#57).
2.12 Biological functions of integrins in tissues and cells include (1) the possible mediation of the attachment of T- and B-lymphocytes and platelets to basement membrane via integrins .alpha..sub.3 .beta..sub.1, .alpha..sub.2 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 and (2) a possible role in hemostasis and homeostasis for these integrins, the latter by contributing to the maintenance of the structure of the integument and epithelia (#s 19-21; 57, 58).
2.13 Possible associations between integrins and laminin ligands include reports that the .alpha..sub.2 .beta..sub.1 integrin is a collagen receptor in human fibrosarcoma cells (59, 60) with affinity for laminin in some cells (61, 62). Laminin is a disulfide-bonded glycoprotein complex composed of three distinct polypeptide chains. Laminin was first isolated from mouse Engelbreth-Holm-Swarn (Elts) tumor (#7), and the subunits were originally designated as follows: A (400 kDa), B1 (220 kDa), and B2 (210 kDa). However, in light of many recent reports describing multiple isoforms of laminin, the original subunits of EHS laminin (laminin-1) have now been designated as .alpha.1 (400 kDa), .beta.1 (220 kDa), and .gamma.1 (210 kDa) (#125).
.alpha..sub.6 .beta..sub.4 integrin has also been suggested as a laminin receptor in human colon carcinoma cells (63), but it reportedly does not bind to the E8 domain of laminin, a ligand domain of laminin that interacts with .alpha..sub.6 .beta..sub.1 integrin (64). .alpha..sub.3 .beta..sub.1 is reportedly one of the most widely expressed integrins in tissues and in cultured epithelial and non-epithelial cells. It also has been suggested as a possible nonspecific laminin receptor in cells (57, 65). The reports of an association of .alpha..sub.3 .beta..sub.1 with laminin either have not determined the apparent binding affinity of the interaction or have determined the association by assays which permit only a relational comparison, i.e., relatively strong or weak. Laminin is reportedly a poor ligand for adhesion of cultured human foreskin keratinocytes (20, 21). In tissue culture, antibody reactive with .alpha..sub.3 .beta..sub.1 reportedly substantially inhibited adhesion of human foreskin keratinocytes to HFK-extracellular matrix. In contrast, antibody reactive with .alpha..sub.6 .beta..sub.4 had only a minor effect, but when both antibodies were added together, adhesion of HFK to HFK-ECM was reportedly completely inhibited (20) but no ligand was identified. Thus, it is not apparent whether the interactions of .alpha..sub.3 .beta..sub.1, and .alpha..sub.6 .beta..sub.4 with laminin are physiologically meaningful, whether laminin is a ligand, or what the physiologically meaningful ligands for these integrins may be in skin.
2.14 The distribution of the .alpha..sub.6 .beta..sub.4, .alpha..sub.3 .beta..sub.1, and .alpha..sub.2 .beta..sub.1 integrins in tissues is varied. The .alpha..sub.6 .beta..sub.4 form of integrin is limited primarily in epithelial and Schwann cells surrounding myelinated nerves (64) and is down-regulated in differentiated spinal cells (20, 21, 66). SAC/hemidesmosome structures have also been observed to be associated with bullous pemphigoid antigen (27, 67). In contrast, the .alpha..sub.3 .beta..sub.1 and .alpha..sub.2 .beta..sub.1 integrins are widely expressed in tissue and particularly evident in proliferating epithelial cells (20, 21) and in transformed cells and activated lymphoblastoid cells. At the ultrastructural level, the .alpha..sub.6 .beta..sub.4, .alpha..sub.3 .beta..sub.1 and .alpha..sub.2 .beta..sub.1 integrins have been visualized by association with focal adhesions (rather than SACs) and actin-containing stress fibers in motile cells (20, 21). In addition, .alpha..sub.3 .beta..sub.1 (68) and possibly .beta..sub.2 .beta..sub.1, have been implicated in cell-cell adhesion because they have been observed to relocate from areas of cell-substrate contact to areas of cell-cell contact in cells, and because antibodies to the .beta..sub.1 integrin polypeptide inhibit cell-cell contact in cells in vitro (20, 21, 69). In general, .alpha..sub.6 .beta..sub.4, .alpha..sub.3 .beta..sub.1 and .alpha..sub.2 .beta..sub.1, appear only in the proliferating basal cell layer; .alpha..sub.6 .beta..sub.4 appears to be restricted to regions of the stem cell basal plasma membrane (58, 20, 21); .alpha..sub.3 .beta..sub.1 appears on basal lateral and apical regions of the stem cell plasma membrane; and .alpha..sub.2 .beta..sub.1 appears primarily on the apical and lateral regions of the stem cell plasma membrane (59, 20, 21). Thus, while integrins .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 have been recognized as glycoproteins involved in cell-substrate contact in vitro, the available information has created a tangled web which does not permit a determination of which interactions may be physiologically meaningful in vivo.
2.15 Integrins are reported to play a possible role in lymphocyte activation. It has been reported recently that in T-lymphocytes, the interaction of cells containing .alpha..sub.3 .beta..sub.1 integrin with collagen and a second signal such as initiated by binding of antibody to CD3 to the cell surface integrin may trigger cellular activation. Whether such effects may also be triggered by integrins in non-lymphoid cells is not known, at present. It has been reported that a complex substrate composed of a gel formed from purified laminin, type IV collagen, heparin sulfate proteoglycan, entactin and nidogen induced clustering of melanocytes (13), formation of tubular structures by Sertoli cells (70), in vivo growth of neurons (71), and in vitro growth of Schwann cells and liver cells (72). However, it is not known whether the complex substrate induced these effects, or whether the complex substrate favored the growth of a few cells which already possessed these features. Epithelial cells grown with this complex substrate, in general, were reported to assume a much greater polarity than on plastic, collagen, laminin, or fibronectin, but again the molecular basis for this reported change is at present unclear.
2.16 Malignant transformation of normal human keratinocytes in vitro has been reported to impair their ability to differentiate, stratify, and form cornified epithelia in vitro, and these properties were correlated with inability of the cells to synthesize ivolucrin and re-expression of fetal cytokeratins (73). Studies of ivolucrin tissue distribution in cases of skin and lung carcinoma have also suggested that basal cell carcinomas may be negative for ivolucrin with low transglutaminase activity while squamous cell carcinomas may be positive for ivolucrin (74-77). In these respects the transformed keratinocytes and basal cell carcinomas seemed to resemble basal (stem) cells. However, the validity of such interpretations based on ivolucrin has been brought into doubt by the finding that ivolucrin is universally present in both benign acne and keratotic lesions as well as in malignant lesions in skin (78) or cervical tissues (79).
2.17 The mechanisms by which cancer cells of epithelial origin arise are largely unknown, and since these mechanisms are unknown it is difficult to structure treatments to restore normal growth control to malignant cells. Recently it has been reported that malignant human cells may be induced to assume a non-malignant phenotype in vitro by fusion with diploid human keratinocytes. The non-malignant phenotype in the fused cells was reportedly correlated with the continued expression of ivolucrin as a marker of keratinocyte terminal differentiation, i.e., cells which reportedly lost the ability to produce ivolucrin during in vitro culture also reacquired the ability to grow progressively in animals (80).
2.18 Mechanisms involved in psoriasis and autoimmune dermatological diseases are also largely unknown. However, it is reported that epidermal tissues may show decreased transglutaminase activity and premature appearance of ivolucrin in the basal cell layer (81), suggesting a possible premature terminal differentiation of basal (stem) cells in this disease, but not suggesting any mechanisms by which this condition may be caused or corrected. Similarly, bullous pemphigoid (BP), cicatrical pemphigoid (CP), and epidemolysis bullosa acquisita (EBA), are autoimmune dermatological diseases where autoantibodies have been reported (in some patients) that bind to antigens in pathological and normal basement membranes. In BP and CP, using immunoelectron microscopy, immunoreactants have been reported to be in skin, and associated with the lamina lucida (82-86) while, in contrast, EPA immunoreactants reportedly are localized just below the Lamina densa (87). Autoantibodies present in some BP patients' sera also reportedly bound antigens in the Lamina lucida (88, 89) and in EBA they reportedly bound to antigens in the Lamina densa (87, 90). The apparent molecular sizes on SDS-PAGE reported for the BP antigens were 220 kDa and 240 kDa (91) and the EBA were 290 kDa and 145 kDa (90). Using suction blisters and split skin techniques to separate the basal layer from the basement membrane, BP antigens (BPA) were reportedly identified in the "roofs" of the blisters and split skin (i.e., associated with the cells and not with the basement membrane) while CP antigens were reportedly located in the "floors" (i.e., associated with the basement membrane) (92, 93). BPA has been associated by immunoelectron microscopy with ultrastructural elements resembling SACs (26, 27). These ultrastructural studies have made the association between the presence of immunoreactants in the Lamina lucida and the antibodies that are present (in some patients) to the antigens presumed to be present on the basal surfaces of the basal (stem) cells in BP, but it is not clear at present what significance these findings may have for understanding these autoimmune diseases. Similarly, it is not clear at present how these findings may relate to the cell biology and biochemistry of normal epithelia.
2.19 Epiligrin is a recently elucidated epithelial basement membrane component that mediates cell adhesion via integrins .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 (113). Epiligrin, a complex of several glycoproteins, is located in the lamina lucida of the basement membrane where the complex comes in direct contact with the overlying epithelial cells. A major constituent of this complex is a 170 kDa protein (EI70) that is encoded by the LamA3 gene (#135). E170 is the .alpha..sub.3 chain of epiligrin, not to be confused with the .alpha..sub.3 chain of integrin (#135).
Epiligrin and nicein, a similar glycoprotein complex, have been shown to be absent from the basement membrane of patients with the gravis form of junctional epidermolysis bullosa (#114, 121, 126, 135). Junctional epidermolysis bullosa is a blistering disorder of the skin that is characterized by a separation of basal cells from the basement membrane due to a decreased number of hemidesmosomes (#126-128). These data establish that epiligrin interactions with integrin .alpha..sub.6 .beta..sub.4 in hemidesmosomes are important for anchorage of basal cells to the basement membrane. Furthermore, it was shown that epidermotrophic T-lymphocytes can interact with epiligrin via integrin .alpha..sub.3 .beta..sub.1 and this interaction may mediate T cell infiltration of the epidermis during pathogenic cutaneous inflammation (#123). Taken together, these results indicated that epiligrin interactions with both integrin .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 are physiologically important. Similar observations were made in studies by Weitzman et al. (1993), Niessen et al. (1994), and Rousselle and Aumailley (1994) (#s 129-131).
Epiligrin is the major adhesion ligand present in epidermal basement membranes and it has been shown to mediate basal cell adhesion via integrins .alpha..sub.3 .beta..sub.1 in focal adhesions and .alpha..sub.6 .beta..sub.4 in hemidesmosome adhesion structures (113, 133).
3. SUMMARY OF THE INVENTION
The present invention is predicated upon the discovery that adhesion of epithelial and lymphoid cells is modified by epiligrin, an epithelial ligand complex composed of disulfide-linked glycoproteins of 200.+-.20 kDa, 170.+-.20 kDa, 145.+-.20 kDa, 135.+-.15 kDa, and 100.+-.10 kDa, with an associated intracellular 36.+-.15 kDa glycoprotein. Epiligrin, as well as constituent epithelial ligand glycoproteins and peptides disclosed herein, are ligands for the .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 integrins. Epiligrin and its constituents are useful for modifying adhesion of epithelial and lymphoid cells. Certain embodiments of the invention thereby provide reagents and methods for restoring normal growth in epithelial cells, e.g., in autoimmune disease and carcinoma. Other embodiments provide reagents and methods for inhibiting the binding of activated lymphoid cells to epithelial cells through the integrins, e.g., for controlling inflammation in epithelial tissues.
The present claims are directed to nucleic acids that encode E170 epithelial ligand glycoproteins, and particularly to such nucleic acids capable of hybridizing under stringent conditions to one or more of the disclosed "Ep-1" (ATCC No. 75540), "1-1" (ATCC No. 75539; deposited under the strain designation "NAS-3 1-1") , and "8-6" (ATCC No. 75538; deposited under the strain designation "NAS-3 8-6") nucleotide sequences. The gene encoding E170 is called LamA3, and is located at human chromosome 18q11.2. The subject nucleic acids are useful in expression systems for production of E170 epithelial ligand glycoproteins, and they also find use as diagnostic and therapeutic agents in identifying and treating patients with the gravis form of junctional epidermolysis bullosa and other epithelial diseases. The claims are directed also to antibodies directed against proteins, as well as to the epiligrin complex itself and the proteins encoded by the claimed nucleic acids.

4. BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows glycoproteins extracted as the epithelial ligand glycoprotein complex (epiligrin) from extracellular matrix.
FIG. 2 depicts glycoproteins in the epiligrin complex which are not related to known basement membrane components.
FIG. 3 shows that the purified HFK-ECM does not contain fibronectin or laminin.
FIGS. 4A-4K illustrate the SACs "ring structures" in which epiligrin is deposited in ECM.
FIGS. 5A-5F depict the co-localization of .alpha..sub.6 .beta..sub.4 (GoH3, FIG. 5B), he subject epithelial ligand integrins (P1E1, FIGS. 5A, 5C and 5E), BPA FIG. 5D), and .alpha..sub.3 .beta..sub.1 (P1 F2, FIG. 5F) in the SACs contained in the purified FK-ECM.
FIGS. 6A-6F demonstrate the attachment of human foreskin fibroblasts HFK-ECM (FIGS. 6D-6F) but not other ECM components.
FIG. 7 illustrates a specific test cell assay for epiligrin in which specific adherence of cells to epiligrin is modulated.
FIGS. 8A-8P illustrate the localization of epiligrin in epithelial basement membranes of skin, tonsil, and lung, and shows epiligrin distribution in sweat glands, lymphoid follicle germinal centers, and in submucosal glands.
FIGS. 9A-9F illustrate the ultrastructural localization of epiligrin in epithelium.
FIG. 10A schematically depicts the strategy used to clone the E170 component of epiligrin.
FIGS. 10B-10C depict a comparison of the domains of .alpha.1 laminin-1 and .alpha..sub.3 epiligrin, as well as the overlapping cDNA clones (FIG. 10D) used in Example 15 to compile the nucleotide sequence encoding E170 epithelial ligand glycoprotein, i.e., as shown in FIGS. 10F, 11A-11C, and 15A-15F. FIG. 10E shows the location of primers used in sequencing.
FIG. 10F shows the nucleotide sequence of E170 epithelial ligand glycoprotein cDNA clone "1-1" from position 1 to position 664 (SEQ ID NO: 21). (The sequence of clone 1-1 was edited to remove a common cloning artifact, the first 150 bp of the Ep-1 cDNA consisting of a cloned fragment of a rRNA.)
FIGS. 11A-11C show 1994 bp (SEQ ID NO: 22) of the nucleotide sequence of E170 epithelial ligand glycoprotein compiled from cloned cDNAs as depicted in FIG. 10A. PCR primers used in cDNA cloning were: MR-12 (corresponding to nucleotides 183-198 in FIG. 11A), MR-11 (nucleotides 340-357 in FIG. 11A), MR-8 (nucleotides 640-657 in FIG. 11A), MR-6 (nucleotides 700-719 in FIG. 11A), MR-7 (nucleotides 992-1012 in FIG. 11B), MR-5 (complement to nucleotides 1055-1073 in FIG. 11B), MR-4 (nucleotides 1277-1296 in FIG. 11B) and MR-3 (nucleotides 1709-1723 in FIG. 11C). The positions at which different cDNA clones begin are position 1, where "1-1" begins, and position 1216, where EP-1 begins. Clone EP-1 ends at position 1742. FIG. 11A shows the sequence from position 1 to position 720. FIG. 11B shows the sequence from position 721 to position 1500. FIG. 11C shows the sequence from position 1501 to position 1994.
FIGS. 11D-11E show schematically the positions of restriction endonuclease sites within the E170 nucleotide sequence shown in FIGS. 11A-11C.
FIG. 12A shows the relative positions of the primers within the EP-1 E170 sequence.
FIG. 12B shows the nucleotide sequences of 8 primers (SEQ ID NOS:1-8) useful in PCR methods for isolating nucleic acids encoding E170 epithelial ligand glycoprotein, as described in Example 15.
FIG. 13 depicts schematically the steps in a representative PCR assay method for isolating nucleic acids encoding E170 epithelial ligand glycoprotein.
FIG. 14 depicts schematically the steps in a representative 5' RACE system for PCR cloning of cDNAs encoding E170 epithelial ligand glycoprotein, as described in Example 15.
FIGS. 15A-15F depict the nucleotide sequence compiled from sequencing cDNA clones corresponding to the .alpha.3.sub.EpA transcript (SEQ ID NO:23).
FIGS. 16A-16B show experiments demonstrating that the clone Ep-1 expresses a fusion protein that corresponds to at least a portion of the 170 kDa subunit of epiligrin.
FIGS. 17A-17B show a Northern blot analysis of .alpha.3.sub.Ep mRNA and illustrates that two distinct transcripts are detectable.
FIGS. 18A-18C illustrate the sequence variability in domain IIIa, near the amino-terminal portion of the protein encoded by .alpha.3.sub.Ep (SEQ ID NOS:26-30).
FIGS. 19A-19R show the amino acid sequence encoded by .alpha.3.sub.EpA (SEQ ID NO:24).
FIGS. 20A-20H illustrate the localization of epiligrin mRNA and protein in 48 hour human wounds, using in situ hybridization with probes derived from .alpha.3.sub.Ep.
FIGS. 20A, 20C, and 20E show the wound site, as compared to normal skin shown in FIGS. 20B, 20D, and 20FFF. FIGS. 20A-20B are labeled with epiligrin anti-sense probe, FIGS. 20C-20D with epiligrin sense probe, and FIGS. 20E-20F with keratin anti-sense probe. FIGS. 20G and 20H show wound sites labeled with anti-epiligrin and anti-.alpha.3 antibodies, respectively.
FIG. 21 shows the localization of the human LamA3 gene to chromosome 18q11.2.
FIGS. 22A-22B are graphical representations depicting that integrins .alpha..sub.6 .beta..sub.4 and .alpha..sub.3 .beta..sub.1 mediate anchorage and motility, respectively, on epiligrin via distinct signal pathways, as described in Example 18.

5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The scientific literature contains several examples wherein the discovery of ubiquitous extracellular proteins (e.g., laminin and fibronectin) led to the subsequent identification and purification of the cellular receptors binding these ligands. In contrast, in the present case the inventors recognized that existing background art which identified laminin as a putative ligand for binding two of these cellular receptors, .alpha..sub.3 .beta..sub.4 and .alpha..sub.6 .beta..sub.4 integrins, probably described physicochemically minor binding interactions. The inventors had previously observed that the .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 integrins were co-distributed in epithelial tissues including human skin; however, the significance of this observation was not readily apparent and the distribution could have been due to both cellular receptors binding to laminin in the tissues. However, in distinction to the teachings in the literature, they reasoned that (a) laminin was not the ligand, and (b) that the two cellular receptors co-distributed because they shared some other (new) extracellular matrix complex as a ligand. With this recognition of the problem, they sought to identify the novel ligand. Because it was not possible to investigate this problem in tissue sections of human biopsy material, they recognized that it would be necessary to select the proper cell type for study in vitro. Since they had previously observed that the two forms of integrin were present together on cells in regions of human skin that contained keratinocytes, fibroblasts, and other specialized epithelial cells, they focused on those regions as a possible source of cells for in vitro study. In considering among these possible different cell types the inventors recognized that human fetal keratinocytes (HFKs) expressed both the .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 integrins. Although keratinocytes were recognized by the literature to be a differentiated form of epithelial cell, both with respect to their microscopic appearance and their biosynthetic activities, the inventors reasoned that cultures of these cells might synthesize and secrete the novel extracellular matrix ligand, and might be suitable for in vitro study. (In fact, as the detailed description of the invention (appearing below) shows, if they had chosen to study fibroblasts or continuous epithelial cell lines, they would not have succeeded in identifying the ligand which is an embodiment of this invention.) Armed with this recognition of the problem and its possible solution, the inventors succeeded in identifying the novel ligand for the .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 integrins. Surprisingly, the cellular receptors and ligands identified and isolated from keratinocytes in tissue culture were the same as those utilized by the basal (stem) cells in epithelial tissue.
In the research described below, the molecular mechanisms by which epithelial cells establish contact with the basement membrane are elucidated, the cell receptor and its extracellular basement membrane ligand are identified and substantially purified, and the mechanisms are unraveled through which growth and differentiation are controlled in the epithelium. The novel ligand which is a subject of the invention is termed "epiligrin." Research from other laboratories has identified GB3 antigen/nicein (Verrando et al., 1987, 1988) and kalinin (Rouselle et al., 1991; Marinkovich et al., 1993) which are probably identical to epiligrin. Epiligrin is a covalently linked glycoprotein complex that mediates epithelial cell attachment to the basement membrane through .alpha..sub.3 .beta..sub.1 integrin acting as a cellular receptor. In this application, the terms "epiligrin" and "epithelial ligand glycoproteins" are used interchangeably to refer to the same glycoprotein complex. Individual protein components of epiligrin are sometimes referred to as "epithelial ligand glycoproteins." Epiligrin is present in the lamina lucida of basement membrane and is associated with those cell membrane ultrastructural features previously termed focal adhesions. These focal adhesions are located on the basal surface of the cells in areas of contact with the basement membrane substratum, and they are also involved in cell motility. Epiligrin also interacts with the .alpha..sub.6 .beta..sub.4 integrin, a cellular receptor that is present in ultrastructural membrane features previously termed hemidesmosomes and stable adhesion complexes. The invention provides an understanding, for the first time, of how these two different ultrastructural features (frozen in time by fixation for electron microscopy) can function in a living cell to mediate adhesion, control of cell growth, and determination of the fate of daughter cells derived from cell division in the basal layer of the epithelium.
Burgeson et al. (#125) have proposed nomenclature that categorizes epiligrin as a kind of "laminin." Accordingly, the inventors have denoted the gene encoding E170 as "LamA3." However, following this nomenclature can convey the misleading impression that E170 is demonstrably similar to the .alpha..sub.3 chains of laminin 5, 6, and 7. First, there is no published sequence available for the Burgeson scheme's .alpha..sub.3 chain of laminin-5, laminin-6, or laminin-7 which would provide any way of comparing those sequences with the .alpha.3.sub.EpA and .alpha.3.sub.EpB sequence. Second, the new nomenclature is based on the unproven assumption that .alpha..sub.3 chains of laminin-5, laminin-6, and laminin-7 are indistinguishable. In contrast, the Applicants' data clearly show that there are two distinct .alpha.3.sub.Ep transcripts, suggesting that there is heterogeneity in the .alpha..sub.3 polypeptide chains (135). In addition, the .alpha..sub.3 chain described for nicein (#137) contains a significantly smaller G domain and is reported to have a different structural organization than the Applicants observed for the .alpha.3.sub.EpA or .alpha.3.sub.EpB transcripts of epiligrin. This suggests the possible existence of a third .alpha.3.sub.Ep transcript (#137), but no nucleotide sequences for nicein are known, and nicein may be encoded by a locus distinct from LamA3.
The .alpha..sub.3 .beta..sub.1, integrin which binds epiligrin is one of the most widely expressed of all integrins in tissue, but its physiological ligand has not been identified until now. Novel test cell assays, extracellular matrix compositions, and immunochemical reagents were created which allowed identification for the first time of epiligrin, in basement membranes as the physiologically significant ligand for plasma membrane-based .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 integrins. Only a few epithelial cells in culture (e.g., keratinocytes) express significant quantities of epiligrin, and this glycoprotein complex is of a large molecular size and has poor solubility in aqueous solutions. Epiligrin's size and poor solubility have undoubtedly contributed to the lack of previous recognition of this ligand in binding to integrins.
The role of the .alpha..sub.6 .beta..sub.4 integrin as a receptor for the epithelia ligand (i.e., in stable adhesion complexes) is less impressive than the adhesion mediated by the .alpha..sub.3 .beta..sub.1 integrin but is potentially more significant. The findings described below indicate that .alpha..sub.6 .beta..sub.4 integrin is involved in cellular adhesion to basement membranes, and it may also localize the focal adhesions in a pattern which encircles the regions of the stable anchoring contracts. This process of encirclement, as well as the localization of .alpha..sub.6 .beta..sub.4 integrin in cell-cell adhesion sites, determines the fate of the daughter cells formed by division in the basal (stem) cell layer of the epithelium.
Migration of epithelial cells is an important aspect of at least wound healing, inflammation, and tumor metastasis. Focal adhesions containing .alpha..sub.3 .beta..sub.1 integrin are involved in cell movement, and the stable anchoring contacts containing .alpha..sub.6 .beta..sub.4 integrin are involved in stopping cell movement. Epiligrin binds to both .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 integrins. This inventive recognition, pursuant to the present disclosure, allows one skilled in the art to identify specific binding partners to epiligrin (as disclosed in greater detail, below), and provides for the first time compositions which can modify movement and adhesion of cells of epithelial origin. The invention also provides, for the first time, an understanding at the molecular level of how polarized self-regulated growth and differentiation are achieved in epithelial tissues through the binding of the transmembrane integrins in the plasma membrane to extracellular epiligrin, the epithelial ligand complex, and possibly through intracellular signaling accomplished by the 36.+-.15 kDa epiligrin glycoprotein. These events occur at discrete plasma membrane sites in the stable anchoring contacts, and a second cytoplasmic polypeptide was also discovered to be a recognized SACs protein termed bullous pemphigoid antigen. Armed with the new information and understanding provided in the present disclosure, one skilled in the art is able to recognize how malignant carcinoma cells may arise through loss of the control mechanisms provided by epiligrin, and how it is possible to consider reestablishing these normal control mechanisms in carcinoma cells by using the understanding provided by the invention to select for epiligrin derivatives and other pharmaceutical agents that induce the cells to correct their defect in epithelial ligand regulation.
Conclusions based on the following findings and on reinterpretation of previous reports in light of the new insights gained from the present invention are: (i) Purified epiligrin was shown to induce cell adhesion and localization of the .alpha..sub.3 .beta..sub.1 integrin in focal adhesions better than laminin, fibronectin, or collagen. Further, cell adhesion to epiligrin was specifically inhibited with monoclonal antibodies to .alpha..sub.3 .beta..sub.1 integrin. (ii) Epiligrin was the major component of the extracellular matrix synthesized by human foreskin keratinocytes. In cultures of stationary keratinocytes, epiligrin was deposited and co-distributed with the transmembrane .alpha..sub.6 .beta..sub.4 integrin and with cytoplasmic bullous pemphigoid antigens which are recognized components of hemidesmosome-like stable adhesion complexes. All three of these components in the stable adhesion complexes were resistant to sequential extraction with detergent, 2 M urea/1 M NaCl, and 8 M urea. In contrast, the .beta..sub.1 -containing integrins in the focal adhesions were not stable to this extraction. The .alpha..sub.3 .beta..sub.1 integrin-containing focal adhesions were observed to form rings around the periphery of the .alpha..sub.6 .beta..sub.4 integrin containing stable anchoring contacts. (iii) In tissue, epiligrin localized in most epithelial basement membranes, but not in the basement membranes of muscle, or endothelium. At the ultrastructural level, epiligrin localized to the lamina lucida of the epidermal/dermal basement membrane of skin. Consistently, epiligrin localized with the .alpha..sub.3 .beta..sub.1, integrin in the basal plasma membrane, as well as with the .alpha..sub.6 .beta..sub.4 integrin-containing hemidesmosomes of basal (stem) cells. These data indicate that epiligrin is the ligand for which .beta..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 act as receptors.
The subject epiligrin derived from HFK is an epithelial ligand glycoprotein complex that includes at least three major covalently linked disulfide-bonded glycoproteins having apparent molecular sizes of 170 kDa, 145 kDa, and 135 kDa. A glycoprotein of 36 kDa is also associated with the epiligrin complex. Other observed components of epiligrin include a 100 kDa protein that is antigenically related to the 145 kDa protein, and a 200 kDa protein that is antigenically related to the 170 kDa protein. The individual epithelial ligand glycoproteins are visible following reduction and SDS-PAGE (under reducing conditions). These constituent glycoproteins are at times referred to herein by reference to their apparent molecular weight on SDS-PAGE, i.e., E200, E170, E145, E135, E100, and E36, respectively. The 145 kDa protein in some instances is referred to as E145/100. The subject epithelial ligand complex has the ability to bind to .alpha..sub.6 .beta..sub.4 and .alpha..sub.3 .alpha..sub.1 integrins and thereby modify cellular adhesion to a substratum (#s 113, 133, 134).
Skilled artisans will recognize a variety of epithelial cells from which the subject epiligrin and its constituent glycoproteins may be purified, or substantially pure nucleic acids prepared. The following direction is provided with regard to representative sources of constituent epiligrin glycoproteins. E36 may be found in the culture supernatant (CS) and extracellular matrix of HFK cells (HFK-ECM); E100 accumulates in CS; E170 is usually not found in CS but may be found in a Triton X-100 extract of HFK-ECM as well as in the insoluble HFK-ECM fraction after the Triton X-100 extraction; and E200, E140, and E130 are usually not found in CS or the Triton X-100 soluble fraction of HFK-ECM, but only in the Triton X-100 insoluble fraction of HFK-ECM. A variety of biochemical and immunochemical methods may be utilized to purify the subject epiligrin glycoproteins, e.g., affinity chromatography in buffers containing Triton X-100 and/or mixtures of ionic, nonionic, or zwitterionic detergents. Treatment with proteases (e.g., trypsin) may be useful for preparation of soluble epithelial ligand glycopeptides, some of which, while failing to mediate cellular adhesion to a surface may still retain the ability to block cellular adherence to epithelial ligand coated surfaces. The following immunochemical direction is provided with regard to the antigenic relatedness of the subject epiligrin glycoproteins: E200 appears to be antigenically related to E170; E145 appears antigenically related to E100; and E135 does not appear to be related to other glycoproteins in the epithelial ligand complex. The inventors currently believe that E170 may be derived from E200 by proteolytic degradation (and/or processing) and, in a similar manner, E100 may be derived from E145.
Epiligrin antigens are associated with the basal surfaces of basal (stem) cells in epithelia at limited points of cellular contact with basement membranes. Embodiments of the invention also relate to the isolation of epiligrin glycoprotein complexes for modifying adhesion of cells to substrata and for achieving polarized and self-regulated growth and differentiation in cells of epithelial origin. Other embodiments relate to antibodies to the epiligrin glycoprotein complex for modifying cellular adhesion to substrata and for identifying epiligrin-like antigens in biological fluids, as well as epiligrin antigens for identifying antibodies in patient samples. Still other embodiments relate to nucleotide sequences of E170 epithelial ligand glycoprotein useful as specific probes for measuring the presence of epithelial ligand mRNA in a tissue, as well as the level of expression in different cells in the tissue. Embodiments of the invention provide compositions and test methods for identifying diseased epithelial cells, and for distinguishing at least between the epithelial abnormalities in such autoimmune dermatological diseases as bullous pemphigoid, cicatrical pemphigoid, and epidemolysis bullosa acquisita.
The subject test methods and compositions are useful for determining the level of expression of epiligrin in a tissue. Expression of epiligrin is a hallmark of a regenerating epithelial tissue (see Example 15). The level of expression of E170 epiligrin glycoprotein was found to provide a tool useful for distinguishing between regenerating epithelial tissues (where expression was high) and non-regenerative epithelial tissues or malignant tissues (where expression was low). Diagnostic histopathology is frequently complicated because it is not easy to distinguish tissue repair (e.g., resulting from traumatic injury or infection) from an abnormality that might be a neoplastic or preneoplastic event. Examining the levels of E170 epithelial ligand expression (e.g., using immuno-histochemical techniques, in situ hybridization with an oligonucleotide or cDNA probes, or PCR of isolated tissue mRNA), is useful for distinguishing between repair and malignant (or premalignant) changes in epithelial tissues.
The invention provides nucleic acids capable of hybridizing under stringent conditions to at least one nucleotide sequence selected from the group consisting of the nucleotide sequence shown in FIGS. 11A-11C (SEQ ID NO:22), the cDNA clone Ep-1 (ATCC No. 75540) shown in FIG. 10F, the cDNA clone 1-1 (ATCC No. 75539), and the cDNA clone 8-6 (ATCC No. 75538), or the nucleotide sequences shown in FIGS. 15A-15F (SEQ ID NO:23). The subject nucleic acids are preferably capable of encoding an E170 epithelial ligand glycoprotein. A partial nucleotide sequence of nucleic acid encoding E170 epithelial ligand glycoprotein is provided in FIGS. 11A-11C (SEQ ID NO:22) compiled from the cDNAs shown in FIG. 10D as schematically depicted in FIG. 10A. The entire nucleotide region encoding E170 is depicted in FIGS. 15A-15F, and corresponds to the sequence of .alpha.3.sub.EpA, one of the two distinct .alpha.3.sub.Ep transcripts discovered by the Applicants. FIGS. 15A-15F (SEQ ID NO:23) consist of a composite sequence derived from the several overlapping clones shown in FIG. 10D
Although only a single (+) strand of the cDNA is shown in FIGS. 10F (SEQ ID NO:21), 11A-11C (SEQ ID NO:22), and 15A-15F (SEQ ID NO:23), those skilled in the art will recognize that the complementary (-) strands are thereby disclosed as well. According to the convention used herein to describe PCR primers, the "(-) strand" is complementary to E170 mRNA.
By nucleic acid molecule is meant DNA, RNA, and/or synthetic nucleotide sequences such as oligonucleotides that are the same as, homologous with, or complementary to, at least one helical turn (about 10 to 15 nucleotides) of the illustrated E170 epithelial ligand glycoprotein nucleotide sequence. At least two alternative forms of E170 transcripts are disclosed herein in HFK cells, one mRNA of about 5 kb and another of about 6 kb. Both mRNA species are identifiable to those skilled in the art in RNA from HFK by standard Northern blotting methods (e.g., using radiolabeled Ep-1 as a probe as illustrated in Example 15). The invention relates to at least four classes of E170 encoding nucleotide sequences, 1) alternative splicing transcript sequences, 2) sequences resulting from genetic polymorphism of E170, 3) sequences resulting from translocation of E170 in tumorigenesis and genetic diseases, and 4) sequences of E170 family members having greater than 75% homology with E170 over a conserved region of at least 30 nucleotides. In all cases the latter four classes of E170 nucleotide sequences are identifiable as hybridizing under stringent conditions with an E170 nucleotide sequence of FIGS. 11A-11C (SEQ ID NO:22), e.g., cDNA clone 1-1, Ep-1, or 8-6, while the several clones depicted in FIG. 10D encompass the entire nucleotide sequence encoding an E170 epithelial ligand glycoprotein, skilled artisans will recognize that additional cDNA clones may be obtained using nucleotide sequences contained within the subject cDNAs as probes and primers for obtaining additional cDNA clones. An illustrative example of a PCR cloning method for obtaining additional cDNA clones through PCR cloning is provided in Example 15, below. PCR primers are additionally provided in FIG. 12B (SEQ ID NOS:1-8) and Table 1 (SEQ ID NOS:9-20), below, and the steps of an illustrative PCR method are outlined in FIG. 13.
TABLE I__________________________________________________________________________Primers for PCR Primer-extended Sequencing__________________________________________________________________________Primer 4 (SEQUENCE ID NO: 9): 5' AGCACGAAGGTCACTGAGTT 3'Primer 5 (SEQUENCE ID NO: 10): 5' AAGTCACCTGAAGGCACG 3'Primer 6 (SEQUENCE ID NO: 11): 5' TGGACGTGCGACTTGACCAG 3'Primer 13 (SEQUENCE ID NO: 12): 5' AACTCGCTTGCAGTTGAC 3'- Primer 14 (SEQUENCE ID NO: 13): 5' GATGGCTGTGGATCTTTG 3'Primer 15 (SEQUENCE ID NO: 14): 5' TCCACAGCAAGTGCTATG 3'Primer 16 (SEQUENCE ID NO: 15): 5' ATGACAGTGCTGTCTGGAC 3'Primer 17 (SEQUENCE ID NO: 16): 5' TCTCCGAGATGGTCTTCATG 3'Primer 18 (SEQUENCE ID NO: 17): 5' TTATCTGCATCAGTCAGAGC 3'Primer 20 (SEQUENCE ID NO: 18): 5' TGACCAGTGAGCTGTACATC 3'Primer 29 (SEQUENCE ID NO: 19): 5' AGAGACCATTCGATTCAGAT 3'Primer 30 (SEQUENCE ID NO: 20): 5' AGCTTCTGAGAAATAGCAAA 3'__________________________________________________________________________
The PCR method in FIG. 13 was used successfully to isolate mRNA encoding E170 from normal epidermal tissue as well as from cells of patients with Epidermolysis bullosa. Primers MR-4 and MR-7 and primers MR-5 and MR-7 (FIGS. 12A-12B; SEQ ID NOS:1-8) and the primers shown in Table 1 (SEQ ID NOS:9-20) have also been used for PCR amplification and isolation of genomic DNA from normal and patient samples. The latter isolated genomic DNA contained both intron and exon sequences. The intron coded for a junctional amino acid sequence between an EGF-like region and a helix region in E170, and the exon was recognized by the presence of non-coding sequence and stop codons.
The subject nucleic acid capable of hybridizing under stringent conditions to a nucleotide sequence in FIGS. 11A-11C (SEQ ID NO:22) and FIGS. 15A-15F (SEQ ID NO:23), (e.g., cDNA clones "Ep-1", 3-1-1, 5-4-2, 3-8-6, 5-4-1, 3-8-2, or 8-6-1), find a variety of in vitro and in vivo uses. For instance, in a preferred embodiment the nucleic acids are useful (as illustrated in Example 15) in expression systems that produce E170 epithelial ligand glycoprotein. The expressed epiligrin glycoproteins, in turn, find a variety of uses: e.g., as adhesive agents for cells; as antigens for production of antibodies; and, as antigens useful in detection of patient autoantibodies such as those described in the serum of patients with acquired subepidermal blistering diseases (Domologe-Hultsch et al., citation #114, incorporated herein by reference).
In another example, the subject nucleotide sequences of the subject nucleic acids are useful for constructing antisense oligonucleotides (as illustrated in Example 15 below). The antisense oligonucleotides have nucleotide sequences capable of hybridizing under stringent conditions with the subject nucleic acids and are complementary with a nucleotide sequence encoding an E170 epithelial ligand glycoprotein. The subject antisense nucleotides have been used successfully for in situ hybridization, as shown in FIG. 21. The subject antisense nucleotides may be further characterized by their ability to transiently inhibit expression of an epiligrin gene in a cell, e.g., by transiently binding and inhibiting translation of an mRNA encoding an epiligrin constituent. Epithelial cells whose expression of epiligrin was transiently blocked by antisense oligonucleotides did not adhere as strongly to HFK-ECM in vitro, and they became more rounded in appearance and form multicellular aggregates in suspension. The cells in the aggregates were observed to be differentiating. Thus, it is considered most likely that one or more regulatory feedback mechanisms exist in epithelial cells through which the binding of epiligrin to its .alpha..sub.3 .beta..sub.1 receptor transduces a signal through a second messenger pathway that stops cellular proliferation and induces differentiation. It is thought highly likely that abnormalities in the latter signal transduction pathway will exist in certain epithelial cells because of defects in expression levels of epiligrin, or abnormalities in one or more epiligrin glycoproteins or in the epithelial .alpha..sub.3 .beta..sub.1 integrin. The affected cells may exhibit a phenotype of either uncontrolled growth or premature differentiation. Antisense nucleic acids (e.g., oligonucleotides) may thus be useful for inducing epithelial differentiation in diseased cells that are exhibiting uncontrolled growth resulting from a failure to properly regulate epiligrin expression. In an additional use for the subject antisense nucleic acids, expression of E170 epiligrin glycoprotein was increased in rapidly dividing cells in the migratory tongue of epithelium in wound sites (Example 16). Exuberant (uncontrolled) wound healing is a frequent condition in scarring and keloid formation, and poor quality wound healing is also a problem encountered in large wound sites, e.g., in bum patients and in diabetic and paraplegic patients with dicubitous ulcers. In the latter ulcers a thin tongue of migrating epithelium may form across a wound site, but the cells frequently fail to properly initiate terminal differentiation. Antisense nucleic acids may be useful therapeutically for inducing epithelial differentiation in ulcers, and for restoring normal differentiation to prevent keloid formation and scarring conditions. The subject antisense nucleic acids may be introduced into a host cell by transfection (e.g., of an oligonucleotide) or by transduction of a nucleic acid encoding an antisense nucleic acid (e.g., using retroviral vectors). The subject antisense nucleic acids are all characterized by their ability to hybridize under stringent conditions with a (+) or a (-) strand of a nucleic acid encoding an E170 epithelial ligand glycoprotein, e.g., as represented in FIG. 10F (SEQ ID NO:21), FIGS. 11A-11C (SEQ ID NO:22), and FIG. 15A-15F (SEQ ID NO:23).
Methods are disclosed in Example 16, below, for up-regulating expression of epiligrin through the addition of TGF.alpha. or TGF.beta. to epithelial cells. These methods may be useful for increasing expression of epiligrin in patients suffering diminished synthetic capacity, e.g., in patients with a variety of blistering disorders and idiopathic urticarias (hives). Skilled practitioners will note that an effective dosage of TGF.alpha. or TGF.beta. may be determined in screening assays (i.e., in vitro and in vivo in animal models) where the dosage in contact with the epithelial cells is escalated in a stepwise manner until synthesis of an epiligrin glycoprotein is increased (i.e., as measured by mRNA or protein). Also, a variety of systemic and topical methods for application may be tested by examining the levels of expression of an epiligrin glycoprotein in the treated cells before and after the treatment.
The subject nucleic acids also find use in gene therapy for inducing overexpression of epiligrin in diseased cells, and for gene replacement therapy in genetic disease. For example, junctional epidermolysis bullosa gravis can be a lethal genetic disease of infants that is associated with failure to normally express epiligrin. Gene transfer may be accomplished using vectors (e.g., a retroviral vector) containing a construct that has in serial array: a promoter, a subject nucleic acid that encodes one or more epithelial ligand glycoproteins, e.g., E170, and a polyA tail. In genetic replacement therapy for treating lethal junctional epidermolysis bullosa gravis, constitutive expression of epiligrin in vivo may result in establishment of epithelium-basement membrane integrity in diseased epidermal tissues as well as in the lung, urogenital tract, gastrointestinal tract, and other sites of epiligrin expression (representatively illustrated in the Examples, below).
These and other aspects of the invention are described below:
5.1 Definition of Terms
The following terms used herein are intended to have the meanings set forth below:
"Epithelial ligand glycoprotein" means a constituent glycoprotein of the epithelial ligand complex epiligrin.
"Substantially-pure" means of a purity sufficient that more than 70% of the polypeptides in the preparation can be determined by SDS-PAGE and protein staining to be the composition so specified.
"Covalently linked" means polypeptides chemically bonded to one another, as through for example (but not limited to) disulfide-bonds, thiol-ester bonds, ester bonds, amide bonds, or the like.
"Capable of binding" means physical interaction between two materials, such as between a specific binding partner and a ligand, where the interaction is sufficiently strong to permit measurement of a chemical association (or dissociation) constant (i.e., Ka or Kd).
"Capable of hybridizing under stringent conditions" means annealing of a nucleic acid molecule to at least a region of the disclosed E170 epithelial ligand glycoprotein nucleic acid sequence (whether as cDNA, cRNA, mRNA, or genomic DNA), or to its complementary strand under standard conditions, e.g., high temperature and/or low salt content, which tend to disfavor hybridization of noncomplementary nucleotide sequences. A suitable protocol is described in Maniatis, T., et al. (#118 which is hereby incorporated by reference), at pages 387-389, wherein following the hybridization step filters are washed in 0.1.times.SSC, 68.degree. C. for 2 hours. Other protocols for achieving stringent hybridization are well-known to those skilled in the art, and can be selected from those presented in Maniatis (#118). Such hybridizing molecules may be related to the disclosed sequence by deletion, point mutation, base substitute, frameshift, alternative ORFs, mRNA splicing or processing, or post-transcriptional modification (e.g., methylation and the like).
"Substratum" means an insoluble material upon which cells may be deposited by gravity.
"Non-adhesive substratum" means a substratum to which fewer than 20% of the cells will bind in 24 hours at 37.degree. C. and from which 80% of the cells can be removed by washing with medium, e.g., such a substratum is provided by microbiological grade polystyrene plastic petri dishes.
"Epithelial cells" means, in this disclosure, the cells originating through mitosis in epithelial tissues which cover the free surfaces of the body and line the body cavities and ducts, as well as cells of epithelial origin such as malignant carcinoma cells. Further examples of epithelial cells as they are commercially available are provided in Table 2, below, as listed in the "Catalogue of Cell Lines and Hybridomas", 6th Edition, 1988, the American Type Culture Collection, Rockville, Md.
"Modulate" means to effect an increase or decrease of a specified parameter to a measurable extent.
"Adhesion assay" means an assay conducted with test cells, such as HT1080 in Example 6 below, to measure adhesion of cells to a protein-coated "non-adhesive" substratum under defined test conditions of tissue culture.
"Differentiation" means a staged process, e.g., in development, through which a cell progressively acquires distinguishably new phenotypic attributes.
"Confluent cell culture" means a culture in which more than 85% of the cells are observed microscopically to be in physical contact with their neighboring cell.
"Resistant to digestion" means that no substantial change in physical properties is observed following incubation of the polypeptide with an enzyme for a substantial period of time.
"Co-migrate" means substantially the same electrophoretic migration when two polypeptides are either run together in the same lane of an SDS-PAGE gel, or when they are run side-by-side in adjacent lanes.
"Molecular size" means the apparent molecular radius of the polypeptide as observed under denaturing conditions in SDS-PAGE, and as recorded in kilodaltons (kDa.+-.) of mass as determined by comparison with other polypeptides of known molecular mass.
TABLE 2______________________________________Examples of Commercially-Available Human Epithelial CellsTissue Name/ATCC No. Description______________________________________Endometrium RL95-2/CRL1671 Adenosquamous carcinomaSkin WM-115/CRL1675 epitheloid melanoma WS-1/CRL1502 fetal skinPancreas AsPC-1/CRL1682 adenocarcinoma PANC-1/CRL1469 epitheloid carcinomaStomach AGS/CRL1739 adenocarcinomaBladder UM-UC-3/CRL1749 bladder carcinoma HT-1197/CRL1473 bladder carcinomaColon CCD841CoN/CRL1790 fetal epithelial-like NCI-H548/CCL249 adenocarcinomaTongue SCC-9/CRL1629 squamous cell carcinomaKidney ACHN/CRL1611 adenocarcinomaCervix C-41/CRL1595 carcinoma CaSki/CRL1550 epidermoid carcinomaOvary PA-1/CRL1572 teratocarcinomaEpidermis A-431/CRL1555 epidermoid carcinomaBreast ZR-75-1/CRL1500 mammary carcinoma MCF-7/HTB22 adenocarcinomaPharynx Detroit 562/CCL138 carcinomaAdrenal cortex SW-13/CCL105 adenocarcinomaLung WI-38/CCL75 fetal diploid______________________________________
5.2 Keratinocyte Extracellular Matrix and Immunoprecipitation of Epiligrin: The Major Glycoprotein Complex in Adhesive HFK-ECM
For this study, the extracellular matrix synthesized and secreted by HFKs shall be referred to as HFK-ECM and that synthesized and secreted by HFFs as HFF-ECM. Endogenous HFK-ECM is that which is intracellular or plasma membrane associated. HFK-ECM secreted into the conditioned culture medium during the time course of an assay, or that which can be purified from culture dishes or glass cover slips (after the removal and/or extraction of the HFKs, as by the three-step extraction procedure detailed below), is referred to as exogenous HFK-ECM.
To identify a physiologically significant ligand for .alpha..sub.3 .beta..sub.1 and/or .alpha..sub.6 .beta..sub.4 integrins in epithelial cells, we first examined the composition of the ECM produced by HFK. Radiolabeled HFK-ECM and HFK were prepared by incubating HFK in culture dishes for 15 hours in KGM containing .sup.35 S-methionine, .sup.3 H-glucosamine, or .sup.35 SO.sub.4.sup.-2, and 1 mg/ml HD-BSA (Sigma) as a carrier protein. Radiolabeled HFKs were sequentially extracted in a sequential three-step extraction procedure, as described previously (Wayner and Carter, 1987): (1) with 1% (w/v) Triton X-100 (Sigma; to solubilize membranes and cytoplasmic constituents) and 2 mM N-ethylmaleimide (Sigma, to prevent intramolecular cross-linking); (2) with a solution containing 2 M Urea and 1 M NaCl (to remove nuclear and cytoskeletal components); and (3) with 8 M Urea (to solubilize residual cellular components). All extraction buffers contained 1 mM phenylmethyl sulfonyl fluoride (PMSF; Sigma Chemical Co., St. Louis, Mo.) as a protease inhibitor, and 2 mM N-ethylmaleimide (Sigma) as an inhibitor of intramolecular cross-linking. The constituent radiolabeled glycoproteins were separated by SDS-PAGE (12) and visualized by fluorography. The results of the sequential extraction procedure are presented in FIG. 1 where lanes 1-3 show the glycoproteins extracted in the steps 1, 2, and 3 (above), respectively.
To examine the nature of the 8 M urea-insoluble HFK-ECM glycoproteins remaining on culture dishes after the extraction step 3, 0.5% (w/v) SDS was added to the culture dishes, and glycoproteins were physically dissociated by mechanical scraping with a rubber policeman. The glycoproteins obtained in this manner did not enter an 8% SDS-PAGE gel (FIG. 1, lane 5) unless they were reduced on SDS-PAGE under reducing conditions (i.e., with 2-mercaptoethanol; 2ME) and visualized by fluorography. They consisted essentially of at least five major glycoproteins visualized by protein staining with Coomassie brilliant blue (FIG. 1, lane 8) or following biosynthetically radiolabeled with .sup.35 S-methionine (FIG. 1, lane 4), or .sup.3 H-glucosamine (FIG. 1, lane 9); these glycoproteins having apparent Mr of 200 kDa, 170 kDa, 145 kDa, 135 kDa, and 36 kDa (FIG. 1, lane 9). (Migration of molecular mass standards are indicated in the left margin of FIG. 1 (i.e., 180, 116, 84, 58, 49, and 37 kDa).) The HFK-ECM glycoproteins detected with protein stain showed slightly decreased amounts of the 200 kDa glycoprotein (FIG. 1, lane 8). The five major glycoproteins were designated E200, E170, E145, E135, and E36, based on relative molecular mass under reducing conditions on 8% SDS-PAGE. The E170 band was inconsistently resolved into two bands (FIG. 1, lane 9). Under non-reducing conditions the five glycoproteins did not enter the polyacrylamide gel (FIG. 1, lane 5), indicating that they were subunits of one or more high molecular mass complexes, cross-linked by intermolecular disulfide bonds. This mass (or masses) is known as epiligrin. Although the glycoprotein subunits were not labeled with .sup.38 SO.sub.4.sup.-2, three additional sulfate-labeled components, probably glycosaminoglycan or proteoglycan, were also present in the exogenous HFK-ECM (FIG. 1, lane 10, marked with *). In control experiments, metabolic labeling for different times did not detect any precursor product relationship among the five glycoprotein subunits of the complex. However, antigenic similarities suggest that E200 is a precursor to E170. Comparison of the molecular masses of the five glycoprotein subunits in the complex to known basement membrane components failed to detect any obvious relationships. To evaluate further any possible relationship between the exogenous HFK-ECM glycoproteins and the collagens, non-reduced and reduced (2-mercaptoethanol; Sigma) .sup.35 S-methionine biosynthetically radiolabeled HFK-ECM was treated at 37.degree. C. for 18 hours with 100 units/ml collagenase (Advanced Biofactures, Form III) under conditions which degrade collagen standards, as described previously (98). The collagenase-digested radiolabeled HFK-ECM was extracted using the same three-step extraction procedure described above, and the glycoproteins were separated using SDS-PAGE and visualized by fluorography. None of the five major glycoprotein components in HFK-ECM was digested with collagenase either when non-reduced (FIG. 1, lanes 6 and 7) or reduced prior to digestion, indicating that they were not collagens. In addition, the HFK-ECM glycoproteins (FIG. 3, HFK-ECM) did not co-migrate on 8% SDS-PAGE with purified protein standards of EHS sarcoma laminin (FIG. 3, EHS-LN; LN A; LN B1 and B2), fibronectin (FN); when visualized by staining for protein with Coomassie blue (FIG. 3, PROTEIN), entactin, or tenascin, but E170 did co-migrate with pepsinized human placental laminin (FIG. 3, compare HFK-ECM to H LN). In contrast (and as expected), proteins in conditioned medium from HFK cells (HFK CS, FIG. 3) contained a multiplicity of proteins, some of which co-migrated with the protein standards (FIG. 3, HFK CS). To further evaluate any possible relationship between fibronectin (or laminin) and the components in exogenous HFK-ECM, three types of experiments were conducted. First, the glycoproteins in exogenous HFK-ECM were separated on SDS-PAGE, blotted onto nitrocellulose as described previously (98) and tested for their immunoblot reactivity with rabbit antibodies directed toward laminin (Anti-LN, FIG. 3) or fibronectin (Anti-FN; FIG. 3). Anti-FN bound to antigens in HFK-conditioned medium (HFK CS) and in purified fibronectin (FN) but not in human placental laminin (H LN), sarcoma EHS laminin (EHS LN) or HFK-ECM; anti-LN bound to antigens in HFK-CS, H LN, and EHS-LN but not in FN or HFK-ECM (FIG. 3). In summary, immunoblotting of HFK-ECM with antilaminin or anti-fibronectin (FIG. 3, Panel "Anti-LN and Anti-FN") failed to detect any relationship between these known extracellular matrix glycoproteins and the glycoproteins in HFK-ECM. Second, polyvalent antibodies to laminin or fibronectin were also used to prepare an immunoprecipitate of exogenous HFK-ECM. Immunoprecipitation with antibodies against laminin, fibronectin, tenascin, entactin, or bullous pemphigoid antigen (BPA) failed to detect any immunological cross-reaction among those known BM proteins and the five major glycoprotein subunits of the HFK-ECM. Third, HFK-ECM was scraped from the substratum and used to immunize rabbits to induce antiserum. The resultant antisera did not react with laminin or fibronectin, but did react with E170, E145, and E135 in the HFK-ECM.
In order to further characterize the HFK-ECM, we prepared monoclonal antibodies (MAbs) against the HFK-ECM glycoprotein complex using HFKs as an immunogen.
5.3 Binding Partners as Exemplified by Monoclonal Antibody to HFK-ECM
Binding partners as exemplified by MAbs to HFK-ECM were produced by the methods of Oi and Herzenberg (99) and Taggart and Samloff (100) as described (59). Spleen cells from RBF/DN mice immunized with cultured HFKs were fused with NS-1/FOX-NY myeloma cells. Viable heterokaryons were selected in RPMI 1640 medium supplemented with adenine/aminopterine/thymidine.
Hybridomas P1E1 (ATCC No. HB10590) and P1H8 (ATCC No. HB10682) producing antibody specifically directed to HFK-ECM were selected using immunofluorescence microscopy and HFK-ECM or HFF-ECM on glass cover slips. We selected MAbs P1E1 and P1H8 that reacted with HFK-ECM but not HFF-ECM produced by the dermal fibroblasts. P1E1 and P1H8 were cloned by limiting dilution. P1E1 and P1H8 (with rabbit anti-mouse IgG) immunoprecipitated five relatively minor disulfide-bonded subunits from the conditioned culture medium of .sup.35 S-methionine-labeled HFKs. The results presented in FIG. 2 show examples of three (1, 2, 3) such immunoprecipitation experiments conducted with P1E1 in which HFK cells were metabolically radiolabeled with .sup.35 S-methionine, as described above, and antigens in the conditioned medium (FIG. 2; CS) and HFK-ECM (FIG. 2; ECM) were immunoprecipitated. The five subunits of the P1E1 antigen(s) co-migrated with the five major glycoprotein subunits of the exogenous HFK-ECM (FIG. 2, compare ECM in the far left lane of the figure with P1E1, experiment 1). The E170 subunit in FIG. 2 in the precipitated P1E1 antigen was increased relative to the other subunits in all three experiments, suggesting that E170 contained the epitope recognized by the P1E1 MAb. In a similar manner, the E36 component of glycoprotein complex was increased in the immunoprecipitate prepared in this manner between radiolabeled HFK-CS and P1H8, suggesting that E36 may contain the antigenic epitope for P1H8. The possibility that the glycoprotein complex recognized by P1E1 may contain antigens previously identified was once more evaluated, this time utilizing immunoprecipitation techniques. Preclearing of HFK conditioned culture medium (FIG. 2; CS) by immunoprecipitation with polyvalent anti-fibronectin (FIG. 2, experiment 2; FN), polyvalent anti-entactin, or mouse monoclonal anti-tenascin prior to precipitation with P1E1 had no effect on subsequent precipitation of P1E1 antigens. However, preclearing (i.e., immunoprecipitating) with polyvalent anti-laminin (FIG. 2; experiment 3, LN) removed E200 and 50% of the other subunits from the P1E1 precipitate. Since none of the glycoproteins (i.e., E200, E170, E145, E135, or E36) reacted with anti-laminin antibodies by Western immunoblotting after SDS-PAGE (FIG. 3), we conclude that: (a) E200 in the complex is not laminin; and (b) glycoprotein complex may be associated with laminin so that it forms a complex that can be precipitated with the anti-laminin antibody. This type of interaction of laminin has not been reported previously, and the composition of the precipitate differs significantly from previously reported complexes of laminin interacting with other glycoproteins.
In summary, the P1E1 and P1H8 antigens correspond in molecular sizes to the glycoproteins in exogenous HFK-ECM, which consists of at least five subunits: E200, E170, E145, E135, and E36, which are visualized on SDS-PAGE after reduction, and that are distinct from any previously identified adhesion ligand(s) present in basement membranes or extracellular matrix. The complex recognized by P1E1 and P1H8 is the major component of exogenous HFK-ECM and also a minor component in HFK-conditioned culture medium. Based on the unique characteristics of this complex, and in order to simplify the following discussion, we shall henceforth refer to the covalently linked glycoprotein complex as "epithelial ligand" or "epiligrin."
5.4 Epiligrin Distribution in Motile and Non-Motile HFKs
The organization of epiligrin deposited in HFK-ECM was examined by immunofluorescence microscopy, using MAb P1E1 and P1H8 and antibodies directed toward other extracellular matrix adhesive ligands. It was found that P1H8 stained only cells which were permeabilized to allow staining of cytoplasmic proteins, indicating that the P1H8 antigen was a cytoplasmic constituent of cells expressing .alpha..sub.3 .beta..sub.1 integrin. Subsequent studies, detailed below, utilized only the P1E1 MAb.
HFKs were grown for 24 hours on glass cover slips coated with either fibronectin (FIGS. 4A-4B) or BSA (FIGS. 4C-4K), as described above (see "Cellular Adhesion to Extracellular Matrix Adhesive Ligand-Coated Substrates"). Glass cover slips and cells were then incubated with mouse or rat MAbs or rabbit polyclonal primary antibodies diluted in 1% heat HD-BSA overnight as previously described (21). The cover slips were washed with PBS; incubated with dilutions of affinity-purified, species-specific, FITC-conjugated goat anti-mouse/rat IgG or rhodamine-conjugated goat anti-rabbit IgG secondary antibodies (respectively) for 1 hour, washed with PBS, and fixed with 2% formaldehyde prior to immunofluorescence microscopy. The organization of epiligrin was dependent on the ligand to which the HFKs were attached. When HFKs attached to fibronectin (FIG. 4A), collagen, or laminin, the cells migrated over the ligand surface leaving trails of epiligrin.
To investigate whether the .alpha..sub.3 - and .alpha..sub.6 -containing integrins (i.e., .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4) were associated with epiligrin on the cell surface, tests were conducted simultaneously to visualize the integrin and its putative ligand on HFKs using a double immunofluorescence technique. Epiligrin (P1E1, FIGS. 4A, 4C, 4F, and 4I) was localized relative to .alpha..sub.6 (FIGS. 4B and 4D; GoH3), BPA (FIG. 4G) and .alpha..sub.3 .beta..sub.1, (FIG. 4J; P1F2). SACs and FAs were identified in each field by interference reflection microscopy (FIGS. 4E, 4H, and 4K). Arrows in panels I, J, K identify .alpha..sub.3 .beta..sub.1 in FAs in relation to epithelial ligand in SACs. HFKs were incubated with: (1) mouse MAb anti-.alpha..sub.6 (GoH3); followed by (2) incubation with rhodamine-conjugated goat-antimouse IgG and IgM; after which the cells were fixed and reacted with (3) biotinylated with mouse P1E1 MAb; followed by (4) fluorescein Avidin. In migrating HFK cells, .alpha..sub.6 .beta..sub.4 was expressed on the apical surface of the cells and at the trailing edge. Small quantities of .alpha..sub.6 .beta..sub.4 co-distributed with the epiligrin antigen in the trails of these cells (FIG. 4B).
As described (20), when HFKs are grown on BSA-coated surfaces, the cells migrate less and form hemidesmosome-like stable anchoring contacts (SACs) on their basal surface. In the present study, by immunofluorescence microscopy, all the SACs on the basal surface of the stationary HFK cells contained .alpha..sub.6 .beta..sub.4 and most contained BPA. As seen in FIG. 4C, HFKs grown on BSA deposited epiligrin antigen on the substrata in "ring-like structures" characteristic of SACs. The distribution of epiligrin antigen (P1E1; FIGS. 4A, 4C, and 4F) in relation to .alpha..sub.6 (GoH3; FIGS. 4B and 4D), and BPA (FIG. 4G) was most strikingly similar in the "ring structures." To further distinguish SACs from focal adhesions, interference reflection microscopy (IRM) was performed basically as described (Izzard and Lochner, 1976) and was used to identify focal adhesions (FAs) in the same field as the two color immunofluorescence which identified the SACs. FAs were also localized by the antibody exclusion technique (101). Epiligrin (identified by P1E1) in .alpha..sub.6 .beta..sub.4 /BPA-SACs corresponded to contact sites with the adhesion surface as determined by interference reflection microscopy (FIGS. 4E and 4H). The co-localization and similar stabilities indicated that the deposits of epiligrin were at adhesion sites linked to .alpha..sub.6 .beta..sub.4 /BPA-SACs.
As an additional test for the localization of epiligrin in SACs, since we had previously observed that .alpha..sub.6 .beta..sub.4 and BPA in SACs are extraordinarily stable and are resistant to sequential extraction with 1% Triton X-100 detergent and 2M urea/1 M NaCl, while the .beta..sub.1 -containing integrins in focal adhesions are soluble under these extraction conditions (20), we therefore next examined the distribution of epiligrin, .alpha..sub.6 .beta..sub.4, BPA, and .alpha..sub.3 .beta..sub.1 in HFK SACs extracted in this manner. HFKs were grown for 24 hours on surfaces coated with BSA, then extracted with 1% Triton X-100 detergent followed by 2 M urea containing 1 M NaCl. The adherent cell residue containing SACs was stained with anti-epiligrin (P1E1, FIGS. 5A, 5C, and 5E), anti-.alpha..sub.6 (.beta..sub.4) (GoH3, FIG. 5B), anti-BPA (FIG. 5D), and anti-.alpha..sub.3 .beta..sub.1, (FIG. 5F; P1F2). Consistently, we observed that epiligrin antigen was present in sequentially extracted HFK SACs (P1E1; FIGS. 5A, 5C, and 5E). In these studies .alpha..sub.6, .alpha..sub.3, .beta..sub.1, epiligrin, or BPA antigen was visualized using a double immunofluorescence technique. Epiligrin co-distributed with the .alpha..sub.6 (GoH3, FIG. 5B), and BPA (FIG. 5D) in the extracted HFK-ECM. The co-distribution of epiligrin with .alpha..sub.6 .beta..sub.4 and BPA in both non-extracted and sequentially extracted HFKs (Triton X-100, 2 M urea/1 M NaCl, above) indicated a stable linkage between the cytoplasmic intermediate filament BPA, the intrinsic membrane .alpha..sub.6 .beta..sub.4 integrin and the extracellular epiligrin glycoprotein complex ligand, as major constituents of hemidesmosome-like SACs.
5.5 The Epithelial Ligand Complex Epiligrin is a Ligand for a .alpha..sub.3 .beta..sub.1 -FAs
We have previously reported that .alpha..sub.3 .beta..sub.1 in HFK-ECM is localized into FAs in proximity to, but excluded from, .alpha..sub.6 .beta..sub.4 /BPA-SACs (20, 21). HFKs that deposited epithelial ligand in SAC, usually localized .alpha..sub.3 .beta..sub.1 to FAs at the periphery of SACs as detected by interference reflection microscopy (FIGS. 4I-4K). Epiligrin was not detectable by immunofluorescence in the .alpha..sub.3 .beta..sub.1 -FAs probably due to physical exclusion of anti-.alpha..sub.3 .beta..sub.1 antibodies from the adhesion sites (20, 21, 101). In contrast to the results obtained above with extraction of .alpha..sub.6 .beta..sub.4 /BPA/epiligrin in SACs, the .alpha..sub.3 .beta..sub.1 integrin in FAs was readily solubilized with 1% Triton X-100 detergent (FIGS. 5E-5F), further distinguishing the organization and stability of FAs from SACs (20). We consistently observed .alpha..sub.3 .beta..sub.1 integrins in FAs encircling the .alpha..sub.6 .beta..sub.4 integrins in the SACs suggesting to us a functional relationship and/or common ligand for both integrins in the SAC and FA adhesion structures.
To further evaluate the role of .alpha..sub.3 .beta..sub.1 in adhesion to epiligrin in isolation from the .alpha..sub.6 .beta..sub.4 integrin, we first sought to identify cells by immunofluorescence microscopy that did not express .alpha..sub.6 .beta..sub.4 or epiligrin antigen, but did express .alpha..sub.3 .beta..sub.1. Nine different cell populations were examined, including: HFFs; HT1080 fibrosarcoma; Tera-2 teratocarcinoma; T-47D mammary carcinoma cells; Ovcar-4 ovarian carcinoma; and FEPE1 L-8, FE-A, T-47D and FE-H18L, four HSK cell lines resulting from papillomavirus transformation. Examination of the nine cell lines and primary HFKs (for comparison) by immunofluorescence microscopy with P1E1 identified only one--the primary HFKs, that produced significant quantities of epiligrin antigen (thus, further justifying our initial belief that HFK may produce an ECM that is unique from other ECMs). In contrast to primary HFKs, human foreskin fibroblasts (HFFs), HT-1080 fibrosarcoma, Tera-2 teratocarcinoma, and T-47D mammary tumor carcinoma cells, while positive for .alpha..sub.3 .beta..sub.1, were all negative for expression of epiligrin. Ovcar-4, an ovarian carcinoma cell line, and FEPE1L-8, FE-A, and FE-H18L, the human papilloma virus-transformed-HFKs (94, 95), expressed epithelial ligand but at low levels relative to HFKs. Expression of .alpha..sub.6 .beta..sub.4 was also investigated with immunofluorescence microscopy. of the nine cell lines and primary HFKs cells, only the HFKs, T-47D, FEPE1L8, FE-A, and FE-H18L cells expressed .alpha..sub.6 .beta..sub.4. Thus, HFF and HT1080 fibrosarcoma cells expressed .alpha..sub.3 .beta..sub.1, but not epithelial ligand or .alpha..sub.6 .beta..sub.4 and provided us a model system to study the interactions of .alpha..sub.3 .beta..sub.1 with the epithelial ligand glycoprotein complex.
We previously observed that HFFs localized the .alpha..sub.5 .beta..sub.1 and .alpha..sub.2 .beta..sub.1 integrins in focal adhesions when the cells were attached to fibronectin- and collagen-coated surfaces respectively (21), and this property was considered to be associated with ligand-induced receptor redistribution on the cell surface. The .alpha..sub.3 .beta..sub.1 integrin was not previously examined during the interaction of these cells with fibronectin or collagen. To study .alpha..sub.3 .beta..sub.1, integrin redistribution, HFFs were attached to surfaces coated with fibronectin (FIG. 6A), type I collagen (FIG. 6B), laminin (FIG. 6C), or HFK-ECM (FIGS. 6D-6F) for 1 hour. The fixed and permeabilized cells were stained with anti-.alpha..sub.3 .beta..sub.1 (P1F2, FIGS. 6A-6D). FIGS. 6D-6F are all the same field. The field in FIG. 6E was stained for epiligrin (P1E1), and FAs were detected by interference reflection microscopy as shown in FIG. 6D. Arrows in FIGS. 6D-6F indicate localization of .alpha..sub.3 .beta..sub.1 in FAs that contact the adhesion surface and exclude anti-epiligrin antibody. When HFFs attached to fibronectin or collagen, they distributed .alpha..sub.3 .beta..sub.1, over the entire cell surface with no localization of .alpha..sub.3 .beta..sub.1 in FAs (FIGS. 6A and 6B). When attached to surfaces coated with laminin, the laminin induced thin FAs that were weakly positive for .alpha..sub.3 .beta..sub.1 (FIG. 6C). Thus, neither fibronectin, collagen, nor laminin appears to constitute a major ligand capable of redistributing the .alpha..sub.3 .beta..sub.1 integrin on the surface of human foreskin fibroblasts in vitro. In contrast, HFFs that attached to HFK-ECM for only 1 hour localized .alpha..sub.3 .beta..sub.1 into FAs as determined by interference reflection microscopy and exclusion of the P1E1 antibody (FIGS. 6D-6F). The .alpha..sub.3 .beta..sub.1 co-distributed with epiligrin in both FAs and the ring structures characteristic of SACs. These results indicated that epiligrin, as the major component of HFK-ECM, controlled the formation of .alpha..sub.3 .beta..sub.1 -FAs better than any previously identified ECM ligand.
5.6 Immunopurification of Epiligrin
Epiligrin was immunopurified from conditioned culture medium. This was accomplished in a stepwise fashion, first, by affinity-purification of MAb P1E1 from hybridoma culture medium on Protein G-Sepharose (Pharmacia, Piscataway, N.J.). Second, the purified monoclonal antibody was covalently coupled to Affigel-10 (Bio-Rad Laboratories, Richmond, Calif.; forming the P1E1-affinity-column). Third, conditioned culture medium from confluent cultures of HFKs was passed over a gelatin-Sepharose column (Pharmacia) to remove fibronectin. Fourth, the flow-through from the gelatin sepharose column was then passed over the P1E1-affinity-column. Unbound protein was removed by washing with PBS; and then the bound epithelial ligand antigen was eluted with 3 M KSCN and dialyzed against PBS. The epiligrin purified on the P1E1 affinity-column contained the complex of E200, E170, E145, and E135 covalently linked subunits as well as the E36 and E100, although lower levels of E200 were present than in HFK-ECM.
5.7 Specificity of an Integrin .alpha..sub.3 .beta..sub.1 -Mediated Cellular Adherence to Epiligrin
Soluble, purified epiligrin glycoprotein complex was coated on non-adhesive polystyrene plastic surfaces to examine its ability to promote adhesion of HT1080 cells through the .alpha..sub.3 .beta..sub.1 receptor. Inhibition of cell adhesion to various ligands was performed as previously described (20, 21, 59). The specificity of the adhesion for .alpha..sub.3 .beta..sub.1 was evaluated by testing for inhibition of adhesion with anti-.alpha..sub.3 .beta..sub.1 MAb (P1B5). For comparison, epiligrin (EN; 1 .mu.g/ml), human plasma fibronectin (FN) 10 .mu.g/ml), type I collagen (CN; 10 .mu.g/ml), EHS laminin (LN; 10 .mu.g/ml), or BSA (5 mg/ml) were coated on non-adhesive plastic surfaces (2 hours), washed, and blocked with heat denatured BSA for 1 hour. The cells were labeled with Na.sub.2 .sup.51 CrO.sub.2 (New England Nuclear; 50 .mu.Ci/ml for 2-4 hours) and were allowed to adhere (in the presence of the following inhibitory antibodies) to the protein-coated surfaces in the presence of the hybridoma supernatants for 1.5 hours. The inhibitory antibodies indicated in FIG. 7 include: SP2 as a control, non-inhibitory antibody. P4C10, inhibits cell adhesion via all .beta..sub.1 -containing integrins. GoH3, anti-.alpha..sub.6 (.beta..sub.1) laminin receptor in HT1080. P1H5, anti-.alpha..sub.2 .beta..sub.1 collagen receptor. P1D6, anti-.alpha..sub.5 .beta..sub.1 fibronectin receptor. P1B5, anti-.alpha..sub.3 .beta..sub.1 epiligrin receptor. The bars in FIG. 7 represent the mean values of three assays. Unattached cells were removed by washing and the adherent cells dissolved in SDS/NaOH and quantitated in a gamma counter. The results presented in FIG. 7 show that purified epiligrin mediated adhesion of HT1080 cells to the previously non-adhesive plastic surface, and the cellular adhesion to epiligrin-coated plastic was blocked in a specific manner by the P1B5 MAb to the .alpha..sub.3 .beta..sub.1 integrin. More specifically, the data presented in FIG. 7 show that HT1080 cells attached to epiligrin-, fibronectin-, and collagen-coated and non-adhesive plastic surfaces and laminin (FIG. 7). Antibodies against the .alpha..sub.5 .beta..sub.1, (P1D6) fibronectin receptor, the .alpha..sub.2 .beta..sub.1 (P1H5) collagen receptor, and the .alpha..sub.6 .beta..sub.1, (GoH3) laminin receptor (64, 102) specifically inhibited HT1D80 adhesion to their corresponding ligands but had no inhibitory effect on adhesion to epiligrin. Anti-.beta..sub.1 MAb (P4C10) inhibited cell adhesion to all ligands involving .beta..sub.1 -containing integrins.
The testing was next expanded to include cells other than HT1080. P1B5 (anti-.alpha..sub.3 .beta..sub.1) was found to inhibit the adhesion of HFK and FE-H18L cells to epiligrin. These results established .alpha..sub.3 .beta..sub.1, as a primary receptor for cell adhesion to epiligrin. Further, the MAb inhibition results clearly distinguish cellular adhesion to laminin via .alpha..sub.6 .beta..sub.1 from epiligrin via a .alpha..sub.3 .beta..sub.1. These findings will establish a test cell assay system useful for identifying epiligrin produced by other epithelial cells.
5.8 Epiligrin Localization in Normal Epithelial Basement Membrane
We compared the distributions of epiligrin to laminin, .alpha..sub.3 .beta..sub.1, and .beta..sub.1 by immunoperoxidase staining of cryostat sections of normal skin, tonsil (below), and lung (below) (FIGS. 8A-8P). The results show cryostat sections of the SKIN (human neonatal foreskin) (FIGS. 8A-8D) and SPLIT SKIN (skin from a patient with junctional epidermolyses bullosis that spontaneously separates between the BM and basal cells) (FIGS. 8E-8H). TONSIL (FIGS. 8I-8L) and LUNG (FIGS. 8M-8P) were stained with the indicated antibodies (ANTI-EPILIGRIN LIGAND, etc.). (The magnification in FIGS. 8A-8P prior to photographic enlargement was 160.times..) (Arrows and letter abbreviations are used in FIGS. 8A-8P to identify the following structures: BM=epidermal basement membrane; S=epithelial sweat glands in dermis; D=duct of sweat gland in dermis; V=venule; BC=basal cells of epidermis; C=BM of capsular epithelium; LF=lymphoid follicles (germinal centers); E=BM of ciliated epithelium in bronchus; M=bundles of smooth muscle cells adjacent bronchus; and SMG=submucosal glands.)
The distribution of receptors and ligands in tissue was determined by immunoperoxidase microscopy of the cryostat sections. Cryostat sections (.mu.) were prepared from human tissues embedded in OCT medium after snap freezing in isopentant/liquid nitrogen. All sections were fixed with 2% formaldehyde in 0.1 M NaCacodylate pH 7.2 in 0.1 M sucrose for 20 minutes and then permeabilized with 1% Triton X-100 for 15 minutes. The sections were incubated with primary antibodies and peroxidase-conjugated secondary antibodies.
In skin (FIGS. 8A-8D), antibodies against epiligrin, laminin, .alpha..sub.3 .beta..sub.1 and .beta..sub.4 localized to the BM region separating the epidermis and dermis and to epithelial sweat glands (S) and ducts (D) in the dermis. Epiligrin antigen was not present in laminin-positive endothelial BMs in venules (V) in the dermis.
5.9 Epiligrin Antigen Localization in Diseased Epithelial Basement Membrane
Split skin from a patient with junctional epidermolyses bullosa (JEB) was also analyzed by immunoperoxidase staining in FIGS. 8E-8H for epiligrin antigen, laminin, .alpha..sub.3 .beta..sub.1, and .beta..sub.4. JEB is an inherited disorder that results in disruption of basal cell attachment to the BM with a corresponding decrease in hemidesmosomes (103, 104). In cryostat sections of skin from a patient with JEB (FIGS. 8E-8H), the basal epidermis spontaneously separated from the BM. Epiligrin antigen and laminin both localized to the BM floor of the split skin indicating that epiligrin was a component of the BM. In contrast, .alpha..sub.3 .beta..sub.1 and .beta..sub.4 localized to the roof of the split in the basal cells (BC).
5.10 Epiligrin Localization in Lymphoid Tissues
In tonsil (FIGS. 8I-8L), P1E1 (ANTI-EPILIGRIN) localized to lymphoid follicles (LF), or germinal centers as a fine filamentous network, possibly in reticular fibers, and the basement membrane of the lymph node capsular epithelium (C). In contrast, laminin (ANTI-LAMININ (R5922), FIG. 8I) was weakly expressed in the lymphoid follicles and capsular BM and strongly expressed in the venous sinuses (V). Both .alpha..sub.3 .beta..sub.1, and .beta..sub.4 were expressed in basal cells associated with the capsular BM. However, neither .alpha..sub.3 .beta..sub.1 nor .beta..sub.4 was detectable as major components of lymphoid follicles.
5.11 Epiligrin Localization in Lung Tissues
In lung (FIGS. 8M-8P), epiligrin and laminin localized to the BM of ciliated epithelium (E) and submucosal glands (SMG) in the bronchus. .alpha..sub.3 .beta..sub.1 was adjacent to epiligrin antigen in the basal plasma membranes of the ciliated epithelial cells. In contrast, .beta..sub.4 was only sporadically expressed along the basal plasma membrane (E). Both laminin and .alpha..sub.3 .beta..sub.1 were strongly expressed in bundles of smooth muscle cells (M) and veins (V) while epiligrin was absent.
5.12 Epiligrin Localization in Other Tissues and Organs
Epiligrin was absent from BM of heart muscle, mesothelium, brain, and glomerulus and tubules in kidney, while laminin was expressed. Epiligrin was present in the BM separating the intestinal epithelium from the lamina propria. These results identified epiligrin as a component of epithelial BMs particularly in organs of endodermal and ectodermal (but not neural) origin. Epiligrin was not present in muscle, neural, and endothelial BMs.
5.13 Epiligrin, .alpha..sub.3 .beta..sub.1 and .beta..sub.4 Localize at the Cell-Basement Membrane Junction
The ultrastructural localization of epiligrin, .alpha..sub.3 .beta..sub.1, and .beta..sub.4 was determined by immunoelectron microscopy of human skin. Electron micrographs are presented in FIGS. 9A-9F of immunoperoxidase-stained human neonatal foreskin which was stained with the following antibodies and achieving the following results: (FIG. 9A) control staining with SP2 culture (supernatant is negative; hemidesmosomes and desmosomes are detectable), (FIG. 9B) P1F2 (.alpha..sub.3 .beta..sub.1 is detectable on the apical, lateral, and basal membranes; staining was also observed in desmosomes); (FIG. 9C) and (FIG. 9D) E31 (the .beta..sub.4 subunit is localized to the basal surface and increased staining localized to hemidesmosomes at the origin of keratin filaments); and (FIG. 9E) and (FIG. 9F) P1E1 (epiligrin is present in the lamina lucida along the entire basal membrane but particularly adjacent hemidesmosomes). (Abbreviations used in FIGS. 9A-9F include: BM=basement membrane; IC=intercellular contacts; BS=basal membrane surface; KF=intermediate filaments; HD=hemidesmosomes; D=desmosomes; and C=collagen filaments.)
We reported previously that .alpha..sub.6 .beta..sub.4 -containing SACs in HFKs are homologous to hemidesmosomes in skin (20). Consistent with this suggestion and the report of Stepp et al. (19), immunoelectron microscopy localized .beta..sub.4 to hemidesmosomes at origins for intermediate filaments (FIGS. 9C-9D).
For immunoelectron microscopy, tissue was fixed (30 minutes in 3% paraformaldehyde/0.5% glutaraldehyde in PBS) prior to freezing and cryostat sectioning (6.mu.), followed by immunoperoxidase staining with P1F2 and P1E1. Because MAb 3E1 required milder fixation conditions, tissue was cryostat sectioned, then fixed (2% paraformaldehyde in PBS for 15 minutes) followed by peroxidase staining and further fixation (2.0% paraformaldehyde and 2.5% glutaraldehyde in 0.1 M Ca-codylate buffer). All tissue sections were post-fixed for 1 hour in 1% osmium tetroxide, alcohol dehydrated and infiltrated with Epon 812-tm resin (Polysciences, Warrington, Pa.) as described (105). Thin sections were cut (600-800 .ANG.). No uranyl acetate staining was performed.
Consistently, epiligrin localized in the lamina lucida of epidermal BM (FIGS. 9E-9F). Epiligrin appeared to directly contact the entire basal surface of the basal cell plasma membrane but was elevated in concentration adjacent .beta..sub.4 -containing hemidesmosomes. .alpha..sub.3 .beta..sub.1 localized along the basal membrane as well as the lateral and apical membranes of basal cells (FIG. 9A), consistent with the dual roles for .alpha..sub.3 .beta..sub.1, in adhesion to epithelial ligand glycoprotein complex and in cell-cell adhesion (21). In many fields, we observed .alpha..sub.3 .beta..sub.1 localization in desmosomes indicating an association of .alpha..sub.3 .beta..sub.1 and epiligrin with desmosomes. Nonspecific staining of controls (FIG. 9A) was not detectable while hemidesmosomes and desmosomes were identifiable with anti-.alpha..sub.3 .beta..sub.1 and P1E1.
The foregoing is exemplified by the representative examples that follow. Specific protocols are described in the appended Materials and Methods section.
EXAMPLES
6. Example 1
Process for Preparing HFK-ECM and HFF-ECM
Human foreskin keratinocytes (HFKs) were prepared as described by Boyce and Ham (106) and maintained by serial passage in serum-free keratinocyte growth medium (KGM; Clonetics, San Diego, Calif.) containing insulin, 10 ng/ml epidermal growth factor hydrocortisone, and 50 .mu.g/ml bovine pituitary extract.
Keratinocytes have a distinctive composition of glycoproteins which is extracted with SDS sample buffer (12) and is visualized by SDS-PAGE (12): namely, (a) cytokeratins glycoproteins No. 5 (58 kDa); No. 6 (56 kDa); No. 14/15 (50 kDa); No. 16 (48 kDa); and, No. 17 (46 kDa); (b) and the ivolucrin glycoprotein. Several or all of these keratins are visualized by protein staining, e.g., with Coomassie brilliant blue, or alternatively by Western immunoblotting (107) with monoclonal antibodies AE1 and AE3 (45). Ivolucrin is visualized at an apparent Mr of approximately 140 kDa in human keratinocytes by SDS-PAGE (107). Keratinocytes also have a distinctive ultrastructure in tissue culture visible by electron microscopy where the cellular colonies are 5 to 6 cells thick with characteristic keratin filaments, tonofilaments, and numerous desmosomes.
Human foreskin fibroblasts (HFFs) were prepared by protease/collagenase digestion (Methods in Enzymology). For preparation of HFK-ECM or HFF-ECM of HFK or HFF cells, respectively, were seeded in KGM into 7.5 cm diameter tissue culture plastic dishes, and the dishes were incubated at 37.degree. C. in a humidified atmosphere consisting of 95% air/5% CO2 preferably for 1-3 days. The HFK-ECM or HFF-ECM was prepared by a three-step extraction procedure. First, the adherent HFK and HFF cells and their membrane and cytoplasmic constituents were removed by extraction with detergent in the continuous presence of protease inhibitors and 2 mM N-ethylmalaeimide (to inhibit intramolecular cross-linking). Suitable detergents and concentrations for this first step include for example 1% (v/v) Triton X-100-tm anionic detergent (Sigma), Empigen BB-tm Zwitterionic detergent or 100 mM octyl glucoside. Suitable protease inhibitors include diisopropyl fluorophosphate (DFP; Sigma), benzamidine, polybrene, kallikrein inhibitor, or phenyl methyl sulfonyl fluoride (PMSF; Sigma), which may be used individually or in combination as necessary to inhibit cellular protease activity (as evidenced by successful preparation by the complete three-step extraction procedure of HFK-ECM capable of adhering HFF or HT1080 cells in a manner inhabitable with antibodies to the .alpha..sub.3 .beta..sub.1 integrin; see below; Example 6, "Functional Properties of Epithelial Ligand"). (These same protease inhibitors were used at the same concentrations in the solutions used in the second and third steps, below.) The second step, in the three-step extraction procedure, involves solubilizing and removing nuclear and cytoskeletal components with a solution containing 2 M urea (ammonium-free), 1 M NaCl, and protease inhibitors; and the third step involves solubilization of any residual cellular components with a solution of 8 M urea and protease inhibitors. The ECM remaining attached to the culture dish after the three-step extraction procedure of HFK culture dishes, or HFF culture dishes, is referred to as HFK-ECM or HFF-ECM, respectively.
HFK-ECM can be solubilized into 0.5% w/v SDS by scraping the culture dishes with a rubber policeman; its constituent glycoproteins consist essentially of four to five covalently linked disulfide-bonded glycoproteins with an apparent Mr>450 kDa; i.e., they do not enter an 8% SDS-PAGE (12), traverse the upper 3.5% stacking gel, and stop at the 8% gel interface; and the four to five covalently linked glycoproteins can be separated by reduction and SDS-PAGE run under reducing conditions (12) into components with apparent Mr of 200 kDa, 170 kDa, 145 kDa, 135 kDa and 36 kDa. In contrast, the matrix produced by cultured fibroblasts consists essentially of a non-covalently linked dissociable complex of type I collagen, fibronectin, and heparin-containing and chondroitin-sulfate-containing proteoglycans (108), most of which is extracted by the three-step sequential extraction procedure.
7. Example 2
Process for Preparing Antibody Binding Partners to Epiligrin as Exemplified by Rabbit Antisera and Monoclonal Antibody Specific for Epiligrin Glycoprotein Complex
Useful antigens for producing monoclonal and polyclonal antibodies include HFK cells, and also include HFK-ECM (prepared as described in Example 1), or individual glycoproteins present in HFK-ECM which are physically separable by techniques obvious to those skilled in the art including at least SDS-PAGE.
Various procedures well known in the art are useful for the production of polyclonal antibodies to antigenic epitopes in HFK-ECM. Various host animals can be immunized by injection with HFK-ECM proteins, fragments thereof, or synthetic peptides constructed to mimic the amino acid sequence in an HFK-ECM protein. Adjuvants may be used to augment the immune response and immunogenicity of small proteins, and peptides may be enhanced by coupling them to larger "carrier" molecules.
Monoclonal antibodies for therapeutic use may be human monoclonal antibodies or chimeric human-mouse (or other species) of monoclonal antibodies. Human monoclonals may be made by numerous techniques known in the art and the subject of many reviews and detailed techniques manuals, e.g., Olsson et al., Methods in Enzymology 92:3-16 (1982). Similarly, techniques are well known by which chimeric antibody molecules may be prepared containing a mouse V-region antigen binding domain with human constant regions. Molecular cloning of antibodies may also be used to construct recombinant DNA molecules which encode monoclonal antibody, and chimeric monoclonal antibodies from different species, and these methods are also well known to those skilled in the art.
HFK cells for use as an immunogen to produce mono clonal antibodies were prepared as follows. First, HFK cells were seeded in plastic tissue culture dishes. After 7 days the cells were detached from the substrata and collected by centrifugation. The cell pellet was resuspended in PBS and mixed with an equal volume of Complete Freund's Adjuvant. 0.2 ml was injected into each of 2sc and 2im sites in RBF/Dr mice. Third, the animals were boosted after 14 and 21 days.
HFK-ECM was collected from the surface of culture dishes by scraping with a rubber policeman into 0.5% SDS and dialyzing against PBS to remove the SDS. This HFK-ECM aggregated protein suspension was mixed with an equal volume of Complete Freund's Adjuvant and 100 .mu.l of the adjuvant solution was injected at each of 2sc and 2im sites in New Zealand white rabbits. The animals were boosted at 14 and 21 days.
Immune spleen cells from HFK-immunized mice were prepared and fused with NS-1 /FOX-NY murine myeloma cells using polyethylene glycol as described (59, 99, 100). (These and the following methods (below) are also useful for producing monoclonal antibodies from mice immunized with HFK-ECM and individual glycoproteins present in HFK-ECM). Viable heterokaryons were selected in RPMI 1640 supplemented with adenine/aminopterin/thymidine (AAT; 100). Heterokaryons producing antibodies (termed "hybridomas") specific for HFK-ECM and not binding to HFF-ECM were selected. The clones designated P1E1 and P1H8 were derived, as an example, by this method.
Other immunochemical methods for selecting positive hybridomas producing antibodies reacting with epithelial ligand glycoprotein complexes will be obvious to those skilled in the art, including at least selection by ELISA, RIA, and Western blotting using purified epithelial ligand antigens (Example 3, below) and/or HFK-ECM and HFF-ECM.
It will also be understood that antibodies other than monoclonal antibodies may be produced (e.g., by immunizing rabbits, goats, or other animals), and will be equally useful.
The specific immunochemical properties of monoclonal (or other) antibodies specific for epiligrin antigens are detailed below in Example 5.
8. Example 3
Process for Preparing Epiligrin
Epiligrin (epithelial ligand complex) was substantially purified by mechanically scraping HFK-ECM (prepared in Example 1) into 0.5% SDS. When subject to reduction of disulfide bonds, e.g., with DTT or 2-mercaptoethanol, the epithelial ligand complex prepared in this manner exhibited epithelial ligand glycoproteins with apparent molecular sizes of 200 kDa (E200), 170 kDa (E170), 145 kDa (E145), 135 kDa (E135), and 36 kDa (E36) when reduced and electrophoresed under reducing conditions on 8% SDS-PAGE with a 3.5% stacking gel (12).
A mixture containing predominantly a covalently-linked epithelial ligand glycoprotein complex was substantially purified from the conditioned medium of HFK cells as outlined in FIG. 3. This was accomplished in a stepwise fashion involving, first, affinity purification of MAb P1E1 from hybridoma culture medium on Protein G-sepharose using the methods recommended by the manufacturer (Pharmacia, Piscataway, N.J.). Second, the P1E1 antibody was immobilized on a matrix i.e., to form a P1E1-affinity-column) by covalently coupling purified monoclonal antibody to Affigel-10 according to the manufacturer's instructions (Bio-Rad Laboratories, Richmond, Calif.). Third, conditioned medium from confluent cultures of HFK cells was passed over a gelatin-sepharose column (Pharmacia) to remove fibronectin. Fourth, the flow-through from the gelatin-sepharose column was passed over the P1E1-affinity-column; unbound protein was removed by washing with PBS until the wash had an OD280 of less than 0.001 units; the bound epithelial ligand glycoprotein complex was eluted with 3 M KSCN, and the fractions containing the eluted protein were pooled and dialyzed overnight at 4.degree. C. against at least 10 volumes of PBS. The substantially-purified covalently-linked epithelial ligand glycoprotein complex purified in this manner (i.e., from conditioned media) comprised predominantly E170, E145, E135, and E36, although low levels of E200 and E100 were also present by SDS-PAGE.
It will be understood by those skilled in the art that MAb P1E1 is purified sing affinity chromatography on other chromatographic resins containing compositions binding murine Ig (i.e., protein A-sepharose, or anti-IgG or protein M-sepharose); or alternatively, by specific binding of MAb P1E1 to epithelial ligand complex or epithelial ligand glycoprotein covalently bound to a matrix (e.g., Affigel-10, Bio-Rad or CNBr-sepharose, Pharmacia).
It is also obvious to those skilled in the art that the relatively large molecular size of the epithelial ligand glycoprotein complex (calculated to at least greater than 450 kDa to 650 kDa, assuming equimolar amounts of each epithelial ligand glycoprotein), and insolubility of HFK-ECM glycoproteins in aqueous solutions will be used to advantage in purification schemes designed to separate these complexes from numerous smaller soluble cellular components. Purification of epithelial ligand glycoprotein complex from HFK-ECM or HFK-conditioned medium by conventional column chromatography was not possible due to the relatively poor solubility of the complex and its large molecular weight. It is also obvious that reduction and alkylation of the disulfide bonds will be useful for producing epithelial ligand glycoproteins, where intramolecular cross-linking (leading to formation of aggregates) is inhibited by 2 mM n-ethyl malaeimide and similar chemical agents. However, it was also discovered that reduction and alkylation leads to inactivation of the epiligrin adherence-promoting activity and it is apparent that preserving the secondary structure of epithelial ligand glycoproteins is important to preserving their functional activity.
The epiligrin (E170) protein was substantially purified from either HFK-ECM or the affinity-purified epithelial ligand glycoprotein complex by SDS-PAGE. It is understood by those skilled in the art that epithelial ligand for integrins is also purified by other conventional means from conditioned media of other epithelial cells under other conditions of growth.
The physical, immunochemical, and functional properties of the epithelial ligand glycoprotein complex epiligrin is detailed in Examples 4, 5, and 6, respectively, below.
9. Example 4
Physical Properties of HFK-ECM, and Epithelial Ligand Glycoprotein Complex
HFKs were seeded into 7.5 mm plastic tissue culture dishes, as described in Example 1, and incubated in KGM medium (supplemented as described in Example 1) and containing .sup.35 S-methionine or alternatively .sup.3 H-glucosamine. HFK-ECM was prepared according to Example 1, which includes sequential extraction with 1% Triton X-100, 2 M urea/1 M NaCl, and then 8 M urea, These conditions are known by those skilled in the art to frequently be sufficient to dissociate non-covalently associated proteins, and also, to be sufficient to denature other proteins. HFK-ECM is also stable to extraction with 6 M guanidine hydrochloride and 4 M sodium trichloroacetate. Thus, it may be said that the epiligrin complex is relatively stable to denaturing conditions, and relatively resistant to extraction from the plastic tissue culture substrata (although it has been observed that some low levels of epithelial ligand glycoprotein complex are extracted with 8 M urea).
.sup.35 S-methionine biosynthetically-radiolabeled HFK-ECM glycoproteins (above) and non-radiolabeled HFK-ECM glycoproteins were solubilized into 0.5% SDS (w/v) (sodium dodecyl sulfate; Bio-Rad) by mechanical scraping of the tissue culture dishes with a rubber policeman, and the glycoproteins solubilized in this manner were then subjected to SDS-PAGE essentially according to Laemmli (12) op. cit. on 8% gels under non-reducing and reducing conditions using a 3.5% stacking gel. Non-radiolabeled glycoproteins were visualized by staining with Coomassie Brilliant Blue (Bio-Rad) and the radiolabeled glycoproteins were visualized by fluorography although other methods known to those skilled in the art for detecting biosynthetically radiolabeled glycoproteins are equally useful. Under reducing conditions five glycoproteins were visualized in epiligrin complex with apparent molecular sizes in the 8% gel of 200 kDa (E200), 170 kDa (E170), 145 kDa (E145), 135 kDa (E135) and 36 kDa (E36), (FIG. 1, lanes 4 and 6, .sup.35 S-methionine biosynthetically radiolabeled); lane 9 (.sup.3 H glucosamine-radiolabeled); and lane 8 (nonradiolabeled). The five glycoproteins appeared to be present in about equal amounts in the biosynthetically radiolabeled HFK-ECM samples (FIG. 1, lanes 4 and 9). An approximate combined Mr for the non-reduced epithelial ligand glycoprotein complex was calculated to be at least 450 kDa-650 kDa (excluding any contribution of proteoglycan to the molecular weight, see below). The non-radiolabeled sample of HFK-ECM appeared to contain lesser amounts of the E200 precursor (relative to E170, E145, or E135) than that present in biosynthetically-radiolabeled samples. This may be because there are differences in the amounts of E200 in the epithelial ligand glycoprotein complexes at different stages in HFK cell growth (e.g., subconfluent vs. confluent). It is also possible that (1) recently synthesized E200 may be covalently associated with the epithelial ligand glycoprotein complex and that (2) with time, reduction of the disulfide bonds (e.g., with glutathione or disulfide-exchange) may lead to liberation of processed peptides from the complex, leaving behind a 170 kDa protein. Under nonreducing conditions the epithelial ligand complex in HFK-ECM was visualized as a high molecular weight complex which did not enter the 8% gel. (FIG. 1, lane 5).
The five glycoproteins in the epithelial ligand complex were not biosynthetically radiolabeled with .sup.35 SO.sub.4.sup.-2 (FIG. 1, lane 10) indicating that they are not sulfated proteoglycans. However, independent of the epithelial ligand complex the HFK-ECM (biosynthetically radiolabeled for 15 hours with 50 .mu.Ci/ml of .sup.35 SO.sub.4.sup.-2 in KGM containing 1 mg/ml HD-BSA as a carrier protein) contained three high-Mr sulfated proteoglycans that were associated with the HFK-ECM (FIG. 1, lane 10) and thus with the epithelial ligand complex in the HFK-ECM (FIG. 1, lane 9). The first sulfated proteoglycan did not enter the 3.5% stacking gel and the second barely entered the stacking gel but did not enter the 8% running gel.
10. Example 5
Immunochemical Properties of Epithelial Ligand Antigen, Epithelial Ligand Complex, and Monoclonal Antibody to Epiligrin
Monoclonal antibodies P1E1 and P1H8 selected (above, Example 2) for specific binding to HFK-ECM and not to HFF-ECM, e.g., P1E1, bound to .sup.35 S-methionine radiolabeled epiligrin complex in HFK-conditioned media (prepared as in Example 3, above) and the immunoprecipitate formed by adding a second antibody (i.e., rabbit or goat anti-murine IgG and IgM H and L chain sera) with carrier proteins (e.g., diluted murine sera containing murine IgG and IgM) contained E200, E170,E145,E135 and E36. (FIG. 2, lanes marked "P1E1").
P1E1 did not bind to any of the epithelial ligand glycoproteins when they had been reduced and subjected to SDS-PAGE under reducing conditions, suggesting that the P1E1 antigenic epitope may be conformational and denatured in these treatments.
The glycoproteins immunoprecipitated by P1E1 include relatively greater amounts of E170 than E135, E145, or E200. These findings indicate: a) that E170 may contain the P1E1-reactive antigenic epitope in the epiligrin complex; and b) that E170 may also exist in HFK-conditioned media as a glycoprotein independent of the epiligrin complex.
P1H8, while binding to HFK-ECM and soluble epiligrin complex in HFK-conditioned media, did not bind to the endogenous epiligrin complex in HFK cells unless the plasma membrane was permeabilized to allow entry of antibodies into the cytoplasm. P1H8 immunoprecipitated E36 from HFK-conditioned media in amounts relatively greater than E200, E170, E145 or E135 indicating: a) that E36 contains the P1H8 antigenic epitope of the epiligrin glycoprotein complex; and b) that E36 is also present in HFK-conditioned media as a glycoprotein independent of the epithelial ligand complex.
Verification that monoclonal (or polyclonal) antibody is directed to epiligrin complex is obtained by .sup.35 S-methionine or 3H-glucosamine biosynthetically-radiolabeling HFK cells, collecting the conditioned medium, and using the antibody in question to form an immunoprecipitate with the biosynthetically radiolabeled antigens in the conditioned medium. Antigens in the epiligrin complex exhibit characteristic molecular weights of 170.+-.20 kDa, 145.+-.20 kDa, 135.+-.20 kDa, 36.+-.15 kDa (with variable amounts of E200.+-.20 kDa) under reducing conditions on 8% SDS-PAGE and when run according to Laemmli (12).
Additional verification that monoclonal (or polyclonal) antibody is directed to epiligrin can be obtained by examining the pattern of staining of cells in epithelial tissues by immunoperoxidase staining with cryostat sections of tissues (prepared as described above, see "Epithelial Ligand Localization in Normal Epithelial BM") (see "Epithelial Ligand, .alpha..sub.3 .beta..sub.1, and .beta..sub.4 localization at the cell-BM Junction"). Antibodies to epiligrin stain basement membrane materials in normal skin, tonsil, and lung essentially as described (see "Epiligrin Localization in Normal Epithelial BM"; "Epiligrin Localization in Lymphoid Tissues"; "Epiligrin Localization in Lung Tissues"; above). Antibodies to epiligrin do not stain BM materials of heart muscle, mesothelium, brain, or glomerulus and tubules in kidney (see "Epiligrin Localization in Other Tissues and Organs").
When HFK cells are grown on BSA-coated surfaces the epiligrin complex is contained within characteristic "ring structures" in the ECM that are visualized by immunofluorescent staining with P1E1 (see, "Epiligrin Distribution in Motile and Non-motile HFKs"). An example of these characteristic "ring structures" formed by epithelial ligand glycoprotein complex in HFK-ECM is provided in FIGS. 4A, 4C, and 4F. Confirmation that "ring structures" produced by other cells of epithelial origin (i.e., Epith-ECM; i.e., other than HFK) contain epiligrin will be possible using monoclonal antibodies to epiligrin, such as P1E1, and as a preferred embodiment, using these anti-epiligrin antibodies in a double antibody immunofluorescence microscopic technique with antibodies binding .alpha..sub.6 .beta..sub.4 integrin (e.g., FIGS. 4B and 4D) or BPA (e.g., FIG. 4G). In the latter case, the simultaneous presence of epiligrin antigens and .alpha..sub.6 .beta..sub.4 or BPA in a "ring structure" will confirm that the ECM structure contains the epiligrin complex. Additional verification that the "ring structures" identified in this manner contain epiligrin will be obtained by extracting the epithelial-ECM sequentially with 1% Triton X-100, 2 M urea/1M NaCl, and then 8 M urea as described in Example 1, above, and in connection with FIGS. 5A-5F. The "ring structures" containing epiligrin complex will be stable under these conditions, in a manner similar to those in HFK-ECM (FIGS. 5A-5E).
11. Example 6
Functional Properties of Epiligrin Complex: Cell Adhesion Assays
Test cells which express functional .alpha..sub.3 .beta..sub.1 integrin will bind to ligand in the epiligrin complex, and if epiligrin is coated onto the surface of a normally non-adhesive substratum (epithelial ligand-coated substratum) the interaction between the epiligrin and the .alpha..sub.3 .beta..sub.1 integrin is sufficient to modulate adhesion of the test cells, in this case, by increasing their adhesion to the epiligrin-coated substratum. The adhesion of the test cells to the substratum will be optimal after 24 hours of incubation at 37.degree. C. to allow washing to remove non-adherent cells, and the relative number of adherent cells will be determined by microscopically counting the adherent test cells or by radiolabeling the test cells prior to incubation in the assay, such as with Na.sup.51 CrO.sub.4 or other suitable label known to those skilled in the art. The preferred embodiments relate to test cells which do not express the .alpha..sub.6 .beta..sub.4 receptor or epiligrin in amounts sufficient to be detected by immunofluorescence microscopy, and HFF and HT1080 fibrosarcoma cells are examples of such test cells. Polystyrene plastic petri dishes (i.e., bacteriological grade petri dishes as opposed to tissue culture plastic dishes) are examples of a non-adhesive substratum which will be useful for coating with epiligrin. The epiligrin coating on the non-adhesive substrate may be applied by any of a variety of means known to those skilled in the art (e.g., by soaking, spraying, dipping, etc.) using a concentration of protein sufficient to accomplish the desired result of test cell adhesion to the epiligrin-coated substratum. Epiligrin useful for coating the non-adhesive substratum will be, as an example, the epithelial ligand glycoprotein complex purified in Example 3, above, from HFK-conditioned medium, although other cellular sources, preparative purification methods, and substantially equivalent epithelial ligand compositions will also be useful. To verify that the adherence of the test cells to the epiligrin-coated substratum involves a specific binding interaction between .alpha..sub.3 .sym..sub.1 integrin and the epiligrin, it will be obvious to one skilled in the art that controls will be required including at least non-coated non-adhesive substrata incubated for the same period of time with the test cells. In addition, it will be useful to test the specificity of the adherence of test cells to the epiligrin-coated substratum utilizing reagents specifically binding to either the receptor (e.g., monoclonal antibodies, such as P1 B5 to the .alpha..sub.3 .beta..sub.1 integrin, or MAb to the .alpha..sub.3 or .beta..sub.1 chains; or peptide portions of the epiligrin complex which will competitively or non-competitively inhibit specific binding of the receptor), or alternatively, to the ligand (e.g., monoclonal antibodies to epiligrin which will inhibit adhesion of test cells in a specific manner or peptide portions of .alpha..sub.3 .beta..sub.1 integrin polypeptide chains which will inhibit the adhesion of test cells in a specific manner).
As an additional test for epithelial ligand complexes, the ability of such ligands to co-distribute on epithelial cells with .alpha..sub.3 .beta..sub.1, .alpha..sub.6 .beta..sub.4, or BPA antigens will be useful. Examples of these embodiments of the invention can be found above (see "Epiligrin Distribution in Motile and Non Motile HFKs" and "Epiligrin is a Ligand for .alpha..sub.3 .beta..sub.1 -FAs").
12. Example 7
Epiligrin Adherence of Lymphoid Test Cells
Human peripheral blood lymphocytes lack cellular .alpha..sub.3 .beta..sub.1 integrin but acquire this receptor when they are activated in tissue culture with Interleukin-2 and Interleukin-3 (59). Such tissue cultures contain a class of nonspecific "killer" lymphocyte commonly referred to as LAK cells (lymphokine-activated killer cells). LAK have been tested, previously by others, for their potential therapeutic anti-tumor effects in cancer patients by intravenous fusion. One observed property of LAK cells infused in this manner was a capacity to localize nonspecifically in epithelial tissues.
Activated lymphoid cells expressing a .alpha..sub.3 .beta..sub.1 receptors bind in a specific manner to epiligrin-coated non-adhesive substrata in the cell adhesion assay described in Example 6, above, or Example 11, below. The binding of activated lymphoid cells to epiligrin-coated substrata is inhibited in a specific manner by reagents specifically binding to either the .alpha..sub.3 .beta..sub.1, receptor or to epiligrin, such as that described in Example 6, above and Example 11, below. One of ordinary skill in the art is able to use the test cell assay described here with activated lymphoid cells to screen for reagents (e.g., peptides mimicking the receptor binding domain in epithelial ligand, or alternatively, integrin peptides mimicking the receptor domain which specifically inhibit binding of activated lymphoid cells to epiligrin). These reagents are also useful for specifically inhibiting the binding of activated lymphoid cells at sites of chronic and acute inflammation, for example, but not limited to, autoimmune dermatological diseases, rheumatoid arthritis, graft-versus-host disease and transplant rejection sites. Embodiments of the invention relate to activated lymphoid cells which include but are not limited to LAK cells; interleukin, cytokine, and specific antigen-activated T- and B-lymphocytes; and activated mononuclear phagocytes (e.g., but not limited to, treatment with LPS), and/or antigen-activated mast cells (e.g., but not limited to, treatment with allergens).
13. Example 8
Wound Healing Compositions
Wound strength depends on cellular and molecular factors which include granulation tissue deposition, deposition of extracellular matrix, and re-epithelialization. Re-epithelialization depends upon migration of epithelial cells from the periphery of the wound site in a migratory tongue into the wound site. This migratory process is encouraged and promoted by epiligrin complex, epiligrin component glycoproteins, and portions thereof; particularly .alpha..sub.6 .beta..sub.4 and .alpha..sub.3 .beta..sub.1 receptor binding portions of epiligrin glycoproteins. Agents which stimulate increased expression of .alpha..sub.6 .beta..sub.4 and .alpha..sub.3 .beta..sub.1 integrins on cells also promote cellular migration, which is advantageous in wound healing.
The epiligrin compositions and receptor binding portions disclosed herein promote the formation of SACs, and the proliferation of basal (stem) cells in epithelial tissues by cytokines, since they act as "second signals" to potentiate the action of cytokines. The binding of .alpha..sub.6 .beta..sub.4 and .alpha..sub.3 .beta..sub.1 receptors to the epiligrin complex serves as a nucleation site for the formation of SACs, and stimulates synthesis of epiligrin glycoproteins which ultimately results in a migratory cell becoming stationary. Thus, migratory behavior also promoted by agents which down-regulate epiligrin glycoprotein synthesis, or interfere with formation of the epiligrin complex. These agents and compositions are within the scope of the embodiments of the invention, and the methods and processes of the invention provide examples of how these agents may be identified.
The premature terminal differentiation of basal (stem) cells in wound sites slows the process of wound healing and contributes to wounds having lesser tensile strength than wounds in which terminal differentiation of epithelial cells can be slowed or completely retarded to allow proliferation of basal (stem) cells. Also, epiligrin complex provides a natural basement membrane material for basal (stem) cells and epithelial tissue explants which favors terminal differentiation of the epithelial cells into complex structures such as sweat glands and hair follicles, this process is not currently possible with existing wound healing compositions. Epiligrin is also useful for screening reagent compositions in vitro that promote wound healing and epithelial cell growth in vivo, for example, but not limited to, cytokines and growth factors, epithelial ligand peptides, and .alpha..sub.3 .beta..sub.1 receptor binding partners, such as described in Example 6, above, and in Examples 10 and 11, below.
14. Example 9
Role for Epiligrin in Polarized Asymmetric Cell Division, and Growth and Differentiation of Cells of Epithelial Origin
Asymmetric cell division of epithelial basal cells is characterized by retention of one proliferative daughter cell at the BM (the first daughter cell) and dissociation of the other differentiating daughter (second daughter cell) from the basal layer with movement into the upper layers (i.e., the Malpighian layer of the skin and spinous strata in nervous tissue) (109). In general, .alpha..sub.3 .beta..sub.1 and epiligrin are associated with proliferating basal cells (57, 110, 111), and epiligrin synthesis ceases as cells leave the basal layer. Cellular control of asymmetric cell division is manifest through cytoplasmic polarization created by asymmetrical localization of adhesion sites (e.g., SACs and FAs) on the cell plasma membrane of the basal stem cells. Such asymmetry involves cytoplasmic glycoproteins associated with SACs and FAs and their interactions with epiligrin and the .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 integrins in these structures, e.g., cytoplasmic actin and the 36.+-.15 kDa epithelial ligand associated glycoprotein. These (and other) cytoplasmic glycoprotein components of SACs and FAs bind to cytoplasmic cytoskeletal elements and create the cytoplasmic polarization sufficient to create a first daughter cell which is distinctly different in cytoplasmic organization from the second daughter cell. .alpha..sub.6 .beta..sub.4 and .alpha..sub.3 .beta..sub.1 interact with epiligrin in the proliferative first daughter at the basal surface of the cell (i.e., in association with BM). .alpha..sub.3 .beta..sub.1 relocates to proximal sites of intercellular cell-cell adhesion in the basal cell which creates an asymmetrical force upon the differentiating second daughter cell. The lack of physical binding of the second daughter cell to the basement membrane, the down-regulation of epiligrin synthesis, and increased cell-cell adhesion in the upper Malpighian or spinous layers creates a physical force to draw the differentiating second daughter away from the proliferative first daughter. Regulation of these polarized adhesion functions facilitates separation of the daughter cells and the resultant polarized/asymmetric cell division in epithelial tissues. Epiligrin functions to maintain the proliferative functions of the basal (stem) cells through dual roles in anchoring the cell to the substratum and promoting (as a second signal) the activities of cytokines. Lack of epiligrin functions to create the class of "second daughter cells" committed to differentiation. Thus, the epiligrin complex, epithelial ligand glycoproteins, and portions thereof (particularly ligand portions which interact with the .alpha..sub.3 .beta..sub.1 and the .alpha..sub.6 .beta..sub.4 integrins) are useful for promoting basal (stem) cell growth in epithelial cells and modulation of epiligrin synthesis promotes differentiation of epithelial cells such as cancer cells, cells in autoimmune disease states, and cells in psoriasis. Thus, the differentiation of these cells reverses the processes by which the cells cause disease. In addition, .alpha..sub.3 .beta..sub.1 receptor specific binding partners, such as (for example) antibody to the receptor, promotes aggregation of cells lacking epiligrin, and this also is useful for mimicking the effects of epiligrin in inducing proliferation and differentiation of epithelial cells.
15. Example 10
Use of Epiligrin to Identify the Receptor Binding Portions of the .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 Integrins
An alignment of the adjusted .alpha..sub.6 amino acid sequence (as reported by Tamura, 56) with the .alpha..sub.3 amino acid sequence as they appear in GeneBank results in 37% identity, a value greater than with any other integrin chain. Amino acid sequence of a protein that is related to the functional properties of the protein are frequently evolutionarily conserved. The present finding that epiligrin complex binds to both .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 provides for the first time a relationship between these two integrins and a functional basis for regions of conserved amino acid sequence(s). Knowing that there is a 37% sequence identity between .alpha..sub.3 and .alpha..sub.6, and that both .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 bind to epiligrin, one can select and employ conserved peptide sequence(s) to modulate binding of epiligrin to the .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 integrins as follows. "Limited sequence portions" of the (.alpha..sub.3 and .alpha..sub.6 chains, i.e., peptides which are at least 30% homologous or identical over at least 3 to 30 amino acids, are identified by direct comparison of the aligned amino acid sequences. From these template "limited sequence portions" in .alpha..sub.3 and .alpha..sub.6 chains, homologous peptides are constructed (".alpha..sub.3 or .alpha..sub.6 test peptides") which are composed of amino acid sequences that are at least 30% homologous and/or identical to the amino acid sequence in the "limited sequence portions." Such "limited sequence portions" and/or ".alpha..sub.3 and .alpha..sub.6 test peptides" are then assayed pursuant to this disclosure to determine and select "reagent peptides" which will function as inhibitors (".alpha..sub.3 and .alpha..sub.6 inhibitory test peptides"), antagonists, and agonists of the natural binding of .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 integrins to the epiligrin.
In a representative example, cellular adhesion assays such as those described in Example 6, above, are used to determine and select which of the "limited sequence portions" and ".alpha..sub.3 and .alpha..sub.6, inhibitory test peptides" inhibit cellular adhesion by at least 20% to epiligrin-coated substrata at a physiologically significant molar concentration (i.e., to determine the ".alpha..sub.3 or .alpha..sub.6 inhibitory peptides"). Test cells are allowed to adhere to epiligrin-coated substrata in tissue culture medium within 2 to 24 hours, and preferably 2 to 18 hours, and this adherence of the test cells is inhibited by at least 20% when the ".alpha..sub.3 or .alpha..sub.6 inhibitory test peptide" is added to the tissue culture medium at a physiologically significant molar concentration, i.e., of 10.sup.-5 M to 10.sup.-10 M and preferably 10.sup.-6 M to 10.sup.-10 M. A plurality of assays with a plurality of test cells and ".alpha..sub.3 or .alpha..sub.6 inhibitory test peptides" are run to identify the ".alpha..sub.3 or .alpha..sub.6 inhibitory peptide(s)" which inhibit test cell adherence in the assay by at least 20% at a physiologically significant molar concentration.
The selected inhibitors, antagonists, and agonists may be engineered to, e.g., improve their stability, half-life in blood or binding affinity for ligands. Such improvements are made either by substitution of one or more amino acid(s) in the ".alpha..sub.3 or .alpha..sub.6 inhibitor peptide" for a "natural amino acid" (the "natural amino acid" is that amino acid that is present more than 40% of the time at that particular position when the .alpha..sub.3 and .alpha..sub.6 chains from at least 5 different animal species are properly aligned). Improvements are also made by biochemical or chemical modification of the ".alpha..sub.3 or .alpha..sub.6 inhibitor peptide" to create at least one synthetic amino acid, or a plurality of synthetic amino acids, in the amino acid sequence of the ".alpha..sub.3 or .alpha..sub.6 inhibitor peptide" to produce ".alpha..sub.3 and .alpha..sub.6 inhibitor analogues." Alternatively, by conformationally modeling the ".alpha..sub.3 and .alpha..sub.6 inhibitor peptides" and their interaction with epiligrin, it is possible to construct an ".alpha..sub.3 or .alpha..sub.6 inhibitor mimetic" which mimics the ".alpha..sub.3 or .alpha..sub.6 inhibitor peptide" interaction with epiligrin by filling at least 50% of the three-dimensional fluid space occupied by the ".alpha..sub.3 or .alpha..sub.6 inhibitor peptide" in tissue culture medium at physiological pH and ionic strength when the ".alpha..sub.3 or .alpha..sub.6 inhibitor peptide" is interacting with the epiligrin complex.
16. Example 11
Use of .alpha..sub.3 and .alpha..sub.6 Inhibitor Peptides; .alpha..sub.3 and .alpha..sub.6 Inhibitor Analogues; and .alpha..sub.3 and .alpha..sub.6 Inhibitor Mimetics for Inhibiting the Binding of Lymphoid Test Cells to Epithelial Basement Membrane Compositions
Certain of the compositions described in Example 10 are useful for inhibiting the binding of activated T lymphocytes through the integrins to basement membrane compositions having at least epiligrin. Using the test cell assay disclosed in Example 7 (above), it is possible to assay a plurality of the inhibitor, antagonist, and agonist compositions disclosed in Example 10 to determine which compositions inhibit by at least 20% the adherence of lymphoid test cells at a physiologically meaningful concentration, e.g., between 10.sup.-5 M to 10.sup.-10 M (i.e., "lymphoid inhibitory compositions"). The "lymphoid inhibitory compositions" are useful for preventing and slowing the accumulation of activated lymphoid cells (as defined in Example 7) at sites of chronic or acute inflammation, for example (but not limited to) in graft vs. host disease, transplant rejection, autoimmune dermatological and rheumatic diseases, such as rheumatoid and nonrheumatoid arthritis, bullous pemphigoid, CP, and EBA.
17. Example 12
Use of Epiligrin to Identify Autoantibodies in Patient Sera
Epiligrin complex and its constituent antigens (as described in Examples 1-3 and as, for example, prepared according to Example 3) are useful for identifying autoantibody in patients with autoimmune disease, for example (but not limited to) greater than 50% of the patients with cicatrical pemphigoid and less than 20% of the patients with BP or EBA; they are useful for distinguishing CP from BP and EBA.
Immunochemical diagnostic assay formats, for example, which are useful include at least enzyme-linked immunoadsorbent assays (ELISA), radioimmunoassays (RIA), fluorescence immunoassays (FIA), Western immunoblot assays, time-resolved fluorescence assays (TRF), particle agglutination assays (e.g., latex, red cell, etc.). In these assays the bound antibody (or antigen) is separated from free antibody (or antigen) by physical means involving, for example, the use of a solid-phase adsorption of antibody (or antigen) in tubes, microtiter plates, and on polymeric membranes, dipsticks, and beads (e.g., magnetic beads or polystyrene or nylon-66-tm beads); or, alternatively, bound antibody (or antigen) is separated from free antibody (or antigen) through the use of a washing step wherein the assays are run in steps involving at least binding of antibody (or antigen), separation of bound antibody (or antigen) from the free antibody (or antigen) with washing, and assaying for the amount (or presence) of bound antibody (or antigen).
18. Example 13
Epiligrin Complex for Promoting the Growth of Epithelial Basal (Stem) Cells in Biopsy Materials: Use for Transplantation
Epiligrin-complex-coated substratum is optimal for promoting the growth of epithelial basal (stem) cells and for preventing the differentiation of this population of cells into other cell types, such as keratinocytes in the skin. For example, primary cultures of epithelial cells, e.g., from biopsy samples, are grown on epiligrin-coated substrata in KGM medium (e.g., keratinocyte growth medium, containing growth factors such as PDGF, EGF, FGF, and insulin, and serum, such as 1-10% fetal bovine serum), and the basal (stem) cells in the samples continue to exhibit mitotic activity. To confirm the mitotic activity of basal (stem) cells in these cultures, and to distinguish from the mitotic activity of other contaminating cell types (e.g., fibroblasts in skin biopsy samples) it is possible to observe the basal (stem) cells microscopically after fixing, staining, and embedding the cell layer for autoradiography, e.g., using a photographic emulsion. Basal (stem) cells cultured on epiligrin-coated substrata retain their mitotic activity for a period of time which is longer than that of biopsy samples grown on control substrata, i.e., HD-BSA; 7 to 14 days is a convenient length of time for assessing this activity (although it is also possible to visually assess the cultures on a daily basis by inverted microscopy, and those skilled in the art are readily able to determine the optimal time for determining mitotic activity in an individual experiment). The mitotic activity is microscopically visible in the autoradiograph as increased numbers of silver grains over the nucleus of the basal (stem) cells. In any cases where doubt may exist as to the nature of the cells in the mitosis assay, it is possible to combine autoradiographic analysis with the uses of immunochemical or other differentiation markers and in these cases, the basal (stem) cells lack the differentiation marker and are thus distinguished.
The ability of epiligrin-complex-coated substrata to support mitosis and growth of epithelial basal (stem) cells creates, for the first time, the opportunity to establish tissue cultures of continuously proliferating and differentiating epithelia that mimic normal biological processes and provides a superior source of epithelial cell sheets for transplantation. Such cell sheets are obtained from any epithelial tissue; for example, in the case of skin they are useful for skin transplants; in the case of epithelial cells in the bone marrow and lymphoid tissues they are useful in bone marrow transplantation methods; and, in the case of gastrointestinal ulcers, the cell sheets are useful for repopulating denuded areas of ulcerated tissues through noninvasive transplantation procedures, such as through the use of a catheter.
19. Example 14
Therapeutic Compositions
The subject epiligrin complex, and epiligrin glycoproteins and peptide compositions may be administered to a human patient or other mammalian host in need of treatment by a variety of conventional routes of administration, including orally, parenterally, intravenously, intraperitoneally, intradermally, subcutaneously or intramuscularly. Compositions may also be administered transdermally (as in a lipid-soluble vehicle for a timed-release skin patch), or by nasal or oral instillation into the lungs (as with a nebulizer). In general, these compounds will be administered at dosages between 1 and 250 mg per kg body weight of the subject to be treated per day. However, some variation in dosage will necessarily occur depending on the condition of the patient being treated, and the physician will, in any event, determine the appropriate dose for the individual patient.
Pharmaceutically acceptable salts can be readily prepared from sorbinil and sorbinil analogs by conventional methods. Thus, such salts may be prepared by treating the sorbinil or sorbinil analog with an aqueous solution of the desired pharmaceutically acceptable metallic hydroxide or other metallic base and evaporating the resulting solution to dryness, preferably under reduced pressure. Alternatively, a lower alkanoic solution of the sorbinil or sorbinil analog may be mixed with an alkoxide of the desired metal, and the solution subsequently evaporated to dryness. The pharmaceutically acceptable hydroxides, bases, and alkoxides include those with cations that form metal salts with the acidic compounds of sorbinil and its analogs and that are nontoxic at the dosages administered to a patient in need of treatment. Suitable cations for this purpose include, but are not limited to, potassium, sodium, ammonium, calcium and magnesium.
The compounds may be administered alone or in combination with pharmaceutically acceptable carriers, in either single or multiple doses. Suitable pharmaceutical carriers include inert solid diluents or fillers, sterile aqueous solutions and various nontoxic organic solvents. The pharmaceutical compositions formed by combining the sorbinil or sorbinil analog with the pharmaceutically acceptable carrier are then readily administered in a variety of dosage forms, such as tablets, powders, lozenges, syrups, injectable solutions and the like. These pharmaceutical compositions can, if desired, contain additional ingredients such as flavorings, binders, excipients, and the like. Thus, for purposes of oral administration, tablets containing various excipients such as sodium citrate, calcium carbonate, and calcium phosphate may be employed along with various disintegrants such as starch, and preferably potato or tapioca starch, alginic acid, and certain complex silicates, together with binding agents such as polyvinylpyrrolidine, sucrose, gelatin and acacia. Additionally, lubricating agents, such as magnesium stearate, sodium lauaryl sulfate, and talc are often useful for tableting purposes. Solid compositions of a similar type may also be employed as fillers in salt and hard-filled gelatin capsules; preferred materials for this purpose include lactose or milk sugar and high molecular weight polyethylene glycols. When aqueous suspensions of elixirs are desired for oral administration, the essential active ingredient therein may be combined with various sweetening or flavoring agents, colored matter or dyes, and, if desired, emulsifying or suspending agents, together with diluents such as water, ethanol, propylene glycol, glycerin, and combinations thereof. For parenteral administration, solutions of the sorbinil or sorbinil analog in sesame or peanut oil or in aqueous propylene glycol may be employed, as well as sterile aqueous solutions of the corresponding water soluble pharmaceutically acceptable metal salts previously described. Such an aqueous solution should be suitably buffered if necessary and the liquid diluent first rendered isotonic with sufficient saline or glucose. These particular aqueous solutions are especially suitable for intravenous, intramuscular, subcutaneous and intraperitoneal injection purposes. In this connection, the sterile aqueous media employed are all readily obtainable by standard techniques well known to those skilled in the art. Additionally, it is also possible to administer the aforesaid compounds topically via an appropriate solution suitable for the present purposes at hand.
The subject compounds, when formulated as described above, will typically be packaged with printed instructions specifying their use as anti-cancer or anti-inflammatory compounds, e.g., for reestablishing normal growth control in carcinoma cells, or for inhibiting adhesion of activated lymphoid cells to epithelium, respectively.
20. Materials and Methods
20.1 Cells and Cell Culture
Normal newborn human foreskin keratinocytes (HFKs) were prepared as described by Boyce and Ham (1985) and maintained in serum-free Keratinocyte Growth Medium (KGM; Clonetics, San Diego, Calif.) containing insulin, epidermal growth factor (10 ng/ml), hydrocortisone, and bovine pituitary extract. The FE-A, FEPE1L-8 and FE-H18L cell lines are HFKs that have been transfected with transforming genes E6 and E7 from human papilloma virus 16 and 18 (94; 95).
Primary cultures of human foreskin fibroblasts (HFFs) were prepared by collagenase digestion of neonatal foreskins (e.g., Methods in Enzymology). HT1080 human fibrosarcoma cells were obtained from the American Type Culture Collection (Rockville, Md.). Tera-2 cells, human embryonal carcinoma, were obtained from Dr. Bruce Fenderson (Biomembrane Institute, Seattle, Wash.). OVCAR-4 cells (human ovarian carcinoma and T-47D cells (human mammary tumor) were obtained as gifts from Dr. Arnoud Sonnenberg (Central Lab. of Netherlands Red Cross, Amsterdam Holland). Peroxidase-, fluorescein-, and rhodamine-conjugated (goat) anti-mouse and anti-rat IgG and IgM (H and L chains) or peroxidase and rhodamine-conjugated (goat) anti-rabbit IgG and IgM (H and L chains) were obtained from Tago, Inc. (Burlingame, Calif.).
20.2 Antibodies and Immunochemical Reagents
Peroxidase-, fluorescein-, and rhodamine-conjugated (goat) anti-mouse and anti-rat IgG and IgM (H and L chains) or peroxidase and rhodamine-conjugated (goat) anti-rabbit IgG and IgM (H and L chains) were obtained from Tago, Inc. (Burlingame, Calif.). Fluorescein-conjugated avidin was from Vector Labs (Burlingame, Calif.). N-hydroxysuccinimido-Biotin was from CalBiochem (La Jolla, Calif.).
MAbs to the integrins .alpha..sub.3 .beta..sub.1 (P1B5, P1F2), .alpha..sub.2 .beta..sub.1 (P1H5), .alpha..sub.5 .beta..sub.1 (P1D6), and .beta..sub.1 (P4C1O) have been described (20, 21, 57, 59, 96). P1H5 and P1D6 inhibit fibroblast, keratinocyte, and platelet adhesion to collagen-coated and fibronectin-coated substrates, respectively (21, 57, 59, 97). MAb P4C10 reacts with all .beta..sub.1 -containing integrins and inhibits cell adhesion to laminin, collagen, and fibronectin (20, 21). SP2 is a control-conditioned culture medium from the SP2 mouse melanoma. Monoclonal anti-tenascin, F9A5, was prepared in this lab (Maxwell and Carter, unpublished results). Monoclonal anti-.alpha..sub.6 (GoH3) was from Dr. Arnoud Sonnenberg (Amsterdam, Holland) and inhibits platelet adhesion to laminin via .alpha..sub.6 .beta..sub.1, (Sonnenberg et al., 1988) and carcinoma adhesion to laminin via .alpha..sub.6 .beta..sub.4 (63). Rabbit anti-laminin (R5922) and anti-fibronectin were prepared as previously described (59 and 98, respectively). Mouse MAb 3E1 against integrin b.sub.4 was a gift from Dr. Eva Engvall (La Jolla Cancer Res. Ctr., La Jolla, Calif.). Rabbit polyclonal antiserum against the carboxy terminus of the bullous pemphigoid antigen (BPA; R1086) was a gift from Dr. John R. Stanley (Dermatology Branch of the National Institutes of Health, Bethesda, Md.). Rabbit polyclonal anti-entactin was from Upstate Biotechnology, Inc. (Lake Placid, N.Y.).
20.3 Extracellular Matrix Adhesive Ligands
Mouse laminin (derived from EHS sarcoma, grown in mice) was purchased from Collaborative Research Inc. (Bedford, Mass.) or prepared in this lab. Plasma fibronectin and collagen type I were prepared as described (Wayner et al., 1988). Entactin was from Upstate Biotechnology, Inc. (Lake Placid, N.Y.). Tenascin and pepsinized human placental laminin were from Telios (San Diego, Calif.).
20.4 Cellular Adhesion to Extracellular Matrix Adhesive Ligand-Coated Substrates
For immunofluorescence and interference reflection microscopy HFK-ECM was prepared by growing HFKs (or HFF) for three days in KGM on acid-washed glass cover slips (25 mm diameter). The adherent cells were removed by a three-step sequential extraction procedure: first, with 1% v/v Triton x-100 detergent (Sigma) in 10 mM sodium phosphate, buffered, pH 7.4, 0.14 M saline (PBS); second, with 2 M urea/1 M NaCl; and, third, with 8 M urea. The HFK-ECM was digested with DNase I for 30 minutes in 1% w/v HD-BSA (Sigma)/PBS. The resulting cover slips were washed with PBS, and blocked with HD-BSA (i.e., to avoid nonspecific binding of test antibody to the glass).
To test adhesion of cells to purified extracellular matrix ligands, acid-washed glass cover slips (25 mm diameter) were derivatized with dimethyldichlorosilane (Pierce, Rockford, Ill.); then coated with purified ligands (1 to 10 "N" symbol protein/ml); and finally blocked with 1% w/v HD-BSA in PBS as previously described (20, 21). Cells were adhered to the cover slips in KGM medium for periods of 1 hour to 3 days.
21. Example 15
Complete Nucleotide Sequence Transcripts and Polypeptide Corresponding to E170 Epiligrin Glycoprotein
As disclosed above, epiligrin is a major component of epithelial basement membranes that mediates basal cell adhesion via integrin .alpha..sub.3 .beta..sub.1. In an effort to further characterize epiligrin glycoproteins, a cDNA expression library was screened using a polyclonal rabbit antibody prepared against the extracellular matrix of human foreskin keratinocytes, i.e., HFK-ECM. A lambda gt11 expression library generated from human keratinocytes was screened with an affinity purified polyclonal antibody prepared against HFK-ECM using a method previously described (124). A 600 base pair cDNA clone, referred to as Ep-1 (deposited at the American Type Culture Collection, Rockville, N. Mex. and assigned ATCC No. 75540) was isolated, plaque purified, and used for additional studies.
Ep-1 was shown by two independent immunological methods to express a polypeptide immunologically indistinguishable from the 170 kDa component of epiligrin, herein referred to as E170. First, Ep-1 cDNA was expressed as a fusion protein, and the fusion protein was shown to serve as a specific antigen in preparation of immunosorbents that affinity purified anti-epiligrin antibodies from a polyclonal anti-HFK-ECM serum. For these experiments the Ep-1 fusion protein was immobilized on nitrocellulose and then incubated with anti-HFK-ECM polyclonal antiserum. The nitrocellulose blot was washed and the bound antibody eluted using 0.1 M glycine-HCl, pH 3.0. The eluate was neutralized using 1 M Tris-HCl, pH 7.4, and dialyzed against 0.1 M phosphate buffer, pH 7.4, 0.14 M saline (PBS). Finally, the Ep-1-expressed fusion-protein-adsorbed antibodies were tested for immunoreactivity against epiligrin, in this case purified by affinity chromatography on monoclonal P1E1 (as described in the Examples above). The adsorbed EP-1 fusion protein-reactive antibodies bound specifically to E170 in epiligrin after electrophoresis in SDS-PAGE (under reducing conditions) and following blotting of the polypeptide onto nitrocellulose (i.e., in a Western blot).
Second, polyclonal immune serum was raised to the Ep-1 fusion protein and shown to react specifically in immunoblot analysis with the E170 epiligrin glycoprotein. For these experiments Ep-1 cDNA was cloned into pGEX-1N (Amrad Corporation, Australia), which expresses a portion of the glutathione S-transferase gene. The fusion protein encoded by the chimeric construct was purified using glutathione agarose beads and then SDS-PAGE. An SDS-PAGE gel band containing the purified fusion protein was used to immunize a rabbit, and the resulting anti-serum was tested for immunoreactivity to purified epiligrin by Western blot analysis against the Ep-1 fusion protein, HFK-ECM (under reducing conditions), and P1E1-purified epiligrin. Anti-GST-Ep-1 fusion protein serum bound specifically to E170 in these Western blot analyses.
The experiments depicted in FIGS. 16A-16B illustrate the experiments showing that Ep-1 fusion protein expressed in pGEX-.sup.1 N can purify antibodies that recognize the 170-kDa subunit of epiligrin. The left panel (PROTEIN) shows a Coomassie Blue stain of purified epiligrin (P1E1 Ag) under reducing (+2-ME) and nonreducing conditions (-2-ME). The subunits of epiligrin are designated E170, E150, E135, and E100, based on molecular size in kilodaltons. "A" identifies high molecular mass disulfide-bonded aggregates of epiligrin. The right panel (IMMUNOBLOT) shows that the fusion protein expressed by the clone (Ep-1) can immunopurify antibodies from anti-HFK ECM polyclonal antiserum that react specifically with the 170-kDa subunit of epiligrin (P1E1 Ag). A second band of slightly lower molecular weight is detectable and may correspond to a degradation product or a second related polypeptide. The negative control antibody (CONTROL) showed no reactivity to epiligrin. B, Ep-1 fusion protein was used to generate a rabbit polyclonal antiserum. The Ep-1 immune serum reacts specifically with the 170-kDa subunit of epiligrin on an immunoblot containing purified epiligrin (P1E1 Ag) and HFK-conditioned culture media (Cond. Media). A nonspecific band was detected by the preimmune serum in the lane containing conditioned media. It should be noted that this band does not comigrate with the second band of slightly lower molecular weight that is detected by the Ep-1 immune serum. The negative control (Pre-Immune Serum) showed no reactivity to purified epiligrin (P1E1 Ag).
Heterogeneity of transcripts hybridizing to Ep-1 probe. Northern blot analysis was conducted using RNAs from human foreskin keratinocytes, fibroblasts, and transformed keratinocytes with .sup.32 P-DNA full length Ep-1 cDNA used as the probe. The results of these experiments showed (as expected) no expression of Ep-1 mRNA in fibroblasts.
Interestingly, in HFK cells Ep-1 transcripts were present as a doublet of bands at about 5 kb and about 6 kb, indicating two mRNA species for E170, and the possibility of alternatively spliced forms of E170. To further elucidate these two forms of transcript, the cDNA probe Ep-1 was used to examine factors that affect expression of epiligrin mRNA in cultured cells (FIGS. 17A-17B). Total cellular RNA was isolated by the guanidine isothiocyanate/ultracentrifugation method (Kingston et al., 1991), run on a 1% denaturing agarose gel, and transferred to nitrocellulose (Brown, 1993). DNA was radiolabeled with .sup.32 P by random priming, hybridized overnight at 42.degree. C. in 50% formamide solution (#118, Maniatis), and washed at 54.degree. C. in 0.1.times.SSC, 0.1% SDS.
This mRNA analysis revealed two different-sized .alpha.3.sub.Ep transcripts (approximately 5 and 6 Kb in size) to be present in HFK RNA (FIG. 17A, lane 1). Lanes 2 and 3 indicate respectively that both .alpha.3.sub.Ep transcripts were present at lower levels in RNA isolated from FEP18-11 and FEP1L-8, two lines of HFK that have been immortalized with human papilloma virus (FIG. 17A) (Kaur and McDougall, 1988; Kaur et al, 1989). These papilloma virus transformed cells lines display altered adhesive capabilities (ref. to Carter et al, 1990b; Kaur and Carter, 1992) which may be due in part to the down regulation of epiligrin mRNA that has been observed by the inventors. HFF cells, which do not express epiligrin, were included in lane 4 as a control (FIG. 17A). Positive hybridization to tubulin mRNA indicates that comparable amounts of RNA were loaded in FIG. 17A, lanes 1-4.
These observations were consistent with the results of multiple sequence alignments which had indicated that there are two distinct .alpha..sub.3 transcripts that display variability within domain IIIa (see FIGS. 18A-18B; SEQ ID NOS:25 and 27). First, the cDNA clone 5-4-1 was independently isolated and shown to encode an amino-terminal domain which is different from that presented in FIGS. 19A-19R (SEQ ID NO:24). This second distinct transcript, referred to as .alpha.3.sub.EpB, maintains homology to .alpha.1 laminin throughout domain III1 and into domain IV (FIG. 18B; SEQ ID NO:27 and 28). Second, PCR was performed in order to determine if both the .alpha..sub.3 transcripts are expressed. Briefly, primer 11, which corresponds to a region of nondivergent sequence in cDNA clones 3-1-1, 5-4-1, and 5-4-2, was used to synthesize cDNA from mRNA using reverse transcriptase. Next, primers 11 and 14, as well as primers 11 and 16, were used to amplify distinct PCR products. A control RNA sample was included to ensure that the PCR products were generated from reverse-transcribed cDNA and not genomic DNA. DNA sequencing of the PCR products generated from reverse-transcribed mRNA confirmed that both the .alpha..sub.3 message forms are present in HFK mRNA. Since the cDNA clones 5-4-1, 5-4-2, and 3-1-1 contain sequences which are absolutely identical throughout the 3' end of each clone (FIG. 18C; SEQ ID NO:29 and 30), the most reasonable explanation is that they represent two different products of the same gene. Third, sequencing of genomic clones corresponding to the LamA3 gene contained sequences for both the .alpha.3.sub.EpA and the .alpha.3.sub.EpB transcripts. It should be noted that the sequence provided in FIG. 18B (SEQ ID NO:27) was deduced from sequencing of the cDNA clone 5-4-1 and does not correspond to the 5' end of the .alpha.3.sub.EpB transcript. A 5' RACE experiment was performed, and the size of the anchored PCR product revealed that the 5' end of the .alpha.3.sub.EpB transcript extends approximately 2.0 kb beyond the sequence presented in FIG. 18B (SEQ ID NO:27). Preliminary sequencing of the RACE product revealed that the .alpha.3.sub.EpB transcript maintains similarity to .alpha.1 laminin and encodes a second EGF-like region upstream of domain IV. Despite the sequence of the .alpha.3.sub.EpB transcript being incomplete, these data show clearly that the differential expression of the two .alpha.3.sub.Ep transcripts would produce variability in domain IIIa, leading to the presence of two .alpha..sub.3 epiligrin chains with different amino-terminal sequences.
The Applicants also examined the effect of differentiation in HFK cells on the level of .alpha.3.sub.Ep transcripts. FIG. 17B shows that when proliferating HFK cells are induced to differentiate by adding calcium (1.3 mM Ca++, lane 2) or by increased cell density (lane 3), .alpha.3.sub.Ep expression is concomitantly down regulated. In contrast, RNA isolated from subconfluent cultures expressed significantly higher levels of .alpha.3.sub.Ep mRNA (FIG. 17B, lane 1). Under these conditions, a third transcript was detectable that appeared to be migrating behind the 7.5 Kb molecular weight marker (lane 1). Therefore, while the 6 Kb transcript appears to be the most abundant, there are clearly additional .alpha.3.sub.Ep transcripts present in HFK RNA. As shown below, the Applicants have succeeded in isolating cDNA clones corresponding to at least two distinct .alpha.3.sub.EpA transcripts.
These findings indicate that expression of E170 epiligrin glycoprotein (as measured with antibodies to E170 and probes for E170 mRNA) is an early marker for commitment of cells to differentiate into a cells of the epithelial lineage. In normal epithelial differentiation E170 is down-regulated so that mature basal epithelial stem cells (and their progeny) express only low levels of E170 mRNA. Basal stem cells, however, retain the capacity to express E170 following wounding (as described in Example 16, below), and E170 expression is increased in the epithelial "tongue" of cells that are migrating into wound sites. Thus, E170 is a useful marker for assessing damage to, and regeneration of, epithelial tissues.
Elucidation of nucleotide sequences encoding E170. As disclosed above, the first cDNA isolated that encodes a E170 epiligrin glycoprotein (Ep-1), was obtained by expression screening with polyclonal antibody. Since the experiments described above (e.g., FIGS. 16A-16B) provided convincing evidence that Ep-1 encodes a portion of the 170 kDa subunit of epiligrin, the inventors utilized Ep-1 as a probe to identify additional cDNA clones by screening cDNA libraries. Additional overlapping cDNA clones were isolated also by using the 5' RACE system. Both of these methods are discussed below, and are schematically depicted in FIG. 10A.
Analysis of the overlapping cDNA clones revealed two distinct transcripts that share some degree of sequence and structural homology, with the .alpha.1 chain of laminin (see FIGS. 10B-10C). To maintain consistence with the laminin nomenclature proposed by Burgeson et al., the gene for epiligrin A chain has been designated as LamA3 and the two distinct transcripts as .alpha.3.sub.EpA and .alpha.3.sub.EpB.
As compared with .alpha.3.sub.EpA, .alpha.3.sub.EpB mRNA encodes a larger amino-terminal domain and contains additional EGF repeats and sequences corresponding to domain IV of .alpha.1 laminin (FIG. 18B; SEQ ID NO:27). FIGS. 18A (SEQ ID NO:26) and 18B (SEQ ID NO:28), compare the partial amino-terminal sequences of proteins encoded by the .alpha.3.sub.EpA and .alpha.3.sub.EpB cDNAs. FIG. 18C (SEQ ID NO:30) depicts the common protein domain of .alpha.3.sub.EpA and .alpha.3.sub.EpB, which is encoded by cDNA clones 3-1-1, 5-4-1, and 5-4-2 (FIG. 10F; SEQ ID NO:21). Nucleic acid sequencing of PCR products showed that HFK cells contain two distinct .alpha..sub.3 transcripts in which either sequences A and C are continuous or sequences B and C are continuous.
Sequence Encoding E170
(1) 5' RACE system (GIBCO BRL, Gathersburg, Md.). Primer MR-3 (FIGS. 12A-12B; SEQ ID NOS:1-8) was used to prepare cDNA from total cellular RNA using reverse transcriptase. The cDNA clones that were generated were then tailed with dCTP using terminal transferase. Next, PCR was performed using an anchor primer (i.e., a primer hybridizing to the polyC tail) and primer MR-4 (FIGS. 12A-12B; SEQ ID NOS: 1-8). The resulting PCR product (also referred to herein as the "race-product") was shown by sequencing and hybridization in Northern and Southern blots to overlap with the original Ep-1 cDNA clone. The steps involved in this RACE method are depicted in FIG. 14.
(2) Library screening with nucleic acid probes. Primers MR4 and MR-8 (FIGS. 12A-12B; SEQ ID NOS:1-8) were used to synthesize a 650 bp fragment that overlaps with the Ep-1 cDNA. This 650 bp fragment was then labeled with .sup.32 P and used to rescreen the cDNA library (FIG. 10A). Over 100 potential positive clones hybridized on a primary screening. Since this number of positive clones seemed too high, it was assumed that the amplified sequence was also hybridizing with a common sequence in several gene products. To impart specificity to the screening method the same filters were rescreened using .sup.32 P-radiolabeled Ep-1 as a probe. Four positive clones were identified in this screening and were isolated for further testing: cDNA clones "1-1" (about 2 kb in size), "2-3" (about 1.1 kb), "8-2" (about 1 kb), and "8-6" (about 1.6 kb). Clones 1-1 and 2-3 contain cDNA overlapping with each other and with cDNA in clone Ep-1, as well as with the 650 bp PCR product (above).
By nucleotide sequencing, Ep-1 was shown to contain 600 bp encoding a helix region of the E170 polypeptide. A cloning artifact was also identified in the first 150 bp of the clone sequence, namely, ribosomal RNA nucleotide sequence unrelated to E170. (The compiled nucleotide sequence in FIGS. 11A-11C (SEQ ID NO:22) and 15A-15F (SEQ ID NO:23) were edited to remove the unrelated rRNA sequence.)
The overlapping cDNAs used to compile the E170 nucleotide sequence (FIGS. 15A-15F; SEQ ID NO:23) are shown in FIG. 10D. Sequence analysis revealed that clone Ep-1 encodes a helix region of E170 glycoprotein; clone "1-1" an EGF-like region of E170 (FIG. 10F; SEQ ID NO:21); and, clone "8-6" encodes a potentially globular region of E170. The complete E170 nucleotide and protein sequences are shown in FIGS. 15A-15F (SEQ ID NO:23) and the composite nucleotide sequence of E170 as contained in 1-1, the Race-product (above), and EP-1 is shown in FIGS. 11A-11C (SEQ ID NO:22).
Characterization of the E170 transcript and the protein it encodes. The composite sequence provided in FIGS. 15A-15F (SEQ ID NO:23) depict the entire .alpha.3.sub.EpA transcript. The adenine residue presented as nucleotide 1 (FIG. 15A; SEQ ID NO:23) is based on sequence analysis of a 5' RACE product that showed this residue to correspond to the 5' end of the .alpha.3.sub.EpA transcript.
The open reading frame shown in FIGS. 15A-15F (SEQ ID NO:23) corresponds to the .alpha.3.sub.EpA transcript and encodes a probable signal peptide followed by domains IIIa, II/I, and G. FIGS. 15A-15F depict the nucleotide sequence and FIGS. 19A-19R (SEQ ID NO:24) the polypeptide sequence. The initiator methionine (amino acid 1) was designated as such because it is followed by a sequence that likely corresponds to the signal peptide (FIG. 19A; SEQ ID NO:24), and it is flanked by a nucleotide sequence that is consistent with the consensus sequence reported for translation initiation of vertebrate mRNAs (#137). The proposed signal peptide is followed by a short protein domain and then by a cysteine-rich domain comprised of multiple EGF repeats with similarity to those found in domain IIIa of the laminin .alpha.1 chain (ref. Sasaki et al., 1988). Domain IIIa (FIGS. 19B-19C; SEQ ID NO:24, residues 46-201) of the .alpha.3.sub.EpA translation product contains two complete EGF repeats that show conserved spacing between cysteine residues 1, 2, and 8 and between cysteine residues 5, 6, and 7. This conserved spacing is strictly maintained in the EGF repeats that have been identified in all three laminin chains (Sasaki et al., 1987, 1988; Sasaki and Yamada, 1987). The last EGF repeat of the .alpha.3.sub.EpA chain diverges from the .alpha.1 chain of laminin and is a partial repeat containing 4 cysteine residues that conform with the arrangement described by Sasaki et al., (1988). The sequence identity in domain IIIa between the human .alpha..sub.3 and .alpha..sub.1 (Nissinen et al., 1991) laminin chains was found to be 46%, whereas a comparison of the human .alpha..sub.3 and .alpha..sub.2 merosin chains (Ehrig et al., 1990; Vuolteenaho et al., 1994) revealed a slightly higher sequence identity (48%). Regions of high sequence homology across domain III were also observed upon comparison of the .alpha..sub.3 chain of epiligrin with a Drosophila .alpha. chain homologue (ref., Garrison et al., 1991). In particular, a differentially expressed region encoding the first one-half EGF repeat of domain IIIa in the .alpha.3.sub.EpB transcript (FIG. 18B; SEQ ID NO:27) showed high conservation across the Drosophila and vertebrate .alpha. chain homologues. The sequence identity between the .alpha..sub.3 and .alpha..sub.1 laminin chains is only 22% in domains I and II; however, the structural similarity is maintained.
FIGS. 19A-19R (SEQ ID NO:24) diagram several features of the translated amino acid sequence of .alpha.3.sub.EpA. The proposed signal peptide (S.P.) is identified in FIG. 19A (SEQ ID NO:24). Structural protein domains and the 3'-untranslated sequence (3' UTR) are shown in FIGS. 19B-C, 19D-H, 19I-J, 19K-L, 19M-N, 19O-P, and 19Q-R (SEQ ID NO:24). Cysteine residues are shown as "Cys". The first cysteine residue of the EGF-repeats are marked with a black triangle and the first two cysteine residues in domains I/II are marked with a black diamond. Potential glycosylation sites are boxed, and consensus sequences for adhesion recognition sites are shaded.
The .alpha..sub.3 chain of epiligrin contains a series of heptad repeats (FIGS. 19D-H; SEQ ID NO:24, residues 202-793) which are characteristic of proteins that form an .alpha.-helical coiled coil structure (ref., Cohen and Parry, 1986; Beck et al., 1990). The presence of an .alpha.-helical domain in the .alpha..sub.3 chain of epiligrin suggests that it is capable of interacting with laminin chains to form a heterodimeric coiled structure (Hunter, 1990). The two cysteine residues which are found at the beginning of domain II (residues 202 and 205) could stabilize epiligrin heterotrimers by forming intermolecular disulfide bonds as was proposed previously for EGS laminin (Sasaki et al., 1988). These cysteine residues are also present in the .beta..sub.3 chain of laminin-5 (B1k; Gerecke et al., 1994) and K2 chain (B2t; Kallunki et al., 1992) suggesting that they may be important for stabilizing the isoforms of laminin that are found in skin.
The .alpha..sub.3 chain of epiligrin contains two potential cell adhesion recognition sequences, RGD (FIG. 19G; SEQ ID NO:24, residues 658-660) and LDV (FIG. 19D; SEQ ID NO:24, residues 313-314), within the .alpha.-helical domain. These sequences were shown to mediate cell adhesion to fibronectin through integrin .alpha..sub.5 .beta..sub.1 (Wayner et al., 1989; Guan and Hunes, 1989; Komoriya et al., 1991), respectively. A sequence SKVAV (FIG. 19H; SEQ ID NO:24, residues 765-769) was also identified at the carboxyl-terminal end of the .alpha.-helical domain which is homologous in sequence and position to a regulatory sequence in the laminin .alpha.1 chain (SIKVAV) that mediated cell growth (Kubota et al., 1992) and metastases (Kanemoto et al., 1990).
Amino acids 794 through 1713 (FIG. 19I; SEQ ID NO:24), comprise the G domain of the .alpha.3.sub.EpA transcript. In EHS sarcoma laminin, the G domain has been shown to have an internal repeating structure composed of five tandem repeats with approximately 180 amino acids per repeat (Sasaki et al., 1988). Data compiled from a multiple sequence alignment (Schuler et al., 1991) indicated that the .alpha..sub.3 chain of epiligrin contains five subdomains which are individually related to the Drosophila and vertebrate .alpha. chains. A Dotplot analysis (Maizel and Lenk, 1981; Wilbur, 1983) comparing the .alpha..sub.3 chain to itself and to other a chains revealed that the .alpha..sub.3 subdomains (G1-G5) are more closely related across different .alpha. chains than they are to one another. This is consistent with a report by Garrison (1991) which compared the sequence of the G domain form Drosophila with other laminin .alpha. chains. A BLAST protein search (Altschul et al., 1990) revealed that the G4 and G5 subdomains of epiligrin are also related to the heparin sulfate proteoglycan core protein (Noonan et al., 1991) and the neurexin family of proteins (Ushkaryov et al., 1992).
Although multiple sequence alignments (Schuler et al., 1991; Altschul et al., 1990) identified five G subdomains in .alpha..sub.3 epiligrin (FIGS. 19I-R; SEQ ID NO:24, subdomains G1-G5) that are related to G subdomains described by Sasaki et al. (1988), there is evidence of increased sequence divergence in the .alpha..sub.3 chain. A comparison of the .alpha..sub.3 G domain to either the .alpha.1 (Nissenen et al., 1991) or .alpha.2 (merosin; Ehrig et al., 1990) G domains revealed less than 25% identity. In contrast, when the .alpha.1 and .alpha.2 chains are compared with one another, they share 41.8% sequence identity across the G domain (Vuolteenaho et al., 1994). This suggests that the .alpha..sub.3 chain of epiligrin may represent a new category of functionally distinct .alpha. chain homologues.
The structure of E170 glycoprotein deduced from the nucleotide sequence of FIGS. 15A-15F (SEQ ID NO:23) have overall similarity to the structure found in laminin A chain, but (as shown in the Examples, above) antibodies to laminin fail to bind to epiligrin, P1E1 fails to bind to laminin, polyclonal antibodies raised to epiligrin fail to bind to laminin, and .sup.32 P-radiolabeled full length Ep-1 used as probe in Northern blots fails to detect any species of mRNA other than 5 kb and 6 kb transcripts that are appropriate in size for E170 glycoprotein.
As disclosed in the Examples, E170 polypeptide, antibodies to E170, and E170 mRNA are markers useful in identifying abnormal patterns of epiligrin expression and thus monitoring basal cell differentiation in the epithelium. For instance, epiligrin is not expressed in basal cell carcinoma and skin diseases such as junctional epidermolysis bullosa gravis (as disclosed in the Examples, above; and also independently confirmed, 114).
Moreover, the amino acid sequences shown in FIGS. 19A-R (SEQ ID NO:24) provide one skilled in the art with the information needed to create synthetic polypeptides whose properties resemble those of epiligrin E170. Synthetic polypeptides of the invention comprise at least 5 amino acids, corresponding to at least 15 consecutive nucleic acids from the sequence of FIGS. 15A-15F (SEQ ID NO:23). Methods are well known to those skilled in the art for synthesizing polypeptides having a predetermined amino acid sequence.
Epiligrin expression in healing wounds. To further examine changes in the patterns of expression of epiligrin in regenerating tissues, expression of Ep-1 mRNA was investigated in wound sites using in situ hybridization and immunochemical staining. For the in situ work, Ep-1 (600 bp) was cloned in both orientations into a Bluescript expression vector (Stratagene, La Jolla, Calif.) so that sense and anti-sense cRNA probes could be synthesized using the T7 promoter. cRNA probes were labeled with digoxigenin-11-UTP (Boehringer Mannheim Biochemicals, St. Louis, Mo.) and then cleaved by alkaline hydrolysis to an average size of 100-150 nucleotides. Probes were incubated with tissue slides containing formaldehyde-fixed cryostat sections of punch biopsies from wounded epidermis (including adjacent non-wounded epidermis), and processed for immunohistochemical staining. Bound probes were visualized using affinity purified anti-digoxigenin antibody coupled to alkaline phosphatase and a colorimetric assay was used to localize bound probe within the tissue. (Ep-1 sense probes were used as a control and they showed no signal above background on the indicated tissues.)
The highest observed steady state of .alpha.3.sub.Ep mRNA observed by the inventors has been in subconfluent keratinocytes that are still actively migrating. Taking this observation one step further, the inventors used the above-described methods to examine the expression of this mRNA in human skin harvested 55 h after the introduction of a wound. The wounding of skin results in the transition of keratinocytes from a sedentary to a migratory state (Grinnell, 1992). As shown in FIG. 20A, the antisense cRNA probe localized .alpha.3.sub.Ep mRNA to keratinocytes in the wound site, but not to keratinocytes flanking the wound site (FIG. 20B). The sense probe (FIGS. 20C-20D) was negative as expected. An antisense probe for keratin 14 (FIGS. 20E-20F) showed that keratin 14 mRNA is detectable in the basal cells of both wounded and normal epidermis. FIGS. 20E and 20H illustrate the localization of epiligrin and integrin .alpha..sub.3 .beta..sub.1 in the wound site. Immunoperoxidase staining using anti-epiligrin (MAb P1E1, FIG. 20G) and anti-.alpha..sub.3 antibodies (MAb P1F2, FIG. 20H) shows that epiligrin protein is present in the newly synthesized basement membrane (BM) (FIG. 20E, arrows), and integrin .alpha..sub.3 .beta..sub.1 relocalizes from the apical and lateral surfaces to the basal surface (FIG. 20H, arrows). The epidermis and dermis are marked as E and D, respectively.
The localization of the .alpha.3.sub.Ep transcript in the wound site is correlated with the reorganization of integrin .alpha..sub.3 .beta..sub.1 from the apical and lateral to the basal surface of the keratinocytes (FIG. 20H) in contact with the newly synthesized epiligrin present in the basement membrane (FIG. 20G). The reorganization of integrin .alpha..sub.3 .beta..sub.1 suggests that keratinocytes may utilize integrin .alpha..sub.3 .beta..sub.1 in cell/substrate adhesion mediated by epiligrin for motility during wound repair. Thus, expression of E170 epithelial ligand glycoprotein in epidermal tissues distinguishes between regenerating epithelial tissues (where expression is high) and non-regenerative epithelial tissues or malignant tissues (where expression is low). Many situations exist in histopathological examination where it would be most helpful to be able to distinguish between a normal regenerative event in an epithelial tissue (e.g., resulting from traumatic injury or infection) and an abnormality that might be a neoplastic or preneoplastic event. Examining E170 epiligrin glycoprotein expression (e.g., using immunochemical techniques or in situ hybridization) provides a way in which normal regenerative events can be distinguished from premalignant and malignant events.
22. Materials and Methods for Example 15
22.1 DNA Sequencing. cDNA inserts were amplified using Taq Polymerase (Perkin-Elmer Cetus), purified on an agarose gel, and directly sequenced using either the Taq DyeDeoxy.TM. Terminator Cycle Sequencing Kit (Applied Biosystems, Inc., Foster City, Calif.) or a modified version of Sanger et al. (120) with Sequenase (USB, Cleveland, Ohio). Deduced amino acid sequence was compared to the available data bases through searches with both Blast/ncbi.nlm.nih.gov. and Blitz/EMBL-heidelberg.de using the homology matrix described by Henikoff and Henikoff (115).
22.2 Northern Blot Analysis. Human foreskin keratinocytes, fibroblasts, and transformed keratinocytes were prepared as previously described (113; 166-117). Total cellular RNA from each of these cell types was isolated by the guanidine isothyocyanate method, run on a 1% denaturing agarose gel, and transferred to nitrocellulose (118). Ep-1 cDNA (0.6 kb) was radiolabeled with .sup.32 P by random priming, hybridized overnight at 42.degree. C. in 50% formamide solution (118), and washed at 54.degree. C. in 0.1.times.SSC/0.1% SDS.
22.3 In situ Hybridization. Ep-1 (600 bp) was cloned in both orientations into a Bluescript expression vector (Stratagene, La Jolla, Calif.) so that sense and antisense cRNA probes could be synthesized using the T7 promoter. cRNA probes were synthesized using T7 RNA polymerase and labeled with digoxigenin-1 1-UTP (Boehringer Mannheim Biochemicals, St. Louis, Mo.). Full length probes were then cleaved by alkaline hydrolysis to an average size of 100-150 nucleotides. Probes were incubated with slides containing formaldehyde-fixed cryostat sections overnight at 50.degree. C. in hybridization buffer (50% formamide/5.times.SSC/1 mg/ml yeast tRNA/100 .mu.g/ml heparin/1.times. Denhardts/0.1% Tween 20/0.1% CHAPS). Slides were treated for 30 minutes at 37.degree. C. with 20 .mu.g/ml of RNase A, washed twice at room temperature with 2.times. SSC for 30 minutes, and washed twice at 50C in 0.1.times. SSC for 30 minutes. Next, slides were equilibrated in PBS and processed for immunohistochemical staining. An affinity purified anti-digoxigenin antibody coupled to alkaline phosphatase (Boehringer Mannheim Biochemicals) followed by a colorimetric assay was used to localize bound probe within the tissue.
22.4 Tissue Preparation. Punch biopsies of wounded epidermis, including adjacent non-wounded epidermis, was taken from a human volunteer at several different time points (22, 55, and 79 hours) and then embedded directly in OCT. Cryostat sections (12 .mu.m) were placed on aminoalkylsilane-treated slides, fixed in 4% paraformaldehyde, treated with 0.25% acetic anhydride in 0.1 M triethanolamine, rinsed in 2.times. SSC, and then dehydrated through a series of alcohol solutions (30%, 50%, 70%, 95%, 100%).
23. Example 16
Regulation of Epiligrin Expression: Effects of Cell Density, Wounding, Oncogenic Transformation and Growth Factors
Epidermal wound healing is characterized by migration of the regenerating epithelium in a migratory tongue across a bed of newly formed granulation tissue. Using immunochemical techniques and several different monoclonal antibodies directed to epiligrin, it has been observed that epiligrin is deposited in the basement membrane at the leading edge of the migratory tongue of epithelium 24, 48, and 72 hours after wounding in normal human volunteers. In these wound sites epiligrin and .alpha..sub.3 .beta..sub.1 were localized to the basal surface of the cells in the migrating epithelial tongue. In situ hybridization with antisense cRNA probes specific for E170 identified elevated E170 mRNA levels in the epithelial cells in the wound site (see, e.g., FIG. 20A). These data suggest that .alpha..sub.3 .beta..sub.1 and epiligrin are involved in wound repair, perhaps in relation to deposition and assembly of epiligrin in the basement membrane upon which the epithelial cells must migrate. Further, when the migrating epithelial tongue reestablished contact with the surrounding epidermis, the level of epiligrin expression observed immunocytochemically was decreased. Thus, epiligrin expression may serve to limit migration of the epithelial tongue and prevent keloid formation in the epidermis. In contrast to the findings with epiligrin, laminin and .alpha..sub.6 .beta..sub.4 were reduced in the cells at the leading edge of the migratory epidermal tongue, consistent with a possible role of laminin in forming stable (i.e., non-migratory) hemidesmosome structures for non-migrating cells.
Cell-cell contact down-regulates expression of certain cellular proteins in normal cells, but not tumor cells, and is commonly studied by establishing cell cultures at different cell densities. A comparison was made of E170 expression in HFK cells grown at low and high cell density (i.e., confluence) using Northern blot analysis to examine the levels of expression (FIG. 17B). E170 expression was dramatically increased in cells grown at low density, and expression was decreased in confluent cells. Further, detachment of HFK cells from the substratum in vitro caused a decrease in the level of epiligrin expression observed immunohistochemically. Oncogenic transformation of HFK cells, i.e., using retroviral vectors encoding HPV E6 and E7, resulted in decreased expression of E170 (FIG. 17A). Considering these findings in the light of epiligrin expression during wound healing (above) and disease, it seems likely that lowering cell density at an epithelial site (i.e., by wounding) may induce increased epiligrin expression, and detachment of the epidermis from dermis (e.g., in blistering diseases) may inhibit expression of epiligrin. In the latter case, decreasing cell density and restoring epithelial cell contact with a material containing epiligrin may prove useful for therapeutic intervention in epithelial dysjunction diseases such as acquired and genetic epidermal disorders, ulcerative colitis, Crohns disease, and cholera. It should also be noted that decreased expression of epiligrin in transformed cells contrasts markedly with the observed expression in wound sites, and that pathological metastasis of malignant cells into tissue sites may be distinguished from normal regeneration by examining the level of epiligrin expression in the cells (e.g., using in situ hybridization or immunocytochemical methods). In the latter case normal regenerating cells have high levels of epiligrin expression and tumor cells have low levels.
The combined results (above) suggest that interaction of epiligrin with the .alpha..sub.3 .beta..sub.1 receptor regulates migration and growth of epithelial cells. Additional experiments were conducted in which the receptor-ligand interaction was disrupted and the effects were observed. Incubation of keratinocytes in vitro with anti-.alpha..sub.3 .beta..sub.1 was observed to inhibit cell adhesion to epiligrin, stop migration of the cells on the tissue culture surface, and induce cell-cell adhesion that resulted in rounded balls of aggregated cells. The differentiative state of the cells in the keratinocyte aggregates was examined using immunohistochemical identification of involucrin, a marker for epithelial cell differentiation. Keratinocytes in the cellular aggregates exhibited increased involucrin expression, and a subcellular morphology consistent with differentiation. Thus, the results are consistent with the notion that inhibition of epiligrin binding to .alpha..sub.3 .beta..sub.1 induces terminal differentiation in keratinocytes. The observed effects of epiligrin are contrasted with those of fibronectin, which interacts with .alpha..sub.5 .beta..sub.1 receptors in cells to induce decreased (rather than increased) expression of involucrin. Because fibronectin is expressed in wounded epidermis, and not in normal regenerating epidermis, it is most likely that .alpha..sub.5 .beta..sub.1 -fibronectin interactions inhibit differentiation during wound repair, while the .alpha..sub.3 .beta..sub.1 -epiligrin interaction plays a role in normal epithelial regeneration by preventing basal stem cells from differentiating (i.e., while in contact with epithelial ligand) and by stimulating terminal differentiation in progeny cells (i.e., when released from contact with epiligrin).
The role of the .alpha..sub.3 .beta..sub.1 -epiligrin interaction in regenerating epidermis was studied further by testing the effects of dermal growth factors, i.e., TGF.alpha. and TGF.beta., on expression of epiligrin in vitro as measured by Northern blotting for E170 mRNA. For these experiments, HFK cells were established in cell culture and grown to approximately 75% confluency so that expression was down-regulated and the cells assumed a resting state. Next, to determine whether dermal growth factors could induce expression of epiligrin, 30 ng/ml of TGF.alpha., or 20 ng/ml of TGF.beta., were added to separate cultures and the cells were cultured for an additional 24 hrs. A control culture was included in which the medium was changed but no growth factors were added. Finally, epithelial ligand expression was measured by Northern blotting for E170 mRNA. The results obtained showed about a 2-fold increase in epiligrin expression with either TGF.alpha. or TGF.beta. over the level of expression seen in the control culture.
24. Example 17
Chromosomal Localization of the Human LamA3 Gene
Fluorescent in situ hybridization was performed using the P1 genomic clone DMPC-HFF#1-1034F10 which contained coding sequences for the human LamA3 gene. The results, shown in FIG. 21, localized the human LamA3 gene to chromosome 18q11.2. The human laminin .alpha..sub.1 chain (LamA1) was also found on chromosome 18 but mapped to 18p11.3 (Nagayoshi et al., 1989), a locus distinct from that of LamA3.
The probe for the chromosomal localization was prepared by nick-translation with biotin label and was hybridized to normal human metaphase cells as described previously (VanDevanter and Yirdaw, 1993). Hybridized probe was detected with Texas red avidin and chromosomes were identified by fluorescence R-banding with chromomycin A3/distamycin A (VanDevanter et al., 1994). Texas red and chromomycin A3 signals were excited independently using a Nikon Optiphot-2 epifluorescence microscope and captured as 8-bit black and white digital TIFF images using an intensified CCD camera and a SAMBA 4000 image analysis system (Imaging Products International, Chantilly, Va.). Chromomycin A3 intensities were linearly reduced to generate gray countersignals, digitally added to Texas red signals collected from the same fields, and printed as black and white images on a Phaser IISDX dye sublimation printer (Techtronix, Beaverton, Oreg.).
25. Example 18
Novel Assay for Epiligrin Function
25.1 Trypsin-treated HFK-ECM: "Epiligrin-ECM"
As described above, differential extraction with Triton X-100 and urea may be used to prepare a tissue culture surface coated with substantially purified epiligrin complex. The yield of epiligrin coated matrices is relatively low, and so studies were conducted to determine whether detaching HFK from ECM with trypsin (i.e., as cells were passaged) left an epiligrin that might be suitable for use in adhesion assays. To distinguish epiligrin made in this manner from those of previous methods the preparations are referred to herein as "epiligrin-ECM" was an adhesive substrate in adhesion assay, and surprisingly, the substrate adhered cells more rapidly (i.e., more than >90% of HFK were attached in less than 5 minutes) and tightly (i.e., not easily removed with strong shaking) than epiligrin substrates.
As a first step, the relative role of epiligrin in the attachment was investigated using anti-epiligrin monoclonal antibody and .alpha..sub.3 -transfected K562 cells (.alpha..sub.3 -K562). Weitzman et al. (1993) reported that expression of .alpha..sub.3 integrin in K562 was sufficient for adhesion to HFK-ECM differentially extracted to prepare an epiligrin-coated substratum. These findings were confirmed and extended in the present studies. When .sup.51 Cr-labeled .alpha..sub.3 -K562 were incubated with different ECM ligands, the cell preferentially attached and spread on the epiligrin-ECM.sup.t. EHS laminin, collagen type I (COL; .alpha..sub.2 .beta..sub.1 -mediated) and BSA failed to support adhesion of .alpha..sub.3 -K562. A partially purified laminin preparation from human placental basement membranes also failed to induce adhesion. Adhesion of .alpha..sub.3 -K562 to epiligrin-ECM.sup.t was inhibited with anti-.alpha..sub.3 .beta..sub.1 (P1H8) and anti-.beta..sub.1 (P4C10) monoclonal antibodies, confirming the involvement of both the transfected .alpha..sub.3 and the .beta..sub.1 subunits in attachment (i.e., the .alpha..sub.5 and .beta..sub.1 subunits are biosynthetic products of K562 cells, and adhesion of .alpha..sub.3 -K562 cells to fibronectin was inhibited by anti-.alpha..sub.5 confirming the existence of the .alpha..sub.5 .beta..sub.1 receptor). Anti-.alpha..sub.5 had no effect on adhesion to epiligrin-ECM.sup.t.
As a second step, the adhesion of HFK to epiligrin-ECM.sup.t was tested. While the results with .alpha..sub.3 -K562 (above) followed a relatively predictable pattern, a surprising observation was made with HFKs. Adhesion of HFKs to epiligrin-ECM.sup.t was not inhibited with anti-.alpha..sub.3 or anti-.beta..sub.1, (i.e., suggesting the involvement of a receptor other than .alpha..sub.3 .beta..sub.1) but, spreading of HFK on epiligrin-ECM.sup.t was inhibited with both anti-.alpha..sub.3 and anti-.beta..sub.1. These combined results suggested that .alpha..sub.3 .beta..sub.1 mediated spreading of HFK but some other receptor mediated attachment.
25.2 Dual Roles of .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 in Attachment and Spreading of HFK
As described above, adhesion of human foreskin keratinocytes (HFK) to epiligrin is mediated through .alpha..sub.3 .beta..sub.1 in focal adhesions and .alpha..sub.6 .beta..sub.4 in hemidesmosomes. Studies were conducted in which the relative roles of .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 were determined i) by investigating epiligrin-ECM.sup.t adhesion of .alpha..sub.3 -transfected K562, human fibroblasts, and HT1080 cells, (all of which have only the .alpha..sub.3 .beta..sub.1 receptor) and comparing the results with those obtained with HFK (having both the .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 receptors); and, ii) by evaluating .alpha..sub.6 .beta..sub.4 mechanisms at 4.degree. C., (i.e., a condition that inhibits .alpha..sub.3 .beta..sub.1 -dependent cell adhesion). The results obtained in these experiments are summarized below.
For .alpha..sub.3 .beta..sub.1 mediated adhesion, attachment and motility of .alpha..sub.3 -transfected K562, human fibroblasts, and HT1080 cells were blocked by monoclonal antibodies to .alpha..sub.3 .beta..sub.1, and epiligrin, or by culture at 4.degree. C.; in the latter case, 4.degree. C. inhibits energy metabolism required for actin rearrangement in the cytoskeleton and test cells that express .alpha..sub.3 .beta..sub.1, but not .alpha..sub.6 .beta..sub.4 (e.g., HFF, HFM, and HT1080), adhere to epiligrin-ECM.sup.t and collagen at 37.degree. C. but not to any ligand at 4.degree. C. Adhesion to epiligrin via .alpha..sub.3 .beta..sub.1 induced transmembrane signaling through tyrosine-phosphorylation of a focal adhesion kinase (FAK; 125 kDa).
For .alpha..sub.6 .beta..sub.4 mediated adhesion, the attachment of HFK occurred without spreading at 4.degree. C., did not require energy metabolism and actin cytoskeletal rearrangement, and was inhibited by anti-.alpha..sub.6 alone. Thus, .alpha..sub.6 .beta..sub.4 was capable of mediating attachment of HFK independent of .alpha..sub.3 .beta..sub.1. Hemidesmosome adhesion structures assembled on epiligrin at 4.degree. C. contained .alpha..sub.6, .beta..sub.4 and bullous pemphigoid antigen I (BPA1) as a Triton X-100-insoluble complex. .alpha..sub.6 .beta..sub.4 mediated adhesion of HFK to epiligrin was distinguished from that mediated by .beta..sub.1 integrins in the following manner: (1) it was more rapid; (2) it occurred at 4.degree. C.; (3) it did not result in cell spreading; (4) it did not induce phosphorylation of FAK; (5) it did not induce formation of Triton X-100 detergent-insoluble adhesion structures (i.e., the type involved when both .alpha..sub.3 .beta..sub.1, and .alpha..sub.6 .beta..sub.4 mediate adhesion, below). At 4.degree. C. HFK failed to adhere to fibronectin and EHS laminin, indicating that under these conditions the assay is specific for .alpha..sub.6 .beta..sub.4 receptors, and that the .alpha..sub.6 .beta..sub.4 receptors form stable adhesion contact only with epiligrin at 4.degree. C.
For .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 mediated adhesion, HFK attachment and motility at 37.degree. C. required both .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 ; monoclonal antibodies to .alpha..sub.3 blocked spreading but not attachment; and, anti-.alpha..sub.6 blocked neither spreading nor attachment, but the combination of anti-.alpha..sub.3 and anti-.alpha..sub.6 successfully blocked both spreading and attachment. In addition, both .alpha..sub.3 .beta..sub.1 and .alpha..sub.6 .beta..sub.4 appeared to mediate their effects through epiligrin, since anti-epiligrin monoclonal antibodies blocked adhesion through both receptors.
Thus, epithelial cells, in contrast to many other cells that express only .alpha..sub.3 .beta..sub.1 receptors, control motility on epiligrin (i.e., through .alpha..sub.3 .beta..sub.1 and transmembrane signaling) and stable anchorage on epiligrin (i.e., through .alpha..sub.6 .beta..sub.4) by differential expression of these two integrin receptors in hemidesmosomes.
The foregoing may be better understood in connection with FIGS. 22A-22B. As shown in FIG. 22A, suspended cells (1) that express .alpha..sub.3 .beta..sub.1 (including .alpha..sub.3 -K562 cells, melanocytes, HT1080 cells, and fibroblasts) attach and spread on epiligrin via .alpha..sub.3 .beta..sub.1 at 37.degree. C. (3), but not at 4.degree. C. (2) or in the presence of anti-.alpha..sub.3 or anti-epiligrin. Attachment and spreading involves formation of FAs and phosphorylation of FAK (FAK.fwdarw.P-FAK). As shown in FIG. 22B, suspended cells (1) that express .alpha..sub.3 .beta..sub.1, and .alpha..sub.6 .beta..sub.4 (including HFKs) utilize .alpha..sub.3 .beta..sub.1 for motility (attachment, spreading and migration) at 37.degree. C. (3) and .alpha..sub.6 .beta..sub.4 for stable anchorage without spreading at 4.degree. C. (2) and 37.degree. C. (3). Adhesion at either temperature is blocked with anti-epiligrin monoclonal antibodies. HFKs anchored at 4.degree. C. via .alpha..sub.6 .beta..sub.4 (2) will spread via .alpha..sub.3 .beta..sub.1 when warmed to 37.degree. C. (3). This spreading is blocked with anti-.alpha..sub.3 .beta..sub.1. Anchorage via .alpha..sub.6 .beta..sub.4 at 4.degree. C. does not require phosphorylation of FAK while spreading via .alpha..sub.3 .beta..sub.1 induces tyrosine phosphorylation of FAK (3).
25.3 The .alpha..sub.6 .beta..sub.4 Receptor Participates in Adhesion and HDs in Migratory HFK at 37.degree. C.
The effects of anti-.alpha..sub.6 on the distribution of the .alpha..sub.6, .beta..sub.4, BPA1, epiligrin, Talin protein components of HDs and FAs was examined using immunohistochemical techniques and interference reflection microscopy to identify co-localization of the proteins in FAs and HDs. Anti-.alpha..sub.6 -treated cells continued to adhere and spread, but failed to form colonies and acquired an elongate morphology indicative of migratory cells. Anti-.alpha..sub.6 did not disrupt localization of .alpha..sub.3 or Talin in FAs, but did disrupt the co-localization of .alpha..sub.6, .beta..sub.4, and BPA1 (a cytoplasmic component of HDs) in FAs. These results confirm that at 37.degree. C. .alpha..sub.6 associates with .beta..sub.4 and BPA1 in immature HDs and contributes to adhesion of HFKs on epiligrin-ECM.sup.t.
25.4 Domain-Specific Anti-Epiligrin Antibodies
It was considered highly likely that the epiligrin ligand protein amino acid sequence domain involved in integrin .alpha..sub.3 .beta..sub.1 receptor binding to epiligrin-ECM.sup.t were different than those involved in .alpha..sub.3 .beta..sub.1 or .alpha..sub.6 .beta..sub.4 binding to non-trypsin-treated epiligrin. To identify the additional functional domain in epiligrin, monoclonal antibodies were selected that inhibited binding of cells to epiligrin-ECM.sup.t. For these experiments HFK were grown on cellophane sheets, and the HFK-ECM deposited on the sheets by the cells was used as an antigen for immunization of BALB/c mice. Hybridoma clones were selected based on immunoreactivity in a solid phase ELISA with epiligrin (i.e., solid phase antigen). Three monoclonal antibodies from the resulting library of clones were selected for additional testing for their ability to immunoprecipitate .sup.35 S-methionine biosynthetically-radiolabeled HFK-ECM proteins (i.e., in the presence of Staphlococcal Protein A). Anti-epiligrin monoclonal antibody P1E1 was used as a control. Immunoprecipitated proteins were evaluated on SDS-PAGE under reducing (i.e., using 2-mercaptoethanol) or non-reducing conditions. The results showed that monoclonal antibodies P1E1, C2-9, G3-3, and B4-6 specifically immunoprecipitate a disulfide-bonded high molecular mass complex from HFK-ECM (non-reduced) that contained only E170, E135, and E100/145 (i.e., following reduction). Monoclonal antibodies C2-9, G3-3, and B4-6 were not reactive with human or mouse laminin, tenascin, thrombospondin, collagen types I, IV or VII, fibronectin, human placental basement membrane proteins, or BSA.
Next, monoclonal antibodies capable of inhibiting adhesion and spreading of HFK on epiligrin-ECM.sup.t were identified using .sup.51 Cr-radiolabeled test cells, and the assays described in the Examples above in regard to P1E1. Adhesion of .alpha..sub.3 -transfected K562 cells to epiligrin-ECM.sup.t (i.e., via the .alpha..sub.3 .beta..sub.1 receptor) was inhibited to about 43% (of the control level of cpm bound) by monoclonal antibody C2-9, but not by D3-4, B4-6, G3-3 or P1E1. Control experiments demonstrated that C2-9 had no inhibitory effect on binding of the .alpha..sub.3 -K562 to collagen (i.e., through the .alpha..sub.5 .beta..sub.1 receptor). Thus, monoclonal antibody C2-9 identifies an amino acid sequence domain present in epiligrin-ECM.sup.t, and epiligrin, that is a functional requisite for binding by at least .alpha..sub.3 .beta..sub.1 integrin receptors.
25.5 Kinetics of Binding of Epiligrin at 4.degree. C. and 37.degree. C.
Kinetic binding assays were conducted wherein the binding of .alpha..sub.6 .beta..sub.4 -receptor bearing test cells (i.e., HFK) to epiligrin-ECM.sup.t was evaluated at 4.degree. C. and 37.degree. C. The rate of adherence of HFK test cells, or HFF control cells, to epiligrin-ECM.sup.t was determined using .sup.51 Cr-radiolabeled HFK and the test cell assays described above. The results are presented in TABLE 3, below.
TABLE 3______________________________________ 4.degree. C. Assay 37.degree. C. Assay (% Adherent (% AdherentTime Cells) Cells)(minutes) HFF HFK HFF HFK______________________________________ 0 1-2 30 0 0 2 1-2 28 4 10 5 1-2 28 6 1010 1-2 25 8 2015 1-2 37 18 2625 1-2 35 29 3630 1-2 31 30 3845 1-2 30 38 5060 1-2 35 57 60______________________________________
Adherence of HFK test cells to epiligrin-ECM.sup.t was rapid, occurring to maximal values within 2 minutes, and adherence was specific for .alpha..sub.6 .beta..sub.4 -receptor bearing test cells, i.e., .alpha..sub.6 .beta..sub.4 -receptor-negative HFF control cells did not adhere under these conditions. Similar results were obtained with HT1080 control cells.
25.6 Composition of ECM Assembled by HFK at 4.degree. C. and 37.degree. C.
Previous studies indicated that detergent extraction (i.e., Triton X-100, as above) solubilizes .alpha..sub.3 .beta..sub.1, but not .alpha..sub.6, .beta..sub.4 or BPA1 that are associated with SACs formed at 37.degree. C. Since HFKs attached but did not spread at 4.degree. C., a question arose as to the composition of the ECM under these conditions. HFK were allowed to adhere overnight at 4.degree. C. to epiligrin-ECM.sup.t. The next day the cells were removed with Triton X-100 and fluorescence microscopy was used to examine the detergent-insoluble cellular skeletons left by cells, with the following findings: namely, .alpha..sub.6, .beta..sub.4 and BPA1 were co-localized within the residual detergent insoluble ECM material. .alpha..sub.3 .beta..sub.1 was not detected in the extracted ECM. These results suggest that HFK adhesion to epiligrin at 4.degree. C. is mediated via .alpha..sub.6 .beta..sub.4 in HDs that results in the formation of Triton-insoluble SACs.
25.7 A Specific Assay for Identification of Functional Epiligrin in Tissues
The binding of cells containing .alpha..sub.6 .beta..sub.4 receptors to epiligrin-ECM.sup.t at 4.degree. C., described above, formed the functional basis for a novel microscopic epiligrin-specific "rosetting" assay. In this assay cryostat sections of normal human skin were incubated at 4.degree. C. with fluorescently-labeled .alpha..sub.6 .beta..sub.4 -receptor bearing HFK cells (i.e., HFK containing cytoplasmic FITC). Functional epiligrin in tissues was identified by binding of the labeled cells at 4.degree. C. to only the basal stem cell basement membrane layer in the human epidermis. In contrast, at 37.degree. C. the labeled cells bound to so many different cells types that no definitive structures could be identified. Thus, the 4.degree. C. assay provides a simple and definitive test for identifying functional epiligrin ligand in normal and diseased epithelial tissues including e.g. epithelia in skin, gastric mucosa, lung, organs, endocrine glands, and the like. Suitable .alpha..sub.6 .beta..sub.4 -receptor bearing test cells that have been used in the assay include HFK and human papilloma virus transformed immortalized HFKs (i.e., E1L-8; Kaur et al., 1992). As a negative control, (e.g., for maintaining a constant 4.degree. C. temperature during the assay), it may be desirable to use an .alpha..sub.6 .beta..sub.4 -receptor-negative control cell on a parallel cryostat section of tissue. Suitable negative control cells that have been used include HFFs, melanocytes, HT1080 cells, and .alpha..sub.3 -K562 cells. As a positive control, (e.g., for the overall health of the tissue section and for the activity of the .alpha..sub.6 .beta..sub.4 -receptor on the test cells), .alpha..sub.6 .beta..sub.4 -receptor bearing test cells were incubated with the cryostat tissue section at 37.degree. C. (i.e., to allow both the .alpha..sub.6 .beta..sub.4 and .alpha..sub.3 .beta..sub.1 -receptor).
Epidermal basal stem cells in patients with junctional epidermolysis bullosus (JEB) gravis are defective in epiligrin synthesis (Domloge-Hultsch et al.) and the patients exhibit a lethal blistering disease. It is thought highly likely that patients who synthesize functionally defective epiligrin (e.g., mutant epiligrin) will present clinically in a wide variety of seemingly unrelated skin diseases, which upon testing according to the assay of the invention will share a common underlying epiligrin-related etiology. Skin biopsy samples collected from patients exhibiting less severe forms of blistering and skin diseases, e.g., non-lethal JEB, psoriasis, and the like, may be processed as follows. First, pieces of the biopsy sample are quick frozen in preservative and prepared for cryostat sectioning according to routine procedures. Second, the 4.degree. C. epiligrin-rosetting assay (developed above with FITC-labeled HFK cells), is used to identify locations in the patient tissue where functional epiligrin, (i.e., capable of binding an .alpha..sub.6 .beta..sub.4 -receptor positive test cell), is resident. It may be convenient to use a tissue sample of similar type from a normal individual as a positive control in the assay. Patients lacking a normal functional epiligrin are identified by qualitative and/or quantitative difference in the binding of the labeled .alpha..sub.6 .beta..sub.4 -receptor positive test cells. For example, the biosynthesis of a functionally defective epiligrin in a patient may be identified by fewer test cells binding, or a decreased rate of binding, at histological locations that would normally bind large numbers of test cells (i.e., in a normal tissue). Decreased numbers of test cells may be observed binding in the basement membrane zone in a skin biopsy sample within a 5 minute time interval. (In a similar manner, patients having autoimmune anti-epiligrin antibodies may show decreased binding of the test cells in tissues as a result of auto-antibodies blocking epiligrin ligand binding sites for the .alpha..sub.6 .beta..sub.4 -receptors on the test cells.) Alternatively, qualitative alterations in the distribution of epiligrin can be identified according to the assay, and these may result from defects in FA, HD, or SAC formation in the tissues of a patient, e.g., an actin cytoskeletal defect (or related energy metabolism defect) that prevents epiligrin from co-localizing with .alpha..sub.6, .beta..sub.4, and BPA1 in HDs.
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__________________________________________________________________________# SEQUENCE LISTING- (1) GENERAL INFORMATION:- (iii) NUMBER OF SEQUENCES: 30- (2) INFORMATION FOR SEQ ID NO:1:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 24 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see FIGURE 12BON: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:# 24CTCG TAGG- (2) INFORMATION FOR SEQ ID NO:2:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 30 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see FIGURE 12BON: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:# 30 AAGG TCACTGAGTT- (2) INFORMATION FOR SEQ ID NO:3:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 28 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see FIGURE 12BON: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:# 28 CCTG AAGGCACG- (2) INFORMATION FOR SEQ ID NO:4:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see FIGURE 12BON: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:# 20 CCAG- (2) INFORMATION FOR SEQ ID NO:5:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see FIGURE 12BON: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:# 20 GCAC- (2) INFORMATION FOR SEQ ID NO:6:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 18 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see FIGURE 12BON: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:# 18 TG- (2) INFORMATION FOR SEQ ID NO:7:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 18 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see FIGURE 12BON: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:# 18 AG- (2) INFORMATION FOR SEQ ID NO:8:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 18 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see FIGURE 12BON: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:# 18 CG- (2) INFORMATION FOR SEQ ID NO:9:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:# 20 AGTT- (2) INFORMATION FOR SEQ ID NO:10:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 18 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:# 18 CG- (2) INFORMATION FOR SEQ ID NO:11:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:# 20 CCAG- (2) INFORMATION FOR SEQ ID NO:12:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 18 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:# 18 AC- (2) INFORMATION FOR SEQ ID NO:13:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 18 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:# 18 TG- (2) INFORMATION FOR SEQ ID NO:14:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 18 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14:# 18 TG- (2) INFORMATION FOR SEQ ID NO:15:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 19 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15:# 19 GAC- (2) INFORMATION FOR SEQ ID NO:16:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:16:# 20 CATG- (2) INFORMATION FOR SEQ ID NO:17:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17:# 20 GAGC- (2) INFORMATION FOR SEQ ID NO:18:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:18:# 20 CATC- (2) INFORMATION FOR SEQ ID NO:19:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19:# 20 AGAT- (2) INFORMATION FOR SEQ ID NO:20:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 20 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#primer; see TABLE 1PTION: PCR- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20:# 20 CAAA- (2) INFORMATION FOR SEQ ID NO:21:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 664 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA (A) DESCRIPTION: cDNA s - #equence corresponding FIGURE 10F- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:21:- CGGGGATGCC TCCAGCAGTG ACCCGGTCAG CCTGCAGCAT GGGATGGCTG TG - #GATCTTTG 60- GGGCAGCCCT GGGGCAGTGT CTGGGCTACA GTTCACAGCA GCAAAGGGTG CC - #ATTTCTTC 120- AGCCTCCCGG TCAAAGTCAA CTGCAAGCGA GTTATGTGGA GTTTAGACCC AG - #CCAGGGTT 180- GTAGCCCTGG ATACTATCGG GATCATAAAG GCTTGTATAC CGGACGGTGT GT - #TCCCCTGC 240- AATTGCAACG GACATTCAAA TCAATGCCAG GATGGCTCAG GCATATGTGT TA - #ACTGTCAG 300- CACAACACCG CGGGAGCACT GTCATCGCTG CCAGGAGGGC TACTATGGCA AC - #GCCGTCCA 360- CGGATCCTGC AGGCCCTGCC CATGTCCTCA CACTAACAGC TTGCCTCTGC CT - #GTGTGGTG 420- AATGGGGGAG ACGTACGGCG CTCCTGCAAA GCTGGGTACA CAGGAACCCA GT - #GTGTAAGG 480- TGTGCACCGG GATATTTCGG GAATCCCCAG AAATTCGGAG GTAGCTGCCA AC - #CATGCAGT 540- TGTAACAGCA ATGGCCAGCT GGGCAGCTGT CATCCCCTGA CTGGAGGCTG CA - #TAAACCAA 600- GAAACCAAAG ATAACAACCC TGCAGAAGAA TGTGATGATT GCGACACCTG TG - #TGATGACC 660# 664- (2) INFORMATION FOR SEQ ID NO:22:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 1994 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA (A) DESCRIPTION: cDNA s - #equence corresponding to FIGURES 11A-11C- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:22:- CGGGGATGCC TCCAGCAGTG ACCCGGTCAG CCTGCAGCAT GGGATGGCTG TG - #GATCTTTG 60- GGGCAGCCCT GGGGCAGTGT CTGGGCTACA GTTCACAGCA GCAAAGGGTG CC - #ATTTCTTC 120- AGCCTCCCGG TCAAAGTCAA CTGCAAGCGA GTTATGTGGA GTTTAGACCC AG - #CCAGGGTT 180- GTAGCCCTGG ATACTATCGG GATCATAAAG GCTTGTATAC CGGACGGTGT GT - #TCCCCTGC 240- AATTGCAACG GACATTCAAA TCAATGCCAG GATGGCTCAG GCATATGTGT TA - #ACTGTCAG 300- CACAACACCG CGGGAGCACT GTCATCGCTG CCAGGAGGGC TACTATGGCA AC - #GCCGTCCA 360- CGGATCCTGC AGGCCCTGCC CATGTCCTCA CACTAACAGC TTGCCTCTGC CT - #GTGTGGTG 420- AATGGGGGAG ACGTACGGCG CTCCTGCAAA GCTGGGTACA CAGGAACCCA GT - #GTGTAAGG 480- TGTGCACCGG GATATTTCGG GAATCCCCAG AAATTCGGAG GTAGCTGCCA AC - #CATGCAGT 540- TGTAACAGCA ATGGCCAGCT GGGCAGCTGT CATCCCCTGA CTGGAGGCTG CA - #TAAACCAA 600- GAAACCAAAG ATAACAACCC TGCAGAAGAA TGTGATGATT GCGACACCTG TG - #TGATGACC 660- CTCCTGAACG ACCTGGCCAC CATGGGCGAG CAGCTCCGCC TGGTCAAGTC TC - #AGCTGCAG 720- GGCCTGAGTG CCAGCGCAGG GCTTCTGGAG CAGATGAGGC ACATGGAGAC CC - #AGGCCAAG 780- GACCTGAGGA ATCAGTTGCT CAACTACCGT TCTGCCATTT CAAATCATGG AT - #CAAAAATA 840- GAAGGCCTGG AAAGAGAACT GACTGATTTG AATCAAGAAT TTGAGACTTT GC - #AAGAAAAG 900- GCTCAAGTAA ATTCCAGAAA AGCACAAACA TTAAACAACA ATGTTAATCG GG - #CAACACAA 960- AGCGCAAAAG AACTGGATGT GAAGATTAAA AATGTCATCC GGAATGTGCA CA - #TTCTTTTA1020- AAGCAGATCT CTGGGACAGA TGGAGAGGGA AACAACGTGC CTTCAGGTGA CT - #TTTCCAGA1080- GAGTGGGCTG AAGCCCAGCG CATGATGAGG GAACTGCGGA ACAGGAACTT TG - #GAAAGCAC1140- CTCAGAGAAG CAGAAGCTGA TAAAAGGGAG TCGCAGCTCT TGCTGAACCG GA - #TAAGGACC1200- TGGCAGAAAA CCCACCAGGG GGAGAACAAT GGGCTTGCTA ACAGTATCCG GG - #ATTCTTTA1260- AATGAATACG AAGCCAAACT CAGTGACCTT CGTGCTCGGC TGCAGGAGGC AG - #CTGCCCAA1320- GCCAAGCAGG CAAATGGCTT GAACCAAGAA AACGAGAGAG CTTTGGGAGC CA - #TTCAGAGA1380- CAAGTGAAAG AAATAAATTC CCTGCAGAGT GATTTCACCA AGTATCTAAC CA - #CTGCAGAC1440- TCATCTTTGT TGCAAACCAA CATTGCGCTG CAGCTGATGG AGAAAAGCCA GA - #AGGAATAT1500- GAAAAATTAG CTGCCAGTTT AAATGAAGCA AGACAAGAAC TAAGTGACAA AG - #TAAGAGAA1560- CTTTCCAGAT CTGCTGGCAA AACATCCCTT GTGGAGGAGG CAGAAAAGCA CG - #CGCGGTCC1620- TTACAAGAGC TGGCAAAGCA GCTGGAAGAG ATCAAGAGAA ACGCCAGCGG GG - #ATGAGCTG1680- GTGCGCTGTG CTGTGGATGC CGCCACCGCC TACGAGAACA TCCTCAATGC CA - #TCAAAGCG1740- GCCGAGGACC GAGCCAACAG GGCTCGCAGT GCATCTGAAT CTGCCCTCCA GA - #CAGTGATA1800- AAGGAAGATC TGCCAAGAAA AGCTAAAACC CTGAGTTCCA ACAGTGATAA AC - #TGTTAAAG1860- AAGCCAAGAT GACACAAAAG AAGCTAAAGC AAGAAGTCAG TCCAGCTCTC AA - #CAACCTAC1920- AGCAAACCCT GAATATTGTG ACAGTTCAGA AAGAAGTGAT AGACACCAAT CT - #CACAACTC1980# 1994- (2) INFORMATION FOR SEQ ID NO:23:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 5496 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA (A) DESCRIPTION:Sequence o - #f cDNA to 3EpA cDNA; see FIGURES 15A-15F- (iii) HYPOTHETICAL: NO- (iv) ANTI-SENSE: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 59..5200- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:23:- AGCCAGCGGA CGTCCAGGAA CCGGGATGCC TCCAGCAGTG AGGCGGTCAG CC - #TGCAGC 58- ATG GGA TGG CTG TGG ATC TTT GGG GCA GCC CT - #G GGG CAG TGT CTG GGC 106Met Gly Trp Leu Trp Ile Phe Gly Ala Ala Le - #u Gly Gln Cys Leu Gly# 15- TAC AGT TCA CAG CAG CAA AGG GTG CCA TTT CT - #T CAG CCT CCC GGT CAA 154Tyr Ser Ser Gln Gln Gln Arg Val Pro Phe Le - #u Gln Pro Pro Gly Gln# 30- AGT CAA CTG CAA GCG AGT TAT GTG GAG TTT AG - #A CCC AGC CAG GGT TGT 202Ser Gln Leu Gln Ala Ser Tyr Val Glu Phe Ar - #g Pro Ser Gln Gly Cys# 45- AGC CCT GGA TAC TAT CGG GAT CAT AAA GGC TT - #G TAT ACC GGA CGG TGT 250Ser Pro Gly Tyr Tyr Arg Asp His Lys Gly Le - #u Tyr Thr Gly Arg Cys# 60- GTT CCC TGC AAT TGC AAC GGA CAT TCA AAT CA - #A TGC CAG GAT GGC TCA 298Val Pro Cys Asn Cys Asn Gly His Ser Asn Gl - #n Cys Gln Asp Gly Ser# 80- GGC ATA TGT GTT AAC TGT CAG CAC AAC ACC GC - #G GGA GAG CAC TGT GAA 346Gly Ile Cys Val Asn Cys Gln His Asn Thr Al - #a Gly Glu His Cys Glu# 95- CGC TGC CAG GAG GGC TAC TAT GGC AAC GCC GT - #C CAC GGA TCC TGC AGG 394Arg Cys Gln Glu Gly Tyr Tyr Gly Asn Ala Va - #l His Gly Ser Cys Arg# 110- GCC TGC CCA TGT CCT CAC ACT AAC AGC TTT GC - #C ACT GGC TGT GTG GTG 442Ala Cys Pro Cys Pro His Thr Asn Ser Phe Al - #a Thr Gly Cys Val Val# 125- AAT GGG GGA GAC GTG CGG TGC TCC TGC AAA GC - #T GGG TAC ACA GGA ACA 490Asn Gly Gly Asp Val Arg Cys Ser Cys Lys Al - #a Gly Tyr Thr Gly Thr# 140- CAG TGT GAA AGG TGT GCA CCG GGA TAT TTC GG - #G AAT CCC CAG AAA TTC 538Gln Cys Glu Arg Cys Ala Pro Gly Tyr Phe Gl - #y Asn Pro Gln Lys Phe145 1 - #50 1 - #55 1 -#60- GGA GGT AGC TGC CAA CCA TGC AGT TGT AAC AG - #C AAT GGC CAG CTG GGC 586Gly Gly Ser Cys Gln Pro Cys Ser Cys Asn Se - #r Asn Gly Gln Leu Gly# 175- AGC TGT CAT CCC CTG ACT GGA GAC TGC ATA AA - #C CAA GAA CCC AAA GAT 634Ser Cys His Pro Leu Thr Gly Asp Cys Ile As - #n Gln Glu Pro Lys Asp# 190- AGC AGC CCT GCA GAA GAA TGT GAT GAT TGC GA - #C AGC TGT GTG ATG ACC 682Ser Ser Pro Ala Glu Glu Cys Asp Asp Cys As - #p Ser Cys Val Met Thr# 205- CTC CTG AAC GAC CTG GCC ACC ATG GGC GAG CA - #G CTC CGC CTG GTC AAG 730Leu Leu Asn Asp Leu Ala Thr Met Gly Glu Gl - #n Leu Arg Leu Val Lys# 220- TCT CAG CTG CAG GGC CTG AGT GCC AGC GCA GG - #G CTT CTG GAG CAG ATG 778Ser Gln Leu Gln Gly Leu Ser Ala Ser Ala Gl - #y Leu Leu Glu Gln Met225 2 - #30 2 - #35 2 -#40- AGG CAC ATG GAG ACC CAG GCC AAG GAC CTG AG - #G AAT CAG TTG CTC AAC 826Arg His Met Glu Thr Gln Ala Lys Asp Leu Ar - #g Asn Gln Leu Leu Asn# 255- TAC CGT TCT GCC ATT TCA AAT CAT GGA TCA AA - #A ATA GAA GGC CTG GAA 874Tyr Arg Ser Ala Ile Ser Asn His Gly Ser Ly - #s Ile Glu Gly Leu Glu# 270- AGA GAA CTG ACT GAT TTG AAT CAA GAA TTT GA - #G ACT TTG CAA GAA AAG 922Arg Glu Leu Thr Asp Leu Asn Gln Glu Phe Gl - #u Thr Leu Gln Glu Lys# 285- GCT CAA GTA AAT TCC AGA AAA GCA CAA ACA TT - #A AAC AAC AAT GTT AAT 970Ala Gln Val Asn Ser Arg Lys Ala Gln Thr Le - #u Asn Asn Asn Val Asn# 300- CGG GCA ACA CAA AGC GCA AAA GAA CTG GAT GT - #G AAG ATT AAA AAT GTC1018Arg Ala Thr Gln Ser Ala Lys Glu Leu Asp Va - #l Lys Ile Lys Asn Val305 3 - #10 3 - #15 3 -#20- ATC CGG AAT GTG CAC ATT CTT TTA AAG CAG AT - #C TCT GGG ACA GAT GGA1066Ile Arg Asn Val His Ile Leu Leu Lys Gln Il - #e Ser Gly Thr Asp Gly# 335- GAG GGA AAC AAC GTG CCT TCA GGT GAC TTT TC - #C AGA GAG TGG GCT GAA1114Glu Gly Asn Asn Val Pro Ser Gly Asp Phe Se - #r Arg Glu Trp Ala Glu# 350- GCC CAG CGC ATG ATG AGG GAA CTG CGG AAC AG - #G AAC TTT GGA AAG CAC1162Ala Gln Arg Met Met Arg Glu Leu Arg Asn Ar - #g Asn Phe Gly Lys His# 365- CTC AGA GAA GCA GAA GCT GAT AAA AGG GAG TC - #G CAG CTC TTG CTG AAC1210Leu Arg Glu Ala Glu Ala Asp Lys Arg Glu Se - #r Gln Leu Leu Leu Asn# 380- CGG ATA AGG ACC TGG CAG AAA ACC CAC CAG GG - #G GAG AAC AAT GGG CTT1258Arg Ile Arg Thr Trp Gln Lys Thr His Gln Gl - #y Glu Asn Asn Gly Leu385 3 - #90 3 - #95 4 -#00- GCT AAC AGT ATC CGG GAT TCT TTA AAT GAA TA - #C GAA GCC AAA CTC AGT1306Ala Asn Ser Ile Arg Asp Ser Leu Asn Glu Ty - #r Glu Ala Lys Leu Ser# 415- GAC CTT CGT GCT CGG CTG CAG GAG GCA GCT GC - #C CAA GCC AAG CAG GCA1354Asp Leu Arg Ala Arg Leu Gln Glu Ala Ala Al - #a Gln Ala Lys Gln Ala# 430- AAT GGC TTG AAC CAA GAA AAC GAG AGA GCT TT - #G GGA GCC ATT CAG AGA1402Asn Gly Leu Asn Gln Glu Asn Glu Arg Ala Le - #u Gly Ala Ile Gln Arg# 445- CAA GTG AAA GAA ATA AAT TCC CTG CAG AGT GA - #T TTC ACC AAG TAT CTA1450Gln Val Lys Glu Ile Asn Ser Leu Gln Ser As - #p Phe Thr Lys Tyr Leu# 460- ACC ACT GCA GAC TCA TCT TTG TTG CAA ACC AA - #C ATT GCG CTG CAG CTG1498Thr Thr Ala Asp Ser Ser Leu Leu Gln Thr As - #n Ile Ala Leu Gln Leu465 4 - #70 4 - #75 4 -#80- ATG GAG AAA AGC CAG AAG GAA TAT GAA AAA TT - #A GCT GCC AGT TTA AAT1546Met Glu Lys Ser Gln Lys Glu Tyr Glu Lys Le - #u Ala Ala Ser Leu Asn# 495- GAA GCA AGA CAA GAA CTA AGT GAC AAA GTA AG - #A GAA CTT TCC AGA TCT1594Glu Ala Arg Gln Glu Leu Ser Asp Lys Val Ar - #g Glu Leu Ser Arg Ser# 510- GCT GGC AAA ACA TCC CTT GTG GAG GAG GCA GA - #A AAG CAC GCG CGG TCC1642Ala Gly Lys Thr Ser Leu Val Glu Glu Ala Gl - #u Lys His Ala Arg Ser# 525- TTA CAA GAG CTG GCA AAG CAG CTG GAA GAG AT - #C AAG AGA AAC GCC AGC1690Leu Gln Glu Leu Ala Lys Gln Leu Glu Glu Il - #e Lys Arg Asn Ala Ser# 540- GGG GAT GAG CTG GTG CGC TGT GCT GTG GAT GC - #C GCC ACC GCC TAC GAG1738Gly Asp Glu Leu Val Arg Cys Ala Val Asp Al - #a Ala Thr Ala Tyr Glu545 5 - #50 5 - #55 5 -#60- AAC ATC CTC AAT GCC ATC AAA GCG GCC GAG GA - #C GCA GCC AAC AGG GCT1786Asn Ile Leu Asn Ala Ile Lys Ala Ala Glu As - #p Ala Ala Asn Arg Ala# 575- GCC AGT GCA TCT GAA TCT GCC CTC CAG ACA GT - #G ATA AAG GAA GAT CTG1834Ala Ser Ala Ser Glu Ser Ala Leu Gln Thr Va - #l Ile Lys Glu Asp Leu# 590- CCA AGA AAA GCT AAA ACC CTG AGT TCC AAC AG - #T GAT AAA CTG TTA AAT1882Pro Arg Lys Ala Lys Thr Leu Ser Ser Asn Se - #r Asp Lys Leu Leu Asn# 605- GAA GCC AAG ATG ACA CAA AAG AAG CTA AAG CA - #A GAA GTC AGT CCA GCT1930Glu Ala Lys Met Thr Gln Lys Lys Leu Lys Gl - #n Glu Val Ser Pro Ala# 620- CTC AAC AAC CTA CAG CAA ACC CTG AAT ATT GT - #G ACA GTT CAG AAA GAA1978Leu Asn Asn Leu Gln Gln Thr Leu Asn Ile Va - #l Thr Val Gln Lys Glu625 6 - #30 6 - #35 6 -#40- GTG ATA GAC ACC AAT CTC ACA ACT CTC CGA GA - #T GGT CTT CAT GGG ATA2026Val Ile Asp Thr Asn Leu Thr Thr Leu Arg As - #p Gly Leu His Gly Ile# 655- CAG AGA GGT GAT ATT GAT GCT ATG ATC AGT AG - #T GCA AAG AGC ATG GTC2074Gln Arg Gly Asp Ile Asp Ala Met Ile Ser Se - #r Ala Lys Ser Met Val# 670- AGA AAG GCC AAC GAC ATC ACA GAT GAG GTT CT - #G GAT GGG CTC AAC CCC2122Arg Lys Ala Asn Asp Ile Thr Asp Glu Val Le - #u Asp Gly Leu Asn Pro# 685- ATC CAG ACA GAT GTG GAA AGA ATT AAG GAC AC - #C TAT GGG AGG ACA CAG2170Ile Gln Thr Asp Val Glu Arg Ile Lys Asp Th - #r Tyr Gly Arg Thr Gln# 700- AAC GAA GAC TTC AAA AAG GCT CTG ACT GAT GC - #A GAT AAC TCG GTG AAT2218Asn Glu Asp Phe Lys Lys Ala Leu Thr Asp Al - #a Asp Asn Ser Val Asn705 7 - #10 7 - #15 7 -#20- AAG TTA ACC AAC AAA CTA CCT GAT CTT TGG CG - #C AAG ATT GAA AGT ATC2266Lys Leu Thr Asn Lys Leu Pro Asp Leu Trp Ar - #g Lys Ile Glu Ser Ile# 735- AAC CAA CAG CTG TTG CCC TTG GGA AAC ATC TC - #T GAC AAC ATG GAC AGA2314Asn Gln Gln Leu Leu Pro Leu Gly Asn Ile Se - #r Asp Asn Met Asp Arg# 750- ATA CGA GAA CTA ATT CAG CAG GCC AGA GAT GC - #T GCC AGT AAG GTT GCT2362Ile Arg Glu Leu Ile Gln Gln Ala Arg Asp Al - #a Ala Ser Lys Val Ala# 765- GTC CCC ATG AGG TTC AAT GGT AAA TCT GGA GT - #C GAA GTC CGA CTG CCA2410Val Pro Met Arg Phe Asn Gly Lys Ser Gly Va - #l Glu Val Arg Leu Pro# 780- AAT GAC CTG GAA GAT TTG AAA GGA TAT ACA TC - #T CTG TCC TTG TTT CTC2458Asn Asp Leu Glu Asp Leu Lys Gly Tyr Thr Se - #r Leu Ser Leu Phe Leu785 7 - #90 7 - #95 8 -#00- CAA AGG CCC AAC TCA AGA GAA AAT GGG GGT AC - #T GAG AAT ATG TTT GTG2506Gln Arg Pro Asn Ser Arg Glu Asn Gly Gly Th - #r Glu Asn Met Phe Val# 815- ATG TAC CTT GGA AAT AAA GAT GCC TCC CGG GA - #C TAC ATC GGC ATG GCA2554Met Tyr Leu Gly Asn Lys Asp Ala Ser Arg As - #p Tyr Ile Gly Met Ala# 830- GTT GTG GAT GGC CAG CTC ACC TGT GTC TAC AA - #C CTG GGG GAC CGT GAG2602Val Val Asp Gly Gln Leu Thr Cys Val Tyr As - #n Leu Gly Asp Arg Glu# 845- GCT GAA CTC CAA GTG GAC CAG ATC TTG ACC AA - #G AGT GAG ACT AAG GAG2650Ala Glu Leu Gln Val Asp Gln Ile Leu Thr Ly - #s Ser Glu Thr Lys Glu# 860- GCA GTT ATG GAT CGG GTG AAA TTT CAG AGA AT - #T TAT CAG TTT GCA AGG2698Ala Val Met Asp Arg Val Lys Phe Gln Arg Il - #e Tyr Gln Phe Ala Arg865 8 - #70 8 - #75 8 -#80- CTT AAT TAC ACC AAA GGA GCC ACA TCC AGT AA - #A CCA GAA ACA CCC GGA2746Leu Asn Tyr Thr Lys Gly Ala Thr Ser Ser Ly - #s Pro Glu Thr Pro Gly# 895- GTC TAT GAC ATG GAT GGT AGA AAT AGC AAT AC - #A CTC CTT AAT TTG GAT2794Val Tyr Asp Met Asp Gly Arg Asn Ser Asn Th - #r Leu Leu Asn Leu Asp# 910- CCT GAA AAT GTT GTA TTT TAT GTT GGA GGT TA - #C CCA CCT GAT TTT AAA2842Pro Glu Asn Val Val Phe Tyr Val Gly Gly Ty - #r Pro Pro Asp Phe Lys# 925- CTT CCC AGT CGA CTA AGT TTC CCT CCA TAC AA - #A GGT TGT ATT GAA TTA2890Leu Pro Ser Arg Leu Ser Phe Pro Pro Tyr Ly - #s Gly Cys Ile Glu Leu# 940- GAT GAC CTC AAT GAA AAT GTT CTG AGC TTG TA - #C AAC TTC AAA AAA ACA2938Asp Asp Leu Asn Glu Asn Val Leu Ser Leu Ty - #r Asn Phe Lys Lys Thr945 9 - #50 9 - #55 9 -#60- TTC AAT CTC AAC ACA ACT GAA GTG GAG CCT TG - #T AGA AGG AGG AAG GAA2986Phe Asn Leu Asn Thr Thr Glu Val Glu Pro Cy - #s Arg Arg Arg Lys Glu# 975- GAG TCA GAC AAA AAT TAT TTT GAA GGT ACG GG - #C TAT GCT CGA GTT CCA3034Glu Ser Asp Lys Asn Tyr Phe Glu Gly Thr Gl - #y Tyr Ala Arg Val Pro# 990- ACT CAA CCA CAT GCT CCC ATC CCA ACC TTT GG - #A CAG ACA ATT CAG ACC3082Thr Gln Pro His Ala Pro Ile Pro Thr Phe Gl - #y Gln Thr Ile Gln Thr# 10050- ACC GTG GAT AGA GGC TTG CTG TTC TTT GCA GA - #A AAC GGG GAT CGC TTC3130Thr Val Asp Arg Gly Leu Leu Phe Phe Ala Gl - #u Asn Gly Asp Arg Phe# 10205- ATA TCT CTA AAT ATA GAA GAT GGC AAG CTC AT - #G GTG AGA TAC AAA CTG3178Ile Ser Leu Asn Ile Glu Asp Gly Lys Leu Me - #t Val Arg Tyr Lys Leu# 10401030 - # 1035- AAT TCA GAG CTA CCA AAA GAG AGA GGA GTT GG - #A GAC GCC ATA AAC AAC3226Asn Ser Glu Leu Pro Lys Glu Arg Gly Val Gl - #y Asp Ala Ile Asn Asn# 10550- GGC AGA GAC CAT TCG ATT CAG ATC AAA ATT GG - #A AAA CTC CAA AAG CGT3274Gly Arg Asp His Ser Ile Gln Ile Lys Ile Gl - #y Lys Leu Gln Lys Arg# 10705- ATG TGG ATA AAT GTG GAC GTT CAA AAC ACT AT - #A ATT GAT GGT GAA GTA3322Met Trp Ile Asn Val Asp Val Gln Asn Thr Il - #e Ile Asp Gly Glu Val# 10850- TTT GAT TTC AGC ACA TAT TAT CTG GGA GGA AT - #T CCA ATT GCA ATC AGG3370Phe Asp Phe Ser Thr Tyr Tyr Leu Gly Gly Il - #e Pro Ile Ala Ile Arg# 11005- GAA AGA TTT AAC ATT TCT ACG CCT GCT TTC CG - #A GGC TGC ATG AAA AAT3418Glu Arg Phe Asn Ile Ser Thr Pro Ala Phe Ar - #g Gly Cys Met Lys Asn# 11201110 - # 1115- TTG AAG AAA ACC AGT GGT GTC GTT AGA TTG AA - #T GAT ACT GTG GGA GTA3466Leu Lys Lys Thr Ser Gly Val Val Arg Leu As - #n Asp Thr Val Gly Val# 11350- ACC AAA AAG TGC TCG GAA GAC TGG AAG CTT GT - #G CGA TCT GCC TCA TTC3514Thr Lys Lys Cys Ser Glu Asp Trp Lys Leu Va - #l Arg Ser Ala Ser Phe# 11505- TCC AGA GGA GGA CAA TTG AGT TTC ACT GAT TT - #G GGC TTA CCA CCT ACT3562Ser Arg Gly Gly Gln Leu Ser Phe Thr Asp Le - #u Gly Leu Pro Pro Thr# 11650- GAC CAC CTC CAG GCC TCA TTT GGA TTT CAG AC - #C TTT CAA CCC AGT GGC3610Asp His Leu Gln Ala Ser Phe Gly Phe Gln Th - #r Phe Gln Pro Ser Gly# 11805- ATA TTA TTA GAT CAT CAG ACA TGG ACA AGG AA - #C CTG CAG GTC ACT CTG3658Ile Leu Leu Asp His Gln Thr Trp Thr Arg As - #n Leu Gln Val Thr Leu# 12001190 - # 1195- GAA GAT GGT TAC ATT GAA TTG AGC ACC AGC GA - #T AGC GGC GGC CCA ATT3706Glu Asp Gly Tyr Ile Glu Leu Ser Thr Ser As - #p Ser Gly Gly Pro Ile# 12150- TTT AAA TCT CCA CAG ACG TAT ATG GAT GGT TT - #A CTG CAT TAT GTA TCT3754Phe Lys Ser Pro Gln Thr Tyr Met Asp Gly Le - #u Leu His Tyr Val Ser# 12305- GTA ATA AGC GAC AAC TCT GGA CTA CGG CTT CT - #C ATC GAT GAC CAG CTT3802Val Ile Ser Asp Asn Ser Gly Leu Arg Leu Le - #u Ile Asp Asp Gln Leu# 12450- CTG AGA AAT AGC AAA AGG CTA AAA CAC ATT TC - #A AGT TCC CGG CAG TCT3850Leu Arg Asn Ser Lys Arg Leu Lys His Ile Se - #r Ser Ser Arg Gln Ser# 12605- CTG CGT CTG GGC GGG AGC AAT TTT GAG GGT TG - #T ATT AGC AAT GTT TTT3898Leu Arg Leu Gly Gly Ser Asn Phe Glu Gly Cy - #s Ile Ser Asn Val Phe# 12801270 - # 1275- GTC CAG AGG TTA TCA CTG AGT CCT GAA GTC CT - #A GAT TTG ACC AGT AAC3946Val Gln Arg Leu Ser Leu Ser Pro Glu Val Le - #u Asp Leu Thr Ser Asn# 12950- TCT CTC AAG AGA GAT GTG TCC CTG GGA GGC TG - #C AGT TTA AAC AAA CCA3994Ser Leu Lys Arg Asp Val Ser Leu Gly Gly Cy - #s Ser Leu Asn Lys Pro# 13105- CCT TTT CTA ATG TTG CTT AAA GGT TCT ACC AG - #G TTT AAC AAG ACC AAG4042Pro Phe Leu Met Leu Leu Lys Gly Ser Thr Ar - #g Phe Asn Lys Thr Lys# 13250- ACT TTT CGT ATC AAC CAG CTG TTG CAG GAC AC - #A CCA GTG GCC TCC CCA4090Thr Phe Arg Ile Asn Gln Leu Leu Gln Asp Th - #r Pro Val Ala Ser Pro# 13405- AGG AGC GTG AAG GTG TGG CAA GAT GCT TGC TC - #A CCA CTT CCC AAG ACC4138Arg Ser Val Lys Val Trp Gln Asp Ala Cys Se - #r Pro Leu Pro Lys Thr# 13601350 - # 1355- CAG GCC AAT CAT GGA GCC CTC CAG TTT GGG GA - #C ATT CCC ACC AGC CAC4186Gln Ala Asn His Gly Ala Leu Gln Phe Gly As - #p Ile Pro Thr Ser His# 13750- TTG CTA TTC AAG CTT CCT CAG GAG CTG CTG AA - #A CCC AGG TCA CAG TTT4234Leu Leu Phe Lys Leu Pro Gln Glu Leu Leu Ly - #s Pro Arg Ser Gln Phe# 13905- GCT GTG GAC ATG CAG ACA ACA TCC TCC AGA GG - #A CTG GTG TTT CAC ACG4282Ala Val Asp Met Gln Thr Thr Ser Ser Arg Gl - #y Leu Val Phe His Thr# 14050- GGC ACT AAG AAC TCC TTT ATG GCT CTT TAT CT - #T TCA AAA GGA CGT CTG4330Gly Thr Lys Asn Ser Phe Met Ala Leu Tyr Le - #u Ser Lys Gly Arg Leu# 14205- GTC TTT GCA CTG GGG ACA GAT GGG AAA AAA TT - #G AGG ATC AAA AGC AAG4378Val Phe Ala Leu Gly Thr Asp Gly Lys Lys Le - #u Arg Ile Lys Ser Lys# 14401430 - # 1435- GAG AAA TGC AAT GAT GGG AAA TGG CAC ACG GT - #G GTG TTT GGC CAT GAT4426Glu Lys Cys Asn Asp Gly Lys Trp His Thr Va - #l Val Phe Gly His Asp# 14550- GGG GAA AAG GGG CGC TTG GTT GTG GAT GGA CT - #G AGG GCC CGG GAG GGA4474Gly Glu Lys Gly Arg Leu Val Val Asp Gly Le - #u Arg Ala Arg Glu Gly# 14705- AGT TTG CCT GGA AAC TCC ACC ATC AGC ATC AG - #A GCG CCA GTT TAC CTG4522Ser Leu Pro Gly Asn Ser Thr Ile Ser Ile Ar - #g Ala Pro Val Tyr Leu# 14850- GGA TCA CCT CCA TCA GGG AAA CCA AAG AGC CT - #C CCC ACA AAC AGC TTT4570Gly Ser Pro Pro Ser Gly Lys Pro Lys Ser Le - #u Pro Thr Asn Ser Phe# 15005- GTG GGA TGC CTG AAG AAC TTT CAG CTG GAT TC - #A AAA CCC TTG TAT ACC4618Val Gly Cys Leu Lys Asn Phe Gln Leu Asp Se - #r Lys Pro Leu Tyr Thr# 15201510 - # 1515- CCT TCT TCA AGC TTC GGG GTG TCT TCC TGC TT - #G GGT GGT CCT TTG GAG4666Pro Ser Ser Ser Phe Gly Val Ser Ser Cys Le - #u Gly Gly Pro Leu Glu# 15350- AAA GGC ATT TAT TTC TCT GAA GAA GGA GGT CA - #T GTC GTC TTG GCT CAC4714Lys Gly Ile Tyr Phe Ser Glu Glu Gly Gly Hi - #s Val Val Leu Ala His# 15505- TCT GTA TTG TTG GGG CCA GAA TTT AAG CTT GT - #T TTC AGC ATC CGC CCA4762Ser Val Leu Leu Gly Pro Glu Phe Lys Leu Va - #l Phe Ser Ile Arg Pro# 15650- AGA AGT CTC ACT GGG ATC CTA ATA CAC ATC GG - #A AGT CAG CCC GGG AAG4810Arg Ser Leu Thr Gly Ile Leu Ile His Ile Gl - #y Ser Gln Pro Gly Lys# 15805- CAC TTA TGT GTT TAC CTG GAG GCA GGA AAG GT - #C ACG GCC TCT ATG GAC4858His Leu Cys Val Tyr Leu Glu Ala Gly Lys Va - #l Thr Ala Ser Met Asp# 16001590 - # 1595- AGT GGG GCA GGT GGG ACC TCA ACG TCG GTC AC - #A CCA AAG CAG TCT CTG4906Ser Gly Ala Gly Gly Thr Ser Thr Ser Val Th - #r Pro Lys Gln Ser Leu# 16150- TGT GAT GGA CAG TGG CAC TCG GTG GCA GTC AC - #C ATA AAA CAA CAC ATC4954Cys Asp Gly Gln Trp His Ser Val Ala Val Th - #r Ile Lys Gln His Ile# 16305- CTG CAC CTG GAA CTG GAC ACA GAC AGT AGC TA - #C ACA GCT GGA CAG ATC5002Leu His Leu Glu Leu Asp Thr Asp Ser Ser Ty - #r Thr Ala Gly Gln Ile# 16450- CCC TTC CCA CCT GCC AGC ACT CAA GAG CCA CT - #A CAC CTT GGA GGT GCT5050Pro Phe Pro Pro Ala Ser Thr Gln Glu Pro Le - #u His Leu Gly Gly Ala# 16605- CCA GCC AAT TTG ACG ACA CTG AGG ATC CCT GT - #G TGG AAA TCA TTC TTT5098Pro Ala Asn Leu Thr Thr Leu Arg Ile Pro Va - #l Trp Lys Ser Phe Phe# 16801670 - # 1675- GGC TGT CTG AGG AAT ATT CAT GTC AAT CAC AT - #C CCT GTC CCT GTC ACT5146Gly Cys Leu Arg Asn Ile His Val Asn His Il - #e Pro Val Pro Val Thr# 16950- GAA GCC TTG GAA GTC CAG GGG CCT GTC AGT CT - #G AAT GGT TGT CCT GAC5194Glu Ala Leu Glu Val Gln Gly Pro Val Ser Le - #u Asn Gly Cys Pro Asp# 17105- CAG TAACCCAAGC CTATTTCACA GCAAGGAAAT TCACCTTCAA AAGCACTGA - #T5247Gln- TACCCAATGC ACCTCCCTCC CCAGCTCGAG ATCATTCTTC AATTAGGACA CA - #AACCAGAC5307- AGGTTTAATA GCGAATCTAA TTTTGAATTC TGACCATGGA TACCCATCAC TT - #TGGCATTC5367- AGTGCTACAT GTGTATTTTA TATAAAAATC CCATTTCTTG AAGATAAAAA AA - #TTGTTATT5427- CAAATTGTTA TGCACAGAAT GTTTTTGGTA ATATTAATTT CCACTAAAAA AT - #TAAATGTC5487# 5496- (2) INFORMATION FOR SEQ ID NO:24:- (i) SEQUENCE CHARACTERISTICS:#acids (A) LENGTH: 1713 amino (B) TYPE: amino acid (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: protein (A) DESCRIPTION: E170 p - #rotein as translated from sequence of FIGURE - #S 15A-15F, and as shown also in FIGURES 19A-19R- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:24:- Met Gly Trp Leu Trp Ile Phe Gly Ala Ala Le - #u Gly Gln Cys Leu Gly# 15- Tyr Ser Ser Gln Gln Gln Arg Val Pro Phe Le - #u Gln Pro Pro Gly Gln# 30- Ser Gln Leu Gln Ala Ser Tyr Val Glu Phe Ar - #g Pro Ser Gln Gly Cys# 45- Ser Pro Gly Tyr Tyr Arg Asp His Lys Gly Le - #u Tyr Thr Gly Arg Cys# 60- Val Pro Cys Asn Cys Asn Gly His Ser Asn Gl - #n Cys Gln Asp Gly Ser# 80- Gly Ile Cys Val Asn Cys Gln His Asn Thr Al - #a Gly Glu His Cys Glu# 95- Arg Cys Gln Glu Gly Tyr Tyr Gly Asn Ala Va - #l His Gly Ser Cys Arg# 110- Ala Cys Pro Cys Pro His Thr Asn Ser Phe Al - #a Thr Gly Cys Val Val# 125- Asn Gly Gly Asp Val Arg Cys Ser Cys Lys Al - #a Gly Tyr Thr Gly Thr# 140- Gln Cys Glu Arg Cys Ala Pro Gly Tyr Phe Gl - #y Asn Pro Gln Lys Phe145 1 - #50 1 - #55 1 -#60- Gly Gly Ser Cys Gln Pro Cys Ser Cys Asn Se - #r Asn Gly Gln Leu Gly# 175- Ser Cys His Pro Leu Thr Gly Asp Cys Ile As - #n Gln Glu Pro Lys Asp# 190- Ser Ser Pro Ala Glu Glu Cys Asp Asp Cys As - #p Ser Cys Val Met Thr# 205- Leu Leu Asn Asp Leu Ala Thr Met Gly Glu Gl - #n Leu Arg Leu Val Lys# 220- Ser Gln Leu Gln Gly Leu Ser Ala Ser Ala Gl - #y Leu Leu Glu Gln Met225 2 - #30 2 - #35 2 -#40- Arg His Met Glu Thr Gln Ala Lys Asp Leu Ar - #g Asn Gln Leu Leu Asn# 255- Tyr Arg Ser Ala Ile Ser Asn His Gly Ser Ly - #s Ile Glu Gly Leu Glu# 270- Arg Glu Leu Thr Asp Leu Asn Gln Glu Phe Gl - #u Thr Leu Gln Glu Lys# 285- Ala Gln Val Asn Ser Arg Lys Ala Gln Thr Le - #u Asn Asn Asn Val Asn# 300- Arg Ala Thr Gln Ser Ala Lys Glu Leu Asp Va - #l Lys Ile Lys Asn Val305 3 - #10 3 - #15 3 -#20- Ile Arg Asn Val His Ile Leu Leu Lys Gln Il - #e Ser Gly Thr Asp Gly# 335- Glu Gly Asn Asn Val Pro Ser Gly Asp Phe Se - #r Arg Glu Trp Ala Glu# 350- Ala Gln Arg Met Met Arg Glu Leu Arg Asn Ar - #g Asn Phe Gly Lys His# 365- Leu Arg Glu Ala Glu Ala Asp Lys Arg Glu Se - #r Gln Leu Leu Leu Asn# 380- Arg Ile Arg Thr Trp Gln Lys Thr His Gln Gl - #y Glu Asn Asn Gly Leu385 3 - #90 3 - #95 4 -#00- Ala Asn Ser Ile Arg Asp Ser Leu Asn Glu Ty - #r Glu Ala Lys Leu Ser# 415- Asp Leu Arg Ala Arg Leu Gln Glu Ala Ala Al - #a Gln Ala Lys Gln Ala# 430- Asn Gly Leu Asn Gln Glu Asn Glu Arg Ala Le - #u Gly Ala Ile Gln Arg# 445- Gln Val Lys Glu Ile Asn Ser Leu Gln Ser As - #p Phe Thr Lys Tyr Leu# 460- Thr Thr Ala Asp Ser Ser Leu Leu Gln Thr As - #n Ile Ala Leu Gln Leu465 4 - #70 4 - #75 4 -#80- Met Glu Lys Ser Gln Lys Glu Tyr Glu Lys Le - #u Ala Ala Ser Leu Asn# 495- Glu Ala Arg Gln Glu Leu Ser Asp Lys Val Ar - #g Glu Leu Ser Arg Ser# 510- Ala Gly Lys Thr Ser Leu Val Glu Glu Ala Gl - #u Lys His Ala Arg Ser# 525- Leu Gln Glu Leu Ala Lys Gln Leu Glu Glu Il - #e Lys Arg Asn Ala Ser# 540- Gly Asp Glu Leu Val Arg Cys Ala Val Asp Al - #a Ala Thr Ala Tyr Glu545 5 - #50 5 - #55 5 -#60- Asn Ile Leu Asn Ala Ile Lys Ala Ala Glu As - #p Ala Ala Asn Arg Ala# 575- Ala Ser Ala Ser Glu Ser Ala Leu Gln Thr Va - #l Ile Lys Glu Asp Leu# 590- Pro Arg Lys Ala Lys Thr Leu Ser Ser Asn Se - #r Asp Lys Leu Leu Asn# 605- Glu Ala Lys Met Thr Gln Lys Lys Leu Lys Gl - #n Glu Val Ser Pro Ala# 620- Leu Asn Asn Leu Gln Gln Thr Leu Asn Ile Va - #l Thr Val Gln Lys Glu625 6 - #30 6 - #35 6 -#40- Val Ile Asp Thr Asn Leu Thr Thr Leu Arg As - #p Gly Leu His Gly Ile# 655- Gln Arg Gly Asp Ile Asp Ala Met Ile Ser Se - #r Ala Lys Ser Met Val# 670- Arg Lys Ala Asn Asp Ile Thr Asp Glu Val Le - #u Asp Gly Leu Asn Pro# 685- Ile Gln Thr Asp Val Glu Arg Ile Lys Asp Th - #r Tyr Gly Arg Thr Gln# 700- Asn Glu Asp Phe Lys Lys Ala Leu Thr Asp Al - #a Asp Asn Ser Val Asn705 7 - #10 7 - #15 7 -#20- Lys Leu Thr Asn Lys Leu Pro Asp Leu Trp Ar - #g Lys Ile Glu Ser Ile# 735- Asn Gln Gln Leu Leu Pro Leu Gly Asn Ile Se - #r Asp Asn Met Asp Arg# 750- Ile Arg Glu Leu Ile Gln Gln Ala Arg Asp Al - #a Ala Ser Lys Val Ala# 765- Val Pro Met Arg Phe Asn Gly Lys Ser Gly Va - #l Glu Val Arg Leu Pro# 780- Asn Asp Leu Glu Asp Leu Lys Gly Tyr Thr Se - #r Leu Ser Leu Phe Leu785 7 - #90 7 - #95 8 -#00- Gln Arg Pro Asn Ser Arg Glu Asn Gly Gly Th - #r Glu Asn Met Phe Val# 815- Met Tyr Leu Gly Asn Lys Asp Ala Ser Arg As - #p Tyr Ile Gly Met Ala# 830- Val Val Asp Gly Gln Leu Thr Cys Val Tyr As - #n Leu Gly Asp Arg Glu# 845- Ala Glu Leu Gln Val Asp Gln Ile Leu Thr Ly - #s Ser Glu Thr Lys Glu# 860- Ala Val Met Asp Arg Val Lys Phe Gln Arg Il - #e Tyr Gln Phe Ala Arg865 8 - #70 8 - #75 8 -#80- Leu Asn Tyr Thr Lys Gly Ala Thr Ser Ser Ly - #s Pro Glu Thr Pro Gly# 895- Val Tyr Asp Met Asp Gly Arg Asn Ser Asn Th - #r Leu Leu Asn Leu Asp# 910- Pro Glu Asn Val Val Phe Tyr Val Gly Gly Ty - #r Pro Pro Asp Phe Lys# 925- Leu Pro Ser Arg Leu Ser Phe Pro Pro Tyr Ly - #s Gly Cys Ile Glu Leu# 940- Asp Asp Leu Asn Glu Asn Val Leu Ser Leu Ty - #r Asn Phe Lys Lys Thr945 9 - #50 9 - #55 9 -#60- Phe Asn Leu Asn Thr Thr Glu Val Glu Pro Cy - #s Arg Arg Arg Lys Glu# 975- Glu Ser Asp Lys Asn Tyr Phe Glu Gly Thr Gl - #y Tyr Ala Arg Val Pro# 990- Thr Gln Pro His Ala Pro Ile Pro Thr Phe Gl - #y Gln Thr Ile Gln Thr# 10050- Thr Val Asp Arg Gly Leu Leu Phe Phe Ala Gl - #u Asn Gly Asp Arg Phe# 10205- Ile Ser Leu Asn Ile Glu Asp Gly Lys Leu Me - #t Val Arg Tyr Lys Leu# 10401030 - # 1035- Asn Ser Glu Leu Pro Lys Glu Arg Gly Val Gl - #y Asp Ala Ile Asn Asn# 10550- Gly Arg Asp His Ser Ile Gln Ile Lys Ile Gl - #y Lys Leu Gln Lys Arg# 10705- Met Trp Ile Asn Val Asp Val Gln Asn Thr Il - #e Ile Asp Gly Glu Val# 10850- Phe Asp Phe Ser Thr Tyr Tyr Leu Gly Gly Il - #e Pro Ile Ala Ile Arg# 11005- Glu Arg Phe Asn Ile Ser Thr Pro Ala Phe Ar - #g Gly Cys Met Lys Asn# 11201110 - # 1115- Leu Lys Lys Thr Ser Gly Val Val Arg Leu As - #n Asp Thr Val Gly Val# 11350- Thr Lys Lys Cys Ser Glu Asp Trp Lys Leu Va - #l Arg Ser Ala Ser Phe# 11505- Ser Arg Gly Gly Gln Leu Ser Phe Thr Asp Le - #u Gly Leu Pro Pro Thr# 11650- Asp His Leu Gln Ala Ser Phe Gly Phe Gln Th - #r Phe Gln Pro Ser Gly# 11805- Ile Leu Leu Asp His Gln Thr Trp Thr Arg As - #n Leu Gln Val Thr Leu# 12001190 - # 1195- Glu Asp Gly Tyr Ile Glu Leu Ser Thr Ser As - #p Ser Gly Gly Pro Ile# 12150- Phe Lys Ser Pro Gln Thr Tyr Met Asp Gly Le - #u Leu His Tyr Val Ser# 12305- Val Ile Ser Asp Asn Ser Gly Leu Arg Leu Le - #u Ile Asp Asp Gln Leu# 12450- Leu Arg Asn Ser Lys Arg Leu Lys His Ile Se - #r Ser Ser Arg Gln Ser# 12605- Leu Arg Leu Gly Gly Ser Asn Phe Glu Gly Cy - #s Ile Ser Asn Val Phe# 12801270 - # 1275- Val Gln Arg Leu Ser Leu Ser Pro Glu Val Le - #u Asp Leu Thr Ser Asn# 12950- Ser Leu Lys Arg Asp Val Ser Leu Gly Gly Cy - #s Ser Leu Asn Lys Pro# 13105- Pro Phe Leu Met Leu Leu Lys Gly Ser Thr Ar - #g Phe Asn Lys Thr Lys# 13250- Thr Phe Arg Ile Asn Gln Leu Leu Gln Asp Th - #r Pro Val Ala Ser Pro# 13405- Arg Ser Val Lys Val Trp Gln Asp Ala Cys Se - #r Pro Leu Pro Lys Thr# 13601350 - # 1355- Gln Ala Asn His Gly Ala Leu Gln Phe Gly As - #p Ile Pro Thr Ser His# 13750- Leu Leu Phe Lys Leu Pro Gln Glu Leu Leu Ly - #s Pro Arg Ser Gln Phe# 13905- Ala Val Asp Met Gln Thr Thr Ser Ser Arg Gl - #y Leu Val Phe His Thr# 14050- Gly Thr Lys Asn Ser Phe Met Ala Leu Tyr Le - #u Ser Lys Gly Arg Leu# 14205- Val Phe Ala Leu Gly Thr Asp Gly Lys Lys Le - #u Arg Ile Lys Ser Lys# 14401430 - # 1435- Glu Lys Cys Asn Asp Gly Lys Trp His Thr Va - #l Val Phe Gly His Asp# 14550- Gly Glu Lys Gly Arg Leu Val Val Asp Gly Le - #u Arg Ala Arg Glu Gly# 14705- Ser Leu Pro Gly Asn Ser Thr Ile Ser Ile Ar - #g Ala Pro Val Tyr Leu# 14850- Gly Ser Pro Pro Ser Gly Lys Pro Lys Ser Le - #u Pro Thr Asn Ser Phe# 15005- Val Gly Cys Leu Lys Asn Phe Gln Leu Asp Se - #r Lys Pro Leu Tyr Thr# 15201510 - # 1515- Pro Ser Ser Ser Phe Gly Val Ser Ser Cys Le - #u Gly Gly Pro Leu Glu# 15350- Lys Gly Ile Tyr Phe Ser Glu Glu Gly Gly Hi - #s Val Val Leu Ala His# 15505- Ser Val Leu Leu Gly Pro Glu Phe Lys Leu Va - #l Phe Ser Ile Arg Pro# 15650- Arg Ser Leu Thr Gly Ile Leu Ile His Ile Gl - #y Ser Gln Pro Gly Lys# 15805- His Leu Cys Val Tyr Leu Glu Ala Gly Lys Va - #l Thr Ala Ser Met Asp# 16001590 - # 1595- Ser Gly Ala Gly Gly Thr Ser Thr Ser Val Th - #r Pro Lys Gln Ser Leu# 16150- Cys Asp Gly Gln Trp His Ser Val Ala Val Th - #r Ile Lys Gln His Ile# 16305- Leu His Leu Glu Leu Asp Thr Asp Ser Ser Ty - #r Thr Ala Gly Gln Ile# 16450- Pro Phe Pro Pro Ala Ser Thr Gln Glu Pro Le - #u His Leu Gly Gly Ala# 16605- Pro Ala Asn Leu Thr Thr Leu Arg Ile Pro Va - #l Trp Lys Ser Phe Phe# 16801670 - # 1675- Gly Cys Leu Arg Asn Ile His Val Asn His Il - #e Pro Val Pro Val Thr# 16950- Glu Ala Leu Glu Val Gln Gly Pro Val Ser Le - #u Asn Gly Cys Pro Asp# 17105- Gln- (2) INFORMATION FOR SEQ ID NO:25:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 135 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#of 3EpA cDNA encoding amino-terminal region of - # E170;- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..135- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25:- ATG GGA TGG CTG TGG ATC TTT GGG GCA GCC CT - #G GGG CAG TGT CTG GGC 48Met Gly Trp Leu Trp Ile Phe Gly Ala Ala Le - #u Gly Gln Cys Leu Gly# 15- TAC AGT TCA CAG CAG CAA AGG GTG CCA TTT CT - #T CAG CCT CCC GGT CAA 96Tyr Ser Ser Gln Gln Gln Arg Val Pro Phe Le - #u Gln Pro Pro Gly Gln# 30# 135A CTG CAA GCG AGT TAT GTG GAG TTT AG - #A CCC AGCSer Gln Leu Gln Ala Ser Tyr Val Glu Phe Ar - #g Pro Ser# 45- (2) INFORMATION FOR SEQ ID NO:26:- (i) SEQUENCE CHARACTERISTICS:#acids (A) LENGTH: 45 amino (B) TYPE: amino acid (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: protein#of amino terminal region of E170ce encoded b - #y 3EpA cDNA; see FIGURE 18A- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:26:- Met Gly Trp Leu Trp Ile Phe Gly Ala Ala Le - #u Gly Gln Cys Leu Gly# 15- Tyr Ser Ser Gln Gln Gln Arg Val Pro Phe Le - #u Gln Pro Pro Gly Gln# 30- Ser Gln Leu Gln Ala Ser Tyr Val Glu Phe Ar - #g Pro Ser# 45- (2) INFORMATION FOR SEQ ID NO:27:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 435 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: cDNA to mRNA#of region of 3EpB cDNA encodingnce amino ter - #minal region of E170; see FIGURE 18B- (iii) HYPOTHETICAL: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..435- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:27:- CCC ACC TCC TAC CTG GGG GAC AAG GTT TCT TC - #A TAT GGT GGT TAC CTC 48Pro Thr Ser Tyr Leu Gly Asp Lys Val Ser Se - #r Tyr Gly Gly Tyr Leu# 15- ACT TAC CAA GCC AAG TCC TTT GGC TTG CCT GG - #C GAC ATG GTT CTT CTG 96Thr Tyr Gln Ala Lys Ser Phe Gly Leu Pro Gl - #y Asp Met Val Leu Leu# 30- GAA AAG AAG CCG GAT GTA CAG CTC ACT GGT CA - #G CAC ATG TCC ATC ATC 144Glu Lys Lys Pro Asp Val Gln Leu Thr Gly Gl - #n His Met Ser Ile Ile# 45- TAT GAG GAG ACA AAC ACC CCA CGG CCA GAC CG - #G CTG CAT CAT GGA CGA 192Tyr Glu Glu Thr Asn Thr Pro Arg Pro Asp Ar - #g Leu His His Gly Arg# 60- GTG CAC GTG GTC GAG GGA AAC TTC AGA CAT GC - #C AGC AGC CGT GCC CCA 240Val His Val Val Glu Gly Asn Phe Arg His Al - #a Ser Ser Arg Ala Pro# 80- GTG TCT AGG GAG GAG CTG ATG ACA GTG CTG TC - #T GGA CTG GCA GAT GTG 288Val Ser Arg Glu Glu Leu Met Thr Val Leu Se - #r Gly Leu Ala Asp Val# 95- CGC ATC CAA GGC CTC TAC TTC ACA GAG ACT CA - #A AGG CTC ACC CTG AGC 336Arg Ile Gln Gly Leu Tyr Phe Thr Glu Thr Gl - #n Arg Leu Thr Leu Ser# 110- GAG GTG GGG CTA GAG GAA GCC TCT GAC ACA GG - #A AGT GGG CGC ATA GCA 384Glu Val Gly Leu Glu Glu Ala Ser Asp Thr Gl - #y Ser Gly Arg Ile Ala# 125- CTT GCT GTG GAA ATC TGT GCC TGC CCC CCT GC - #C TAC GCT GGT GAC TCT 432Leu Ala Val Glu Ile Cys Ala Cys Pro Pro Al - #a Tyr Ala Gly Asp Ser# 140# 435Cys145- (2) INFORMATION FOR SEQ ID NO:28:- (i) SEQUENCE CHARACTERISTICS:#acids (A) LENGTH: 145 amino (B) TYPE: amino acid (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: protein#terminal region of E170 encoded by 3EpB; see - # FIGURE 18B.- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:28:- Pro Thr Ser Tyr Leu Gly Asp Lys Val Ser Se - #r Tyr Gly Gly Tyr Leu# 15- Thr Tyr Gln Ala Lys Ser Phe Gly Leu Pro Gl - #y Asp Met Val Leu Leu# 30- Glu Lys Lys Pro Asp Val Gln Leu Thr Gly Gl - #n His Met Ser Ile Ile# 45- Tyr Glu Glu Thr Asn Thr Pro Arg Pro Asp Ar - #g Leu His His Gly Arg# 60- Val His Val Val Glu Gly Asn Phe Arg His Al - #a Ser Ser Arg Ala Pro# 80- Val Ser Arg Glu Glu Leu Met Thr Val Leu Se - #r Gly Leu Ala Asp Val# 95- Arg Ile Gln Gly Leu Tyr Phe Thr Glu Thr Gl - #n Arg Leu Thr Leu Ser# 110- Glu Val Gly Leu Glu Glu Ala Ser Asp Thr Gl - #y Ser Gly Arg Ile Ala# 125- Leu Ala Val Glu Ile Cys Ala Cys Pro Pro Al - #a Tyr Ala Gly Asp Ser# 140- Cys145- (2) INFORMATION FOR SEQ ID NO:29:- (i) SEQUENCE CHARACTERISTICS:#pairs (A) LENGTH: 468 base (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: DNA (genomic) (A) DESCRIPTION: Sequences - # shared by 3EpA and 3EpB cDNAsin the amino - # terminal coding region; see FIGURE 18C- (iii) HYPOTHETICAL: NO- (iv) ANTI-SENSE: NO- (vi) ORIGINAL SOURCE: (A) ORGANISM: Homo sapi - #ens- (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 1..468- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:29:- CAG GGT TGT AGC CCT GGA TAC TAT CGG GAT CA - #T AAA GGC TTG TAT ACC 48Gln Gly Cys Ser Pro Gly Tyr Tyr Arg Asp Hi - #s Lys Gly Leu Tyr Thr# 15- GGA CGG TGT GTT CCC TGC AAT TGC AAC GGA CA - #T TCA AAT CAA TGC CAG 96Gly Arg Cys Val Pro Cys Asn Cys Asn Gly Hi - #s Ser Asn Gln Cys Gln# 30- GAT GGC TCA GGC ATA TGT GTT AAC TGT CAG CA - #C AAC ACC GCG GGA GAG 144Asp Gly Ser Gly Ile Cys Val Asn Cys Gln Hi - #s Asn Thr Ala Gly Glu# 45- CAC TGT GAA CGC TGC CAG GAG GGC TAC TAT GG - #C AAC GCC GTC CAC GGA 192His Cys Glu Arg Cys Gln Glu Gly Tyr Tyr Gl - #y Asn Ala Val His Gly# 60- TCC TGC AGG GCC TGC CCA TGT CCT CAC ACT AA - #C AGC TTT GCC ACT GGC 240Ser Cys Arg Ala Cys Pro Cys Pro His Thr As - #n Ser Phe Ala Thr Gly# 80- TGT GTG GTG AAT GGG GGA GAC GTG CGG TGC TC - #C TGC AAA GCT GGG TAC 288Cys Val Val Asn Gly Gly Asp Val Arg Cys Se - #r Cys Lys Ala Gly Tyr# 95- ACA GGA ACA CAG TGT GAA AGG TGT GCA CCG GG - #A TAT TTC GGG AAT CCC 336Thr Gly Thr Gln Cys Glu Arg Cys Ala Pro Gl - #y Tyr Phe Gly Asn Pro# 110- CAG AAA TTC GGA GGT AGC TGC CAA CCA TGC AG - #T TGT AAC AGC AAT GGC 384Gln Lys Phe Gly Gly Ser Cys Gln Pro Cys Se - #r Cys Asn Ser Asn Gly# 125- CAG CTG GGC AGC TGT CAT CCC CTG ACT GGA GA - #C TGC ATA AAC CAA GAA 432Gln Leu Gly Ser Cys His Pro Leu Thr Gly As - #p Cys Ile Asn Gln Glu# 140# 468GAT AGC AGC CCT GCA GAA GAA TGT GA - #T GATPro Lys Asp Ser Ser Pro Ala Glu Glu Cys As - #p Asp145 1 - #50 1 - #55- (2) INFORMATION FOR SEQ ID NO:30:- (i) SEQUENCE CHARACTERISTICS:#acids (A) LENGTH: 156 amino (B) TYPE: amino acid (D) TOPOLOGY: linear- (ii) MOLECULE TYPE: protein#terminal region of E170 encoded by the seque - #nces shown in FIGURE 18C.- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:30:- Gln Gly Cys Ser Pro Gly Tyr Tyr Arg Asp Hi - #s Lys Gly Leu Tyr Thr# 15- Gly Arg Cys Val Pro Cys Asn Cys Asn Gly Hi - #s Ser Asn Gln Cys Gln# 30- Asp Gly Ser Gly Ile Cys Val Asn Cys Gln Hi - #s Asn Thr Ala Gly Glu# 45- His Cys Glu Arg Cys Gln Glu Gly Tyr Tyr Gl - #y Asn Ala Val His Gly# 60- Ser Cys Arg Ala Cys Pro Cys Pro His Thr As - #n Ser Phe Ala Thr Gly# 80- Cys Val Val Asn Gly Gly Asp Val Arg Cys Se - #r Cys Lys Ala Gly Tyr# 95- Thr Gly Thr Gln Cys Glu Arg Cys Ala Pro Gl - #y Tyr Phe Gly Asn Pro# 110- Gln Lys Phe Gly Gly Ser Cys Gln Pro Cys Se - #r Cys Asn Ser Asn Gly# 125- Gln Leu Gly Ser Cys His Pro Leu Thr Gly As - #p Cys Ile Asn Gln Glu# 140- Pro Lys Asp Ser Ser Pro Ala Glu Glu Cys As - #p Asp145 1 - #50 1 - #55__________________________________________________________________________

Number	Name	Date
4016036	Green	Apr 1977
4304866	Green	Dec 1981
4769317	Hefton	Sep 1988

	Number	Date	Country
Parent	154638	Nov 1993
Parent	654103	Feb 1991

	Number	Date	Country
Parent	115918	Sep 1993
Parent	607137	Oct 1990

Epiligrin, an epithelial ligand for integrins

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