Patent Grant
6902887
1. Field of the Invention
The present invention relates to methods for monitoring expression of a plurality of genes in filamentous fungal cells. The present invention also relates to expressed sequenced tags and to substrates and computer readable media containing such expressed sequenced tags for monitoring expression of a plurality of genes in filamentous fungal cells.
2. Description of the Related Art
Microarray technology is increasingly becoming the method of choice for the quantitative and simultaneous analysis of the expression levels of many thousands of genes. Microarray analyses typically follow the steps of gene selection, microarray synthesis, sample preparation, array hybridization, detection, and data analysis (Watson et al. 1998, Current Opinion in Biotechnology 9: 609-614).
PCR-amplified coding sequences of genomic DNA are particularly useful in microarrays for obtaining global expression profiles where the genome of the organism has been fully sequenced.
Chu et al., 1998, Science 282: 699-705 disclose the use of microarrays containing PCR-amplified genome coding sequences for determining the temporal expression of Saccharomyces cerevisiae genes during sporulation.
For other organisms whose genomes have not been sequenced, global expression profiles may be obtained with arraying (1) random genomic DNA segments or clones (e.g. from a genomic DNA library): (2) random cDNA clones (e.g., from one or more cDNA libraries) that are uncharacterized at the DNA sequence level, or (3) EST clones that have been sequenced and partially characterized with respect to putative identification and function.
However, there are disadvantages with using random genomic or cDNA clones from organisms whose genomes have not been fully sequenced. These disadvantages include (1) more than one gene may be represented on a single clone; (2) no gene(s) may be encoded on a single clone; (3) extensive characterization and DNA sequencing is required to follow-up array spots that appear interesting; and (4) duplicity, multiplicity, and reduncancy add to the follow-up work.
Expressed sequenced tags (ESTs) are partial cDNA sequences of expressed genes. Simply state, an EST is a segment of a sequence from a cDNA clone that corresponds to the mRNA of a specific gene. The use of sequenced ESTs in microarrays compared to genomic clones or random cDNA clones provides several advantages especially for organisms whose genomes have not been sequenced. First, one spot on an array equals one gene or open reading frame, so redundancy is eliminated. Second, since sequence information is available so that redundancy and follow-up characterization is minimized. Third, EST microarrays can be organized based on function of the gene products to facilitate analysis of the results (e.g., ESTs encoding enzymes from the same metabolic pathway can be arranged or grouped accordingly).
Ruan et al., 1998, The Plant Journal 15: 821-833, disclose the use of microarrays containing Arabidopsis thaliana EST sequences for determining the temporal expression of Arabidopsis thaliana genes in root, leaf, and two stages of floral development.
Iyer et al., 1999, Science 283: 83-87, disclose the use of microarrays containing human EST sequences for determining the temporal expression of human fibroblast cells in response to serum.
Hayward et al., 2000, Molecular Microbiology 35: 6-14, disclose shotgun DNA microarrays and stage-specific gene expression in Plasmodium falciparum malaria.
Filamentous fungi are increasingly being used as host microorganisms for the industrial production of enzymes and other proteins whether endogenous or heterogenous to the microorganisms. There is a need in the art to provide methods for monitoring the global expression of genes from filamentous fungal cells to improve the production potential of these microorganisms.
It is an object of the present invention to provide alternative methods for monitoring expression of a plurality of genes in filamentous fungal cells.
The present invention relates to methods for monitoring differential expression of a plurality of genes in a first filamentous fungal cell relative to expression of the same genes in one or more second filamentous fungal cells, comprising:
The present invention further relates to isolated ESTs obtained from Fusarium venenatum (SEQ ID NOs. 1-3770), Aspergillus niger (SEQ ID NOs. 3771-4376), Aspergillus oryzae (SEQ ID NOs. 4377-7401), and Trichoderma reesei (SEQ ID NOs. 7402-7860).
The present invention also relates to computer readable media and substrates containing an array of such filamentous fungal ESTs for monitoring differential expression of a plurality of genes in a first filamentous fungal cell relative to expression of the same genes in one or more second filamentous fungal cells.
The present invention relates to methods for monitoring differential expression of a plurality of genes in a first filamentous fungal cell relative to expression of the same genes in one or more second filamentous fungal cells. The methods comprise (a) adding a mixture of fluorescence-labeled nucleic acids isolated from the two or more filamentous fungal cells with different fluorescent reporters for each cell's nucleic acids to a substrate containing an array of filamentous fungal ESTs under conditions where the nucleic acids hybridize to complementary sequences of the ESTs in the array; and (b) examining the array by fluorescence under fluorescence excitation conditions wherein the relative expression of the genes in the two or more cells is determined by the observed fluorescence emission color of each spot in the array.
The methods of the present invention may be used to monitor global expression of a plurality of genes from a filamentous fungal cell, discover new genes, identify possible functions of unknown open reading frames, and monitor gene copy number variation and stability. For example, the global view of changes in expression of genes may be used to provide a picture of the way in which filamentous fungal cells adapt to changes in culture conditions, environmental stress, or other physiological provocation. Other possibilities for monitoring global expression include spore morphogenesis, recombination, metabolic or catabolic pathway engineering.
The methods of the present invention are particularly advantages because one spot on an array equal one gene or open reading frame; extensive follow-up characterization is unnecessary since sequence information is available, and EST microarrays can be organized based on function of the gene products.
Expressed Sequenced Tags
The term “expressed sequenced tag” or “EST” is defined herein as a segment of a sequence from a cDNA clone of an expressed filamentous fungal gene. The term “EST” will be understood to also include two or more ESTs assembled into a contig. In the methods of the present invention, the filamentous fungal ESTs described herein preferably represent a plurality of genes present in the two or more filamentous fungal cells to be evaluated.
ESTs are generally generated as follows: Total polyadenylated mRNA is isolated from a filamentous fungal cell and reverse transcribed into total cDNA. The total cDNA is digested with a restriction endonuclease, size-selected by agarose gel electrophoresis, isolated, and ligated into a vector, e.g., pZErO-2.1. The ligation mixture is transformed into competent E. coli cells and transformants are selected under selective pressure, e.g., kanamycin selection. The cDNA libraries isolated from the selected transformants are amplified, isolated, and partially sequenced. The partial sequences are then compared to sequences in various publicly available databases for identification.
Any method known in the art may be used for generating ESTs (see, for example, Adams et al., 1991, Science 252: 1651-1656; Fields, 1996, Tibtech 14: 286-289; Weinstock et al., 1994, Current Opinion in Biotechnology 5: 599-603; Matsubara and Okubo, 1993, Current Opinions in Biotechnology 4: 672-677; Nelson et al., 1997, Fungal Genet. Biol. 21: 348-363; Roe at al., http://www.genome.ou.edu/fungal.html).
In the methods of the present invention, the filamentous fungal ESTs are preferably at least about 50 bp in length, more preferably at least about 100 bp in length, even more preferably at least about 150 bp in length, and most preferably at least about 200 bp in length. Furthermore, the ESTs are preferably directional ESTs. However, nondirectional ESTs may also be used. A “directional EST” is defined as a cDNA cloned in the same orientation relative to the vector cloning sites, e.g., 5′→3′ or 3′→5′.
The filamentous fungal ESTs may be obtained from any filamentous fungal cell but preferably from an Acremonium, Aspergillus, Fusarium, Humicola, Mucor, Myceliophthora, Neurospora, Penicillium, Thielavia, Tolypocladium, or Trichoderma cell, and more preferably from an Aspergillus aculeatus, Aspergillus awamori, Aspergillus foetidus, Aspergillus japonicus, Asperigillus nidulans, Aspergillus niger, Aspergillus oryzae, Fusarium bactridioides, Fusarium cerealis, Fusarium crookwellense, Fusarium culmorum, Fusarium graminearum, Fusarium gramimum, Fusarium heterosporum, Fusarium negundi, Fusarium oxysporum, Fusarium reticulatum, Fusarium roseum, Fusarium sambucinum, Fusarium sarcochroum, Fusarium sporotrichioides, Fusarium sulphureum, Fusarium torulosum, Fusarium trichothecioides, Fusarium venenatum, Humicola insolens, Humicola Ianuginosa, Mucor miehei, Myceliophthora thermophila, Neurospora crassa, Penicillium purpurogenum, Thielavia terrestris, Trichoderma harzianium, Trichoderma koningii, Trichoderma longibrachiatum, Trichoderma reesei, or Trichoderma viride cell.
In a preferred embodiment, the ESTs are obtained from Fusarium venenatum. In a more preferred embodiment, the ESTs are obtained from Fusarium venenatum A3/5, which was originally deposited as Fusarium gramincarum ATCC 20334 and recently reclassified as Fusarium venenatum by Yoder and Christianson, 1998, Fungal genetics and Biology 23: 62-80 and O'Donnell et al., 1998, Fungal Genetics and Biology 23: 57-67; as well as taxonomic equivalents of Fusarium venenatum regardless of the species name by which they are currently known. In another more preferred embodiment, the Fusarium venenatum cell is a morphological mutant of Fusarium venenatum A3/5 or Fusarium venenatum ATCC 20334, as disclosed in WO 97/26330. In a most preferred embodiment, the Fusarium venenatum ESTs are selected from the group consisting of SEQ ID NOs. 1-3770, nucleic acid fragments of SEQ ID NOs. 1-3770, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 1-3770.
In another preferred embodiment, the ESTs are obtained from Aspergillus niger. In another more preferred embodiment, the Aspergillus niger ESTs are selected from the group consisting of SEQ ID NOs. 3771-4376, nucleic acid fragments of SEQ ID NOs. 3771-4376, and nucleotide sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 3771-4376.
In another preferred embodiment, the ESTs are obtained from Aspergillus oryzae. In another more preferred embodiment, the ESTs are obtained from Aspergillus oryzae strain IFO 4177. In another most preferred embodiment, the Aspergillus oryzae ESTs are selected from the group consisting of SEQ ID NOs. 4377-7401, nucleic acid fragments of SEQ ID NOs. 4377-7401, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to the sequences of SEQ ID NOs. 4377-7401.
In another preferred embodiment, the ESTs are obtained from Trichoderma reesei. In another more preferred embodiment, the ESTs are obtained from Trichoderma reesei strain RutC-30 (Montenecourt and Eveleigh, 1979, Adv. Chem. Ser. 181: 289-301). In another most preferred embodiment, the Trichoderma reesei ESTs are selected from the group consisting of SEQ ID NOs. 7402-7860, nucleic acid fragments of SEQ ID NOs. 7402-7860, or nucleic acid sequences having at least 95%, preferably at least 99% and most preferably at least 99.9% homology to a sequence of SEQ ID NOs. 7402-7860.
For purposes of the present invention, the degree of homology between two nucleic acid sequences is determined by the Wilbur-Lipman method (Wilbur and Lipman, 1983, Proceedings of the National Academy of Science USA 80: 726-730) using the LASERGENE™ MEGALIGN™ software (DNASTAR, Inc., Madison, Wis.) with an identity table and the following multiple alignment parameters: Gap penalty of 10 and gap length penalty of 10. Pairwise alignment parameters are Ktuple=3, gap penalty=3, and windows=20.
Microarrays
The term “an array of ESTs” is defined herein as a linear or two-dimensional array of preferably discrete elements of ESTs, each having a finite area, formed on the surface of a solid support.
The term “microarray” is defined herein as an array of EST elements having a density of discrete EST elements of at least about 100/cm2, and preferably at least about 1000/cm2. The EST elements in a microarray have typical dimensions, e.g., diameters, in the range of between about 10 to about 250 μm, preferably in the range of between about 10 to about 200 μm, more preferably in the range of between about 20 to about 150 μm, even more preferably in the range of between about 20 to about 100 μm, most preferably in the range of between about 20 to about 75 μm, and even most preferably in the range of between about 25 to about 50 μm, and are separated from other EST elements in the microarray by about the same distance.
Methods and instruments for forming microarrays on the surface of a solid support are well known in the art. See, for example, U.S. Pat. No. 5,807,522; U.S. Pat. No. 5,700,637; and U.S. Pat. No. 5,770,151. The instrument may be an automated device such as described in U.S. Pat. No. 5,807,522.
The term “a substrate containing an array of ESTs” is defined herein as a solid support having deposited on the surface of the support one or more of a plurality of ESTs for use in detecting binding of labeled cDNAs to the ESTs.
The substrate may, in one aspect, be a glass support (e.g., glass slide) having a hydrophilic or hydrophobic coating on the surface of the support, and an array of distinct ESTs electrostatically bound non-covalently to the coating, where each distinct EST is disposed at a separate, defined position.
Each microarray in the substrate preferably contains at least 103 distinct ESTs in a surface area of less than about 1 cm2. Each distinct EST (i) is disposed at a separate, defined position in the array, (ii) has a length of at least 50 bp, and (iii) is present in a defined amount between about 0.1 femtomoles and 100 nanomoles or higher if necessary.
For a hydrophilic coating, the glass slide is coated by placing a film of a polycationic polymer with a uniform thickness on the surface of the slide and drying the film to form a dried coating. The amount of polycationic polymer added should be sufficient to form at least a monolayer of polymers on the glass surface. The polymer film is bound to the surface via electrostatic binding between negative silyl-OH groups on the surface and charged cationic groups in the polymers. Such polycationic polymers include, but are not limited to, polylysine and polyarginine.
Another coating strategy employs reactive aldehydes to couple DNA to the slides (Schena et al., 1996, Proceedings of the National Academy of Science USA 93: 10614-10619; Heller at al., 1997, Proceedings of the National Academy of Science USA 94: 2150-2155).
Alternatively, the surface may have a relatively hydrophobic character, i.e., one that causes aqueous medium deposited on the surface to bead. A variety of known hydrophobic polymers, such as polystyrene, polypropylene, or polyethylene, have desirable hydrophobic properties, as do glass and a variety of lubricant or other hydrophobic films that may be applied to the support surface. A support surface is “hydrophobic” if an aqueous droplet applied to the surface does not spread out substantially beyond the area size of the applied droplet, wherein the surface acts to prevent spreading of the droplet applied to the surface by hydrophobic interaction with the droplet.
In another aspect, the substrate may be a multi-cell substrate where each cell contains a microarray of ESTs, and preferably an identical microarray, formed on a porous surface. For example, a 96-cell array may typically have array dimensions between about 12 and 244 mm in width and 8 and 400 mm in length, with the cells in the array having width and length dimension of {fraction (1/12)} and ⅛ the array width and length dimensions, respectively, i.e., between about 1 and 20 in width and 1 and 50 mm in length.
The solid support may include a water-impermeable backing such as a glass slide or rigid polymer sheet, or other non-porous material. Formed on the surface of the backing is a water-permeable film which is formed of porous material. Such porous materials include, but are not limited to, nitrocellulose membrane nylon, polypropylene, and PVDF polymer. The thickness of the film is preferably between about 10 and 1000 μm. The film may be applied to the backing by spraying or coating, or by applying a preformed membrane to the backing.
The film surface may be partitioned into a desirable array of cells by water-impermeable grid lines typically at a distance of about 100 to 2000 μm above the film surface. The grid lines can be formed on the surface of the film by laying down an uncured flowable resin or elastomer solution in an array grid, allowing the material to infiltrate the porous film down to the backing, and then curing the grid lines to form the cell-array substrate.
The barrier material of the grid lines may be a flowable silicone, wax-based material, thermoset material (e.g., epoxy), or any other useful material. The grid lines may be applied to the solid support using a narrow syringe, printing techniques, heat-seal stamping, or any other useful method known in the art.
Each well preferably contains a microarray of distinct ESTs. “Distinct ESTs” as applied to the ESTs forming a microarray is defined herein as an array member which is distinct from other array members on the basis of a different EST sequence, and/or different concentrations of the same or distinct ESTs, and/or different mixtures of distinct ESTs or different-concentrations of ESTs. Thus an array of “distinct ESTs” may be an array containing, as its members, (i) distinct ESTs, which may have a defined amount in each member, (ii) different, graded concentrations of given-sequence ESTs, and/or (iii) different-composition mixtures of two or more distinct ESTs.
However, any type of substrate known in the art may be used in the methods of the present invention.
The delivery of a known amount of a selected EST to a specific position on the support surface is preferably performed with a dispensing device equipped with one or more tips for insuring reproducible deposition and location of the ESTs and for preparing multiple arrays. Any dispensing device known in the art may be used in the methods of the present invention. See, for example, U.S. Pat. No. 5,807,522. The dispensing device preferably contains a plurality of tips.
For liquid-dispensing on a hydrophilic surface, the liquid will have less of a tendency to bead, and the dispensed volume will be more sensitive to the total dwell time of the dispenser tip in the immediate vicinity of the support surface.
For liquid-dispensing on a hydrophobic surface, flow of fluid from the tip onto the support surface will continue from the dispenser onto the support surface until it forms a liquid bead. At a given bead size, i.e., volume, the tendency of liquid to flow onto the surface will be balanced by the hydrophobic surface interaction of the bead with the support surface, which acts to limit the total bead area on the surface, and by the surface tension of the droplet, which tends toward a given bead curvature. At this point, a given bead volume will have formed, and continued contact of the dispenser tip with the bead, as the dispenser tip is being withdrawn, will have little or no effect on bead volume.
The desired deposition volume, i.e., bead volume, formed is preferably in the range 2 pl (picoliters) to 2 nl (nanoliters), although volumes as high as 100 nl or more may be dispensed. It will be appreciated that the selected dispensed volume will depend on (i) the “footprint” of the dispenser tip(s), i.e., the size of the area spanned by the tip(s), (ii) the hydrophobicity of the support surface, and (iii) the time of contact with and rate of withdrawal of the tip(s) from the support surface. In addition, bead size may be reduced by increasing the viscosity of the medium, effectively reducing the flow time of liquid from the dispensing device onto the support surface. The drop size may be further constrained by depositing the drop in a hydrophilic region surrounded by a hydrophobic grind pattern on the support surface.
At a given tip size, bead volume can be reduced in a controlled fashion by increasing surface hydrophobicity, reducing time of contact of the tip with the surface, increasing rate of movement of the tip away from the surface, and/or increasing the viscosity of the medium. Once these parameters are fixed, a selected deposition volume in the desired pl to nl range can be achieved in a repeatable fashion.
After depositing a liquid droplet of an EST sample at one selected location on a support, the tip may be moved to a corresponding position on a second support, the EST sample is deposited at that position, and this process is repeated until the EST sample has been deposited at a selected position on a plurality of supports.
This deposition process may then be repeated with another EST sample at another microarray position on each of the supports.
The diameter of each EST region is preferably between about 20-200 μm. The spacing between each region and its closest (non-diagonal) neighbor, measured from center-to-center, is preferably in the range of about 20-400 μm. Thus, for example, an array having a center-to-center spacing of about 250 μm contains about 40 regions/cm2 or 1,600 regions/cm2. After formation of the array, the support is treated to evaporate the liquid of the droplet forming each region, to leave a desired array of dried, relatively flat EST regions. This drying may be done by heating or under vacuum.
Filamentous Fungal Cells
In the methods of the present invention, the two or more filamentous fungal cells may be any filamentous fungal cell where one of the cells is used as a reference for identifying differences in expression of the same or similar complement of genes in the other cell. In one aspect, the two or more cells are the same cell. For example, they may be compared under different growth conditions, e.g., oxygen limitation, nutrition, and/or physiology. In another aspect, one or more cells are mutants of the reference cell. For example, the mutant(s) may have a different phenotype. In a further aspect, the two or more cells are of different species (e.g., Aspergillus oryzae and Asperigillus sojae). In another further aspect, the two or more cells are of different genera. In an even further aspect, one or more cells are transformants of the reference cell, wherein the one or more transformants exhibit a different property. For example, the transformants may have an improved phenotype relative to the reference cell and/or one of the other transformants. The term “phenotype” is defined herein as an observable or outward characteristic of a cell determined by its genotype and modulated by its environment. Such improved phenotypes may include, but are not limited to, improved secretion or production of a protein or compound, reduced or no secretion or production of a protein or compound, improved or reduced expression of a gene, desirable morphology, an altered growth rate under desired conditions, relief of over-expression mediated growth inhibition, or tolerance to low oxygen conditions.
The filamentous fungal cells may be any filamentous fungal cells, but preferably Acremonium, Aspergillus, Fusarium, Humicola, Mucor, Myceliophthora, Neurospora, Penicillium, Thielavia, Tolypocladium, or Trichoderma cells, and more preferably Aspergillus aculeatus, Aspergillus awamori, Aspergillus foetidus, Aspergillus japonicus, Aspergillus nidulans, Aspergillus niger, Aspergillus oryzae, Fusarium bactridioides, Fusarium cerealis, Fusarium crookwellense, Fusarium culmorum, Fusarium graminearum, Fusarium graminum, Fusarium heterosporum, Fusarium negundi, Fusarium oxysporum, Fusarium reticulation, Fusarium roseum, Fusarium sambucinum, Fusarium sarcochroum, Fusarium sporotrichioides, Fusarium sulphureum, Fusarium torulosum, Fusarium trichothecioides, Fusarium venenatum, Humicola insolens, Humicola lanuginosa, Mucor miehei, Myceliophthora thermophila, Neurospora crassa, Penicillium purpurogenum, Thielavia terrestris, Trichoderma harzianum, Trichoderma koningii, Trichoderma longibrachiatum, Trichoderma reesei, or Trichoderma viride cells.
In a preferred embodiment, the filamentous fungal cells are Fusarium or Aspergillus cells. In a more preferred embodiment, the Fusarium cells are Fusarium venenatum cells. In another more preferred embodiment, the Aspergillus cells are Aspergillus niger cells. In another more preferred embodiment, the Aspergillus cells are Aspergillus oryzae cells.
In a most preferred embodiment, the Fusarium venenatum cells are Fusarium venenatum A3/5 cells as described herein. In another most preferred embodiment, the Fusarium venenatum cells are morphological mutants of Fusarium venenatum A3/5 as described herein. In another most preferred embodiment, the Aspergillus oryzae cells are Aspergillus oryzae strain IFO 4177 cells.
In the methods of the present invention, the cells are cultivated in a nutrient medium suitable for growth using methods well known in the art for isolation of the nucleic acids to be used as probes. For example, the cells may be cultivated by shake flask cultivation, small-scale or large-scale fermentation (including continuous, batch, fed-batch, or solid state fermentations) in laboratory or industrial fermentors performed in a suitable medium. cultivation takes place in a suitable nutrient medium comprising carbon and nitrogen sources and inorganic salts, using procedures known in the art. Suitable media are available from commercial suppliers or may be prepared according to published compositions (e.g., in catalogues of the American Type Culture Collection).
Nucleic Acid Probes
The nucleic acid probes from the two or more filamentous fungal cells may be any nucleic acid including genomic DNA, cDNA, and RNA, and may be isolated using standard methods known in the art. For example, cDNA probes may be obtained from the total polyadenylated mRNA isolated from the cells using standard methods and reverse transcribed into total cDNA.
The populations of isolated nucleic acid probes may be labeled with colorimetric, radioactive, fluorescent reporters, or other reporters using methods known in the art (Chen et. al., 1998, Genomics 51: 313-324: DeRisi et al., 1997, Science 278: 680-686: U.S. Pat. No. 5,770,367).
In a preferred embodiment, the probes are labeled with fluorescent reporters. For example, cDNA probes may be labeled during reverse transcription from the respective mRNA pools by incorporation of fluorophores as dye-labeled nucleotides (DeRisi et al., 1997, supra), e.g., Cy5-labeled deoxyuridine triphosphate, or the isolated cDNAs may be directly labeled with different fluorescent functional groups. Fluoroescent-labeled nucleotides include, but are not limited to, fluorescein conjugated nucleotide analogs (green fluorescence), lissamine nucleotide analogs (red fluorescence). Fluoroescent functional groups include, but are not limited to, Cy3 (a green fluorescent dye) and Cy5 (red fluorescent dye).
Array Hybridization
The labeled nucleic acids from the two or more filamentous fungal cells are then added to a substrate containing an array of ESTs under conditions where the nucleic acid pools from the two or more filamentous fungal cells hybridize to complementary sequences of the ESTs in the array. For purposes of the present invention, hybridization indicates that the labeled nucleic acids from the two or more cells hybridize to the ESTs under very low to very high stringency conditions.
A small volume of the labeled nucleic acids mixture is loaded onto the substrate. The solution will spread to cover the entire microarray. In the case of a multi-cell substrate, one or more solutions are loaded into each cell which stop at the barrier elements.
For nucleic acid probes of at least about 100 nucleotides in length, very low to very high stringency conditions are defined as prehybridization and hybridization at 42° C. in 5× SSPE, 0.3% SDS, 200 μg/ml sheared and denatured salmon sperm DNA, and either 25% formamide for very low and low stringencies, 35% formamide for medium and medium-high stringencies, or 50% formamide for high and very high stringencies, following standard Southern blotting procedures.
For nucleic acid probes of at least about 100 nucleotides in length, the carrier material is finally washed three times each for 15 minutes using 2× SSC, 0.2% SDS preferably at least at 45° C. (very low stringency), more preferably at least at 50° C. (low stringency), more preferably at least at 55° C. (medium stringency), more preferably at least at 60° C. (medium-high stringency), even more preferably at least at 65° C. (high stringency), and most preferably at least at 70° C. (very high stringency).
For shorter nucleic acid probes which are about 50 nucleotides to about 100 nucleotides in length, stringency conditions are defined as prehybridization, hybridization, and washing post-hybridization at 5° C. to 10° C. below the calculated Tm using the calculation according to Bolton and McCarthy (1962, Proceedings of the National Academy of Sciences USA 48:1390) in 0.9 M NaCl, 0.09 M Tris-HCl pH 7.6, 6 mM EDTA, 0.5% NP-40, 1× Denhardt's solution, 1 mM sodium pyrophosphate, 1 mM sodium monobasic phosphate, 0.1 mM ATP, and 0.2 mg of yeast RNA per ml following standard Southern blotting procedures.
For shorter nucleic acid probes which are about 50 nucleotides to about 100 nucleotides in length, the carrier material is washed once in 6× SCC plus 0.1% SDS for 15 minutes and twice each for 15 minutes using 6× SSC at 5° C. to 10° C. below the calculated Tm.
The choice of hybridization conditions will depend on the degree of homology between the ESTs and the nucleic acids obtained from the two or more filamentous fungal cells. For example, where the cells are the same cell from which the ESTs were obtained, high stringency conditions may be most suitable. Where the cells are from a genus or species different from which the ESTs were obtained, low or medium stringency conditions may be more suitable.
In a preferred embodiment, the hybridization is conducted under low stringency conditions. In a more preferred embodiment, the hybridization is conducted under medium stringency conditions. In a most preferred embodiment, the hybridization is conducted under high stringency conditions.
The entire solid support is then reacted with detection reagents if needed and analyzed using standard calorimetric, radioactive, or fluorescent detection means. All processing and detection steps are performed simultaneously to all of the microarrays on the solid support ensuring uniform assay conditions for all of the microarrays on the solid support.
Detection
The most common detection method is laser-induced fluorescence detection using confocal optics (Cheung et al., 1998, Nat. Genet. 18: 225-230). The array is examined under fluorescence excitation conditions such that (i) the ESTs in the array that hybridize to the nucleic acid probes obtained from one of the first cell and one or more second cells produces a distinct first fluorescence emission color or one or second fluorescence emission colors, respectively, and (ii) ESTs in the array that hybridize to substantially equal numbers of nucleic acid probes obtained from the first cell and one of the one or more second cells produce a distinct combined fluorescence emission color, respectively: wherein the relative expression of the genes in the two or more cells can be determined by the observed fluorescence emission color of each spot in the array.
The fluorescence excitation conditions are based on the selection of the fluorescence reporters. For example, Cy3 and Cy5 reporters are detected with solid state lasers operating at 532 nm and 632 nm, respectively.
Other methods of detection may be used as described herein.
Data Analysis
The fluorescence data obtained from the scanned image may then be analyzed using any of the commercially available image analysis software. The software preferably identifies array elements, subtracts backgrounds, deconvolutes multi-color images, flags or removes artifacts, verifies that controls have performed properly, and normalizes the signals (Chen et al., 1997, Journal of Biomedical Optics 2: 364-374).
Several computational methods have been described for the analysis and interpretation of microarray-based expression profiles including cluster analysis (Eisen et al., 1998, Proc. Nat. Acad. Sci. USA 95: 14863-14868), and supervised clustering methods based on representative hand-picked or computer-generated expression profiles (Chu et al., 1998, Science 282: 699-705).
Computer Readable Media
The filamentous fungal ESTs described herein may be “provided” in a variety of mediums to facilitate their use. The term “provided” refers to a manufacture comprising an array of filamentous fungal ESTs. Such manufactures provide a large portion of the genomes of Fusarium venenatum, Aspergillus niger, Aspergillus oryzae, or Trichoderma reesei and parts thereof (e.g., an open reading frame (ORF)) in a form which allows one skilled in the art to examine the manufacture using means not directly applicable to examining the genome of a subset thereof as it exists in nature or in purified form.
Thus, the present invention also relates to such a manufacture in the form of a computer readable medium comprising an array of ESTs selected from the group consisting of SEQ ID NOs. 1-7860, nucleic acid fragments of SEQ ID NOs. 1-7860, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 1-7860.
In a preferred embodiment, the computer readable medium comprises an array of Fusarium venenatum ESTs selected from the group consisting of SEQ ID NOs. 1—3770, nucleic acid fragments of SEQ ID NOs. 1-3770, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 1-3770. In a more preferred embodiment, the computer readable medium comprises an array of ESTs selected from the group consisting of SEQ ID NOs. 1-3770.
In another preferred embodiment, the computer readable medium comprises an array of Aspergillus niger ESTs selected from the group consisting of SEQ ID NOs. 3771-4376, nucleic acid fragments of SEQ ID NOs. 3771-4376, and nucleotide sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 3771-4376. In another more preferred embodiment, the computer readable medium comprises an array of ESTs selected from the group consisting of SEQ ID NOs. 3771-4376.
In another preferred embodiment, the computer readable medium comprises an array of Aspergillus oryzae ESTs selected from the group consisting of SEQ ID NOs. 4377-7401, nucleic acid fragments of SEQ ID NOs. 4377-7401, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to the sequences of SEQ ID NOs. 4377-7401. In another more preferred embodiment, the computer readable medium comprises an array of ESTs selected from the group consisting of SEQ ID NOs. 4377-7401.
In another preferred embodiment, the computer readable medium comprises an array of Trichoderma reesei ESTs selected from the group consisting of SEQ ID NOs. 7402-7860, nucleic acid fragments of SEQ ID NOs. 7402-7860, or nucleic acid sequences having at least 95%, preferably at least 99% and most preferably at least 99.9% homology to a sequence of SEQ ID NOs. 7402-7860. In another more preferred embodiment, the computer readable medium comprises an array of Trichoderma reesei ESTs selected from the group consisting of SEQ ID NOs. 7402-7860.
In one application of this embodiment, the ESTs of the present invention can be recorded on computer readable media. The term “computer readable media” is defined herein as any medium which can be read and accessed directly by a computer. Such computer readable media include, but are not limited to, magnetic storage media, e.g., floppy discs, hard disc storage medium, and magnetic tape; optical storage media, e.g., CD-ROM, DVD; electrical storage media, e.g., RAM and ROM; and hybrids of these categories, e.g., magnetic/optical storage media. One skilled in the art can readily appreciate how any of the presently known computer readable media can be used to create a manufacture comprising computer readable medium having recorded thereon a nucleotide sequence of the present invention. Likewise, it will be clear to those of skill how additional computer readable media that may be developed also can be used to create analogous manufactures having recorded thereon a nucleotide sequence of the present invention.
As used herein, “recorded” refers to a process for storing information on computer readable medium. One skilled in the art can readily adopt any of the presently known methods for recording information on computer readable medium to generate manufactures comprising the nucleotide sequence information of the present invention.
A variety of data storage structures are available for creating a computer readable medium having recorded thereon a nucleotide sequence of the present invention. The choice of the data storage structure will generally be based on the means chosen to access the stored information. In addition, a variety of data processor programs and formats can be used to store the nucleotide sequence information of the present invention on computer readable medium. The sequence information can be represented in a word processing text file, formatted in commercially-available software such as WordPerfect and Microsoft Word, or represented in the form of an ASCII file, stored in a database application, such as DB2, Sybase, Oracle, or the like. A skilled artisan can readily adapt any number of data-processor structuring formats (e.g., text file or database) in order to obtain computer readable medium having recorded thereon the nucleotide sequence information of the present invention.
Various computer software are publicly available that allow a skilled artisan to access sequence information provided in a computer readable medium. Thus, by providing in computer readable form an array of ESTs selected from the group consisting of SEQ ID NOs. 1-7860, nucleic acid fragments of SEQ ID NOs. 1-7860, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 1-7860 enables one skilled in the art to routinely access the provided sequence information for a wide variety of purposes.
Software utilizing the BLAST (Altschul et al., 1990, Journal of Molecular Biology 215: 403-410) and BLAZE (Brutlag et al., 1993, Comp. Chem. 17: 203-207) search algorithms may be used to identify open reading frames (ORFs) within a genome of interest, which contain homology to ORFs or proteins from both Fusarium venenatum, Aspergillus niger, Aspergillus oryzae, or Trichoderma reesei and from other organisms. Among the ORFs discussed herein are protein encoding fragments of the Fusarium venenatum, Aspergillus niger, Aspergillus oryzae, and Trichoderma reesei genome useful in producing commercially important proteins, such as enzymes used in fermentation reactions and in the production of commercially useful metabolites.
The present invention further provides systems, particularly computer-based systems, which contain the sequence information described herein. Such systems are designed to identify, among other things, genes and gene products—many of which could be products themselves or used to genetically modify an industrial expression host through increased or decreased expression of a specific gene sequence(s).
The term “a computer-based system” is defined here the hardware means, software means, and data storage means used to analyze the nucleotide sequence information of the present invention. The minimum hardware means of the computer-based systems of the present invention comprises a central processing unit (CPU), input means, output means, and data storage means. One skilled in the art can readily appreciate that any currently available computer-based system is suitable for use in the present invention.
As stated above, the computer-based systems of the present invention comprise a data storage means having stored therein a nucleotide sequence of the present invention and the necessary hardware means and software means for supporting and implementing a search means.
The term “data storage means” is defined herein as memory which can store nucleotide sequence information of the present invention, or a memory access means which can access manufactures having recorded thereon the nucleotide sequence information of the present invention.
The term “search means” refers is defined herein as one or more programs which are implemented on the computer-based system to compare a target sequence or target structural motif with the sequence information stored within the data storage means. Search means are used to identify fragments or regions of the present genomic sequences which match a particular target sequence or target motif. A variety of known algorithms are disclosed publicly and a variety of commercially available software for conducting search means are and can be used in the computer-based systems of the present invention. Examples of such software includes, but is not limited to, MacPattern (Fuchs, 1991, Comput. Appl. Biosci. 7: 105-106). BLASTN and BLASTX (NCBI). One skilled in the art can readily recognize that any one of the available algorithms or implementing software packages for conducting homology searches can be adapted for use in the present computer-based systems.
The term “target sequence” is defined here as any DNA or amino acid sequence of six or more nucleotides or two or more amino acids. One skilled in the art can readily recognize that the longer a target sequence is, the less likely a target sequence will be present as a random occurrence in the database. The most preferred sequence length of a target sequence is from about 10 to 100 amino acids or from about 30 to 300 nucleotide residues. However, it is well recognized that searches for commercially important fragments, such as sequence fragments involved in gene expression and protein processing, may be of shorter length.
The term “a target structural motif” or “target motif” is defined herein as any rationally selected sequence or combination of sequences in which the sequence(s) are chosen based on a three-dimensional configuration which is formed upon the folding of the target motif. There are a variety of target motifs known in the art. Protein target motifs include, but are not limited to, enzyme active sites and signal sequences, substrate and cofactor binding domains, transmembrane domains, and sites for post-translational modifications. Nucleic acid target motifs include, but are not limited to, promoter sequences, hairpin structures and inducible expression elements (protein binding sequences), repeats, palindromes, dyad symmetries, intron-exon boundaries, transcription and translation start and stop sites, and polyadenylation signals.
A variety of structural formats for the input and output means can be used to input and output the information in the computer-based systems of the present invention. A preferred format for an output means ranks fragments of the Fusarium venenatum, Aspergillus niger, Aspergillus oryzae, and Trichoderma reesei genomic sequences possessing varying degrees of homology to the target sequence or target motif. Such presentation provides one skilled in the art with a ranking of sequences which contain various amounts of the target sequence or target motif and identifies the degree of homology contained in the identified fragment.
A variety of comparing means can be used to compare a target sequence or target motif with the data storage means to identify sequence fragments of the Fusarium venenatum, Aspergillus niger, Aspergillus oryzae, and Trichoderma reesei genomes. For example, implementing software which utilize the BLAST and BLAZE algorithms, described in Altschul et al., 1990, Journal of Molecular Biology 215: 403-410, may be used to identify open reading frames within the Fusarium venenatum, Aspergillus niger, Aspergillus oryzae, or Trichoderma reesei genome or the genomes of other organisms. A skilled artisan can readily recognize that any one of the publicly available homology search programs can be used as the search means for the computer-based systems of the present invention. Of course, suitable proprietary systems that may be known to those of skill also may be employed in this regard.
Tables 1-4 in the present application provide listings of sequences, which can be products themselves or used to genetically modify an industrial expression host through increased or decreased expression of a specific gene sequence(s). These were generated by applying the above-mentioned computer based systems to the sequences of the invention. Tables 1-4 are generally referred to as lists of annotated EST sequences and furthermore serve an important task in the interpretation of the data generated by the method of the present invention.
Substrates
The present invention also relates to substrates as described herein comprising an array of filamentous fungal ESTs. In a preferred embodiment, the substrate comprises an array of filamentous fungal ESTs selected from the group consisting of SEQ ID NOs. 1-7860, nucleic acid fragments of SEQ ID NOs. 1-7860, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 1-7860. In a more preferred embodiment, the substrate comprises an array of EST sequences selected from the group consisting of SEQ ID NOs. 1-7860.
In a preferred embodiment, the substrate comprises an array of Fusarium venenatum ESTs selected from the group consisting of SEQ ID NOs. 1-3770, nucleic acid fragments of SEQ ID NOs. 1-3770, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 1-3770. In a more preferred embodiment, the substrate comprises an array of Fusarium venenatum ESTs selected from the group consisting of SEQ ID NOs. 1-3770.
In another preferred embodiment, the substrate comprises an array of Aspergillus niger ESTs selected from the group consisting of SEQ ID NOs. 3771-4376, nucleic acid fragments of SEQ ID NOs. 3771-4376, and nucleotide sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 3771-4376. In another more preferred embodiments, the substrate comprises an array of Aspergillus niger ESTs selected from the group consisting of SEQ ID NOs. 3771-4376.
In another preferred embodiment, the substrate comprises an array of Aspergillus oryzae ESTs selected from the group consisting of SEQ ID NOs. 4377-7401, nucleic acid fragments of SEQ ID NOs. 4377-7401, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to the sequences of SEQ ID NOs. 4377-7401. In another more preferred embodiment, the substrate comprises an array of Aspergillus oryzae ESTs selected from the group consisting of SEQ ID NOs. 4377-7401.
In another preferred embodiment, the substrate comprises an array of Trichoderma reesei ESTs selected from the group consisting of SEQ ID NOs. 7402-7860, nucleic acid fragments of SEQ ID NOs. 7402-7860, or nucleic acid sequences having at least 95%, preferably at least 99% and most preferably at least 99.9% homology to a sequence of SEQ ID NOs. 7402-7860. In another more preferred embodiment, the substrate comprises an array of Trichoderma reesei ESTs selected from the group consisting of SEQ ID NOs. 7402-7860.
Isolated Nucleic Acids
The present invention also relates to isolated filamentous fungal ESTs.
In a preferred embodiment, the isolated ESTs are Fusarium venenatum ESTs selected from the group consisting of SEQ ID NOs. 1-3770, nucleic acid fragments of SEQ ID NOs. 1-3770, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 1-3770. In a more preferred embodiment, the Fusarium venenatum ESTs are SEQ ID NOs. 1-3770.
In another preferred embodiment, the isolated ESTs are Aspergillus niger ESTs selected from the group consisting of SEQ ID NOs. 3771-4376, nucleic acid fragments of SEQ ID NOs. 3771-4376, and nucleotide sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to SEQ ID NOs. 3771-4376. In another more preferred embodiment, the Aspergillus niger ESTs are SEQ ID NOs. 3771-4376.
In another preferred embodiment, the isolated ESTs are Aspergillus oryzae ESTs selected from the group consisting of SEQ ID NOs. 4377-7401, nucleic acid fragments of SEQ ID NOs. 4377-7401, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to the sequences of SEQ ID NOs. 4377-7401.
In another preferred embodiment, the isolated ESTs are Trichoderma reesei ESTs selected from the group consisting of SEQ ID NOs. 7402-7860, nucleic acid fragments of SEQ ID NOs. 7402-7860, or nucleic acid sequences having at least 95%, preferably at least 99% and most preferably at least 99.9% homology to a sequence of SEQ ID NOs. 7402-7860. In another more preferred embodiment, the Trichoderma reesei ESTs are SEQ ID NOs. 7402-7860.
The present invention also relates to isolated nucleic acid sequences comprising any of the filamentous fungal ESTs selected from the group consisting of SEQ ID NOs. 1-7860, nucleic acid fragments of SEQ ID NOs. 1-7860, and nucleic acid sequences having at least 90%, preferably at least 95%, more preferably at least 99%, and most preferably at least 99.9% homology to the sequences of SEQ ID NOs. 1-7860.
The present invention is further described by the following examples which should not be construed as limiting the scope of the invention.
Chemicals used as buffers and substrates were commercial products of at least reagent grade.
Fusarium venenatum CC1-3, a morphological mutant of Fusarium strain ATCC 20334 (Wiebe et al., 1991, Mycol. Research 95: 1284-1288), was grown in a two-liter lab-scale fermentor using a fed-batch fermentation scheme with maltose syrup as the carbon source and yeast extract. Ammonium phosphate was provided in the feed. The pH was maintained at 6 to 6.5, and the temperature was kept at 30° C. with positive dissolved oxygen. Mycelial samples were harvested at 2, 4, 6, and 8 days post-inoculum and quick-frozen in liquid nitrogen. The samples were stored at −80° C. until they were disrupted for RNA extraction.
Aspergillus niger strain Bo-95 was fermented in a minimal salts, maltodextrin based medium with a subsequent carbon feed of glucose at pH 4.75 and 34° C. Mycelia were harvested and frozen at −80° C. The Aspergillus niger mycelial sample was ground to a fine powder in the presence of liquid nitrogen prior to extraction of total cellular RNA.
Aspergillus oryzae strain A1560 (IFO 4177) was grown in two 20-liter lab fermentors on a 10-liter scale at 34° C. using yeast extract and dextrose in the batch medium, and maltose syrup, urea, yeast extract, and trace metals in the feed. Fungal mycelia from the first lab fermentor were harvested by filtering through a cellulose filter (pore size 7-11 microns) after 27 hours, 68.5 hours, 118 hours, and 139 hours of growth. The growth conditions for the second fermentor were identical to the first one, except for a slower growth rate during the first 20 hours of fermentation. Fungal mycelia from the second lab fermentor were harvested as above after 68.3 hours of growth. The harvested mycelia were immediately frozen in liquid N2 and stored at −80° C.
The Aspergillus oryzae strain A1560 was also grown in four 20-liter lab fermentors on a 10-liter scale at 34° C. using sucrose in the batch medium, and maltose syrup, ammonia, and yeast extract in the feed.
The first of the four fermentations was carried out at pH 4.0.
The second of the four fermentations was carried out at pH 7.0 with a constant low agitation rate (550 rpm) to achieve the rapid development of reductive metabolism.
The third of the four fermentations was carried out at pH 7.0 under phosphate limited growth by lowering the amount of phosphate and yeast extract added to the batch medium.
The fourth of the four fermentations was carried out at pH 7.0 and 39° C. After 75 hours of fermentation the temperature was lowered to 34° C. At 98 hours of fermentation the addition of carbon feed was stopped and the culture was allowed to starve for the last 30 hours of the fermentation.
Fungal mycelial samples from the four lab fermentors above were then collected as described above, immediately frozen in liquid N2, and stored at −80° C.
Aspergillus oryzae strain A1560 was also grown on Whatman filters placed on Cove-N agar plates for two days. The mycelia were collected, immediately frozen in liquid N2, and stored at −80° C.
Aspergillus oryzae strain A1560 was also grown at 30° C. in 150 ml shake flasks containing RS-2 medium (Kofod et al., 1994, Journal of Biological Chemistry 269: 29182-19189) or a defined minimal medium. Fungal mycelia were collected after 5 days of growth in the RS-2 medium and 3 and 4 days of growth in the defined minimal medium, immediately frozen in liquid N2, and stored at −80° C.
Aspergillus oryzae strain AL-11 was fermented similarly as described above for Aspergillus oryzae strain A1560 in a 20-liter lab fermentor on a 10-liter scale at 34° C. using yeast extract and dextrose in the batch medium, and maltose syrup, urea, yeast extract, and trace metals in the feed with a slow growth rate during the first 20 hours of fermentation. Fungal mycelia were harvested at 74.1 hours as above, immediately frozen in liquid N2 and stored at −80° C.
Trichoderma reesei strain RutC-30 (Montenecourt and Eveleigh, 1979, Adv. Chem. Ser. 181: 289-301) was cultivated in a pilot scale fermentation tank in growth medium containing a complex carbon source. Fungal mycelium was collected from a one-liter sample, and immediately frozen in liquid N2 and stored at −80° C.
Trichoderma reesei strain RutC-30 (Montenecourt and Eveleigh, 1979, Adv. Chem. Ser. 181: 289-301) was cultivated in a pilot scale fermentation tank in growth medium containing a complex carbon source. Fungal mycelium was collected from a one-liter sample, and immediately frozen in liquid N2 and stored at −80° C.
Total cellular RNA was extracted from the Fusarium venenatum mycelial samples described in Example 1 according to the method of Timberlake and Barnard (1981, Cell 26: 29-37), and the RNA samples were analyzed by Northern hybridization after blotting from 1% formaldehyde-agarose gels (Davis et al., 1986, Basic Methods in Molecular Biology. Elsevier Science Publishing Co., Inc., New York). Polyadenylated mRNA fractions were isolated from total RNA with an mRNA Separator Kit™ (Clontech Laboratories, Inc., Palo Alto, Calif.) according to the manufacturer's instructions. Double-stranded cDNA was synthesized using approximately 5 μg of poly(A)+ mRNA according to the method of Gubler and Hoffman (1983, Gene 25: 263-269) except a NotI-(dT)18 primer (Pharmacia Biotech, Inc., Piscataway, N.J.) was used to initiate first strand synthesis. The cDNA was treated with mung bean nuclease (Boehringer Mannheim Corporation, Indianapolis, Ind.) and the ends were made blunt with T4 DNA polymerase (New England Biolabs, Beverly, Mass.).
The cDNA was digested with NotI, size selected by agarose gel electrophoresis (ca. 0.7-4.5 kb), and ligated with pZErO-2.1 (Invitrogen Corporation, Carlsbad, Calif.) which had been cleaved with NotI plus EcoRVm and dephosphorylated with calf-intestine alkaline phosphatase (Boehringer Mannheim Corporation, Indianapolis, Ind.). The ligation mixture was used to transform competent E. coli TOP 10 cells (Invitrogen Corporation, Carlsbad, Calif.). Transformants were selected on 2YT agar plates (Miller, 1992, A Short Course in Bacterial Genetics, A Laboratory Manual and Handbook for Escherichia coli and Related Bacteria, Cold Spring Harbor Press, Cold Spring Harbor, N.Y.) which contained kanamycin at a final concentration of 50 μg/ml.
Two independent directional cDNA libraries were constructed using the plasmid cloning vector pZErO-2.1. Library A was made using mRNA from mycelia harvested at four days, and Library B was constructed with mRNA from the six day time point. One library (prepared from 4 day cells) consisted about 7.5×104 independent clones and a second library B (prepared from 6 day cells) consisted of roughly 1.2×105 clones. Miniprep DNA was isolated from forty colonies in each library and checked for the presence and size of cDNA inserts. In this analysis 39 of 40 colonies (97.5%) from Library A contained inserts with sizes ranging from 600 bp to 2200 bp (avg.=1050 bp). Similarly, 39 of 40 colonies (97.5%) picked from Library B had inserts with sizes ranging from 800 bp to 3600 bp (avg.=1380 bp). Each of these libraries was amplified using standard techniques (Birren, et al., 1998Genome Analysis, Volume 2, Detecting Genes. A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.), and each amplified library was stored as a DNA pool at 4° C. in 10 mM Tris-HCl, pH 7.6, 1 mM EDTA.
From each directional cDNA library described in Example 2, transformant colonies were picked directly from the transformation plates into 96-well microtiter dishes which contained 200 μl of 2YT broth (Miller, 1992, supra) with 50 μg/ml kanamycin. The plates were incubated overnight at 37° C. without shaking. After incubation 100 μl of sterile 50% glycerol was added to each well. The transformants were replicated into secondary, deep-dish 96-well microculture plates (Advanced Genetic Technologies Corporation, Gaithersburg, Md.) containing 1 ml of Magnificent Broth™ (MacConnell Research, San Diego, Calif.) supplemented with 50 μg of kanamycin per ml in each well. The primary microtiter plates were stored frozen at −80° C. The secondary deep-dish plates were incubated at 37° C. overnight with vigorous agitation (300 rpm) on rotary shaker. To prevent spilling and cross-contamination, and to allow sufficient aeration, each secondary culture plate was covered with a polypropylene pad (Advanced Genetic Technologies Corporation, Gaithersburg, Md.) and a plastic microtiter dish cover. DNA was isolated from each well using the 96-well Miniprep Kit protocol of Advanced Genetic Technologies Corporation (Gaithersburg, Md.) as modified by Utterback et al. (1995, Genome Sci. Technol. 1: 1-8).
Total cellular RNA was extracted from the Aspergillus niger mycelial samples described in Example 1 using a QiaEasy RNA maxi kit (QIAGEN, Valencia, Calif.) with the following modification. The extract was sheared by passage up and down in a 16-guage needle three times before the addition of the 70% ethanol step. PolyA+ RNA was isolated using a Qiagen Oligotex kit following the instructions provided by the manufacturer (QIAGEN, Valencia, Calif.).
Double-stranded cDNA was synthesizsed from 5 μg of Aspergillus oryzae A1560 poly(A)− RNA by the RNase H method (Gubler and Hoffman 1983, Gene 25: 263-269; Sambrook et al., 1989, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.) using a hair-pin modification. The poly(A)−RNA (5 μg in 5 μl of 0.1% diethylpyrocarbonate-treated water) was heated at 70° C. for 8 minutes in a pre-siliconized. RNase-free Eppendorf tube, quenched on ice, and combined in a final volume of 50 μl with reverse transcriptase buffer (50 mM Tris-Cl pH 8.3, 75 mM KCl, 3 mM MgCl2, 10 mM DTT) containing 1 mM of dATP, dGTP and dTTP, and 0.5 mM of 5-methyl-dClP (Pharmacia, Uppsala, Sweden), 40 units of human placental ribonuclease inhibitor (Promega, Madison, Wis.), 4.81 μg of oligo(dT)1X-NotI primer (Pharmacia, Uppsala, Sweden) and 1000 units of SuperScript II RNase H—reverse transcriptase (Life Technologies, Gaithersburg, Md.).
First-strand cDNA was synthesized by incubating the reaction mixture at 45° C. for 1 hour. After synthesis, the mRNA cDNA hybrid mixture was gel filtered through a MicroSpin S-400 HR (Pharmacia, Uppsala, Sweden) spin column according to the manufacturer's instructions.
After gel filtration, the hybrids were diluted in 250 μl of second strand buffer (20 mM Tris-Cl pH 7.4, 90 mM KCl, 4.6 mM MgCl2, 10 mM (NH4)2SO4, 0.16 mM βNAD−) containing 200 μM of each dNTP, 60 units of E. coli DNA polymerase 1 (Pharmacia, Uppsala, Sweden), 5.25 units of RNase H (Promega, Madison, Wis.), and 15 units of E. coli DNA ligase (Boehringer Mannheim, Indianapolis, Ind.). Second strand cDNA synthesis was performed by incubating the reaction tube at 16° C. for 2 hours, and an additional 15 minutes at 25° C. The reaction was stopped by addition of EDTA to 20 mM final concentration followed by phenol and chloroform extractions.
The double-stranded cDNA was purified using a QiaQuick PCR spin column according to the manufacturer's instructions (QIAGEN, Valencia, Calif.), washed in 70% ethanol, dried (SpeedVac), and resuspended in 30 μl of Mung bean nuclease buffer (30 mM sodium acetate pH 4.6, 300 mM NaCl, 1 mM ZnSO4, 0.35 mM dithiothreitol, 2% glycerol) containing 25 units of Mung bean nuclease (Pharmacia, Uppsala, Sweden). The single-stranded hair-pin DNA was clipped by incubating the reaction at 30° C. for 30 minutes, followed by addition of 70 μl of 10 mM Tris-Cl, pH 7.5, 1 mM EDTA, phenol extraction, and ethanol precipitation with 2 volumes of 96% ethanol and 0.1 volume 3 M sodium acetate pH 5.2 on ice for 30 minutes.
After treatment of the cDNA with mung bean nuclease, the cDNA was cut with the restriction endonuclease NotI. The cDNA was ligated into a pZERo2 vector (Invitrogen, Carlsbad, Calif.) that had been previously cut with restriction endonucleases EcoRV and NotI. The ligation mixture was used to transform by electroporation E. coli strain DH10B (Life Technologies, Gaithersburg, Md.) to generate approximately 4.5 million kanamycin resistant transformants. The transformants were plated onto 2YT agar plates containing 50 μg/ml kanamycin. The colonies were harvested and DNA was isolated using Qiagen Maxi kits (QIAGEN, Valencia, Calif.) and the instructions supplied by the manufacturer.
An aliquot of the Aspergillus niger DNA preparation was cut with restriction endonuclease NotI and run on an agarose gel. Based upon the migration of standard DNA markers, a band containing DNA from molecular size approximately 3.8 kb to 6.1 kb was excised from the gel and purified with a QiaExII purification kit (QIAGEN, Valencia, Calif.). The cDNA was ligated with T4 DNA polymerase using standard conditions, and used to transform E. coli strain DH10B to kanamycin resistance by electroporation to generate colonies for sequence analysis.
cDNA was isolated from individual kanamycin resistant colonies using a Qiagen 96-well manifold plasmid preparation system (QIAGEN, Valencia, Calif.) and the instructions supplied by the manufacturer.
Total RNA was prepared from the Aspergillus oryzae mycelial samples described in Example 1 by extraction with guanidinium thiocyanate followed by ultracentrifugation through a 5.7 M CsCl cushion (Chirgwin et al., 1979, Biochemistry 18: 5294-5299) using the following modifications. The frozen mycelia were ground in liquid N2 to a fine powder with a mortar and a pestle, followed by grinding in a precooled coffee mill, and immediately suspended in 5 volumes of RNA extraction buffer (4 M guanidinium thiocyanate, 0.5% sodium laurylsarcosine, 25 mM sodium citrate pH 7.0, 0.1 M β-mercaptoethanol). The mixture was stirred for 30 minutes at room temperature and centrifuged (20 minutes at 10 000 rpm, Beckman) to pellet the cell debris. The supernatant was collected, carefully layered onto a 5.7 M CsCl cushion (5.7 M CsCl, 10 mM EDTA, pH 7.5, 0.1% DEPC; autoclaved prior to use) using 26.5 ml supernatant per 12.0 ml of CsCl cushion, and centrifuged to obtain the total RNA (Beckman, SW 28 rotor, 25 000 rpm, room temperature, 24 hours). After centrifugation the supernatant was carefully removed and the bottom of the tube containing the RNA pellet was cut off and rinsed with 70% ethanol. The total RNA pellet was transferred to an Eppendorf tube, suspended in 500 μl of TE, pH 7.6 (if difficult, heat occasionally for 5 minutes at 65° C.), phenol extracted, and precipitated with ethanol for 12 hours at −20° C. (2.5 volumes of ethanol, 0.1 volume of 3M sodium acetate pH 5.2). The RNA was collected by centrifugation, washed in 70% ethanol, and resuspended in a minimum volume of DEPC. The RNA concentration was determined by measuring OD260-280.
The poly(A)− RNA was isolated by oligo(dT)-cellulose affinity chromatography (Aviv & Leder, 1972, Proceedings of the National Academy of Sciences USA 69: 1408-1412). A total of 0.2 g of oligo(dT) cellulose (Boehringer Mannheim, Indianapolis, Ind.) was preswollen in 10 ml of 1× of column loading buffer (20 mM Tris-Cl, pH 7.6, 0.5 M NaCl, 1 mM EDTA, 0.1% SDS), loaded onto a DEPC-treated, plugged plastic column (Poly Prep Chromatography Column, BioRad, Hercules, Calif.), and equilibrated with 20 ml of 1× loading buffer. The total RNA (1-2 mg) was heated at 65° C. for 8 minutes, quenched on ice for 5 minutes and after addition of 1 volume of 2× column loading buffer to the RNA sample loaded onto the column. The eluate was collected and reloaded 2≧3 times by heating the sample as above and quenching on ice prior to each loading. The oligo(dT) column was washed with 10 volumes of 1× loading buffer, then with 3 volumes of medium salt buffer (20 mM Tris-Cl, pH 7.6, 0.1 M NaCl, 1 mM EDTA, 0.1% SDS), followed by elution of the poly(A)− RNA with 3 volumes of elution buffer (10 mM Tris-Cl, pH 7.6, 1 mM EDTA, 0.05% SDS) preheated to 65° C., by collecting 500 μl fractions. The OD260 was read for each collected fraction, and the mRNA containing fractions were pooled and ethanol precipitated at −20° C. for 12 hours. The poly(A)− RNA was collected by centrifugation, resuspended in DEPC-DIW and stored in 5-10 μg aliquots at −80° C.
Double-stranded cDNA was synthesized from 5 μg of Aspergillus oryzae A1560 poly(A)− RNA by the RNase II method (Gubler and Hoffman 1983, supra; Sambrook et al., 1989, supra) using a hair-pin modification. The poly(A)−RNA (5 μg in 5 μl of DEPC-treated water) was heated at 70° C. for 8 minutes in a pre-siliconized. RNase-free Eppendorf tube, quenched on ice, and combined in a final volume of 50 μl with reverse transcriptase buffer (50 mM Tris-Cl pH 8.3, 75 mM KCl, 3 mM MgCl2, 10 mM DTT) containing 1 mM of dATP, dGTP and dTTP, and 0.5 mM of 5-methyl-dCTP, 40 units of human placental ribonuclease inhibitor, 4.81 μg of oligo(dT)18-NotI primer and 1000 units of SuperScript II RNase H—reverse transcriptase.
First-strand cDNA was synthesized by incubating the reaction mixture at 45° C. for 1 hour. After synthesis, the mRNA:cDNA hybrid mixture was gel filtrated through a Pharmacia MicroSpin S-400 HR spin column according to the manufacturer's instructions.
After the gel filtration, the hybrids were diluted in 250 μl of second strand buffer (20 mM Tris-Cl pH 7.4, 90 mM KCl, 4.6 mM MgCl2, 10 mM (NH4)2SO4, 0.16 mM βNAD−) containing 200 μM of each dNTP, 60 units of E. coli DNA polymerase I (Pharmacia, Uppsala, Sweden), 5.25 units of RNase H, and 15 units of E. coli DNA ligase. Second strand cDNA synthesis was performed by incubating the reaction tube at 16° C. for 2 hours, and an additional 15 minutes at 25° C. The reaction was stopped by addition of EDTA to 20 mM final concentration followed by phenol and chloroform extractions.
The double-stranded cDNA was ethanol precipitated at −20° C. for 12 hours by addition of 2 volumes of 96% ethanol and 0.2 volume of 10 M ammonium acetate, recovered by centrifugation, washed in 70% ethanol, dried (SpeedVac), and resuspended in 30 μl of Mung bean nuclease buffer (30 mM sodium acetate pH 4.6, 300 mM NaCl, 1 mM ZnSO4, 0.35 mM dithiothreitol, 2% glycerol) containing 25 units of Mung bean nuclease. The single-stranded hair-pin DNA was clipped by incubating the reaction at 30° C. for 30 minutes, followed by addition of 70 μl of 10 mM Tris-Cl, pH 7.5, 1 mM EDTA, phenol extraction, and ethanol precipitation with 2 volumes of 96% ethanol and 0.1 volume 3 M sodium acetate pH 5.2 on ice for 30 minutes.
The double-stranded cDNAs were recovered by centrifugation (20,000 rpm, 30 minutes), and blunt-ended with T4 DNA polymerase in 30 μl of T4 DNA polymerase buffer (20 mM Tris-acetate, pH 7.9, 10 mM magnesium acetate, 50 mM potassium acetate, 1 mM dithiothreitol) containing 0.5 mM of each dNTP, and 5 units of T4 DNA polymerase by incubating the reaction mixture at +16° C. for 1 hour. The reaction was stopped by addition of EDTA to 20 mM final concentration, followed by phenol and chloroform extractions and ethanol precipitation for 12 h at −20° C. by adding 2 volumes of 96% ethanol and 0.1 volume of 3M sodium acetate pH 5.2.
After the fill-in reaction the cDNAs were recovered by centrifugation as above, washed in 70% ethanol, and the DNA pellet was dried in a SpeedVac. The cDNA pellet was resuspended in 25 μl of ligation buffer (30 mM Tris-Cl, pH 7.8, 10 mM MgCl2, 10 mM dithiothreitol, 0.5 mM ATP) containing 2 μg EcoRI adaptors (0.2 μg/μl, Pharmacia, Uppsala, Sweden) and 20 units of T4 ligase by incubating the reaction mix at 16° C. for 12 hours. The reaction was stopped by heating at 65° C. for 20 minutes, and then placed on ice for 5 minutes. The adapted cDNA was digested with NotI by addition of 20 μl autoclaved water, 5 μl of 10× NotI restriction enzyme buffer and 50 units of NotI, followed by incubation for 3 hours at 37° C. The reaction was stopped by heating the sample at 65° C. for 15 minutes. The cDNAs were size-fractionated by agarose gel electrophoresis on a 0.8% SeaPlaque GTG low melting temperature agarose gel (FMC, Rockland, Me.) in 1× TBE (in autoclaved water) to separate unligated adaptors and small cDNAs. The gel was run for 12 hours at 15 V, and the cDNA was size-selected with a cut-off at 0.7 kb by cutting out the lower part of the agarose gel. Then a 1.5% agarose gel was poured in front of the cDNA-containing gel, and the double-stranded cDNAs were concentrated by running the gel backwards until it appeared as a compressed band on the gel. The cDNA-containing gel piece was cut out from the gel and the cDNA was extracted from the gel using the GFX gel hand purification kit (Amersham, Arlington Heights, Ill.) as follows. The trimmed gel slice was weighed in a 2 ml Biopure Eppendorf tube, then 10 ml of Capture Buffer was added for each 10 mg of gel slice, the gel slice was dissolved by incubation at 60° C. for 10 minutes, until the agarose was completely solublized, the sample at the bottom of the tube by brief centrifugation. The melted sample was transferred to the FGX spin column placed in a collection tube, incubated at 25° C. for 1 minite, and then spun at full speed in a microcentrifuge for 30 seconds. The flow-through was discarded, and the column was washed with 500 μl of wash buffer, followed by centrifugation at full speed for 30 seconds. The collection tube was discarded, and the column was placed in a 1.5 ml Eppendorf tube, followed by elution of the cDNA by addition of 50 μl of TE pH 7.5 to the center of the column, incubation at 25° C. for 1 minute, and finally by centrifugation for 1 minute at maximum speed. The eluted cDNA was stored at −20° C. until library construction.
A plasmid DNA preparation for a EcoRI-NotI insert-containing pYES2.0 cDNA clone, was purified using a QIAGEN Tip-100 according to the manufacturer's instructions (QIAGEN, Valencia, Calif. A total of 10 μg of purified plasmid DNA was digested to completion with NotI and EcoRI in a total volume of 60 μl by addition of 6 μl of 10× NEBuffer for EcoRI (New England Biolabs, Beverly, Mass.), 40 units of NotI, and 20 units of EcoRI followed by incubation for 6 hours at 37° C. The reaction was stopped by heating the sample at 65° C. for 20 minutes. The digested plasmid DNA was extracted once with phenol-chloroform, then with chloroform, followed by ethanol precipitation for 12 hours at −20° C. by adding 2 volumes of 96% ethanol and 0.1 volume of 3 M sodium acetate pH 5.2. The precipitated DNA was resuspended in 25 μl in 1× TE pH 7.5, loaded on a 0.8% SeaKem agarose gel in 1× TBE, and run on the gel for 3 hours at 60 V. The digested vector was cut out from the gel, and the DNA was extracted from the gel using the GFX gel band purification kit (Amersham-Pharmacia Biotech. Uppsala, Sweden) according to the manufacturer's instructions. After measuring the DNA concentration by OD208/280, the eluted vector was stored at −20° C. until library construction.
To establish the optimal ligation conditions for the cDNA library, four test ligations were carried out in 10 μl of ligation buffer (30 mM Tris-Cl pH 7.8, 10 mM MgCl2, 10 mM DTT, 0.5 mM ATP) containing 7 μl of double-stranded cDNA, (corresponding to approximately {fraction (1/10)} of the total volume in the cDNA sample), 2 units of T4 ligase, and 25 ng, 50 ng and 75 ng of EcoRI-NotI cleaved pYES2.0 vector, respectively (Invitrogen). The vector background control ligation reaction contained 75 ng of EcoRI-NotI cleaved pYES.0 vector without cDNA. The ligation reactions were performed by incubation at 16° C. for 12 hours, heated at 65° C. for 20 minutes, and then 10 μl of autoclaved water was added to each tube. One μl of the ligation mixtures was electroporated (200 W, 2.5 kV, 25 mF) to 40 μl electrocompetent E. coli DH10B cells (Life Technologies, Gaithersburg, Md.). After addition of 1 ml SOC to each transformation mix, the cells were grown at 37° C. for 1 hour, 50 μl and 5 μl from each electroporation were plated on LB plates supplemented with ampicillin at 100 μg per ml and grown at 37° C. for 12 hours. Using the optimal conditions, 18 Aspergillus oryzae A1560 cDNA libraries containing 1-2.5×107 independent colony forming units was established in E. coil, with a vector background of ca. 1%. The cDNA library was stored as (1) individual pools (25,000 c.f.u./pool) in 20% glycerol at −80° C.; (2) cell pellets of the same pools at −20° C.; (3) Qiagen purified plasmid DNA from individual pools at −20° C. (Qiagen Tip 100); and (4) directional, double-stranded cDNA at −20° C.
From each cDNA library described in Example 6, transformant colonies were picked directly from the transformation plates into 96-well microtiter dishes (QIAGEN, GmbH, Hilden Germany) which contained 200 μl TB broth (Life Technologies, Frederick, Md.) with 100 μg ampicillin per ml. The plates were incubated 24 hours with agitation (300 rpm) on a rotary shaker. To prevent spilling and cross-contamination, and to allow sufficient aeration, the plates were covered with a microporous tape sheet AirPore™ (QIAGEN GmbH, Hinden Germany).
cDNA was isolated from each well using the QIAprep 96 Turbo kit (QIAGEN GmbH, Hilden Germany).
Total RNA was prepared from the Trichoderma reesi mycelial samples described in Example 1 by extraction with guanidinium thiocyanate followed by ultracentrifugation through a 5.7 M CsCl cushion (Chirgwin et al., 1979, Biochemistry 18: 5294-5299) as described in Example 6. The total RNA concentration was determined by measuring OD260/280.
The poly(A)+RNA was isolated by oligo(dT)-cellulose affinity chromatography (Aviv & Leder, 1972, Proceedings of the National Academy of Sciences USA 69: 1408-1412) as described in example 6. Double-stranded EcoRI-NotI-directional cDNA was synthesized from 5 μg of Trichoderma reesei RutC-30 poly(A)+ RNA by the method described in example 6. The cDNAs wee size-fractionated by agarose gel electrophoresis on a 0.8% SeaPlaque GTG low melting temperature agarose gel (FMC, Rockland, Me.) in 1× TBE (in autoclaved water) to separate unligated adaptors and small cDNAs. The gel was run for 12 hours at 15 V, and the cDNA was size-selected with a cut-off at 0.7 kb by cutting out the lower part of the agarose gel. The cDNAs were recovered from the agarose gel as described in Example 6, and ligated into EcoRI-NotI cleaved pYES2.0 vector, using the optimal ligation conditions described in Example 6, resulting in a cDNA library comprising ca. 1×107 independent colony forming units was established in E. coli, with a vector background of 1%. The cDNA library was stored as (1) individual pools (25,000 c.f.u./pool) in 20% glycerol at −80° C.; (2) cell pellets of the same pools at −20° C.; (3) Qiagen purified plasmid DNA from individual pools at −20° C. (Qiagen Tip 100); and (4) directional, double-stranded cDNA at −20° C.
cDNA was isolated from individual Trichoderma reesei colonies using a Qiagen 96-well manifold plasmid preparation system (QIAGEN, Valencia, Calif.) and the instructions supplied by the manufacturer.
Single-pass DNA sequencing was conducted with a Perkin-Elmer Applied Biosystems Model 377 XI. Automatic DNA Sequencer (Perkin-Elmer Applied Biosystems, Inc., Foster City, Calif.) using dye-terminator chemistry (Giesecke et al., 1992, Journal of Virology Methods 38: 47-60) and the reverse lac sequencing primer.
Nucleotide sequence data were scrutinized for quality, and samples giving improper spacing or ambiguity levels exceeding 2% were discarded or re-run. Vector sequences were trimmed manually with assistance of FACTURA™ software (Perkin-Elmer Applied Biosystems, Inc. Foster City, Calif.). In addition, sequences were truncated at the end of each sample when the number of ambiguous base calls increased. All sequences were compared to each other to construct overlapping contigs using AutoAssembler™ software (Perkin-Elmer Applied Biosystems, Inc., Foster City, Calif.). The contigs were subsequently used in combination with TIGR Assembler software (Sutton et al., 1995, Genome Science and Technology 1: 9019) to determine multiplicity of various cDNA species represented in each library. Lastly, all sequences were translated in three frames and searched against a non-redundant data base (NRDB) using GeneAssist™ software (Perkin-Elmer Applied Biosystems, Inc., Foster City, Calif.) with a modified Smith-Waterman algorithm using the BLOSUM 62 matrix with a threshold score of 70. The NRDB was assembled from Genpept, Swiss-Prot, and PIR databases.
The Fusarium venenatum EST sequences are designated SEQ ID NOs. 1-3770. An “N” in a nucleic acid sequence means that the nucleotide is an A, C, G, or T.
DNA sequencing was performed as described in Example 10. Following DNA sequencing, the generation of individual EST sequence files was performed by removal of flanking vector and polyA sequences, removal of sequences with a high percentage of ambiguous base calls, and removal of all sequences less than 100 processed nucleotides in length. Contiguous EST sequences were identified using the TIGR Assembler software (Sutton et al., 1995, supra).
The Aspergillus niger EST sequences are designated SEQ ID NOs. 3771-4376. An “N” in a nucleic acid sequence means that the nucleotide is an A, C, G, or T.
Single-pass DNA sequencing of the Aspergillus oryzae ESTs was conducted with a Perkin-Elmer Applied Biosystems Model 377 XL Automatic DNA Sequencer (Perkin-Elmer Applied Biosystems, Inc., Foster City, Calif.) using dye-terminator chemistry (Giesecke et al., 1992, Journal of Virology Methods 38: 47-60) and a pYES specific primer (Invitrogen, Carlsbad, Calif.). Vector sequences were removed with the crossmatch program from the Phred/Phrap package (Ewing and Green, 1998, Genome Research 8: 186-194). The sequences were assembled with Phrap also from the Phred/Phrap package. The assembled sequences were searched with fatx3 (Pearson and Lipman, 1988, Proceedings of the National Academy of Science USA 85: 2444-2448; Pearson, 1990, Methods in Enzymology 183: 63-98) against a customized database consisting of protein sequences from SWISSPROT, SWISSPROTNEW, TREMBL, TREMBLNEW, REMTREMBL, PDB and GeneSeqP. The matrix used was BL50.
The Aspergillus oryzae EST sequences are designated SEQ ID NOs. 4377-7401. An “N” in a nucleic acid sequence means that the nucleotide is an A, C, G, or T.
Single-pass DNA sequencing of the Trichoderma reesei ESTs was conducted with a Perkin-Elmer Applied Biosystems Model 377 XL Automatic DNA Sequencer (Perkin-Elmer Applied Biosystems, Inc., Foster City, Calif.) using dye-terminator chemistry (Giesecke et al., 1992, Journal of Virology Methods 38: 47-60) and a pYES specific primer (Invitrogen, Carlsbad, Calif.). Vector sequence and low quality 3′ sequence were removed with the pregap program from the Staden package (MRC, Cambridge, England). The sequences were assembled with Cap2 (Huang, 1996, Genomics 33: 21-31). The assembled sequences were searched with fastx3 (see Pcarson and Lipman, 1988, Proceedings of the National Academy of Science USA 85: 2444-2448; Pearson, 1990, Methods in Enzymology 183: 63-98) against a customized database consisting of protein sequences from SWISSPROT, SWISSPROTNEW, TREMBL, TREMBLNEW, REMTREMBL, PDB and GeneSeqP. The matrix used was BL50.
The Trichoderma reesei EST sequences are designated SEQ ID NOs. 7402-7860. An “N” in a nucleic acid sequence means that the nucleotide is an A, C, G, or T.
Tables 1-4 summarize the open reading frames (ORFs) in the Fusarium venenatum, Aspergillus oryzae, Aspergillus oryzae, and Trichoderma reesei EST sequences of the invention.
The EST's were annotated by searching the databases as specified in Example 12. The description field from the database hit was assigned to a given EST if the z-score exceeded 200.
Functional categorization was done by use of the COG database (Tatusov et al., Science 1997 Oct 24; 278). This database contains 21 complete genomes: Each gene in the database is placed into one of the following categories: Translation, ribosomal structure and biogenesis; transcription; DNA replication, recombination and repair; cell division and chromosome partitioning; posttranslational modification, protein turnover, chaperones; cell envelope biogenesis, outer membrane; cell motility and secretion; inorganic ion transport and metabolism; signal transduction mechanisms; energy production and conversion; carbohydrate transport and metabolism; amino acid transport and metabolism; nucleotide transport and metabolism; coenzyme metabolism; lipid metabolism; general function prediction only; and function unknown. The EST's were searched against the COG database with fastx3 and a functional category was assigned to a sequence if a match was found with a z-score higher than 400.
The sequences were furthermore categorized into enzyme families. Examples of such classification are CAZy (Coutinho, P. M. & Henrissat, B., 1999, Carbohydrate-active enzymes: an integrated database approach, In Recent Advances in Carbohydrate Bioengineering, H. J. Gilbert, G. Davies, B. Henrissat and B. Svensson, eds., The Royal Society of Chemistry, Cambridge, in press) and (Coutinho, P. M. & Henrissat, B. (1999) The modular structure of cellulases and other carbohydrate-active enzymes: an integrated database approach, In “Genetics, Biochemistry and Ecology of Cellulose Degradation”, K. Ohmya. K. Hyashi, K. Sakka, Y. Kobayashi, S. Karita and T. Kimura eds., Uni Publishers Co., Tokyo, pp. 15-23) accessible from Coutinho, P. M. & Henrissat, B. (1999); Carbohydrate-Active Enzymes server at URI, http://afmb.cnrs-mrs.fr/˜pedro/CAZY/db.huml. At this site classifications into (a) Glycosidases and Transglycosidases (or Glycoside Hydrolases), (b) Glycosyltransferases, and (c) Polysaccharide Lyases and Carbohydrate Esterases are available.
Similarly, classifications of peptidases are available at the MEROPS database at http://www.bi.bbsrc.ac.uk/Merops/Merops.htm. This classification is essentially as identified by Rawlings and Barrett (Rawlings, N. D., Barrett A. J., 1993, Evolutionary families of peptidases. Biochemical Journal 290: 205-218; Rawlings N. D., Barrett A. J., 1994, Families of serine peptidases. Methods of Enzymology 244: 19-61; Rawlings N. D., Barrett A. J., 1994, Families of cysteine peptidases. Methods of Enzymology 244: 461-486; Rawlings N. D., Barrett A. J., 1995. Families of aspartic peptidases and those of unknown catalytic mechanism. Methods of Enzymology 248: 105-120; and Rawlings N. D., Barrett A. J., 1995, Evolutionary families of metallopeptidases, Methods of Enzymology 248: 183-228.
Other classifications of lipases and oxidoreductase families were constructed in a similar manner, where structurally related enzymes were separated into distinct categories.
The EST sequences of the invention were compared by means of computer algorithms for homologies to the content of individual families. All sequences from a given family were used individually as a query to search a database of EST sequences of the invention using a number of different homology search algorithms like FASTA and BLAST (W. R. Pearson, 1990, Rapid and Sensitive Sequence Comparison with FASTP and FASTA, Methods in Enzymology 183: 63-98; and Altschul, Stephen F., Warren Gish, Webb Miller, Eugene W. Myers, and David J. Lipman, 1990. Basic local alignment search tool, Journal of Molecular Biology 215: 403-10). A distinct hit to a sequence of a given family predicted the particular EST sequence to encode a protein of that family. Using this method, part of the EST sequences listed in the table were shown to belong to distinct enzyme families.
Fusarium venenatum ESTs
Talaromyces emersonii
Microscilla furvescens
Cladosporium herbarum
T. harzianum exochitinase.
N. crassa glucoamylase.
Trichoderma reesei ACEI
Malassezia fungus ME-5
A. nidulans atrC polypeptide.
B. bassiana POPS reductase
S. brevicaulis beta-
N. crassa mtr gene product.
Aspergillus niger trehalose
A. flavus-derived cDNA clone
B. bassiana POPS reductase
S. cerevisiae uronate
Cercospora nicotianae
S. cerevisiae type 2 methionine
Aspergillus niger adhA gene.
A. niger Bo-1
Aspergillus nidulans essential
Alternaria alternata allergen
Cladosporium herbarum
Schizosaccharomyces pombe
Mortierella alpina cytochrome
C. albicans antigenic protein 4.
C. ELEGANS CDNA YK20F6.3.
S. CEREVISIAE
Chlamydia pneumoniae
N. crassa mtr gene product.
Fusarium sotani pisi.
Trichoderma reesei ACE1
Cladosporium herbarum
Mycobacterium tuberculosis 55
Fusarium oxysporum DSM
Malassezia fungus ME-7
Mycobacterium species protein
Mycobacterium species protein
Trichoderma reesei ACEII
Trichoderma reesei ACEI
Mycobacterium tuberculosis
Fusarium oxysporum.
Aspergillus nidulans essential
T. gondii immunogenic
M. tuberculosis immunogenic
Rhodococcus rhodochrous
Mycobacterium species protein
Mycobacterium species protein
A. oryzae DEBY10.3 locus
Porphorymonas gingivalis
Mycobacterium species protein
C. parvum p23 protein
Mycobacterium species protein
Mycobacterium species protein
T. gondii immunogenic
Chlamydia pneumoniae protein
Streptococcus pneumoniae
Drosophila trithorax zinc
Actinomadura flexuosa
Mycobacterium tuberculosis
T. reesei.
A. oryzae DEBY 10.3 locus
Streptococcus pneumoniae
T. gondii immunogenic
Chlamydia pneumoniae
Mycobacterium species protein
Mycobacierium species protein
Macadamia integrifolia
Aspergillus niger beta-
S. lividans protease PS-6.
T. brucei.
B. burgdorferi antigenic
Mycobacterium tuberculosis
Aspergillus niger ESTs
Porphobilinogen synthase.
Aspergillus awamori
A. oryzae DEBY932 locus
Sphingomonas capsulata
Aspergillus awamori
Aspergillus niger glucoamylase
Aspergillus awamori
Aspergillus awamori
Aspergillus awamori
Aspergillus awamori
Aspergillus awamori
Aspergillus awamori
Aspergillus awamori
Aspergillus awamori
Candida albican fungal
Aspergillus awamori
A. awamori glucoamylase
A. fumigatus allergen rAsp f8
N. crassa mtr gene product.
A. orvzae DEBY1058 locus
Streptomyces clavuligerus
H. pylori GHPO 1315 protein.
S. pneumoniae protein SEQ ID
Aspergillus niger aspartic
Sulfolobus solfataricus esterase
M. tuberculosis recombinant
Streptococcus pneumoniae
T. gondii immunogenic
brucei.
Melanocarpus albomyces.
Thermus thermophilus heat
P. furiosus pyroglutamyl
H. influenzae Hap protein
Aspergillus oryzae ESTs
Aspergillus nidulans essential
A. oryzae
P4-8.1 locus protein
Cladosporium herbarum
Aspergillus niger tpiA gene.
A. oryzae ATCC20386
Aspergillus nidulans essential
A. fumigatus allergen rAsp F8
C. magnoliae carbonyl
S. lipmanii epimerase.
C. magnoliae carbonyl
A. niger pyruvate kinase.
CEREVISIAE YHR110P.
Mortierella alpina cytochrome
P. putida R-(−)-mandelate
Humicola lanuginosa lipase
Aspergillus oryzae protease
P. membranaefaciens NADH
Candida albicans KRE9.
Aspergillus oryzae protease
Saccharomyces cerevisiae
Aspergillus nidulans palmitate-
S. cerevisiae uronate
Aspergillus sp. recombinant
P. putida R-(−)-mandelate
Cryptosporidium parvum
A. flavus-derived cDNA clone
D. immitis ankyrin pDiAnk348
A. niger PacC zinc finger DNA
C. albicans antigenic protein 3.
Cereospora kikuchii membrane
Mycobacterium tuberculosis
M. tuberculosis antigen TbH-
Aspergillus oryzae alpha-
Mycobacterium species protein
Aspergillus oryzae
Teredinibacter endoglucanase.
Aspergillus oryzae AreA
A. niger SFAG 2
Nucleic acid binding domain
S. lavendulae ORF3 gene
M. tuberculosis immunogenic
Aspergillus niger Sulphydryl
A. crysogenum cystathionine
Porphorymonas gingivalis
Acetobacter xylinum CMCase
A. niger 2,3-dihydroxybenzoic
E. brucei.
A. oryzae DEBY1058 locus
M. grisea PTH12 gene product.
T. harzianum.
Aspergillus fumigatus protein
Porphorymonas gingivalis
R. eutropha Mgt partial ORF3
A. oryzae DEBY932 locus
A. niger PacC zinc finger DNA
Aspergillus niger tpiA gene.
Aspergillus oryzae
Microscilla furvescens
Aspergillus oryzae hemA
M. grisea PTH2 gene product.
A. crysogenum cystathionine
Trichoderma reesei ESTs
T. longibrachiatum
A. chrysogenum gamma-actin.
A. niger xylanase regulator
Candida albicans CaCLA4
Klebsiella pneumoniae
Mycobacterium species protein
Trichoderma reesei
endoglucanase.
Mycobacterium species protein
Mycobacterium species protein
Mycobacterium species protein
Details of the construction of a typical microarrayer can be found on the world wide web site of Professor Patrick Brown of Stanford University at the following URL: http://emgm.stanford.edu/pbrown/mguide/index.html. Scanners and computer software for analysis of DNA microarrays are available from several commercial sources such as General Scanning Inc. (Watertown, Mass.; see http://www.genscan.com/sales/loc lifesci.html), or Axon Instruments (Foster City, Calif.: see http://www.axon.com).
Individual fungal EST clones were purified as plasmid minipreps using Qiagen Biorobot 9600 (QIAGEN, Inc., Valencia, Calif.). The plasmid minipreps were precipitated with isopropanol, aliquoted and stored as described on the web site of Professor Patrick Brown of Stanford University at the following URL: http://emgm.stanford.edu/pbrown/mguide/index.html.
The amplified EST targets prepared in this manner were spotted individually onto polylysine-coated glass slides using a microarrayer device as described by DeRisi et al. (1997, Science 278: 680-686). For additional details, see http://cmgm.stanford.edu/pbrown/protocols/index.html). The microarrays were probed with fluorescently labeled cDNA prepared by reverse transcription of polyadenylated mRNA (DeRisi et al., 1997, supra) extracted from fungal mycelia (Example 2). Conditions for pretreatment of the microarrays, hybridization and washing conditions have been described previously (DeRisi et al., 1997, supra; see also http://emgm.stanford.edu/pbrown/protocols/index.html).
To increase the reliability with which changes in expression levels could be discerned, probes prepared from induced or treated cells were labeled with the red fluorescent dye, Cy5 (Amersham Corporation, Arlington Heights, Ill.), and mixed with probes from uninduced, untreated, or “reference” cells were labeled with a green fluorescent dye, Cy3 (Amersham Corporation, Arlington Heights, Ill.) using the procedure described by http://cmgm.stanford.edu/pbrown/protocols/index.html. The relative ratio of fluorescence intensity measured for the Cy3 and Cy5 fluorophors corresponding to each EST target in the arrays was determined using ScanAlyze software, available free of charge at http://rama.stanford.edu/software/. This provides a reliable measure of the relative abundance of the corresponding mRNA in the two cell populations (e.g., treated cells versus reference cells).
DNA microarrays were prepared as described in the preceding example by spotting 1152 selected EST clones from Fusarium venenatum as targets. In one experiment we compared the relative expression of each of these genes (as measured by transcript abundance) among cells grown in medium with glucose as the sole carbon source to the same strain grown with maltose as the sole carbon source. Identical shake flasks were inoculated with Fusarium venenatum strain CC1-3 growing in Vogel's minimal medium with either 2% glucose or 2% maltose as the sole carbon source. After 2 days growth at 28° C., total RNA and mRNA pools were purified from each culture using methods described in the previous examples. One microgram of polyA-selected mRNA was used as a template to prepare fluorescently labeled probes for hybridization (the protocol for fluorescent probe labeling is available at http://emgm.stanford.edu/protocols/index.htm). In this experiment, the probe from glucose-grown cells was labeled with Cy3 and the probe from maltose-grown cells was labeled with Cy5. The probes were combined and hybridized with the 1152 EST targets on the microarray. Methods for hybridization and washing of microarrays are also available at http://cmgm.stanford.edu/protocols/index.html. After hybridization and washing, the microarrays were scanned (see Example 15), ad the images analyzed using ScanAlyze software (see Example 15) to determine the relative ratios of red and green fluorescence in each spot on the arrays. The tab-delimited text file generated by ScanAlyze can be imported into other software programs that are capable of sorting large amounts of data in spreadsheet formats (e.g., Microsoft Excel). In such a format, it is straightforward to sort the data on the basis of relative fluorescence ratios (red intensity/green intensity=RAT2 value) or perform other statistical analyses. For example, in this experiment it was desirable to specifically identify those genes whose expression (a) increased by a factor of approximately two, (b) remained the same, or (c) decreased by a factor of approximately two in response to the presence of maltose as a sole carbon source. A number of genes satisfying these criteria were readily identified as shown in Table 5. The quality of the data is ensured by choosing only spots in which the correlation coefficients are at least 0.75 or greater.
The invention described and claimed herein is not to be limited in scope by the specific embodiments herein disclosed, since these embodiments are intended as illustrations of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. In the case of conflict, the present disclosure including definitions will control.
Various references are cited herein, the disclosures of which are incorporated by reference in their entireties.
This application is a continuation-in-part of U.S. application Ser. No. 09/273,623 filed Mar. 22, 1999 now abandoned, which application is fully incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09273623 | Mar 1999 | US |
| Child | 09533559 | US |
