Claims
- 1. A method for altering the copy number of a heterologous gene integrated into a Drosophila cells genome which comprises: selecting cultured Drosophila cells as a host for transfection; cotransfecting said host cell with (i) a first vector comprising a gene expression unit having a promoter of Drosophila origin and a DNA sequence encoding a heterologous gene product and; (ii) a second vector comprising a promoter of Drosophila origin and a DNA sequence encoding a selection marker, wherein the ratio of said cotransfected vectors is altered such that the first vector is present in the ratio of from about 1 to 100 times that of the second vector; and culturing the transfected Drosophila cells.
- 2. The method of claim 1 wherein the ratio of the first vector to that of the second vector is 9:1.
- 3. The method of claim 1 wherein the ratio of the first vector to that of the second vector is 20:1.
- 4. The method of claim 1 wherein the ratio of the first vector to that of the second vector is 100:1.
- 5. A method to obtain a continuous cell expression system having stably integrated multicopy gene expression units capable of high level production of non-bacterial, non-Drosophila proteins which comprises: selecting Drosophila melanogaster S.sub.2 cells as a host for transfection; cotransfecting said S.sub.2 cells with: (i) a first vector comprising a gene expression unit having a promoter of Drosophila origin and a DNA sequence encoding a heterologous gene product and; (ii) a second vector comprising a promoter of Drosophila origin and a DNA sequence encoding a selection marker, wherein the ratio of said first vector to said second vector is from about 9:1 to 100:1; and culturing the transfected Drosophila cells.
- 6. The method of claim 5 wherein said promoter of Drosophila origin on said first vector is inducible.
- 7. The method of claim 5 wherein said promoter of Drosophila origin on said first vector is constitutive.
CROSS REFERENCE TO RELATED APPLICATIONS
This is a divisional of application Ser. No. 08/098,016, filed Jul. 27, 1993, which is a continuation-in-part of Ser. No. 07/278,386, filed on Dec. 1, 1988 now abandoned and a continuation-in-part of Se. No. 07/574,563 filed on Aug. 27, 1990 now abandoned which is a continuation of Ser. No. 07/428,454 filed on Oct. 30,1989 which is a continuation of Ser. No. 07/047,736 filed on May 8, 1987.
Non-Patent Literature Citations (2)
Entry |
Sinclair et al.,"Regulated Expression of a Drosophila melanogaster Heat Shock Locus after Stable Integration in a Drosophila hydei Cell Line", Molecular and Cellular Biology, vol. 5, Number 11, pp. 3208-3213. |
Kaufman et al.,"Coamplification and Coexpression of Human Tissue-Type Plasminogen Activator and Murine Dihydrofolate Reductase Sequences in Chinese Hamster Ovary Cells", Molecular and Cellular Biology, vol. 5, Number 7, pp. 1750-1759. |
Related Publications (1)
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Number |
Date |
Country |
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574563 |
Aug 1990 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
98016 |
Jul 1993 |
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Continuations (2)
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Number |
Date |
Country |
Parent |
428454 |
Oct 1989 |
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Parent |
47736 |
May 1987 |
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Continuation in Parts (1)
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Parent |
278386 |
Dec 1988 |
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