Abstract
Conditional oncogene expression in transgenic mice is of interest for studying the oncoprotein requirements during tumorigenesis and for deriving cell lines that can be induced to undergo growth arrest and enhance their differentiated functions. We utilized the bacterial tetracycline (Tet)-resistance operon regulatory system (tet) from Tn10 of Escherichia coli to control simian virus 40 (SV40) large tumor (T) antigen (TAg) gene expression and to generate conditionally transformed pancreatic beta cells in transgenic mice. A fusion protein containing the tet repressor (tetR) and the activating domain of the herpes simplex virus protein VP16, which converts the repressor into a transcription activator, was produced in beta cells of transgenic mice under control of the insulin promoter. In a separate lineage of transgenic mice, the TAg gene was introduced under control of a tandem array of tet operator sequences and a minimal promoter, which by itself is not sufficient for gene expression. Mice from the two lineages were then crossed to generate double-transgenic mice. Expression of the tetR fusion protein in beta cells activated TAg transcription, resulting in the development of beta-cell tumors. Tumors arising in the absence of Tet were cultured to derive a stable beta-cell line. Cell incubation in the presence of Tet led to inhibition of proliferation, as shown by decreased BrdUrd and [3H]thymidine incorporation. The Tet derivative anhydrotetracycline showed a 100-fold stronger inhibition compared with Tet. When administered in vivo, Tet efficiently inhibited beta-cell proliferation. These findings indicate that transformed beta cells selected for growth during a tumorigenesis process in vivo maintain a dependence on the continuous presence of the TAg oncoprotein for their proliferation. This system provides an approach for generation of beta-cell lines for cell therapy of diabetes as well as conditionally transformed cell lines from other cell types of interest.
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- D'Ambra R., Surana M., Efrat S., Starr R. G., Fleischer N. Regulation of insulin secretion from beta-cell lines derived from transgenic mice insulinomas resembles that of normal beta-cells. Endocrinology. 1990 Jun;126(6):2815–2822. doi: 10.1210/endo-126-6-2815. [DOI] [PubMed] [Google Scholar]
- Degenkolb J., Takahashi M., Ellestad G. A., Hillen W. Structural requirements of tetracycline-Tet repressor interaction: determination of equilibrium binding constants for tetracycline analogs with the Tet repressor. Antimicrob Agents Chemother. 1991 Aug;35(8):1591–1595. doi: 10.1128/aac.35.8.1591. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Deuschle U., Hipskind R. A., Bujard H. RNA polymerase II transcription blocked by Escherichia coli lac repressor. Science. 1990 Apr 27;248(4954):480–483. doi: 10.1126/science.2158670. [DOI] [PubMed] [Google Scholar]
- Efrat S., Hanahan D. Bidirectional activity of the rat insulin II 5'-flanking region in transgenic mice. Mol Cell Biol. 1987 Jan;7(1):192–198. doi: 10.1128/mcb.7.1.192. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Efrat S., Linde S., Kofod H., Spector D., Delannoy M., Grant S., Hanahan D., Baekkeskov S. Beta-cell lines derived from transgenic mice expressing a hybrid insulin gene-oncogene. Proc Natl Acad Sci U S A. 1988 Dec;85(23):9037–9041. doi: 10.1073/pnas.85.23.9037. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fanning E., Knippers R. Structure and function of simian virus 40 large tumor antigen. Annu Rev Biochem. 1992;61:55–85. doi: 10.1146/annurev.bi.61.070192.000415. [DOI] [PubMed] [Google Scholar]
- Furth P. A., St Onge L., Böger H., Gruss P., Gossen M., Kistner A., Bujard H., Hennighausen L. Temporal control of gene expression in transgenic mice by a tetracycline-responsive promoter. Proc Natl Acad Sci U S A. 1994 Sep 27;91(20):9302–9306. doi: 10.1073/pnas.91.20.9302. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gossen M., Bujard H. Tight control of gene expression in mammalian cells by tetracycline-responsive promoters. Proc Natl Acad Sci U S A. 1992 Jun 15;89(12):5547–5551. doi: 10.1073/pnas.89.12.5547. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hanahan D. Dissecting multistep tumorigenesis in transgenic mice. Annu Rev Genet. 1988;22:479–519. doi: 10.1146/annurev.ge.22.120188.002403. [DOI] [PubMed] [Google Scholar]
- Hanahan D. Heritable formation of pancreatic beta-cell tumours in transgenic mice expressing recombinant insulin/simian virus 40 oncogenes. Nature. 1985 May 9;315(6015):115–122. doi: 10.1038/315115a0. [DOI] [PubMed] [Google Scholar]
- Huang M. T., Gorman C. M. Intervening sequences increase efficiency of RNA 3' processing and accumulation of cytoplasmic RNA. Nucleic Acids Res. 1990 Feb 25;18(4):937–947. doi: 10.1093/nar/18.4.937. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jat P. S., Noble M. D., Ataliotis P., Tanaka Y., Yannoutsos N., Larsen L., Kioussis D. Direct derivation of conditionally immortal cell lines from an H-2Kb-tsA58 transgenic mouse. Proc Natl Acad Sci U S A. 1991 Jun 15;88(12):5096–5100. doi: 10.1073/pnas.88.12.5096. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Labow M. A., Baim S. B., Shenk T., Levine A. J. Conversion of the lac repressor into an allosterically regulated transcriptional activator for mammalian cells. Mol Cell Biol. 1990 Jul;10(7):3343–3356. doi: 10.1128/mcb.10.7.3343. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lakso M., Sauer B., Mosinger B., Jr, Lee E. J., Manning R. W., Yu S. H., Mulder K. L., Westphal H. Targeted oncogene activation by site-specific recombination in transgenic mice. Proc Natl Acad Sci U S A. 1992 Jul 15;89(14):6232–6236. doi: 10.1073/pnas.89.14.6232. [DOI] [PMC free article] [PubMed] [Google Scholar]