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Identification of novel cellular genes transcriptionally suppressed by v-src
1Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029.
Abstract:
Our aim is to identify cellular genes whose transcriptional suppression by the v-src oncogene contributes directly and specifically to the transformed and tumorigenic phenotype. We used a modified PCR-based subtractive hybridization technique to isolate 9 cDNAs whose abundance in NIH3T3 fibroblasts is decreased 3-15-fold following transformation by the activated oncogene, v-src. Sequence analysis reveals that 3 cDNAs are unlike those in GenBank. The remaining 6 cDNAs are indentical or highly similar to rat helix-destabilizing protein gene (hnRNP A1), mouse CTLA-2 alpha cysteine protease, rat cytochrome c oxidase (COX) VIc subunit, mouse Type I collagen, human gravin and a partial human cDNA (clone A7C09) isolated by random automated sequencing. Northern blot analysis indicates that the basal level of transcripts in untransformed NIH3T3 of all the genes except mouse Type I collagen was at least 10-fold lower than that of HMG Co-A Reductase, which is abundantly transcribed. These data suggest that the down-regulation of some or all of these genes contributes to v-src-induced changes in mitogenic control or cell morphology.
Insights
Researchers identified cellular genes suppressed by the v-src oncogene, contributing to cell transformation and tumor formation. This suppression impacts genes involved in cell regulation and morphology.
Area of Science:
- Molecular Biology
- Oncology
- Cell Biology
Background:
- The v-src oncogene promotes cellular transformation and tumorigenesis.
- Identifying specific cellular genes regulated by v-src is crucial for understanding cancer development.
Purpose of the Study:
- To identify cellular genes transcriptionally suppressed by the v-src oncogene.
- To determine the contribution of these suppressed genes to the transformed and tumorigenic phenotype.
Main Methods:
- Utilized a modified PCR-based subtractive hybridization technique.
- Isolated and sequenced 9 complementary DNAs (cDNAs) with decreased abundance post-v-src transformation.
- Performed Northern blot analysis to assess transcript levels.
Main Results:
- Identified 9 cDNAs, with 6 matching known genes including hnRNP A1, CTLA-2 alpha, cytochrome c oxidase VIc, Type I collagen, gravin, and a partial human cDNA.
- Observed 3-15 fold decrease in abundance for these cDNAs in v-src transformed NIH3T3 fibroblasts.
- Found basal transcript levels of most identified genes were significantly lower than HMG Co-A Reductase in untransformed cells.
Conclusions:
- Down-regulation of specific genes, including hnRNP A1 and cytochrome c oxidase, by v-src oncogene contributes to cellular transformation.
- These findings suggest a role for gene suppression in v-src-induced alterations in mitogenic control and cell morphology.