Rapid and selective alterations in the expression of cellular genes accompany conditional transcription of Ha-v-ras in NIH 3T3 cells.

Open Access
Publisher Website
Google Scholar
Abstract
Hormone treatment of NIH 3T3 cells that contain recombinant fusions between the mouse mammary virus long terminal repeat and the v-ras gene of Harvey murine sarcoma virus results in conditional expression of the ras p21 gene product. Levels of ras mRNA and p21 are maximal after 2 to 4 h of hormone treatment. Analysis of cellular RNA by Northern blotting and nuclease S1 protection assays indicates that the expression of two cellular RNA species increases with kinetics similar to v-ras: v-sis-related RNA and retrovirus-related VL30 RNA. Run-on transcription in isolated nuclei shows that the increase in v-sis-related RNA is not dependent on transcription and therefore must arise by a post-transcriptional mechanism. The increase in VL30 expression is a transcriptional effect. Hormone treatment of normal NIH 3T3 cells has no effect on the expression of these DNA sequences. These results suggest that v-ras stimulation of autocrine factors may play a role in transformation of cells by this gene and also suggest a reverse genetic strategy to determine the nucleic acid sequences and cellular factors involved in the regulation of gene expression that is observed.