Suppression and restoration of v-SRC expression in rsv transformed-cells after transfection with N-ras and its antagonist.

Previously, it was shown that hamster cells transformed by Rous Sarcoma Virus (RSV) exhibited a decreased expression of the RSV products (including the pp60 src oncogene) when these cells were supertransfected with the N-ras oncogene. To assess the responsibility of the activated N-ras in the modulation of the RSV viral products, a strategy based on two ras antagonists was used; i.e. i) a rap1A/K-rev1 expression vector known for its capacity to revert the K-ras induced transformed phenotype and ii) a plasmid containing antisense N-ras sequence. We present data showing only the plasmid construct containing the N-ras antisense sequense could inhibit expression or N-ras and, at the same time, restore the expression of v-src, up to a level comparable to that of the parental cells. Our results support the idea that some biological switches, triggered and activated through the N-ras oncogene pathway, might modulate the promoter activity of the RSV LTR.