SUPPRESSION OF V-SRC TRANSFORMATION BY THE DRS GENE

Previously, we isolated a novel gene, drs, which was downregulated by retroviral oncogenes such as v-src and v-K-ras, from a cDNA library of primary rat embryo fibroblasts, Experiments using a temperature-sensi tive mutant of the v-src gene indicated that downregulation of drs mRN A was dependent on functional expression of v-Src. In addition, expres sion of drs mRNA. was also reduced by ser um stimulation of G(0)-arres ted nor mal rat fibroblast cells, To clarify the function of the drs g ene in cell transformation and proliferation, we introduced drs linked to a potent promoter into a normal rat cell line, F2408, and examined the effect of ectopic expression of exogenous drs on the transformati on bg the v-src gene and growth properties, Cells expressing exogenous drs gene showed significantly decreased efficiency of transformation by v-src irrespective of functional expression of v-Src kinase, while the growth rate and G(1)/S progression of the cells were not suppresse d by expression of exogenous drs gene, indicating that drs has the abi lity to suppress v-src transformation without disturbing cell prolifer ation.