TUMOR-SUPPRESSIVE ACTIVITY OF N03 GENE-PRODUCT IN V-SRC-TRANSFORMED RAT 3Y1 FIBROBLASTS

The expression of the N03 gene was significantly reduced in a variety of transformed cells, compared with that in parental rat 3Y1 fibroblas ts. To understand the possible role(s) of its product, we have obtaine d transfectants expressing N03 gene from v-src-transformed 3Y1 cells. Two clones, which overexpressed N03 mRNA, showed a flatter phenotype, a reduced rate of growth, and a decreased ability to grow in soft agar . One of the clones which maintained N03 expression was completely sup pressed in forming tumors in nude mice. These data suggest that the N0 3 gene product may have a suppressive ability on transformed phenotype s.