Viruses carrying either sense or anti-sense orientations of the following genes have been produced: v-raf, c-raf, v-Ha-ras, c- myc(mouse), and PDGF A chain (normal and carboxyl-deleted cistrons). The sense constructs of ras, v-raf, and PDGF A chain were found to produce transformed foci on mouse 3T3 cells. Most produced tumors in nude mice with relatively short latencies. Zip-Ha-ras virus was used to infect immortalized human bronchial epithelial cells (Beas 12). Within 5 weeks from subcutaneous infection of 5 million cells into nude mice, tumors appeared in 80% of the mice. The karyotype of these cultured cells shows them to be human in origin. Zip-Ha-sar virus (ras anti-sense) were used to infect TBE-1 cells (primary human bronchial epithelial cells which were transformed after they were essential with a v-Ha-ras oncogene). We conclude from this experiment that the Ha-ras gene function is necessary to maintain TBE-1 cell proliferation since infected cells, which should grow in the presence of G418, do not as a consequence of anti-sense abrogation of function. The Zip-Ha-sar infected cells lack the previously introduced v-Ha-ras mRNA and have instead the expected 5.4-kb mRNA representing the sar transcript.