DEREGULATION OF C-ABL MEDIATED CELL-GROWTH AFTER RETROVIRAL TRANSFER AND EXPRESSION OF ANTISENSE SEQUENCES

To determine the role of c-abl during cell growth, we constructed a re trovirus vector alpha A, capable of expressing an antisense RNA direct ed against the abl mRNA, Based on v-abl-mediated 3T3 transformation as say, we showed that the number of transformed foci was reduced 50-94% when alpha A-infected 3T3 cells were superinfected with A-MuLV, Up to a 100% of inhibition could be observed when the time of infection was lengthened. Introduction of the antisense sequence into NM3T3 cells re sulted in reduction of growth rate. These cells entered into S phase f rom G1 phase of the cell cycle earlier in time than untransduced cells , Thus c-abl serves as a checkpoint during G1/S transition in the cell cycle, and its reduction resulted in deregulation of cell growth.