Isolation and characterization of revertant cell lines. III. Isolation of density‐revertants of SV40‐transformed 3T3 cells using colchicine

Treatment of the SV40 transformed 3T3 cell line SV101 with colchicine permits the isolation of polyploid revertant sublines Which have lower saturation densities than SV101. These low saturation density lines have also reverted to a high serum requirement for growth, and are unable to form colonies in methocel. Normal SV40 has been recovered from these revertants. 3T3 cells are more resistant to colchicine than SV3T3 cells at all cell densities. Colchicine revertants do not display a 3T3‐like resistance to colchicine at low density, but do survive colchicine at confluent cell densities, presumably due to their increased contact inhibition.