%0 Journal Article %A Bryan, Tracy %A Redder, Roger R. %D 1994 %I Begell House %N 4 %P 331-357 %R 10.1615/CritRevOncog.v5.i4.10 %T SV40-lnduced Immortalization of Human Cells %U https://www.dl.begellhouse.com/journals/439f422d0783386a,364c2d3c454d326b,0905d68652847126.html %V 5 %X For several decades simian virus 40 (SV40) early region genes have been used as a means of generating immortalized human cell lines; however, the molecular mechanisms of this process have begun to be understood only recently. SV40-induced immortalization proceeds via two phases. In the first phase ("lifespan extension"), cells continue proliferating for a limited number of population doublings beyond the point at which normal cells undergo senescence. This is mainly due to the ability of SV40 large T antigen (LTAg) to bind to the protein products of the p53 and retinoblastoma (Rb) genes. The second phase ("immortalization") occurs in only a small minority of cells, and cell hybridization analyses indicate that this is a gene inactivation event. The gene or genes involved are currently unknown, but chromosomal localization data are accumulating which should make their cloning and characterization possible in the near future. %8 1994-09-01