Title 
       SV40 T-antigen is required for maintenance of immortal
       growth in SV40-transformed human fibroblasts. 
Author 
       Tsuyama N; Miura M; Kitahira M; Ishibashi S; Ide T 
Address 
       Department of Cellular and Molecular Biology, Hiroshima
       University School of Medicine, Japan. 
Source 
       Cell Struct Funct, 1991 Feb, 16:1, 55-62 
Abstract 
       Two lines of immortal human fibroblasts were isolated
       following transfection of TIG-3 cells with plasmid DNA,
       pMT-1ODtsA, that contained SV40 early gene with a
       deletion in replication origin and ts mutation in coding
       sequence for T-antigen. These cells continued proliferation
       at 34 degrees C, over 565 population doubling level (PDL)
       which is far over the limited division potential of
       untransformed normal TIG-3 of 70-80 PDL. When the
       culture temperature was shifted to 40 degrees C after 70
       PDL, they ceased proliferation immediately. One of these
       immortal clones, SVts8, lost its ts phenotype after
       retransformation with wtT-antigen gene. These results
       indicated that the function of intact T-antigen is required
       for maintenance of immortal proliferation, at least in one
       of the SV40 transformed immortal clones.