Immortalization of human cells by mutant and chimeric primate polyomavirus T-antigen genes.
Human fibroblasts were morphologically transformed with wild type and mutant SV40 T-antigens (T-Ags) and with SV40/JCV and SV40/BKV chimeric T-Ags. The transformants were then assayed for the attainment of immortal cell growth. Several observations relating T-Ag and T-Ag domains to immortalization were made. Approximately 10% of SV40-transformants became immortal. Transformants generated by transfection or infection of cells with C-terminal T-Ag deletion mutants of SV40 did not immortalize. SV40/JCV and SV40/BKV chimeric T-Ags, containing C-terminal sequences from JCV or BKV, immortalized cells more efficiently than did the intact SV40 T-Ag, suggesting that the C-termini of the JCV and BKV T-Ags contain an enhanced immortalization function. However, chimeras in which the N-terminal or proximal-central portions of T-Ag were composed of JCV sequences failed to immortalize but did induce transformation. Constructs in which the JCV T-Ag Rb binding domain was replaced with SV40 sequences transformed human cells, but again the cells failed to immortalize. Transformants and immortalized cell lines produced by some SV40/JCV chimeras, contained p53 which was unbound by T-Ag. This occurred under conditions where p53 from SV40 and SV40/BKV transformants was bound to T-Ag. This may reflect the reduced stability of the SV40/JCV T-Ags.
O'Neill
F J
FJ
Department of Veterans Affairs Research Service, Salt Lake City, Utah 84148.
Frisque
R J
RJ
Xu
X
X
Hu
Y X
YX
Carney
H
H
D000952:Antigens, Polyomavirus Transforming / Q000235:genetics*; D015139:Blotting, Southern; D002472:Cell Transformation, Viral / Q000235:genetics*; D002478:Cells, Cultured; D004279:DNA, Viral; D005347:Fibroblasts; D006801:Humans; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D000952:Antigens, Polyomavirus Transforming; D004279:DNA, Viral; D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53