| Abstract: | Five types of variation in the appearance of SV40 T antigen have been observed by immunofluorescence in wild-type and tsD*101 transformed BALB and Swiss/3T3 cells: (1) clones having more than 95% uniformly stained nuclei; (2) clones having variable stained nuclei; (3) clones having T-negative nuclei at the periphery at 39 °C, but not at 33 °C; (4) D101 cells having T-negative nuclei at 39 °C, but not at 33 °C, during growth and after saturation; and (5) wild type cells having T-negative nuclei after confluence at both 33 and 39 °C. This fifth type of variation may involve an immuno-specificity change in the T antigen molecule. Any models proposed for the regulation of SV40 T antigen in transformed cells will have to explain these variations. |
