Figure 1. Detection of a 100 kD SV40 sT-ag in SV40-transfomed rat cell clones. SDS gel electrophoresis of immunoprecipitated SV40 T-ag-specific proteins from seven (lane 1 to 7) rat 2 cell lines that were transfected with SV40 DNA coding for the 94 kD T-ag. All cell clones expressed the regular 94 kD T-ag and co-immunoprecipitated T-ag-bound p53. Two highly transformed cell clones 2 and 7 strongly expressed the additional 100 kD sT-ag. A faint 100 kD sT-ag band was also detectable for the normally transformed cell clone 5.