Fig. 4.

The PP2A domain is required for PyST to block ARF signaling to p53. The number of transformed colonies generated after REF52 cells were co-transfected with wild-type middle T-antigen cDNA (MT) together with wild-type or mutant small T-antigen cDNAs (ST) or transfected with bc1051 genomic DNA alone is presented. The average number of transformed colonies per microgram of middle-T antigen DNA from three experiments is shown. The small T-antigen mutants used were the Del 42HPDKGG47 J domain deletion and the Ins 107AL PP2A insertion mutant (see Fig. 3). At the top is shown the organization of the middle and small T-antigen domains in the cDNAs. The numbers indicate the amino acid sequence of the two proteins, and the location of the mutations in the small T-antigen cDNA is shown.