Thermolabile T (tumor) antigen from cells transformed by a temperature-sensitive mutant of simian virus 40

Partially purified tumor (T) antigen from a strain of Chinese hamster lung cells transformed by wild-type simian virus 40 (SV 40) and either of two temperature-sensitive SV 40 mutants has been studied as a DNA binding protein. The DNA binding activity present in the T-antigen-containing fractions is inhibited by purified hamster anti-T IgG but not by equivalent amounts of nonimmune hamster IgG. T from either wild-type- or tsC219-transformed cells is relatively stable during heating at 44 degrees compared to T prepared from tsA239-transformed cells. These results strongly suggest that T is a product of the SV 40 A gene.