The interaction of SV40/TAG with p53, pRb and Hsc70 in the three MEF cell lines. (A) Coimmunoprecipitation of p53, pRb and Hsc70 with SV40/TAG. SV40/TAG proteins were immunoprecipitated from the cell lysates of the MEF/wt (lane 1), MEF/Hsf1-/- (lane 2) and MEF/mHsf1 (lane 3) cells. The immunoprecipitated protein complexes were immunoblotted with antibodies against p53, pRB and Hsc70. (B) The immunoblotting of the expression of SV40/TAG, p53, pRb and Hsc70 proteins in the cell lysates that were subjected to coimmunoprecipitation. SV40/TAG, simian virus 40/T antigen; pRb, phosphorylated retinoblastoma protein; Hsc70, heat shock cognate protein 70; MEF, mouse embryonic fibroblast; wt, wild type; Hsf1, heat shock factor 1; mHsf1, Hsf1 null MEF cells expressing mouse Hsf1; IP, immunoprecipitate; IB; immunoblot.