Polyomavirus Large T Antigen Binds the Transcriptional Coactivator Protein p300

Using coimmunoprecipitation and glutathione S-transferase pulldown experiments, we found that polyomavirus large T antigen binds to p300 in vivo and in vitro. The N-terminal region of the viral protein, including the pRB binding motif, was dispensable for this interaction, which involved several regions within the C-terminal half of the large T antigen. Interestingly, anti-T antibody coimmunoprecipitated a subspecies of p300 which has high histone acetyltransferase activity.