FIG. 3.

Several proteins are coimmunoprecipitated with the SrCap-specific monoclonal antibody. Proteins from ³⁵S-labeled uninfected (−) or adenovirus-infected (+) A549 cell lysates were immunoprecipitated with control (E1A-specific antibody M73), SrCap-specific, DBP-specific, or CBP/p300-specific (NM11) monoclonal antibodies and resolved by SDS–7.5% PAGE, as indicated. A549 cells were infected with adenovirus serotype 2 for 20 h prior to lysis. Positions of known proteins are shown to the left. Positions of molecular mass markers are shown to the right. In addition to the molecular mass markers we used the actual molecular mass of CBP/p300 (ca. 265 kDa) to calculate the expected migration position of SrCap (ca. 315 kDa).