Figure 3.

UV radiation disrupts the interaction between the endogenous p53 and RPA. (A) Lysates were prepared at different times after UV irradiation at 50 J/m². Total RPA in extracts was detected by immunoblotting using an anti-RPA polyclonal antiserum. The 50-kDa band is a degradation product of RPA-70. (B) The lysates were immunoprecipitated by an anti-p53 monoclonal antibody crosslinked to protein G-Sepharose beads. The immunoprecipitates were resolved by SDS/PAGE and immunoblotted using an anti-RPA polyclonal antiserum. (C) The same blot shown in B was stripped and reprobed with the anti-p53 antibody. Lanes 6 in A–C contain purified recombinant proteins as markers.