Co-immunoprecipitation analysis for human BRCA1 and pol β interaction.

<p>Experiments were conducted as described under “Materials and Methods”. Typical results obtained in at least three experiments are shown. Immunoprecipitated proteins were detected by SDS-PAGE and immunoblotting (IB). A. Cell extracts, as indicated, were immunoprecipitated with anti-pol β antibody (lanes 2–5) or non-immune IgG (lane 1). <i>Lanes</i> 2–3 and 4–5 are duplicates. Lane 6 corresponds to immunoblotting of the BRCA1-complemented extract, used here as a source of markers for BRCA1 and pol β. B, Cell extracts as indicated were immunoprecipitated with anti-BRCA1 antibody (lanes 2–5) or non-immune IgG (lane 1). Lanes 2–3 and 4–5 are duplicates, and lane 6 was as described in panel A. C. Purified human BRCA1 and pol β proteins were mixed and immunoprecipitated with anti-pol β antibody (lane 1) or non-immune IgG (lane 3). Pol β was omitted in lane 2, and lane 4 corresponds to the purified proteins used as markers. D. The same purified protein mixture as in panel C, except that immunoprecipitation was with anti-BRCA1 antibody (lane 1) or non-immune IgG (lane 3). BRCA1 was omitted in lane 2.