FIGURE 4:

DDB2 is required for XRCC5 recruitment in a chromatin-enriched fraction in colon cancer cell lines. (A) Whole-cell lysates (WCLs) were prepared from control (ct) or shDDB2 (sh) HCT116 cells. Alternatively, cells were washed with CSK-T buffer (CSK-T resist) or CSK-T buffer supplemented with RNase (RNAse resist) before harvesting in Laemmli sample buffer. Samples were probed for XRCC5, DDB2, and histone H3 by Western blotting. (B) Diagram outlining the sequential fractionation protocol used in the following experiments. S1, S2, S3, and P3 fractions were prepared as described in Materials and Methods. (C) Control and shDDB2 HCT116 cells were sequentially fractionated as outlined. Fractions were probed for XRCC5, DDB2, and histone H3 by Western blotting. (D) SW480 (480) and SW620 (620) cells were used to prepare WCLs or washed with CSK-T buffer supplemented with RNase and then harvested in Laemmli sample buffer (RNase resist). Samples were probed for XRCC5, DDB2, and histone H3 by Western blotting. (E) SW480 and SW620 cells were sequentially fractionated as outlined. Fractions were probed for XRCC5, DDB2, and histone H3 by Western blotting.