Figure 6.

Non-chromatin-associated 53BP1 was degraded in response to CPT. A, parental A549 cells were treated with 500 nm CPT for 0, 2, 4, and 8 h, fractionated into cytoplasmic, soluble nuclear, and insoluble chromatin-enriched nuclear compartments, and protein expression was examined. Protein quantitation was performed as in Fig. 1A. B, A549 control or UbcH7-depleted cells were treated with 500 nm CPT or vehicle for 8 h, fractionated into soluble (a combination of cytoplasm and soluble nucleus) and insoluble (chromatin-enriched) fractions, and protein expression was examined. Whole cell extracts (WCE) were also analyzed.