FIGURE 5.

RIF1 regulates BLM DSB recruitment and chromatin loading. a, defective BLM IRIF formation in RIF1-depleted cells is shown. HeLa cells were infected with shRNAs as indicated. 4 h after irradiation, cells were fixed and immunostained with anti-BLM and anti-γH2Ax antibodies. Three different, nonoverlapping lentiviral shRNAs for RIF1 were used, and the same results were obtained. b, depletion of RIF1 reduces the amount of chromatin-associated BLM. RIF1 and 53BP1 knockdown cells were mocked-treated or treated with ionizing radiation. 1 h after IR, the cells were harvested, and soluble and chromatin fractions of cell lysates were analyzed by immunoblotting using the indicated antibodies.