Figure 4.

BLM and WRN helicases are increased and recruited to the telomeres upon RHPS4 treatment. (A) Western blot analysis of BLM and WRN helicases in BJ-HELT cells untreated or treated with RHPS4 for 96 h. (B) ChIP experiments on BJ-HELT fibroblasts untreated and treated with RHPS4. Protein extracts from cells during S and G₂ phases of cell cycle were subjected to ChIP experiments using antibodies against BLM and WRN. IgG antibody was used as negative control. The total DNA (input) represents 10 and 1% of genomic DNA. Southern blot analysis was performed by using telomeric or ALU repeat-specific probes. (C) The signals obtained were quantified by densitometry, and the percentage of precipitated DNA was calculated as a ratio of input signals and plotted. Three independent experiments were evaluated and error bars indicate the SD. (D) Western blot analysis of BLM in siGFP and siBLM-transfected cells. (E) Western blot analysis of γH2AX in siGFP and siBLM transfected cells untreated or treated with RHPS4.