Fig. 3

HSP90AB1 is shown to regulate BLM at the transcriptional level through its interaction with PARP1. A–C HSP90AB1 was identified as an interaction partner of PARP1 through IP and MS analyses using nuclear protein extracts from PC3 cells. D IF staining of PC3 cells with anti-PARP1 (red) and anti-HSP90AB1 (green) antibodies, visualizing their co-localization. Scale bar: 20 μm. E IP of PC3 cell lysates using anti-PARP1 (top), anti-HSP90AB1 (bottom), or control IgG antibody, followed by western blot analysis with anti-PARP1 and anti-HSP90AB1 antibodies. F Western blot analysis confirming the efficiency of HSP90AB1 knockdown using shRNA in PC3 cells. G–I Detection of BLM promoter activity, mRNA abundance, and protein expression of HSP90AB1 and BLM in PC3 cells transfected with shHSP90AB1 or HSP90AB1oe plasmids. J ChIP-qPCR of BLM promoter was performed with HSP90AB1, or control IgG antibody in PC3 cells. K, L Western blot analysis of PARP1, HSP90AB1, and BLM protein levels in PC3 cells with knockdown or overexpression of HSP90AB1, along with knockdown or overexpression of PARP1. Shown are the means ± SD from 3 experiments (*P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, and “ns” indicated no significant difference)