Figure 1

Transgene expression of mutant NBS1 interacts with MRN after Ad-NBS1 gene transfer and significantly reduces the expression of wild-type RAD50 and NBS1. (A) Anti-MRE11 antibody Co-IP wild-type NBS1 in all cells. It indicated direct interaction between MRE11 and wild-type NBS1 (lanes 2, 4, 6 and 8). Mutant NBS1 was Co-IP in Ad-NBS1-infected cells, indicated direct interaction between MRE11 and mutant NBS1 (lane 8). A significant downregulation of wild-type NBS1 protein was observed in cells infected with Ad-NBS1 (lane 8) relative to non-infected cells (lanes 2, 4 and 6). All lanes shown were run simultaneously on a single gel as contiguous lanes. Lane 1: control cells; lane 2: control cells after Co-IP with MRE11 antibody; lane 3: cells treated with cisplatin (0.3 μg ml⁻¹); lane 4: cisplatin-treated cells after Co-IP with MRE11antibody; lane 5: Ad-GFP-infected cells; lane 6: Ad-GFP-infected cells after Co-IP; lane 7: Ad-NBS1-infected cells and lane 8: Ad-NBS1-infected cells after Co-IP with MRE11 antibody. (B–D) Wild-type MRE11 was not downregulated after infection of JHU006 cells with Ad-NBS1 relative to non-infected controls or Ad-GFP controls (B). Downregulation of wild-type RAD50 (P<0.05; C) and NBS1 proteins (P<0.01; D) is seen after infection with Ad-NBS1 when compared with non-infected controls or Ad-GFP controls.