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. 2007 Aug 9;35(16):5338–5350. doi: 10.1093/nar/gkm550

Figure 4.

Figure 4.

DDB1 and Cul4A protect XPC from degradation upon UV irradiation. (A and B) OSU-2 cells were transfected with DDB1 siRNA (A) or Cul4A siRNA (B) for 48 h. Cells were UV irradiated at 20 J/m2 and allowed to repair for 1 h. The whole cell lysates were subjected to immunoblotting using anti-DDB1, anti-Cul4A, anti-DDB2, anti-XPC and anti-Lamin B antibodies. Relative amount of total XPC in UV-irradiated cells were quantified relative to the respective unirradiated levels, normalized by Lamin B. (C) HeLa-DDB2 cells were transiently transfected with DDB1-V5, Cul4A-c-Myc or a combination of DDB1-V5 plus Cul4A-c-Myc for 48 h. The cultures were treated with 100 μg/ml of CHX, and then UV irradiated at 20 J/m2, or mock treated and further incubated in the medium containing CHX for 1 h. The whole cell lysates were subjected to western blot analysis using anti-XPC, anti-DDB2, anti-V5, anti-c-Myc and anti-Lamin B antibodies. Relative XPC level in UV-irradiated cells were quantified relative to the respective unirradiated levels and normalized by Lamin B. * Exogenously expressed DDB2-FLAG-HA; ** Endogenously expressed DDB2.