Defective NER in centrin-deficient cells. (A) Immunoblot analysis of Chk1 phosphorylation in cells of the indicated genotype was performed before or at different times after 3-J/m2 UV-C treatment, using anti–phospho-Chk1 S345 with monoclonal mouse anti-Chk1 as loading control. (B) Flow cytometry analysis of the DNA content of wild-type and Cetn4/2/3-deficient cells before or at the indicated times after 3-J/m2 UV-C treatment. (C) Immunodot-blot analysis of CPDs in genomic DNA from wild type, Cetn4/2/3-deficient cells, and Cetn4/2/3-deficient cells that were stably transfected with the indicated centrin-expressing transgenes (C4, C2, and C3) before or at the indicated times after 5-J/m2 UV-C treatment. Time 0 is immediately after irradiation. (D) Quantitation of the kinetics of CPD repair in cells of the indicated genotype after 5-J/m2 UV-C treatment. Data show mean ± SD of the CPD signal normalized to time 0 signals in at least three separate experiments in which each sample was blotted in triplicate.
