Dissociation of CAK from Core TFIIH Reveals a Functional Link between XP-G/CS and the TFIIH Disassembly State
Figure 5
The kinase activity of CAK is dispensable for GGR.
(A) Dose-dependent inhibition of Cdk7 kinase activity abolishes Cdk2 phosphorylation in vivo. Asynchronous HCT116-Cdk7+/+ and HCT116-Cdk7as/as cells were incubated 14 h with the indicated concentrations of 1-NMPP1, and the cell lysates were analyzed by Western blotting using anti-phospho-Cdk2 (P-Thr160) antibody. The cellular protein lamin B serves as a loading control. (B and C) CAK inhibition does not affect the removal of CPD and 6-4PP from the genome. HCT116-Cdk7as/as cells were starved in serum-free medium overnight and the cells were pretreated with 1-NMPP1 (10 µM) or DMSO (vehicle) for 14 h. The cells were then UV-irradiated with 20 J/m2 and allowed to repair DNA in fresh medium with similar composition to the pretreatment for the indicated times. Identical amounts of genomic DNA were subjected to immuoslot-blot analysis of CPD and 6-4PP using the corresponding antibodies. The quantitative data presented in the graph indicate mean ± S.E. of the remaining CPD or 6-4PP from three independent experiments.