Figure 6. Effect of UV induced Chk1 activation by reduced levels of circadian clock genes in mouse cells. siRNA transfected, primary mouse skin fibroblast cells 72 h later were irradiated with 5 J/m2 UVC, allowed to grow for 0, 0.5 or 1 h and proteins lysates were prepared for immunoblot analysis. (A and C) indicated proteins were analyzed by immunoblotting with appropriate antibodies at various times after UV damage. (B and D) quantitative analysis of the immunoblots. The averages and standard deviations are from at least three independent experiments.