FIGURE 1.

st induces expression and loading of CDC6 onto chromatin in quiescent NHF, and CDC6 facilitates loading of cyclin E. BJ-hTERT fibroblasts were serum-starved for 72 h (A) or grown to high density as described under “Experimental Procedures” (B and C) and then transduced with the indicated adenoviruses or re-stimulated with FBS. Forty-eight hours following transduction, cells were harvested, and chromatin-bound and soluble fractions were obtained as described under “Experimental Procedures.” 15 μg of the soluble protein fractions and the corresponding equivalent chromatin-bound fractions were analyzed by Western blot using the indicated antibodies. Same exposure times are shown for both fractions. Coomassie Blue staining of the gel is shown as a loading control. Relevant proteins are indicated. Note that as reported earlier exogenously expressed cyclin E migrates as a series of bands that migrate faster that endogenous cyclin E (12).