FIG. 6.

Expression of cyclin E protein is upregulated in nocodazole-treated, adapted cells. Immunoblot analysis of cyclin B1 and cyclin E expression. NIH 3T3 cells were synchronized in low serum for 48 h and released into high serum plus nocodazole. Extracts were prepared at 8-h time points for the next 48 h and analyzed by immunoblotting for cyclin B1 and cyclin E expression. Cyclin E expression was highest in cells entering S phase (16 h) and in cells that had adapted (40 and 48 h), while cyclin B1 expression was highest in mitotic cells (24 h) and declined thereafter. The asterisk indicates a cross-reacting protein detected by cyclin E antibody that serves as an internal loading control.