FIG. 5.

Cell cycle-dependent binding to 6X octamer RNA. A C. fasciculata culture was synchronized by hydroxyurea arrest, and nuclear extracts were prepared at 30-min intervals following release from arrest. Circles, RNA gel shift with 8 μg of nuclear extract by a ³²P-labeled 6X octamer probe; triangles, TOP2 mRNA level determined by Northern blotting with a ³²P-labeled probe for TOP2 coding sequence; squares, percentage of cells having two nuclei as a measure of cell synchronization. RNA gel shifts and Northern blots were quantitated by PhosphorImager analysis.