Figure 6.

 Cdc7 is required to convert plasmid-borne ARS301 to the postreplicative state after HU. (A) cdc7-1 cells (2032) containing the ARS301 plasmid (pCS1) were arrested in G₂/M by nocodazole (lanes 3,4) or in G₁ by α factor (lanes 5,6). G₁-arrested cells were released into HU (lanes 7,8). The culture was split in two. Each half was held in HU and incubated at either 24°C or 37°C for 30 min before release into nocodazole at these temperatures. Samples were taken for genomic footprinting analysis 1 hr and 3 hr after release from HU into nocodazole (lanes 9–16). The primer (JD63b) is specific for the plasmid borne ARS301. Lanes 1 and 2 show primer extensions performed on naked DNA. Exposure levels were adjusted because plasmid recovery was lower from G₁ and S-phase cells and on release from HU at 37°C. (B) Densitometric quantification of Fig. 4A, lanes 4, 6, 8, 10, 12, 14, and 16. Levels were adjusted to a background band marked by an arrowhead. The ORC-induced hypersensitive sites of the post-RC are indicated by asterisks. The functional ARS element is marked by an open box. The position of the ACS is indicated.