Figure 10.

The Dna2p execution step depends upon S phase but not mitosis. (A) DNA2 executes its function after the HU-dependent step. Strains YDF100 (DNA2⁺) and YDF102 (dna2–22) were synchronized with α factor, shifted to 37°C for 3 h, and released from α factor at 37°C into YPD (control) or YPD+0.2 mM HU (+HU). At t = 0 and 60 min after release, cells were diluted into YPD and plated at 30°C. Colonies were counted after 2 d. (B) DNA2 executes its function independent of the nocodazole-dependent step. Cells were treated as in panel A except that, after α factor release, the strains were incubated in either YPD (control) or YPD+15 μg/ml nocodazole +nocodazole). Cells were then diluted and plated as in panel A. Results are expressed as the number of colonies formed at t = 60 min after α factor release divided by the number of colonies formed at t = 0 min after release.