Figure 5.

Homologous recombination is dependent on active Clb–Cdk and not on DNA replication. (A) cdc7-4 cells were arrested at the restrictive temperature and then incubated in galactose-containing medium at the permissive (25°C) or restrictive (37°C) temperatures. FACS analysis of the cdc7-4 cell culture confirmed that cells did not undergo DNA replication at the restrictive temperature. (B) PCR assays for gene conversion in cdc7-4 cells at the permissive and restrictive temperatures. (C) PCR assays for gene conversion were carried out for cdc4-1 and cdc28-4 cells at the permissive and restrictive temperatures, wt G₂-arrested with vector only, or G₁- or G₂-arrested with GAL-SIC1 plasmid. (D) Nondenaturing slot blot analysis of cdc4-1, cdc7-4, cdc28-4 and wt cells overexpressing SIC1. As a positive control for hybridization, equivalent DNA samples were blotted after DNA denaturation (only wt/GAL-SIC is shown here).