Figure 7.

Swi5 does not bind to the HO promoter in the presence of a1-α2. (A) A culture of JRY200 (MATa, URA3::MATα, GAL1,10-CDC20, Swi5-Myc₉) was arrested in mitosis by growth in media lacking galactose, then released by the addition of galactose. Aliquots were taken at the indicated times and crosslinked for ChIP. Cell lysates were divided for ChIP of Swi5-Myc₉ and α2. After reversing the crosslinks, purified DNA was used as a template for multiplex PCR using primer set II (see Figure 1A) and primers that amplify the STE6 (as a positive control for α2) and EGT2 (as a positive control for Swi5) promoters. Primer sets that amplify portions of the YDL238c and YDL223c ORFs (the top and bottom primer sets, respectively, in each lane) were used as negative controls. Lane 1, PCR from template of Total Chromatin (TC) sample of DNA purified from a whole cell lysate. Lanes 2–9, PCR from templates of DNA immunoprecipitated using antibodies to c-Myc (Top, for Swi5-Myc₉) and α2 (Bottom). (B) A culture of the haploid K8144 (MATa, GAL1,10-CDC20, Swi5-Myc₉) strain was arrested in mitosis and processed for ChIP with antibodies to c-Myc as described in (A).