FIG. 7.

ChIP analysis of ABF1 binding to the modified HIS4-MEL1 promoter. ChIP was performed with ABF1 antibody in yeast carrying ABF1(1-731) or the abf1-1 ts mutant at 25°C or after 1 h at 37°C, as indicated. Input and IP samples were amplified in separate reactions with the use of primers for the HIS4-MEL1, SPT15, and ACT1 promoters. Samples were combined prior to electrophoresis, Southern blotting, and hybridization with appropriate probes. Although ACT1 was used as a negative control, its amplification was more efficient than that of HIS4-MEL1 or SPT15 promoters, for unknown reasons. Note, however, that ACT1 shows reduction in the IP lanes relative to the input lanes, and HIS4-MEL1 and SPT15 do not. Ratios of HIS4-MEL1 IP samples to input samples and SPT15 IP samples to input samples, relative to the ratio of ACT1 IP samples to input samples, are shown at the bottom. Similar results were obtained in this and one other independent experiment.