Yeast Ume6p repressor permits activator binding but restricts TBP binding at the HOP1 promoter. Nucleic Acids Res

Ume6p plays essential roles in the regulation of early meiotic genes in Saccharomyces cerevisiae. Ume6p exerts repression via recruitment of the Sin3p-Rpd3p histone deacetylase and Isw2p chro-matin remodeling complexes. The transcriptional step that is ultimately inhibited by Ume6p is unknown. Here, in vivo footprinting shows that transcriptional activators Hap1p and Abf1p occupy upstream sites in repressed and derepressed pro-moters. In contrast, chromatin immunoprecipitation shows that TATA box-binding protein (TBP)-promoter binding is reduced upon repression of HOP1. Fusion of TBP to a zinc cluster DNA binding domain relieves repression at a HOP1 promoter modi®ed to include the zinc cluster target site. We suggest that TBP binding is inhibited through chromatin modi®cation by the Sin3p-Rpd3p and Isw2p complexes recruited by Ume6p