title: Promoter strength influences the S phase requirement for establishment of silencing at the Saccharomyces cerevisiae silent mating type Loci.
abstract: In Saccharomyces cerevisiae, the two cryptic mating type loci, HML and HMR, are transcriptionally silent. Previous studies on the establishment of silencing at HMR identified a requirement for passage through S phase. However, the underlying mechanism for this requirement is still unknown. In contrast to HMR, we found that substantial silencing of HML could be established without passage through S phase. To understand this difference, we analyzed several chimeric HM loci and found that promoter strength determined the S phase requirement. To silence a locus with a strong promoter such as the a1/a2 promoter required passage through S phase while HM loci with weaker promoters such as the α1/α2 or TRP1 promoter did not show this requirement. Thus, transcriptional activity counteracts the establishment of silencing but can be overcome by passage through S phase.
authors.affiliation: Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Ren
authors.forename: Chia-Lin
authors.initials: CL
authors.lastname: Wang
authors.forename: Rolf
authors.initials: R
authors.lastname: Sternglanz
mesh_terms: D002453:Cell Cycle; D004268:DNA-Binding Proteins; D044127:Epigenesis, Genetic; D005434:Flow Cytometry; D015870:Gene Expression; D015966:Gene Expression Regulation, Fungal; D020868:Gene Silencing; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae