Promoter strength influences the S phase requirement for establishment of silencing at the Saccharomyces cerevisiae silent mating type Loci.
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.
Ren
Jie
J
Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA.
Wang
Chia-Lin
CL
Sternglanz
Rolf
R
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
D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae