Cell cycle requirements in assembling silent chromatin in Saccharomyces cerevisiae.
The establishment of silencing at the silent mating-type locus, HMR, in Saccharomyces cerevisiae requires that yeast pass through S phase of the cell cycle, yet requires neither the initiation of DNA replication at the locus destined to become silenced nor the passage of a replication fork through that locus. We tested whether this S-phase requirement reflects a window within the cell cycle permissive for recruitment of Sir proteins to HMR. The S-phase-restricted event necessary for silencing occurred after recruitment of Sir proteins to HMR. Moreover, cells arrested in early S phase formed silent chromatin at HMR, provided HMR was on a nonreplicating template. Replicating templates required a later step for silencing. These results provide temporal resolution of discrete steps in the formation of silent chromatin and suggest that more than one cell cycle-regulated event may be necessary for the establishment of silencing.
Kirchmaier
Ann L
AL
Department of Biochemistry and Purdue Cancer Center, Purdue University, 175 S. University St., West Lafayette, IN 47907, USA. kirchmaier@purdue.edu
Rine
Jasper
J
D002384:Catalysis; D002453:Cell Cycle; D002843:Chromatin / Q000378:metabolism*; D004261:DNA Replication; D016193:G1 Phase; D015966:Gene Expression Regulation, Fungal; D020868:Gene Silencing; D049770:Genes, Mating Type, Fungal; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D020871:RNA Stability; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D056565:Sirtuin 2; D037761:Sirtuins / Q000235:genetics / Q000378:metabolism
D002843:Chromatin; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D006655:Histone Deacetylases