title: Positive roles of SAS2 in DNA replication and transcriptional silencing in yeast.
abstract: Sas2p is a histone acetyltransferase implicated in the regulation of transcriptional silencing, and ORC is the six-subunit origin recognition complex involved in the initiation of DNA replication and the establishment of transcriptionally silent chromatin by silencers in yeast. We show here that SAS2 deletion (sas2Delta) exacerbates the temperature sensitivity of the ORC mutants orc2-1 and orc5-1. Moreover, sas2Delta and orc2-1 have a synthetic effect on cell cycle progression through S phase and initiation of DNA replication. These results suggest that SAS2 plays a positive role in DNA replication and cell cycle progression. We also show that sas2Delta and orc5-1 have a synthetic effect on transcriptional silencing at the HMR locus. Moreover, we demonstrate that sas2Delta reduces the silencing activities of silencers regardless of their locations and contexts, indicating that SAS2 plays a positive role in silencer function. In addition, we show that SAS2 is required for maintaining the structure of transcriptionally silent chromatin.
authors.affiliation: Department of Biology, University of Rochester, Rochester, NY 14627, USA.
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Zou
authors.forename: Xin
authors.initials: X
authors.lastname: Bi
mesh_terms: D000123:Acetyltransferases / Q000235:genetics / Q000502:physiology*; D002843:Chromatin / Q000737:chemistry; D004261:DNA Replication; D017353:Gene Deletion; D020868:Gene Silencing; D051548:Histone Acetyltransferases; D009154:Mutation; D051738:Origin Recognition Complex / Q000235:genetics; D018741:Replication Origin; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; C497215:ORC2 protein, S cerevisiae; C497220:ORC5 protein, S cerevisiae; D051738:Origin Recognition Complex; D029701:Saccharomyces cerevisiae Proteins; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; C469266:Sas2 protein, S cerevisiae