The origin recognition complex, SIR1, and the S phase requirement for silencing.
Silencing of transcription in Saccharomyces cerevisiae has several links to DNA replication, including a role for the origin recognition complex (ORC), the DNA replication initiator, in both processes. In addition, the establishment of silencing at the HML and HMR loci requires cells to pass through the S phase of the cell cycle. Passage through S phase was required for silencing of HMR even under conditions in which ORC itself was no longer required. The requirement for ORC in silencing of HMR could be bypassed by tethering the Sir1 protein to the HMR-E silencer. However, ORC had a Sir1-independent role in transcriptional silencing at telomeres. Thus, the role of ORC in silencing was separable from its role in initiation, and the role of S phase in silencing was independent of replication initiation at the silencers.
Fox
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CA
Department of Molecular and Cell Biology, Division of Genetics, 401 Barker Hall, University of California, Berkeley, CA 94720, USA.
Ehrenhofer-Murray
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AE
Loo
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S
Rine
J
J
D019747:Aldose-Ketose Isomerases; D002843:Chromatin / Q000502:physiology; D015825:Chromosomes, Fungal / Q000502:physiology; D004261:DNA Replication; D004271:DNA, Fungal / Q000235:genetics / Q000502:physiology; D004268:DNA-Binding Proteins / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D051738:Origin Recognition Complex; D011993:Recombinant Fusion Proteins / Q000235:genetics; D016196:S Phase / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D016615:Telomere; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
D002843:Chromatin; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D051738:Origin Recognition Complex; D011993:Recombinant Fusion Proteins; C084121:SIR1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D015534:Trans-Activators; D019747:Aldose-Ketose Isomerases; C490353:TRP1 protein, S cerevisiae