Abstract
During G1 phase, a prereplicative complex (pre-RC) that determines where DNA synthesis initiates forms at origins. The Sir2p histone deacetylase inhibits pre-RC assembly at a subset of origins, suggesting that Sir2p inhibits DNA replication through a unique aspect of origin structure. Here, we identified five SIR2-sensitive origins on chromosomes III and VI. Linker scan analysis of two origins indicated that they share a common organization, including an inhibitory sequence positioned 3' to the sites of origin recognition complex (ORC) binding and pre-RC assembly. This inhibitory sequence (I(S)) required SIR2 for its activity, suggesting that SIR2 inhibits origins through this sequence. Furthermore, I(S) elements occurred within positioned nucleosomes, and Abf1p-mediated exclusion of nucleosomes from the origin abrogated the inhibition. These data suggest that Sir2p and I(S) elements inhibit origin activity by promoting an unfavorable chromatin structure for pre-RC assembly.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Base Sequence
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Centromere / genetics
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Chromatin / metabolism
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Chromatin Immunoprecipitation
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Chromosomes, Fungal / genetics*
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DNA Replication*
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Histone Deacetylases / genetics
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Histone Deacetylases / metabolism*
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Hot Temperature
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Mutation
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Origin Recognition Complex / antagonists & inhibitors*
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Plasmids / genetics
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Replication Origin*
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Saccharomyces cerevisiae / enzymology
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Silent Information Regulator Proteins, Saccharomyces cerevisiae / genetics
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Silent Information Regulator Proteins, Saccharomyces cerevisiae / metabolism*
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Sirtuin 2
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Sirtuins / genetics
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Sirtuins / metabolism*
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Suppression, Genetic
Substances
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CDC6 protein, S cerevisiae
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Cell Cycle Proteins
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Chromatin
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Origin Recognition Complex
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Saccharomyces cerevisiae Proteins
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Silent Information Regulator Proteins, Saccharomyces cerevisiae
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SIR2 protein, S cerevisiae
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Sirtuin 2
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Sirtuins
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Histone Deacetylases