An ARS element inhibits DNA replication through a SIR2-dependent mechanism

Mol Cell. 2008 Apr 25;30(2):156-66. doi: 10.1016/j.molcel.2008.02.019.

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

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Centromere / genetics
  • Chromatin / metabolism
  • Chromatin Immunoprecipitation
  • Chromosomes, Fungal / genetics*
  • DNA Replication*
  • Histone Deacetylases / genetics
  • Histone Deacetylases / metabolism*
  • Hot Temperature
  • Mutation
  • Origin Recognition Complex / antagonists & inhibitors*
  • Plasmids / genetics
  • Replication Origin*
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Silent Information Regulator Proteins, Saccharomyces cerevisiae / genetics
  • Silent Information Regulator Proteins, Saccharomyces cerevisiae / metabolism*
  • Sirtuin 2
  • Sirtuins / genetics
  • Sirtuins / metabolism*
  • Suppression, Genetic

Substances

  • CDC6 protein, S cerevisiae
  • Cell Cycle Proteins
  • Chromatin
  • Origin Recognition Complex
  • Saccharomyces cerevisiae Proteins
  • Silent Information Regulator Proteins, Saccharomyces cerevisiae
  • SIR2 protein, S cerevisiae
  • Sirtuin 2
  • Sirtuins
  • Histone Deacetylases