An ARS element inhibits DNA replication through a SIR2-dependent mechanism.
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.
Crampton
Amber
A
Laboratory of Chromosome Replication, Van Andel Research Institute, Grand Rapids, MI 49503, USA.
Chang
FuJung
F
Pappas
Donald L
DL
Frisch
Ryan L
RL
Weinreich
Michael
M
D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002503:Centromere / Q000235:genetics; D002843:Chromatin / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D015825:Chromosomes, Fungal / Q000235:genetics*; D004261:DNA Replication; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D009154:Mutation; D051738:Origin Recognition Complex / Q000037:antagonists & inhibitors*; D010957:Plasmids / Q000235:genetics; D018741:Replication Origin; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D056565:Sirtuin 2; D037761:Sirtuins / Q000235:genetics / Q000378:metabolism*; D013489:Suppression, Genetic
C066503:CDC6 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002843:Chromatin; D051738:Origin Recognition Complex; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D006655:Histone Deacetylases