Differential requirement of DNA replication factors for subtelomeric ARS consensus sequence protosilencers in Saccharomyces cerevisiae.
The establishment of silent chromatin requires passage through S-phase, but not DNA replication per se. Nevertheless, many proteins that affect silencing are bona fide DNA replication factors. It is not clear if mutations in these replication factors affect silencing directly or indirectly via deregulation of S-phase or DNA replication. Consequently, the relationship between DNA replication and silencing remains an issue of debate. Here we analyze the effect of mutations in DNA replication factors (mcm5-461, mcm5-1, orc2-1, orc5-1, cdc45-1, cdc6-1, and cdc7-1) on the silencing of a group of reporter constructs, which contain different combinations of "natural" subtelomeric elements. We show that the mcm5-461, mcm5-1, and orc2-1 mutations affect silencing through subtelomeric ARS consensus sequences (ACS), while cdc6-1 affects silencing independently of ACS. orc5-1, cdc45-1, and cdc7-1 affect silencing through ACS, but also show ACS-independent effects. We also demonstrate that isolated nontelomeric ACS do not recapitulate the same effects when inserted in the telomere. We propose a model that defines the modes of action of MCM5 and CDC6 in silencing.
Rehman
Muhammad Attiq
MA
Department of Molecular and Cellular Biology, University of Guelph, Ontario, Canada.
Fourel
Genevieve
G
Mathews
Amit
A
Ramdin
Danielle
D
Espinosa
Maria
M
Gilson
Eric
E
Yankulov
Krassimir
K
D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D016384:Consensus Sequence; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020868:Gene Silencing; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D051738:Origin Recognition Complex / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D016615:Telomere
C102209:CDC45 protein, S cerevisiae; C066503:CDC6 protein, S cerevisiae; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C069200:MCM5 protein, S cerevisiae; D009687:Nuclear Proteins; C497215:ORC2 protein, S cerevisiae; C497220:ORC5 protein, S cerevisiae; D051738:Origin Recognition Complex; D029701:Saccharomyces cerevisiae Proteins; C489404:CDC7 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases