Yeast Stn1 promotes MCM to circumvent Rad53 control of the S phase checkpoint.
Curr Genet
; 68(2): 165-179, 2022 Apr.
Article
em En
| MEDLINE
| ID: mdl-35150303
ABSTRACT
Treating yeast cells with the replication inhibitor hydroxyurea activates the S phase checkpoint kinase Rad53, eliciting responses that block DNA replication origin firing, stabilize replication forks, and prevent premature extension of the mitotic spindle. We previously found overproduction of Stn1, a subunit of the telomere-binding Cdc13-Stn1-Ten1 complex, circumvents Rad53 checkpoint functions in hydroxyurea, inducing late origin firing and premature spindle extension even though Rad53 is activated normally. Here, we show Stn1 overproduction acts through remarkably similar pathways compared to loss of RAD53, converging on the MCM complex that initiates origin firing and forms the catalytic core of the replicative DNA helicase. First, mutations affecting Mcm2 and Mcm5 block the ability of Stn1 overproduction to disrupt the S phase checkpoint. Second, loss of function stn1 mutations compensate rad53 S phase checkpoint defects. Third Stn1 overproduction suppresses a mutation in Mcm7. Fourth, stn1 mutants accumulate single-stranded DNA at non-telomeric genome locations, imposing a requirement for post-replication DNA repair. We discuss these interactions in terms of a model in which Stn1 acts as an accessory replication factor that facilitates MCM activation at ORIs and potentially also maintains MCM activity at replication forks advancing through challenging templates.
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1
Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
/
Proteínas de Saccharomyces cerevisiae
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Curr Genet
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Estados Unidos