Reconstitution of translesion synthesis reveals a mechanism of eukaryotic DNA replication restart.
Nat Struct Mol Biol
; 27(5): 450-460, 2020 05.
Article
em En
| MEDLINE
| ID: mdl-32341533
ABSTRACT
Leading-strand template aberrations cause helicase-polymerase uncoupling and impede replication fork progression, but the details of how uncoupled forks are restarted remain uncertain. Using purified proteins from Saccharomyces cerevisiae, we have reconstituted translesion synthesis (TLS)-mediated restart of a eukaryotic replisome following collision with a cyclobutane pyrimidine dimer. We find that TLS functions 'on the fly' to promote resumption of rapid replication fork rates, despite lesion bypass occurring uncoupled from the Cdc45-MCM-GINS (CMG) helicase. Surprisingly, the main lagging-strand polymerase, Pol δ, binds the leading strand upon uncoupling and inhibits TLS. Pol δ is also crucial for efficient recoupling of leading-strand synthesis to CMG following lesion bypass. Proliferating cell nuclear antigen monoubiquitination positively regulates TLS to overcome Pol δ inhibition. We reveal that these mechanisms of negative and positive regulation also operate on the lagging strand. Our observations have implications for both fork restart and the division of labor during leading-strand synthesis generally.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
/
Proteínas de Saccharomyces cerevisiae
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Replicação do DNA
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article