EXO1 resection at G-quadruplex structures facilitates resolution and replication.
Nucleic Acids Res
; 48(9): 4960-4975, 2020 05 21.
Article
en En
| MEDLINE
| ID: mdl-32232411
ABSTRACT
G-quadruplexes represent unique roadblocks to DNA replication, which tends to stall at these secondary structures. Although G-quadruplexes can be found throughout the genome, telomeres, due to their G-richness, are particularly predisposed to forming these structures and thus represent difficult-to-replicate regions. Here, we demonstrate that exonuclease 1 (EXO1) plays a key role in the resolution of, and replication through, telomeric G-quadruplexes. When replication forks encounter G-quadruplexes, EXO1 resects the nascent DNA proximal to these structures to facilitate fork progression and faithful replication. In the absence of EXO1, forks accumulate at stabilized G-quadruplexes and ultimately collapse. These collapsed forks are preferentially repaired via error-prone end joining as depletion of EXO1 diverts repair away from error-free homology-dependent repair. Such aberrant repair leads to increased genomic instability, which is exacerbated at chromosome termini in the form of dysfunction and telomere loss.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Telómero
/
Enzimas Reparadoras del ADN
/
Replicación del ADN
/
Exodesoxirribonucleasas
/
G-Cuádruplex
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Nucleic Acids Res
Año:
2020
Tipo del documento:
Article
País de afiliación:
Estados Unidos