Visualization of recombination-mediated damage bypass by template switching.
Nat Struct Mol Biol
; 21(10): 884-92, 2014 Oct.
Article
em En
| MEDLINE
| ID: mdl-25195051
ABSTRACT
Template switching (TS) mediates damage bypass via a recombination-related mechanism involving PCNA polyubiquitination and polymerase δ-dependent DNA synthesis. Using two-dimensional gel electrophoresis and EM, here we characterize TS intermediates arising in Saccharomyces cerevisiae at a defined chromosome locus, identifying five major families of intermediates. Single-stranded DNA gaps of 150-200 nt, and not DNA ends, initiate TS by strand invasion. This causes reannealing of the parental strands and exposure of the nondamaged newly synthesized chromatid, which serves as a replication template for the other blocked nascent strand. Structures resembling double Holliday junctions, postulated to be central double-strand break-repair intermediates but so far visualized only in meiosis, mediate late stages of TS before being processed to hemicatenanes. Our results reveal the DNA transitions accounting for recombination-mediated DNA-damage tolerance in mitotic cells and replication under conditions of genotoxic stress.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Recombinação Genética
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Saccharomyces cerevisiae
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Moldes Genéticos
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Dano ao DNA
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Reparo do DNA
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Replicação do DNA
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article