Binding and melting of D-loops by the Bloom syndrome helicase.
Biochemistry
; 39(47): 14617-25, 2000 Nov 28.
Article
en En
| MEDLINE
| ID: mdl-11087418
ABSTRACT
Bloom syndrome is a rare autosomal disorder characterized by predisposition to cancer and genomic instability. BLM, the structural gene mutated in individuals with the disorder, encodes a DNA helicase belonging to the RecQ family of helicases. These helicases have been established to serve roles in both promoting and preventing recombination. Mounting evidence has implicated a function for BLM during DNA replication; specifically, BLM might be involved in rescuing stalled or collapsed replication forks by a recombination-based mechanism. We have tested this idea by examining the binding and melting activity of BLM on oligonucleotide substrates containing D-loops, DNA structures that model the presumed initial intermediate formed during homologous recombination. We find that BLM preferentially melts those D-loops that are formed more favorably by the strand exchange protein Rad51, but whose polarity could be less favorable for enabling restoration of an active replication fork. We propose a model in which BLM selectively dissociates recombination intermediates likely to be unfavorable for recombination-promoted replication.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Síndrome de Bloom
/
Daño del ADN
/
Adenosina Trifosfatasas
/
ADN Helicasas
/
Proteínas de Unión al ADN
/
Conformación de Ácido Nucleico
Límite:
Humans
Idioma:
En
Revista:
Biochemistry
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos