Requirements for the nucleolytic processing of DNA ends by the Werner syndrome protein-Ku70/80 complex.
J Biol Chem
; 276(13): 9896-902, 2001 Mar 30.
Article
em En
| MEDLINE
| ID: mdl-11152456
ABSTRACT
Werner syndrome (WS) is an inherited disease characterized by premature onset of aging, increased cancer incidence, and genomic instability. The WS gene encodes a protein with helicase and exonuclease activities. Our previous studies indicated that the Werner syndrome protein (WRN) interacts with Ku, a heterodimeric factor of 70- and 80-kDa subunits implicated in the repair of double strand DNA breaks. Moreover, we demonstrated that Ku70/80 strongly stimulates and alters WRN exonuclease activity. In this report, we investigate further the association between WRN and Ku70/80. First, using various WRN deletion mutants we show that 50 amino acids at the amino terminus are required and sufficient to interact with Ku70/80. In addition, our data indicate that the region of Ku80 between amino acids 215 and 276 is necessary for binding to WRN. Then, we show that the amino-terminal region of WRN from amino acid 1 to 388, which comprise the exonuclease domain, can be efficiently stimulated by Ku to degrade DNA substrates, indicating that the helicase domain and the carboxyl-terminal tail are not required for the stimulatory process. Finally, using gel shift assays, we demonstrate that Ku recruits WRN to DNA. Taken together, these results suggest that Ku-mediated activation of WRN exonuclease activity may play an important role in a cellular pathway that requires processing of DNA ends.
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Base de dados:
MEDLINE
Assunto principal:
Síndrome de Werner
/
DNA
/
Proteínas Nucleares
/
Núcleo Celular
/
DNA Helicases
/
Antígenos Nucleares
/
Proteínas de Ligação a DNA
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Estados Unidos