Molecular analysis of ERCC2 mutations in the repair deficient hamster mutants UVL-1 and V-H1.
Mutat Res
; 385(1): 47-57, 1997 Oct.
Article
en En
| MEDLINE
| ID: mdl-9372848
The cDNA sequence of the Chinese hamster ERCC2 nucleotide excision repair and transcription gene from the UVL-1 Chinese hamster ovary (CHO) mutant cell line and the V-H1 Chinese hamster V79 mutant line was analyzed. ERCC2 encodes a presumed ATP-dependent DNA helicase and is single copy in CHO lines due to the structural hemizygosity of chromosome 9. Both UVL-1 and V-H1 have intermediate levels of (6-4) photoproduct repair but are as highly UV sensitive as the group 2 mutants that have no detectable repair. Deficiency in cyclobutane dimer removal has also been shown for V-H1. In UVL-1, a single base substitution resulting in an Arg75-->Trp substitution in helicase domain Ia was identified. The equivalent amino acid position is also Arg in the human, mouse, Xiphophorus maculatus, Saccharomyces cerevisiae, and Schizosaccharomyces pombe homologs. In V-H1, a single base substitution resulting in a Thr46-->Ile substitution in helicase domain I (the ATP-binding domain) was identified in both alleles. The equivalent amino acid position is also Thr in the five homologs. Analysis of three V-H1 partial revertants revealed that they still have the original V-H1 mutation in both alleles, indicating that these are second site reversion events. Site-specific mutagenesis was used to introduce the Thr46-->Ile, Arg75-->Trp, and Lys48-->Arg (helicase domain I) mutations into a hamster ERCC2 expression plasmid. These plasmids each failed to confer UV resistance to group 2 mutant cells, further demonstrating that the changes identified are the causative mutations in V-H1 and UVL-1. Correlations between specific mutations, biochemical activities, and repair phenotype are discussed.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Factores de Transcripción
/
Proteínas
/
Mutación Puntual
/
ADN Helicasas
/
Proteínas de Unión al ADN
/
Reparación del ADN
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Mutat Res
Año:
1997
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Países Bajos