Molecular characterization of an acidic region deletion mutant of Cockayne syndrome group B protein.
Cockayne syndrome (CS) is a human genetic disorder characterized by post-natal growth failure, neurological abnormalities and premature aging. CS cells exhibit high sensitivity to UV light, delayed RNA synthesis recovery after UV irradiation and defective transcription-coupled repair (TCR). Two genetic complementation groups of CS have been identified, designated CS-A and CS-B. The CSB gene encodes a helicase domain and a highly acidic region N-terminal to the helicase domain. This study describes the genetic characterization of a CSB mutant allele encoding a full deletion of the acidic region. We have tested its ability to complement the sensitivity of UV61, the hamster homolog of human CS-B cells, to UV and the genotoxic agent N-acetoxy-2-acetylaminofluorene (NA-AAF). Deleting 39 consecutive amino acids, of which approximately 60% are negatively charged, did not impact on the ability of the protein to complement the sensitive phenotype of UV61 cells to either UV or NA-AAF. Our data indicate that the highly acidic region of CSB is not essential for the TCR and general genome repair pathways of UV- and NA-AAF-induced DNA lesions.
Department of Molecular and Structural Biology, University of Aarhus, DK-8000 Aarhus C, Denmark.
M
M
Sunesen
R R
RR
Selzer
R M
RM
Brosh
A S
AS
Balajee
T
T
Stevnsner
V A
VA
Bohr
D000099:Acetoxyacetylaminofluorene / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D003057:Cockayne Syndrome / Q000235:genetics*; D006224:Cricetinae; D004265:DNA Helicases / Q000235:genetics* / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D045643:DNA Repair Enzymes; D005816:Genetic Complementation Test; D006801:Humans; D008969:Molecular Sequence Data; D000075223:Poly-ADP-Ribose Binding Proteins; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014466:Ultraviolet Rays
D000075223:Poly-ADP-Ribose Binding Proteins; D018809:Proliferating Cell Nuclear Antigen; D011994:Recombinant Proteins; D000099:Acetoxyacetylaminofluorene; D004265:DNA Helicases; C078673:ERCC6 protein, human; D045643:DNA Repair Enzymes