The Cockayne Syndrome Group B Gene Product is Involved in General Genome Base Excision Repair of 8-hydroxyguanine in DNA

Published

December 7, 2001

Author(s)

J Tuo, M Muftuoglu, C Chen, Pawel Jaruga, R R. Selzer, R M. Brosh, H Rodriguez, Miral M. Dizdar, V. Bohr

Abstract

Cockayne Syndrome (CS) is a human genetic disorder with two complementation groups, CS-A and CS-B. The CSB gene product is involved in transcription-coupled repair of DNA damage but may participate in other pathways of DNA metabolism. The present study investigated the role of different conserved helicase motifs of CSB in base excision repair. Stably transformed human cell lines with site-directed CSB mutations in different motifs within its putative helicase domain were established. We find that CSB null and helicase motif V and VI and VI mutants had greater sensitivity than wild type cells to γ-radiation. Whole cell extracts from CSB null and motif V/VI mutants had lower activity of 8-hydroxyguanine incision in DNA than wild type cells. Also, 8 hydroxyguanine accumulated more in CSB null and motif VI mutant cells than in wild type cells after exposure to γ-radiation. We conclude that a deficiency in general genome base excision repair of selective modified DNA base(s) might contribute to CS pathogenesis. Furthermore, whereas the disruption of helicase motifs V or VI results in a CSB phenotype, mutations in other helicase motifs do not cause this effect. The biological functions of CSB in different DNA repair pathways may be mediated by distinct functional motifs of the protein.

Citation

Journal of Biological Chemistry

Volume

276

Issue

49

Pub Type

Journals

Keywords

8-Hydroxyguanine, base-excision repair, cockayne syndrome, liquid chromatography/mass spectrometry

Citation

Tuo, J. , Muftuoglu, M. , Chen, C. , Jaruga, P. , Selzer, R. , Brosh, R. , Rodriguez, H. , Dizdar, M. and Bohr, V. (2001), The Cockayne Syndrome Group B Gene Product is Involved in General Genome Base Excision Repair of 8-hydroxyguanine in DNA, Journal of Biological Chemistry (Accessed April 19, 2024)