title: Elements That Regulate the DNA Damage Response of Proteins Defective in Cockayne Syndrome.
abstract: Cockayne syndrome (CS) is a premature aging disorder characterized by developmental defects, multisystem progressive degeneration and sensitivity to ultraviolet light. CS is divided into two primary complementation groups, A and B, with the CSA and CSB proteins presumably functioning in DNA repair and transcription. Using laser microirradiation and confocal microscopy, we characterized the nature and regulation of the CS protein response to oxidative DNA damage, double-strand breaks (DSBs), angelicin monoadducts and trioxsalen interstrand crosslinks (ICLs). Our data indicate that CSB recruitment is influenced by the type of DNA damage and is most rapid and robust as follows: ICLs>DSBs>monoadducts>oxidative lesions. Transcription inhibition reduced accumulation of CSB at sites of monoadducts and ICLs, but it did not affect recruitment to (although slightly affected retention at) oxidative damage. Inhibition of histone deacetylation altered the dynamics of CSB assembly, suggesting a role for chromatin status in the response to DNA damage, whereas the proteasome inhibitor MG132 had no effect. The C-terminus of CSB and, in particular, its ubiquitin-binding domain were critical to recruitment, while the N-terminus and a functional ATPase domain played a minor role at best in facilitating protein accumulation. Although the absence of CSA had no effect on CSB recruitment, CSA itself localized at sites of ICLs, DSBs and monoadducts but not at oxidative lesions. Our results reveal molecular components of the CS protein response and point to a major involvement of complex lesions in the pathology of CS.
authors.affiliation: Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA.
authors.forename: Teruaki
authors.initials: T
authors.lastname: Iyama
authors.affiliation: Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA. Electronic address: wilsonda@mail.nih.gov.
authors.forename: David M
authors.initials: DM
authors.lastname: Wilson
mesh_terms: D003057:Cockayne Syndrome / Q000473:pathology*; D004247:DNA / Q000378:metabolism*; D004249:DNA Damage; D004265:DNA Helicases / Q000378:metabolism*; D045643:DNA Repair Enzymes / Q000378:metabolism*; D000075223:Poly-ADP-Ribose Binding Proteins; D011485:Protein Binding; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: C095472:ERCC8 protein, human; D000075223:Poly-ADP-Ribose Binding Proteins; D014157:Transcription Factors; D004247:DNA; D004265:DNA Helicases; C078673:ERCC6 protein, human; D045643:DNA Repair Enzymes
keywords: CSA/ERCC8; CSB/ERCC6; Cockayne syndrome; DNA damage response; DNA repair