title: The C-terminal Region and SUMOylation of Cockayne Syndrome Group B Protein Play Critical Roles in Transcription-coupled Nucleotide Excision Repair.
abstract: Cockayne syndrome (CS) is a recessive disorder that results in deficiencies in transcription-coupled nucleotide excision repair (TC-NER), a subpathway of nucleotide excision repair, and cells from CS patients exhibit hypersensitivity to UV light. CS group B protein (CSB), which is the gene product of one of the genes responsible for CS, belongs to the SWI2/SNF2 DNA-dependent ATPase family and has an ATPase domain and an ubiquitin-binding domain (UBD) in the central region and the C-terminal region, respectively. The C-terminal region containing the UBD is essential for the functions of CSB. In this study, we generated several CSB deletion mutants and analyzed the functions of the C-terminal region of CSB in TC-NER. Not only the UBD but also the C-terminal 30-amino acid residues were required for UV light resistance and TC-NER. This region was needed for the interaction of CSB with RNA polymerase II, the translocation of CS group A protein to the nuclear matrix, and the association of CSB with chromatin after UV irradiation. CSB was modified by small ubiquitin-like modifier 2/3 in a UV light-dependent manner. This modification was abolished in a CSB mutant lacking the C-terminal 30 amino acid residues. However, the substitution of lysine residues in this region with arginine did not affect SUMOylation or TC-NER. By contrast, substitution of a lysine residue in the N-terminal region with arginine decreased SUMOylation and resulted in cells with defects in TC-NER. These results indicate that both the most C-terminal region and SUMOylation are important for the functions of CSB in TC-NER.
authors.affiliation: From the Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-3, Suita, Osaka 565-0871, Japan.
authors.forename: Yooksil
authors.initials: Y
authors.lastname: Sin
authors.affiliation: From the Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-3, Suita, Osaka 565-0871, Japan ktanaka@fbs.osaka-u.ac.jp.
authors.forename: Kiyoji
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: From the Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-3, Suita, Osaka 565-0871, Japan saijom@fbs.osaka-u.ac.jp.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Saijo
mesh_terms: D019943:Amino Acid Substitution; D015153:Blotting, Western; D002460:Cell Line; D053960:DNA Breaks / Q000528:radiation effects; D004265:DNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000528:radiation effects; D045643:DNA Repair Enzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects; D017353:Gene Deletion; D006801:Humans; D047468:Immunoprecipitation; D008239:Lysine; D009154:Mutation; D000075223:Poly-ADP-Ribose Binding Proteins; D054730:Protein Interaction Domains and Motifs; D011836:Radiation Tolerance; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism; D058207:Sumoylation / Q000528:radiation effects; D014158:Transcription, Genetic; D014452:Ubiquitins / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D000075223:Poly-ADP-Ribose Binding Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C117909:SUMO2 protein, human; C492189:SUMO3 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; D014452:Ubiquitins; D004265:DNA Helicases; C078673:ERCC6 protein, human; D045643:DNA Repair Enzymes; D008239:Lysine
keywords: Cockayne syndrome; DNA damage; chromatin; nucleotide excision repair; protein domain; small ubiquitin-like modifier (SUMO); transcription-coupled repair