title: GCN5 protects vertebrate cells against UV-irradiation via controlling gene expression of DNA polymerase η.
abstract: By UV-irradiation, cells are subjected to DNA damage followed by mutation, cell death and/or carcinogenesis. DNA repair systems such as nucleotide excision repair (NER) and translesion DNA synthesis (TLS) protect cells against UV-irradiation. To understand the role of histone acetyltransferase GCN5 in regulation of DNA repair, we studied the sensitivity of GCN5-deficient DT40, GCN5(-/-), to various DNA-damaging agents including UV-irradiation, and effects of GCN5-deficiency on the expression of NER- and TLS-related genes. After UV-irradiation, cell death and DNA fragmentation of GCN5(-/-) were appreciably accelerated as compared with those of DT40. Interestingly, GCN5(-/-) showed a remarkable sensitivity to only UV-irradiation but not to other DNA-damaging agents tested. Semiquantitative RT-PCR showed that transcription of DNA polymerase η (POLH) gene whose deficiency is responsible for a variant form of xeroderma pigmentosum was drastically down-regulated in GCN5(-/-) (to ∼25%). In addition, ectopic expression of human POLH in GCN5(-/-) dramatically reversed the sensitivity to UV-irradiation of GCN5(-/-) to almost the same level of wild type DT40. Moreover, chromatin immunoprecipitation assay revealed that GCN5 binds to the chicken POLH gene 5'-flanking region that contains a typical CpG island and acetylates Lys-9 of histone H3, but not Lys-14 in vivo. These data suggest that GCN5 takes part in transcription regulation of POLH gene through alterations in the chromatin structure by direct interaction with its 5'-flanking region, and protects vertebrate cells against UV-induced DNA damage via controlling POLH gene expression.
authors.affiliation: Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Miyazaki Medical College, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki, 889-1692, Japan. masakari@med.miyazaki-u.ac.jp
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Kikuchi
authors.forename: Futoshi
authors.initials: F
authors.lastname: Kuribayashi
authors.forename: Shinobu
authors.initials: S
authors.lastname: Imajoh-Ohmi
authors.forename: Hideki
authors.initials: H
authors.lastname: Nishitoh
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Takami
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Nakayama
mesh_terms: D000107:Acetylation / Q000528:radiation effects; D000818:Animals; D016923:Cell Death / Q000235:genetics / Q000528:radiation effects; D002460:Cell Line; D002645:Chickens; D018899:CpG Islands / Q000235:genetics; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D053938:DNA Fragmentation / Q000528:radiation effects*; D004260:DNA Repair / Q000235:genetics / Q000528:radiation effects*; D004259:DNA-Directed DNA Polymerase / Q000096:biosynthesis* / Q000235:genetics; D017353:Gene Deletion; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics / Q000528:radiation effects*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D011485:Protein Binding / Q000235:genetics / Q000528:radiation effects; D014158:Transcription, Genetic / Q000235:genetics / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000099224:p300-CBP-Associated Factor; D000099270:Y-Family DNA Polymerases
chemical_list: D004247:DNA; D004259:DNA-Directed DNA Polymerase; D006657:Histones; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases