title: Sequential binding of UV DNA damage binding factor and degradation of the p48 subunit as early events after UV irradiation.
abstract: The UV-damaged DNA binding protein complex (UV-DDB) is implicated in global genomic nucleotide excision repair (NER) in mammalian cells. The complex consists of a heterodimer of p127 and p48. UV-DDB is defective in one complementation group (XP-E) of the heritable, skin cancer-prone disorder xeroderma pigmentosum. Upon UV irradiation of primate cells, UV-DDB associates tightly with chromatin, concomitant with the loss of extractable binding activity. We report here that an early event after UV, but not ionizing, radiation is the transient dose-dependent degradation of the small subunit, p48. Treatment of human cells with the proteasomal inhibitor NIP-L3VS blocks this UV-induced degradation of p48. In XP-E cell lines with impaired UV-DDB binding, p48 is resistant to degradation. UV-mediated degradation of p48 occurs independently of the expression of p53 and the cell's proficiency for NER, but recovery of p48 levels at later times (12 h and thereafter) is dependent upon the capacity of the cell to repair non-transcribed DNA. In addition, we find that the p127 subunit of UV-DDB binds in vivo to p300, a histone acetyltransferase. The data support a functional connection between UV-DDB binding activity, proteasomal degradation of p48 and chromatin remodeling during early steps of NER.
authors.affiliation: Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, E1240 BST, Pittsburgh, PA 15261, USA.
authors.forename: Vesna
authors.initials: V
authors.lastname: Rapić-Otrin
authors.forename: Mary P
authors.initials: MP
authors.lastname: McLenigan
authors.forename: Dawn C
authors.initials: DC
authors.lastname: Bisi
authors.forename: Martin
authors.initials: M
authors.lastname: Gonzalez
authors.forename: Arthur S
authors.initials: AS
authors.lastname: Levine
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D002522:Chlorocebus aethiops; D002843:Chromatin / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004249:DNA Damage / Q000528:radiation effects; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051548:Histone Acetyltransferases; D006801:Humans; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D011233:Precipitin Tests; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding / Q000528:radiation effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000528:radiation effects*; D021122:Protein Subunits; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011839:Radiation, Ionizing; D014157:Transcription Factors; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
chemical_list: D000123:Acetyltransferases; D018797:Cell Cycle Proteins; D002843:Chromatin; D003546:Cysteine Endopeptidases; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D051548:Histone Acetyltransferases; D009097:Multienzyme Complexes; D046988:Proteasome Endopeptidase Complex; D021122:Protein Subunits; D012333:RNA, Messenger; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C091435:DDB1 protein, human; C117669:DDB2 protein, human