title: UV-induced ubiquitination of RNA polymerase II: a novel modification deficient in Cockayne syndrome cells.
abstract: Damage to actively transcribed DNA is preferentially repaired by the transcription-coupled repair (TCR) system. TCR requires RNA polymerase II (Pol II), but the mechanism by which repair enzymes preferentially recognize and repair DNA lesions on Pol II-transcribed genes is incompletely understood. Herein we demonstrate that a fraction of the large subunit of Pol II (Pol II LS) is ubiquitinated after exposing cells to UV-radiation or cisplatin but not several other DNA damaging agents. This novel covalent modification of Pol II LS occurs within 15 min of exposing cells to UV-radiation and persists for about 8-12 hr. Ubiquitinated Pol II LS is also phosphorylated on the C-terminal domain. UV-induced ubiquitination of Pol II LS is deficient in fibroblasts from individuals with two forms of Cockayne syndrome (CS-A and CS-B), a rare disorder in which TCR is disrupted. UV-induced ubiquitination of Pol II LS can be restored by introducing cDNA constructs encoding the CSA or CSB genes, respectively, into CS-A or CS-B fibroblasts. These results suggest that ubiquitination of Pol II LS plays a role in the recognition and/or repair of damage to actively transcribed genes. Alternatively, these findings may reflect a role played by the CSA and CSB gene products in transcription.
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA. bregman@aecom.yu.edu
authors.forename: D B
authors.initials: DB
authors.lastname: Bregman
authors.forename: R
authors.initials: R
authors.lastname: Halaban
authors.forename: A J
authors.initials: AJ
authors.lastname: van Gool
authors.forename: K A
authors.initials: KA
authors.lastname: Henning
authors.forename: E C
authors.initials: EC
authors.lastname: Friedberg
authors.forename: S L
authors.initials: SL
authors.lastname: Warren
mesh_terms: D002460:Cell Line; D002945:Cisplatin / Q000494:pharmacology; D003057:Cockayne Syndrome / Q000201:enzymology* / Q000235:genetics; D004249:DNA Damage; D004260:DNA Repair; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D010766:Phosphorylation; D012319:RNA Polymerase II / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D011994:Recombinant Proteins / Q000378:metabolism / Q000528:radiation effects; D014158:Transcription, Genetic; D014162:Transfection; D014452:Ubiquitins / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D011994:Recombinant Proteins; D014452:Ubiquitins; D006861:Hydrogen Peroxide; D012319:RNA Polymerase II; D002945:Cisplatin