UV-Induced Ubiquitination of RNA Polymerase II: A Novel Modification Deficient in Cockayne Syndrome Cells

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 93; no. 21; pp. 11586 - 11590
• Main Authors: Bregman, David B., Halaban, Ruth, Van Gool, Alain J., Henning, Karla A., Friedberg, Errol C., Warren, Stephen L.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 15.10.1996; National Acad Sciences; National Academy of Sciences
• Subjects: Antibodies; Biochemistry; Cell Line; Cell lines; Cisplatin - pharmacology; Cockayne Syndrome - enzymology; Cockayne Syndrome - genetics; DNA; DNA Damage; DNA Repair; Fibroblasts; Genes; Genetically modified organisms; HeLa Cells; Humans; Hydrogen Peroxide - pharmacology; Lesions; Molecules; Phosphorylation; Recombinant Proteins - metabolism; Recombinant Proteins - radiation effects; RNA Polymerase II - genetics; RNA Polymerase II - metabolism; RNA Polymerase II - radiation effects; Transcription, Genetic; Transfection; Ubiquitins; Ubiquitins - metabolism; Ultraviolet radiation; Ultraviolet Rays
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.93.21.11586

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.