The Cyclin K/Cdk12 complex maintains genomic stability via regulation of expression of DNA damage response genes
- Dalibor Blazek1,2,9,10,
- Jiri Kohoutek3,9,
- Koen Bartholomeeusen1,
- Eric Johansen4,
- Petra Hulinkova3,
- Zeping Luo1,
- Peter Cimermancic5,6,7,
- Jernej Ule8 and
- B. Matija Peterlin1,9
- 1Department of Medicine, Microbiology, and Immunology, Rosalind Russell Medical Research Center, University of California at San Francisco (UCSF), San Francisco, California 94143, USA;
- 2Central European Institute of Technology, Masaryk University, 62500 Brno, Czech Republic;
- 3Department of Toxicology, Pharmacology, and Immunotherapy, Veterinary Research Institute, 62100 Brno, Czech Republic;
- 4UCSF Sandler-Moore Mass Spectrometry Core Facility, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco (UCSF), San Francisco, California 94143, USA;
- 5Department of Bioengineering and Therapeutic Sciences, University of California at San Francisco, San Francisco, California 94158, USA;
- 6Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94158, USA;
- 7California Institute for Quantitative Biosciences, University of California at San Francisco, San Francisco, California 94158, USA;
- 8MRC, Laboratory of Molecular Biology, Cambridge CB20QH, United Kingdom
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↵9 These authors contributed equally to this work.
Abstract
Various cyclin-dependent kinase (Cdk) complexes have been implicated in the regulation of transcription. In this study, we identified a 70-kDa Cyclin K (CycK) that binds Cdk12 and Cdk13 to form two different complexes (CycK/Cdk12 or CycK/Cdk13) in human cells. The CycK/Cdk12 complex regulates phosphorylation of Ser2 in the C-terminal domain of RNA polymerase II and expression of a small subset of human genes, as revealed in expression microarrays. Depletion of CycK/Cdk12 results in decreased expression of predominantly long genes with high numbers of exons. The most prominent group of down-regulated genes are the DNA damage response genes, including the critical regulators of genomic stability: BRCA1 (breast and ovarian cancer type 1 susceptibility protein 1), ATR (ataxia telangiectasia and Rad3-related), FANCI, and FANCD2. We show that CycK/Cdk12, rather than CycK/Cdk13, is necessary for their expression. Nuclear run-on assays and chromatin immunoprecipitations with RNA polymerase II on the BRCA1 and FANCI genes suggest a transcriptional defect in the absence of CycK/Cdk12. Consistent with these findings, cells without CycK/Cdk12 induce spontaneous DNA damage and are sensitive to a variety of DNA damage agents. We conclude that through regulation of expression of DNA damage response genes, CycK/Cdk12 protects cells from genomic instability. The essential role of CycK for organisms in vivo is further supported by the result that genetic inactivation of CycK in mice causes early embryonic lethality.
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Footnotes
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↵10 Corresponding author.
E-mail dblazek{at}med.muni.cz.
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Supplemental material is available for this article.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.16962311.
- Received May 5, 2011.
- Accepted September 12, 2011.
- Copyright © 2011 by Cold Spring Harbor Laboratory Press
