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Osman S, Mohammad E, Lidschreiber M, Stuetzer A, Bazsó FL, Maier KC, Urlaub H, Cramer P. The Cdk8 kinase module regulates interaction of the mediator complex with RNA polymerase II. J Biol Chem 2021; 296:100734. [PMID: 33933450 PMCID: PMC8191332 DOI: 10.1016/j.jbc.2021.100734] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 04/20/2021] [Accepted: 04/28/2021] [Indexed: 11/17/2022] Open
Abstract
The Cdk8 kinase module (CKM) is a dissociable part of the coactivator complex mediator, which regulates gene transcription by RNA polymerase II. The CKM has both negative and positive functions in gene transcription that remain poorly understood at the mechanistic level. In order to reconstitute the role of the CKM in transcription initiation, we prepared recombinant CKM from the yeast Saccharomyces cerevisiae. We showed that CKM bound to the core mediator (cMed) complex, sterically inhibiting cMed from binding to the polymerase II preinitiation complex (PIC) in vitro. We further showed that the Cdk8 kinase activity of the CKM weakened CKM-cMed interaction, thereby facilitating dissociation of the CKM and enabling mediator to bind the PIC in order to stimulate transcription initiation. Finally, we report that the kinase activity of Cdk8 is required for gene activation during the stressful condition of heat shock in vivo but not under steady-state growth conditions. Based on these results, we propose a model in which the CKM negatively regulates mediator function at upstream-activating sequences by preventing mediator binding to the PIC at the gene promoter. However, during gene activation in response to stress, the Cdk8 kinase activity of the CKM may release mediator and allow its binding to the PIC, thereby accounting for the positive function of CKM. This may impart improved adaptability to stress by allowing a rapid transcriptional response to environmental changes, and we speculate that a similar mechanism in metazoans may allow the precise timing of developmental transcription programs.
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Affiliation(s)
- Sara Osman
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Eusra Mohammad
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Michael Lidschreiber
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Alexandra Stuetzer
- Bioanalytical Mass Spectrometry Group, Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Bioanalytics Research Group, Institute for Clinical Chemistry, University Medical Center, Göttingen, Germany
| | - Fanni Laura Bazsó
- Bioanalytical Mass Spectrometry Group, Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Bioanalytics Research Group, Institute for Clinical Chemistry, University Medical Center, Göttingen, Germany
| | - Kerstin C Maier
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Bioanalytics Research Group, Institute for Clinical Chemistry, University Medical Center, Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
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