Project description:The L-Mediator is a general co-activator of RNA Polymerase II transcription and is formed by the reversible association of the S-Mediator and the kinase module harbouring Cdk8. We describe the Cdk11-Lcp1 complex and show that its inactivation alter the global expression profiles in a very similar way than mutations of the kinase module. Cdk11 is broadly distributed onto chromatin and phosphorylate the Med27 and Med4 Mediator subunits on conserved residues. The inactivation of either Cdk11 or the mutation of its target residues on the Mediator leads to a strongly decreased association of the kinase module and the S-Mediator. The results show that Cdk11-Lcp1 regulates that assembly of the L-Mediator complex.
Project description:The L-Mediator is a general co-activator of RNA Polymerase II transcription and is formed by the reversible association of the S-Mediator and the kinase module harbouring Cdk8. We describe the Cdk11-Lcp1 complex and show that its inactivation alter the global expression profiles in a very similar way than mutations of the kinase module. Cdk11 is broadly distributed onto chromatin and phosphorylate the Med27 and Med4 Mediator subunits on conserved residues. The inactivation of either Cdk11 or the mutation of its target residues on the Mediator leads to a strongly decreased association of the kinase module and the S-Mediator. The results show that Cdk11-Lcp1 regulates that assembly of the L-Mediator complex. Total RNA was isolated from two biological replicates for all conditions, and each biological replicate was hybridized in duplicate on Agilent arrays (dye-swap).
Project description:The L-Mediator is a general co-activator of RNA Polymerase II transcription and is formed by the reversible association of the S-Mediator and the kinase module harbouring Cdk8. We describe the Cdk11-Lcp1 complex and show that its inactivation alter the global expression profiles in a very similar way than mutations of the kinase module. Cdk11 is broadly distributed onto chromatin and phosphorylate the Med27 and Med4 Mediator subunits on conserved residues. The inactivation of either Cdk11 or the mutation of its target residues on the Mediator leads to a strongly decreased association of the kinase module and the S-Mediator. The results show that Cdk11-Lcp1 regulates that assembly of the L-Mediator complex. Two independent immunoprecipitations were done for HA-tagged Cdk11 and each biological replicate was hybridized in duplicate on Agilent arrays using input DNA as the reference channel.
Project description:The L-Mediator is a general co-activator of RNA Polymerase II transcription and is formed by the reversible association of the S-Mediator and the kinase module harbouring Cdk8. We describe the Cdk11-Lcp1 complex and show that its inactivation alter the global expression profiles in a very similar way than mutations of the kinase module. Cdk11 is broadly distributed onto chromatin and phosphorylate the Med27 and Med4 Mediator subunits on conserved residues. The inactivation of either Cdk11 or the mutation of its target residues on the Mediator leads to a strongly decreased association of the kinase module and the S-Mediator. The results show that Cdk11-Lcp1 regulates that assembly of the L-Mediator complex.
Project description:CDK11 is an emerging druggable target for cancer therapy due to its prevalent roles in phosphorylating critical transcription and splicing factors and in facilitating cell cycle progression in cancer cells. Like other cyclin-dependent kinases, CDK11 requires its cognate cyclin, cyclin L1 or cyclin L2, for activation. However, little is known about how CDK11 activities might be modulated by other regulators. In this study, we show that CDK11 forms a tight complex with cyclins L1/L2 and SAP30BP, the latter of which is a poorly characterized factor. Acute degradation of SAP30BP mirrors that of CDK11 in causing widespread and strong defects in pre-mRNA splicing. Furthermore, we demonstrate that SAP30BP facilitates CDK11 kinase activities in vitro and in vivo, through ensuring the stabilities and the assembly of cyclins L1/L2 with CDK11. Together, these findings uncover SAP30BP as a critical CDK11 activator that regulates global pre-mRNA splicing.
Project description:Cyclin-dependent kinase 7 (CDK7), part of the general transcription factor TFIIH, promotes gene transcription by phosphorylating the C-terminal domain of RNA polymerase II (RNA Pol II). Here, we combine rapid CDK7 kinase inhibition with multi-omics analysis to unravel the direct functions of CDK7 in human cells. CDK7 inhibition causes RNA Pol II retention at promoters, leading to decreased RNA Pol II initiation and immediate global downregulation of transcript synthesis. Elongation, termination, and recruitment of co-transcriptional factors are not directly affected. Although RNA Pol II, initiation factors, and Mediator accumulate at promoters, RNA Pol II complexes can also proceed into gene bodies without promoter-proximal pausing while retaining initiation factors and Mediator. Further downstream, RNA Pol II phosphorylation increases and initiation factors and Mediator are released, allowing recruitment of elongation factors and an increase in RNA Pol II elongation velocity. Collectively, CDK7 kinase activity promotes the release of initiation factors and Mediator from RNA Pol II, facilitating RNA Pol II escape from the promoter.
Project description:Replication-dependent histones (RDH) are required for packaging of newly synthetized DNA into nucleosomes during the S phase when their expression is highly upregulated. However, the mechanisms of this upregulation in metazoan cells remain poorly understood. Using iCLIP and ChIP–seq, we found that human cyclin-dependent kinase 11 (CDK11) associates with RNA and chromatin of RDH genes primarily in the S phase. Moreover, its amino-terminal region binds FLASH, RDH-specific 3′-end processing factor, which keeps the kinase on the chromatin. CDK11 phosphorylates serine 2 (Ser2) of the carboxy-terminal domain of RNA polymerase II (RNAPII), which is initiated at the middle of RDH genes and is required for further RNAPII elongation and 3′-end processing. CDK11 depletion leads to decreased number of cells in S phase, likely owing to the function of CDK11 in RDH gene expression. Thus, the reliance of RDH expression on CDK11 could explain why CDK11 is essential for the growth of many cancers.
Project description:Cyclin dependent kinase 11 (CDK11) is a protein kinase that regulates RNA transcription, pre-mRNA splicing, mitosis, and cell death. Targeting of CDK11 expression levels is effective in the experimental treatment of breast and other cancers, but these data are lacking in melanoma. To understand CDK11 function in melanoma, we evaluated protein and RNA levels of CDK11, Cyclin L1 and Cyclin L2 in benign melanocytes and BRAF- as well as NRAS-mutant melanoma cell lines. We investigated the effectiveness of reducing expression of this survival kinase using RNA interference on viability, clonal survival, and tumorsphere formation in melanoma cell lines. We examined the impact of CDK11 loss in BRAF-mutant melanoma on more than 700 genes important in cancer signaling pathways. Follow-up analysis evaluated how CDK11 loss alters cell cycle function in BRAF- and NRAS-mutant melanoma cells. We present data on CDK11, CCNL1 and CCNL2 mRNA expression in melanoma patients, including prognosis for survival. In sum, we found that CDK11 is necessary for melanoma cell survival, and a major impact of CDK11 loss in melanoma is to cause disruption of the cell cycle distribution with accumulation of G1- and loss of G2/M-phase cancer cells.