Human cyclin-dependent kinases (CDKs) direct the progression of the cell cycle and transcription. They are deregulated in tumours, and despite their involvement in the regulation of basic cellular processes, many CDKs are promising targets for cancer therapy. CDK11 is an essential gene for the growth of many malignancies; however, its primary cellular function has been obscure, and the mode-of-action of OTS964, the first CDK11 inhibitor and antiproliferative compound, has been unknown. A recent study has shown that OTS964 prevents spliceosome activation, revealing a key role of CDK11 in the regulation of pre-mRNA splicing. In light of these findings, we discuss the therapeutic potential of CDK11 in cancer.

• MeSH
• buněčné dělení MeSH
• buněčný cyklus MeSH
• cyklin-dependentní kinasy * genetika   MeSH
• lidé MeSH
• nádory * farmakoterapie   genetika   MeSH
• sestřih RNA MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• komentáře MeSH
• práce podpořená grantem MeSH

RNA splicing, the process of intron removal from pre-mRNA, is essential for the regulation of gene expression. It is controlled by the spliceosome, a megadalton RNA-protein complex that assembles de novo on each pre-mRNA intron through an ordered assembly of intermediate complexes1,2. Spliceosome activation is a major control step that requires substantial protein and RNA rearrangements leading to a catalytically active complex1-5. Splicing factor 3B subunit 1 (SF3B1) protein-a subunit of the U2 small nuclear ribonucleoprotein6-is phosphorylated during spliceosome activation7-10, but the kinase that is responsible has not been identified. Here we show that cyclin-dependent kinase 11 (CDK11) associates with SF3B1 and phosphorylates threonine residues at its N terminus during spliceosome activation. The phosphorylation is important for the association between SF3B1 and U5 and U6 snRNAs in the activated spliceosome, termed the Bact complex, and the phosphorylation can be blocked by OTS964, a potent and selective inhibitor of CDK11. Inhibition of CDK11 prevents spliceosomal transition from the precatalytic complex B to the activated complex Bact and leads to widespread intron retention and accumulation of non-functional spliceosomes on pre-mRNAs and chromatin. We demonstrate a central role of CDK11 in spliceosome assembly and splicing regulation and characterize OTS964 as a highly selective CDK11 inhibitor that suppresses spliceosome activation and splicing.

• MeSH
• aktivace enzymů účinky léků   MeSH
• chinolony farmakologie   MeSH
• chromatin metabolismus   MeSH
• cyklin-dependentní kinasy * antagonisté a inhibitory   metabolismus   MeSH
• fosfoproteiny * chemie   metabolismus   MeSH
• fosforylace MeSH
• malý jaderný ribonukleoprotein U2 * chemie   metabolismus   MeSH
• prekurzory RNA * genetika   metabolismus   MeSH
• sestřih RNA * účinky léků   MeSH
• spliceozomy * účinky léků   metabolismus   MeSH
• threonin metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

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, an 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 when RNAPII reaches 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.

• MeSH
• chromatin genetika   metabolismus   MeSH
• cyklin-dependentní kinasy genetika   metabolismus   MeSH
• fosforylace MeSH
• genetická transkripce * MeSH
• histony genetika   metabolismus   MeSH
• lidé MeSH
• proteiny regulující apoptózu genetika   metabolismus   MeSH
• proteiny vázající vápník genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• replikace DNA MeSH
• RNA genetika   metabolismus   MeSH
• S fáze MeSH
• serin metabolismus   MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

CDK12 is a kinase associated with elongating RNA polymerase II (RNAPII) and is frequently mutated in cancer. CDK12 depletion reduces the expression of homologous recombination (HR) DNA repair genes, but comprehensive insight into its target genes and cellular processes is lacking. We use a chemical genetic approach to inhibit analog-sensitive CDK12, and find that CDK12 kinase activity is required for transcription of core DNA replication genes and thus for G1/S progression. RNA-seq and ChIP-seq reveal that CDK12 inhibition triggers an RNAPII processivity defect characterized by a loss of mapped reads from 3'ends of predominantly long, poly(A)-signal-rich genes. CDK12 inhibition does not globally reduce levels of RNAPII-Ser2 phosphorylation. However, individual CDK12-dependent genes show a shift of P-Ser2 peaks into the gene body approximately to the positions where RNAPII occupancy and transcription were lost. Thus, CDK12 catalytic activity represents a novel link between regulation of transcription and cell cycle progression. We propose that DNA replication and HR DNA repair defects as a consequence of CDK12 inactivation underlie the genome instability phenotype observed in many cancers.

• MeSH
• cyklin-dependentní kinasy genetika   metabolismus   MeSH
• fosforylace MeSH
• HCT116 buňky MeSH
• kontrolní body fáze G1 buněčného cyklu genetika   fyziologie   MeSH
• lidé MeSH
• oprava DNA genetika   fyziologie   MeSH
• replikace DNA genetika   fyziologie   MeSH
• RNA-polymerasa II genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cyclin-dependent kinases regulate the cell cycle and transcription in higher eukaryotes. We have determined the crystal structure of the transcription kinase Cdk13 and its Cyclin K subunit at 2.0 Å resolution. Cdk13 contains a C-terminal extension helix composed of a polybasic cluster and a DCHEL motif that interacts with the bound ATP. Cdk13/CycK phosphorylates both Ser5 and Ser2 of the RNA polymerase II C-terminal domain (CTD) with a preference for Ser7 pre-phosphorylations at a C-terminal position. The peptidyl-prolyl isomerase Pin1 does not change the phosphorylation specificities of Cdk9, Cdk12, and Cdk13 but interacts with the phosphorylated CTD through its WW domain. Using recombinant proteins, we find that flavopiridol inhibits Cdk7 more potently than it does Cdk13. Gene expression changes after knockdown of Cdk13 or Cdk12 are markedly different, with enrichment of growth signaling pathways for Cdk13-dependent genes. Together, our results provide insights into the structure, function, and activity of human Cdk13/CycK.

• MeSH
• cyklin-dependentní kinasy genetika   metabolismus   MeSH
• fosforylace MeSH
• lidé MeSH
• signální transdukce MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A CD8+ cell non-cytotoxic antiviral response (CNAR), mediated by a CD8+ cell antiviral factor (CAF), is associated with a long-term healthy state in human immunodeficiency virus (HIV) infection. CNAR/CAF reduces viral transcription without a known effect on specific viral sequences in the HIV genome. In studies to define the mechanism involved in the block in viral transcription, we now report that transcription from the HIV-LTR reporter is reduced in infected CD4+ cells upon treatment with CAF. In agreement with this observation, the amount of RNA polymerase II (RNAPII) on the HIV promoter and other viral regions was strongly diminished in HIV-infected CD4+ cells co-cultivated with CNAR-expressing CD8+ cells. These results demonstrate further that CNAR/CAF has a specific role in regulating HIV transcription and a step during the preinitiation complex assembly appears to be sensitive to CNAR/CAF.

• MeSH
• CD4-pozitivní T-lymfocyty virologie   MeSH
• CD8-pozitivní T-lymfocyty imunologie   MeSH
• genetická transkripce * MeSH
• HIV imunologie   fyziologie   MeSH
• kohortové studie MeSH
• kokultivační techniky MeSH
• kultivované buňky MeSH
• lidé MeSH
• RNA-polymerasa II metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

The Cdk12/CycK complex promotes expression of a subset of RNA polymerase II genes, including those of the DNA damage response. CDK12 is among only nine genes with recurrent somatic mutations in high-grade serous ovarian carcinoma. However, the influence of these mutations on the Cdk12/CycK complex and their link to cancerogenesis remain ill-defined. Here, we show that most mutations prevent formation of the Cdk12/CycK complex, rendering the kinase inactive. By examining the mutations within the Cdk12/CycK structure, we find that they likely provoke structural rearrangements detrimental to Cdk12 activation. Our mRNA expression analysis of the patient samples containing the CDK12 mutations reveals coordinated downregulation of genes critical to the homologous recombination DNA repair pathway. Moreover, we establish that the Cdk12/CycK complex occupies these genes and promotes phosphorylation of RNA polymerase II at Ser2. Accordingly, we demonstrate that the mutant Cdk12 proteins fail to stimulate the faithful DNA double strand break repair via homologous recombination. Together, we provide the molecular basis of how mutated CDK12 ceases to function in ovarian carcinoma. We propose that CDK12 is a tumor suppressor of which the loss-of-function mutations may elicit defects in multiple DNA repair pathways, leading to genomic instability underlying the genesis of the cancer.

• MeSH
• cyklin-dependentní kinasy chemie   genetika   metabolismus   MeSH
• cykliny chemie   genetika   metabolismus   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• multiproteinové komplexy genetika   metabolismus   MeSH
• mutace * MeSH
• nádorové buněčné linie MeSH
• nádory vaječníků genetika   metabolismus   patologie   MeSH
• oprava DNA genetika   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• regulace genové exprese u nádorů MeSH
• RNA interference MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• terciární struktura proteinů MeSH
• vazba proteinů MeSH
• western blotting MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cytochrome P450 1B1 (CYP1B1) is an enzyme that has a unique tumor-specific pattern of expression and is capable of bioactivating a wide range of carcinogenic compounds. We have reported previously that coordinated upregulation of CYP1B1 by inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and the aryl hydrocarbon receptor ligands, may increase bioactivation of promutagens, such as benzo[a]pyrene (BaP) in epithelial cells. Here, we extend those studies by describing a novel mechanism participating in the regulation of CYP1B1 expression, which involves activation of the p38 mitogen-activated protein kinase (p38) and mitogen- and stress-activated protein kinase 1 (MSK1). Using inhibitors of p38 and MSKs, as well as mouse embryonic cells derived from p38α-deficient and MSK1/2 double knockout mice, we show here that TNF-α potentiates CYP1B1 upregulation via the p38/MSK1 kinase cascade. Effects of this inflammatory cytokine on CYP1B1 expression further involve the positive transcription elongation factor b (P-TEFb). The inhibition of the P-TEFb subunit, cyclin-dependent kinase 9 (CDK9), which phosphorylates RNA polymerase II (RNAPII), prevented the enhanced CYP1B1 induction by a combination of BaP and inflammatory cytokine. Furthermore, using chromatin immunoprecipitation assays, we found that cotreatment of epithelial cells with TNF-α and BaP resulted in enhanced recruitment of both CDK9 and RNAPII to the Cyp1b1 gene promoter. Overall, these results have implications concerning the contribution of inflammatory factors to carcinogenesis, since enhanced CYP1B1 induction during inflammation may alter metabolism of exogenous carcinogens, as well as endogenous CYP1B1 substrates playing role in tumor development.

• MeSH
• cyklin-dependentní kinasa 9 genetika   MeSH
• cytochrom P450 CYP1B1 biosyntéza   genetika   MeSH
• cytokiny metabolismus   MeSH
• karcinogeneze účinky léků   genetika   MeSH
• karcinogeny toxicita   MeSH
• lidé MeSH
• mitogenem aktivované proteinkinasy p38 antagonisté a inhibitory   genetika   metabolismus   MeSH
• myši MeSH
• nádory chemicky indukované   genetika   patologie   MeSH
• pozitivní transkripční elongační faktor b genetika   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• RNA-polymerasa II genetika   MeSH
• signální transdukce účinky léků   MeSH
• TNF-alfa metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Phosphorylation of the RNA polymerase II C-terminal domain (CTD) by cyclin-dependent kinases is important for productive transcription. Here we determine the crystal structure of Cdk12/CycK and analyse its requirements for substrate recognition. Active Cdk12/CycK is arranged in an open conformation similar to that of Cdk9/CycT but different from those of cell cycle kinases. Cdk12 contains a C-terminal extension that folds onto the N- and C-terminal lobes thereby contacting the ATP ribose. The interaction is mediated by an HE motif followed by a polybasic cluster that is conserved in transcriptional CDKs. Cdk12/CycK showed the highest activity on a CTD substrate prephosphorylated at position Ser7, whereas the common Lys7 substitution was not recognized. Flavopiridol is most potent towards Cdk12 but was still 10-fold more potent towards Cdk9. T-loop phosphorylation of Cdk12 required coexpression with a Cdk-activating kinase. These results suggest the regulation of Pol II elongation by a relay of transcriptionally active CTD kinases.

• MeSH
• cyklin-dependentní kinasy chemie   metabolismus   MeSH
• cykliny chemie   metabolismus   MeSH
• ELISA MeSH
• HeLa buňky MeSH
• hmotnostní spektrometrie MeSH
• imunoprecipitace MeSH
• konformace proteinů MeSH
• krystalizace MeSH
• lidé MeSH
• molekulární modely * MeSH
• multiproteinové komplexy chemie   metabolismus   MeSH
• substrátová specifita MeSH
• western blotting MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

The cyclin-dependent kinases (Cdks) regulate many cellular processes, including the cell cycle, neuronal development, transcription, and posttranscriptional processing. To perform their functions, Cdks bind to specific cyclin subunits to form a functional and active cyclin/Cdk complex. This review is focused on Cyclin K, which was originally considered an alternative subunit of Cdk9, and on its newly identified partners, Cdk12 and Cdk13. We briefly summarize research devoted to each of these proteins. We also discuss the proteins' functions in the regulation of gene expression via the phosphorylation of serine 2 in the C-terminal domain of RNA polymerase II, contributions to the maintenance of genome stability, and roles in the onset of human disease and embryo development.

• Publikační typ
• časopisecké články MeSH