scholarly journals Selective Kinase Inhibition Shows That Bur1 (Cdk9) Phosphorylates the Rpb1 Linker In Vivo

2019 ◽  
Vol 39 (15) ◽  
Author(s):  
Yujin Chun ◽  
Yoo Jin Joo ◽  
Hyunsuk Suh ◽  
Gaëlle Batot ◽  
Christopher P. Hill ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Sh2 Domain ◽  
Multiple Roles ◽  
Elongation Complex ◽  
Gene Deletions ◽  
Content Type ◽  
Phosphorylation Mechanism ◽  
Heptad Repeats ◽  
Dynamic Exchange

ABSTRACT Cyclin-dependent kinases play multiple roles in RNA polymerase II transcription. Cdk7/Kin28, Cdk9/Bur1, and Cdk12/Ctk1 phosphorylate the polymerase and other factors to drive the dynamic exchange of initiation and elongation complex components over the transcription cycle. We engineered strains of the yeast Saccharomyces cerevisiae for rapid, specific inactivation of individual kinases by addition of a covalent inhibitor. While effective, the sensitized kinases can display some idiosyncrasies, and inhibition can be surprisingly transient. As expected, inhibition of Cdk7/Kin28 blocked phosphorylation of the Rpb1 C-terminal domain heptad repeats at serines 5 and 7, the known target sites. However, serine 2 phosphorylation was also abrogated, supporting an obligatory sequential phosphorylation mechanism. Consistent with our previous results using gene deletions, Cdk12/Ctk1 is the predominant kinase responsible for serine 2 phosphorylation. Phosphorylation of the Rpb1 linker enhances binding of the Spt6 tandem SH2 domain, and here we show that Bur1/Cdk9 is the kinase responsible for these modifications in vivo.

scholarly journals Selective kinase inhibition shows that Bur1 (Cdk9) phosphorylates the Rpb1 linker in vivo

2018 ◽  
Author(s):  
Yujin Chun ◽  
Hyunsuk Suh ◽  
Yoo Jin Joo ◽  
Gaelle Batot ◽  
Christopher P. Hill ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Multiple Roles ◽  
Elongation Complex ◽  
Yeast Saccharomyces Cerevisiae ◽  
Gene Deletions ◽  
Cyclin Dependent Kinases ◽  
Heptad Repeats ◽  
Dynamic Exchange ◽  
Rna Polymerase Ii Transcription

Cyclin-dependent kinases play multiple roles in RNA polymerase II transcription. Cdk7/Kin28, Cdk9/Bur1, and Cdk12/Ctk1 phosphorylate the polymerase and other factors to drive the dynamic exchange of initiation and elongation complex components over the transcription cycle. We engineered strains of the yeast Saccharomyces cerevisiae for rapid, specific inactivation of individual kinases by addition of a covalent inhibitor. While effective, the sensitized kinases can display some idiosyncrasies, and inhibition can be surprisingly transient. As expected, inhibition of Cdk7/Kin28 blocked phosphorylation of the Rpb1 C-terminal domain heptad repeats at Serines 5 and 7, which are known target sites, but also at Serine 2. Consistent with our previous results using gene deletions, Cdk12/Ctk1 is the predominant kinase responsible for Serine 2 phosphorylation. Phosphorylation of the Rpb1 linker enhances binding of the Spt6 tSH2 domain, and here we show that Bur1/Cdk9 is the kinase responsible for this modification in vivo.

scholarly journals Regulation of P-TEFb Elongation Complex Activity by CDK9 Acetylation

2007 ◽  
Vol 27 (13) ◽  
pp. 4641-4651 ◽  
Author(s):  
Junjiang Fu ◽  
Ho-Geun Yoon ◽  
Jun Qin ◽  
Jiemin Wong
Keyword(s):  
Rna Polymerase Ii ◽  
Elongation Factor ◽  
Transcriptional Elongation ◽  
Elongation Complex ◽  
Complex Activity ◽  
Interacting Protein ◽  
Pol Ii ◽  
Carboxy Terminal

ABSTRACT P-TEFb, comprised of CDK9 and a cyclin T subunit, is a global transcriptional elongation factor important for most RNA polymerase II (pol II) transcription. P-TEFb facilitates transcription elongation in part by phosphorylating Ser2 of the heptapeptide repeat of the carboxy-terminal domain (CTD) of the largest subunit of pol II. Previous studies have shown that P-TEFb is subjected to negative regulation by forming an inactive complex with 7SK small RNA and HEXIM1. In an effort to investigate the molecular mechanism by which corepressor N-CoR mediates transcription repression, we identified HEXIM1 as an N-CoR-interacting protein. This finding led us to test whether the P-TEFb complex is regulated by acetylation. We demonstrate that CDK9 is an acetylated protein in cells and can be acetylated by p300 in vitro. Through both in vitro and in vivo assays, we identified lysine 44 of CDK9 as a major acetylation site. We present evidence that CDK9 is regulated by N-CoR and its associated HDAC3 and that acetylation of CDK9 affects its ability to phosphorylate the CTD of pol II. These results suggest that acetylation of CDK9 is an important posttranslational modification that is involved in regulating P-TEFb transcriptional elongation function.

scholarly journals A three-step pathway of transcription initiation leading to promoter clearance at an activation RNA polymerase II promoter.

1996 ◽  
Vol 16 (4) ◽  
pp. 1614-1621 ◽  
Author(s):  
Y Jiang ◽  
M Yan ◽  
J D Gralla
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Potential Effect ◽  
Multiple Roles ◽  
Elongation Complex ◽  
Terminal Domain ◽  
Step Model ◽  
Dna Strands

The progress of transcription bubbles during inhibition in vitro was followed in order to learn how RNA polymerase II begins transcription at the activated adenovirus E4 promoter. The issues addressed include the multiple roles of ATP, the potential effect of polymerase C-terminal domain phosphorylation, and the ability of polymerase to clear the promoter for reinitiation. The results lead to a three-step model for the transition from closed complex to elongation complex, two steps of which use ATP independently. In the first step, studied previously, ATP is hydrolyzed to open the DNA strands over the start site. In a second step, apparently independent of ATP, transcription bubbles move into the initial transcribed region where RNA synthesis can stall. In the third step, transcripts can be made as polymerase is released from these stalled positions with the assistance of an ATP-dependent process, likely phosphorylation of the polymerase C-terminal domain. After this third step, the promoter becomes cleared, allowing for the reinitiation of transcription.

scholarly journals RNA Binding by Histone Methyltransferases Set1 and Set2

2017 ◽  
Vol 37 (14) ◽  
Author(s):  
Camille Sayou ◽  
Gonzalo Millán-Zambrano ◽  
Helena Santos-Rosa ◽  
Elisabeth Petfalski ◽  
Samuel Robson ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
High Throughput Sequencing ◽  
Rna Binding ◽  
Rna Recognition Motif ◽  
Rna Recognition ◽  
Content Type ◽  
Histone Methyltransferases ◽  
Intergenic Spacers ◽  
High Enrichment

ABSTRACT Histone methylation at H3K4 and H3K36 is commonly associated with genes actively transcribed by RNA polymerase II (RNAPII) and is catalyzed by Saccharomyces cerevisiae Set1 and Set2, respectively. Here we report that both methyltransferases can be UV cross-linked to RNA in vivo. High-throughput sequencing of the bound RNAs revealed strong Set1 enrichment near the transcription start site, whereas Set2 was distributed along pre-mRNAs. A subset of transcripts showed notably high enrichment for Set1 or Set2 binding relative to RNAPII, suggesting functional posttranscriptional interactions. In particular, Set1 was strongly bound to the SET1 mRNA, Ty1 retrotransposons, and noncoding RNAs from the ribosomal DNA (rDNA) intergenic spacers, consistent with its previously reported silencing roles. Set1 lacking RNA recognition motif 2 (RRM2) showed reduced in vivo cross-linking to RNA and reduced chromatin occupancy. In addition, levels of H3K4 trimethylation were decreased, whereas levels of dimethylation were increased. We conclude that RNA binding by Set1 contributes to both chromatin association and methyltransferase activity.

scholarly journals Role of MurT C-Terminal Domain in the Amidation of Staphylococcus aureus Peptidoglycan

2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Bárbara V. Gonçalves ◽  
Raquel Portela ◽  
Ricardo Lobo ◽  
Teresa A. Figueiredo ◽  
Inês R. Grilo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Species ◽  
Multiple Roles ◽  
Great Effort ◽  
Content Type ◽  
Terminal Domain ◽  
Oxacillin Resistance ◽  
Amidation Reaction

ABSTRACT Glutamate amidation, a secondary modification of the peptidoglycan, was first identified in Staphylococcus aureus. It is catalyzed by the protein products of the murT and gatD genes, which are conserved and colocalized in the genomes of most sequenced Gram-positive bacterial species. The MurT-GatD complex is required for cell viability, full resistance to β-lactam antibiotics, and resistance to human lysozyme and is recognized as an attractive target for new antimicrobials. Great effort has been invested in the study of this step, culminating recently in three independent reports addressing the structural elucidation of the MurT-GatD complex. In this work, we demonstrate through the use of nonstructural approaches the critical and multiple roles of the C-terminal domain of MurT, annotated as DUF1727, in the MurT-GatD enzymatic complex. This domain provides the physical link between the two enzymatic activities and is essential for the amidation reaction. Copurification of recombinant MurT and GatD proteins and bacterial two-hybrid assays support the observation that the MurT-GatD interaction occurs through this domain. Most importantly, we provide in vivo evidence of the effect of substitutions at specific residues in DUF1727 on cell wall peptidoglycan amidation and on the phenotypes of oxacillin resistance and bacterial growth.

scholarly journals Genome-Wide Association of Mediator and RNA Polymerase II in Wild-Type and Mediator Mutant Yeast

2014 ◽  
Vol 35 (1) ◽  
pp. 331-342 ◽  
Author(s):  
Emily Paul ◽  
Z. Iris Zhu ◽  
David Landsman ◽  
Randall H. Morse
Keyword(s):  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
Open Reading Frames ◽  
Temperature Sensitive ◽  
Gene Promoters ◽  
Content Type ◽  
Genome Wide ◽  
A Genome ◽  
Wide Range

Mediator is a large, multisubunit complex that is required for essentially all mRNA transcription in eukaryotes. In spite of the importance of Mediator, the range of its targets and how it is recruited to these is not well understood. Previous work showed that inSaccharomyces cerevisiae, Mediator contributes to transcriptional activation by two distinct mechanisms, one depending on the tail module triad and favoring SAGA-regulated genes, and the second occurring independently of the tail module and favoring TFIID-regulated genes. Here, we use chromatin immunoprecipitation sequencing (ChIP-seq) to show that dependence on tail module subunits for Mediator recruitment and polymerase II (Pol II) association occurs preferentially at SAGA-regulated over TFIID-regulated genes on a genome-wide scale. We also show that recruitment of tail module subunits to active gene promoters continues genome-wide when Mediator integrity is compromised inmed17temperature-sensitive (ts) yeast, demonstrating the modular nature of the Mediator complexin vivo. In addition, our data indicate that promoters exhibiting strong and stable occupancy by Mediator have a wide range of activity and are enriched for targets of the Tup1-Cyc8 repressor complex. We also identify a number of strong Mediator occupancy peaks that overlap dubious open reading frames (ORFs) and are likely to include previously unrecognized upstream activator sequences.

scholarly journals Cyclin-Dependent Kinase 9 (Cdk9) of Fission Yeast Is Activated by the CDK-Activating Kinase Csk1, Overlaps Functionally with the TFIIH-Associated Kinase Mcs6, and Associates with the mRNA Cap Methyltransferase Pcm1 In Vivo

2006 ◽  
Vol 26 (3) ◽  
pp. 777-788 ◽  
Author(s):  
Yi Pei ◽  
Hongyan Du ◽  
Juliet Singer ◽  
Courtney St. Amour ◽  
Selena Granitto ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Rna Polymerase Ii ◽  
Elongation Factor ◽  
Growth Defect ◽  
Transcriptional Elongation ◽  
Cyclin Dependent Kinase ◽  
Elongation Complex ◽  
Pol Ii

ABSTRACT Cyclin-dependent kinase 9 (Cdk9) of fission yeast is an essential ortholog of metazoan positive transcription elongation factor b (P-TEFb), which is proposed to coordinate capping and elongation of RNA polymerase II (Pol II) transcripts. Here we show that Cdk9 is activated to phosphorylate Pol II and the elongation factor Spt5 by Csk1, one of two fission yeast CDK-activating kinases (CAKs). Activation depends on Cdk9 T-loop residue Thr-212. The other CAK—Mcs6, the kinase component of transcription factor IIH (TFIIH)—cannot activate Cdk9. Consistent with the specificities of the two CAKs in vitro, the kinase activity of Cdk9 is reduced ∼10-fold by csk1 deletion, and Cdk9 complexes from csk1Δ but not csk1 + cells can be activated by Csk1 in vitro. A cdk9 T212A mutant is viable but phenocopies conditional growth defects of csk1Δ strains, indicating a role for Csk1-dependent activation of Cdk9 in vivo. A cdk9 T212A mcs6 S165A strain, in which neither Cdk9 nor Mcs6 can be activated by CAK, has a synthetic growth defect, implying functional overlap between the two CDKs, which have distinct but overlapping substrate specificities. Cdk9 forms complexes in vivo with the essential cyclin Pch1 and with Pcm1, the mRNA cap methyltransferase. The carboxyl-terminal region of Cdk9, through which it interacts with another capping enzyme, the RNA triphosphatase Pct1, is essential. Together, the data support a proposed model whereby Cdk9/Pch1—the third essential CDK-cyclin complex described in fission yeast—helps to target the capping apparatus to the transcriptional elongation complex.

scholarly journals Structures and Functions of the Multiple KOW Domains of Transcription Elongation Factor Spt5

2015 ◽  
Vol 35 (19) ◽  
pp. 3354-3369 ◽  
Author(s):  
Peter A. Meyer ◽  
Sheng Li ◽  
Mincheng Zhang ◽  
Kentaro Yamada ◽  
Yuichiro Takagi ◽  
...  
Keyword(s):  
High Resolution ◽  
Nucleic Acids ◽  
Rna Polymerase Ii ◽  
Transcription Elongation ◽  
Chromatin Modification ◽  
Elongation Factor ◽  
Content Type ◽  
Processing Pathways

The eukaryotic Spt4-Spt5 heterodimer forms a higher-order complex with RNA polymerase II (and I) to regulate transcription elongation. Extensive genetic and functional data have revealed diverse roles of Spt4-Spt5 in coupling elongation with chromatin modification and RNA-processing pathways. A mechanistic understanding of the diverse functions of Spt4-Spt5 is hampered by challenges in resolving the distribution of functions among its structural domains, including the five KOW domains in Spt5, and a lack of their high-resolution structures. We present high-resolution crystallographic results demonstrating that distinct structures are formed by the first through third KOW domains (KOW1-Linker1 [K1L1] and KOW2-KOW3) ofSaccharomyces cerevisiaeSpt5. The structure reveals that K1L1 displays a positively charged patch (PCP) on its surface, which binds nucleic acidsin vitro, as shown in biochemical assays, and is important forin vivofunction, as shown in growth assays. Furthermore, assays in yeast have shown that the PCP has a function that partially overlaps that of Spt4. Synthesis of our results with previous evidence suggests a model in which Spt4 and the K1L1 domain of Spt5 form functionally overlapping interactions with nucleic acids upstream of the transcription bubble, and this mechanism may confer robustness on processes associated with transcription elongation.

scholarly journals The exon junction complex regulates the release and phosphorylation of paused RNA polymerase II

2018 ◽  
Author(s):  
Junaid Akhtar ◽  
Nastasja Kreim ◽  
Federico Marini ◽  
Giriram Kumar Mohana ◽  
Daniel Brune ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Exon Skipping ◽  
Exon Junction Complex ◽  
Elongation Complex ◽  
Exon Definition ◽  
Pol Ii ◽  
Exon Junction ◽  
Transcriptional Regulatory

SUMMARYPromoter proximal pausing of RNA polymerase II (Pol II) is a widespread transcriptional regulatory step across metazoans. Here we find that the nuclear exon junction complex (pre-EJC) plays a critical and conserved role in this process. Depletion of pre-EJC subunits leads to a global decrease in Pol II pausing and to premature entry into elongation. This effect occurs, at least in part, via non-canonical recruitment of pre-EJC components at promoters. Failure to recruit the pre-EJC at promoters results in increased binding of the positive transcription elongation complex (P-TEFb) and in enhanced Pol II release. Notably, restoring pausing is sufficient to rescue exon skipping and the photoreceptor differentiation defect associated with depletion of pre-EJC components in vivo. We propose that the pre-EJC serves as an early transcriptional checkpoint to prevent premature entry into elongation, ensuring proper recruitment of RNA processing components that are necessary for exon definition.

scholarly journals A novel SH2 recognition mechanism recruits Spt6 to the doubly phosphorylated RNA polymerase II linker at sites of transcription

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Matthew A Sdano ◽  
James M Fulcher ◽  
Sowmiya Palani ◽  
Mahesh B Chandrasekharan ◽  
Timothy J Parnell ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Sh2 Domain ◽  
Heptad Repeat ◽  
Side Chain ◽  
Phosphate Binding ◽  
Recognition Mechanism ◽  
Repressive Chromatin ◽  
Repeat Domain

We determined that the tandem SH2 domain of S. cerevisiae Spt6 binds the linker region of the RNA polymerase II subunit Rpb1 rather than the expected sites in its heptad repeat domain. The 4 nM binding affinity requires phosphorylation at Rpb1 S1493 and either T1471 or Y1473. Crystal structures showed that pT1471 binds the canonical SH2 pY site while pS1493 binds an unanticipated pocket 70 Å distant. Remarkably, the pT1471 phosphate occupies the phosphate-binding site of a canonical pY complex, while Y1473 occupies the position of a canonical pY side chain, with the combination of pT and Y mimicking a pY moiety. Biochemical data and modeling indicate that pY1473 can form an equivalent interaction, and we find that pT1471/pS1493 and pY1473/pS1493 combinations occur in vivo. ChIP-seq and genetic analyses demonstrate the importance of these interactions for recruitment of Spt6 to sites of transcription and for the maintenance of repressive chromatin.

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