scholarly journals Functional Interaction between Ssu72 and the Rpb2 Subunit of RNA Polymerase II in Saccharomyces cerevisiae

2000 ◽  
Vol 20 (22) ◽  
pp. 8343-8351 ◽  
Author(s):  
Donald L. Pappas ◽  
Michael Hampsey
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Essential Gene ◽  
Functional Interaction ◽  
Gene Encoding ◽  
General Transcription Factor ◽  
Physical Interactions ◽  
Rnap Ii

ABSTRACT SSU72 is an essential gene encoding a phylogenetically conserved protein of unknown function that interacts with the general transcription factor TFIIB. A recessive ssu72-1 allele was identified as a synthetic enhancer of a TFIIB (sua7-1) defect, resulting in a heat-sensitive (Ts−) phenotype and a dramatic downstream shift in transcription start site selection. Here we describe a new allele, ssu72-2, that confers a Ts− phenotype in a SUA7 wild-type background. In an effort to further define Ssu72, we isolated suppressors of thessu72-2 mutation. One suppressor is allelic toRPB2, the gene encoding the second-largest subunit of RNA polymerase II (RNAP II). Sequence analysis of the rpb2-100suppressor defined a cysteine replacement of the phylogenetically invariant arginine residue at position 512 (R512C), located within homology block D of Rpb2. The ssu72-2 andrpb2-100 mutations adversely affected noninduced gene expression, with no apparent effects on activated transcription in vivo. Although isolated as a suppressor of the ssu72-2Ts− defect, rpb2-100 enhanced the transcriptional defects associated with ssu72-2. The Ssu72 protein interacts directly with purified RNAP II in a coimmunoprecipitation assay, suggesting that the genetic interactions between ssu72-2 and rpb2-100 are a consequence of physical interactions. These results define Ssu72 as a highly conserved factor that physically and functionally interacts with the RNAP II core machinery during transcription initiation.

scholarly journals Promoter-Specific Shifts in Transcription Initiation Conferred by Yeast TFIIB Mutations Are Determined by the Sequence in the Immediate Vicinity of the Start Sites

2001 ◽  
Vol 21 (14) ◽  
pp. 4427-4440 ◽  
Author(s):  
Silviu L. Faitar ◽  
Seth A. Brodie ◽  
Alfred S. Ponticelli
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Genetic Selection ◽  
Functional Domain ◽  
Start Site ◽  
Recessive Mutations ◽  
Transcription Factor Iib ◽  
General Transcription Factor

ABSTRACT The general transcription factor IIB (TFIIB) is required for transcription of class II genes by RNA polymerase II. Previous studies demonstrated that mutations in the Saccharomyces cerevisiae SUA7 gene, which encodes TFIIB, can alter transcription initiation patterns in vivo. To further delineate the functional domain and residues of TFIIB involved in transcription start site utilization, a genetic selection was used to isolate S. cerevisiae TFIIB mutants exhibiting downstream shifts in transcription initiation in vivo. Both dominant and recessive mutations conferring downstream shifts were identified at multiple positions within a highly conserved homology block in the N-terminal region of the protein. The TFIIB mutations conferred downstream shifts in transcription initiation at the ADH1 and CYC1 promoters, whereas no significant shifts were observed at the HIS3 promoter. Analysis of a series of ADH1-HIS3 hybrid promoters and variant ADH1 and HIS3 promoters containing insertions, deletions, or site-directed base substitutions revealed that the feature that renders a promoter sensitive to TFIIB mutations is the sequence in the immediate vicinity of the normal start sites. We discuss these results in light of possible models for the mechanism of start site utilization by S. cerevisiae RNA polymerase II and the role played by TFIIB.

scholarly journals RNA Polymerase II Localizes in Tetrahymena thermophila Meiotic Micronuclei When Micronuclear Transcription Associated with Genome Rearrangement Occurs

2004 ◽  
Vol 3 (5) ◽  
pp. 1233-1240 ◽  
Author(s):  
Kazufumi Mochizuki ◽  
Martin A. Gorovsky
Keyword(s):  
Life Cycle ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Genome Rearrangement ◽  
Tetrahymena Thermophila ◽  
Germ Line ◽  
Essential Gene ◽  
Gene Encoding ◽  
Sexual Process ◽  
Rnap Ii

ABSTRACT The germ line micronucleus in Tetrahymena thermophila is transcriptionally silent in vegetatively growing cells. However, micronuclear transcription has been observed in the early (“crescent”) stages of the sexual process, conjugation. This transcription is proposed to play a central role in identifying sites for subsequent genome rearrangements that accompany development of the somatic macronucleus from the micronucleus. RPB3 (cnjC), a gene encoding a protein homologous to the third largest subunit of RNA polymerase II (RNAP II), was previously reported to be expressed specifically during conjugation, suggesting a role in micronucleus-specific transcription. Rpb3p localized in the micronucleus only during the meiotic prophase, when micronuclear transcription occurs, and its intranuclear distribution is strikingly similar to that for previously described sites of micronuclear RNA synthesis. By contrast, Rpc5p, the homologous subunit shared by RNAPs I and III, was not detectable in the micronucleus at any stage of the life cycle. However, Rpb3p is not specific to the transcribing micronucleus. Like Rpc5p, it also localizes to macronuclei in all stages of the life cycle. Rpb3p is encoded by a unique, essential gene in Tetrahymena. Thus, RNAP II is associated with both somatic transcription and crescent transcription and probably has an important role in genome rearrangement.

scholarly journals Rct1, a Nuclear RNA Recognition Motif-Containing Cyclophilin, Regulates Phosphorylation of the RNA Polymerase II C-Terminal Domain

2007 ◽  
Vol 27 (10) ◽  
pp. 3601-3611 ◽  
Author(s):  
Monika Gullerova ◽  
Andrea Barta ◽  
Zdravko J. Lorkovic
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Essential Gene ◽  
Close Association ◽  
Rna Recognition Motif ◽  
Rna Recognition ◽  
Terminal Domain ◽  
Important Player ◽  
Rnap Ii

ABSTRACT Phosphorylation of the C-terminal domain (CTD) of RNA polymerase II (RNAP II) is a dynamic process that regulates transcription and coordinates it with pre-mRNA processing. We show here that Rct1, a nuclear multidomain cyclophilin from Schizosaccharomyces pombe, is encoded by an essential gene that interacts with the CTD and regulates its phosphorylation in vivo. Downregulation of Rct1 levels results in increased phosphorylation of the CTD at both Ser2 and Ser5 and in a commensurate decrease in RNAP II transcription. In contrast, overexpression of Rct1 decreases phosphorylation on both sites. The close association of Rct1 with transcriptionally active chromatin suggests a role in regulation of RNAP II transcriptional activity. These data, together with the pleiotropic phenotype upon Rct1 deregulation, suggest that this multidomain cyclophilin is an important player in maintaining the correct phosphorylation code of the CTD and thereby regulating CTD function.

scholarly journals Subnuclear Localization of Ku Protein: Functional Association with RNA Polymerase II Elongation Sites

2002 ◽  
Vol 22 (22) ◽  
pp. 8088-8099 ◽  
Author(s):  
Xianming Mo ◽  
William S. Dynan
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Genome Stability ◽  
Strand Break ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Rnap Ii

ABSTRACT Ku is an abundant nuclear protein with an essential function in the repair of DNA double-strand breaks. Various observations suggest that Ku also interacts with the cellular transcription machinery, although the mechanism and significance of this interaction are not well understood. In the present study, we investigated the subnuclear distribution of Ku in normally growing human cells by using confocal microscopy, chromatin immunoprecipitation, and protein immunoprecipitation. All three approaches indicated association of Ku with RNA polymerase II (RNAP II) elongation sites. This association occurred independently of the DNA-dependent protein kinase catalytic subunit and was highly selective. There was no detectable association with the initiating isoform of RNAP II or with the general transcription initiation factors. In vitro protein-protein interaction assays demonstrated that the association of Ku with elongation proteins is mediated, in part, by a discrete C-terminal domain in the Ku80 subunit. Functional disruption of this interaction with a dominant-negative mutant inhibited transcription in vitro and in vivo and suppressed cell growth. These results suggest that association of Ku with transcription sites is important for maintenance of global transcription levels. Tethering of double-strand break repair proteins to defined subnuclear structures may also be advantageous in maintenance of genome stability.

scholarly journals Functional Interaction between TFIIB and the Rpb2 Subunit of RNA Polymerase II: Implications for the Mechanism of Transcription Initiation

2004 ◽  
Vol 24 (9) ◽  
pp. 3983-3991 ◽  
Author(s):  
Bo-Shiun Chen ◽  
Michael Hampsey
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Site Selection ◽  
Transcription Initiation ◽  
Growth Defect ◽  
Nucleoside Triphosphate ◽  
Start Site ◽  
Functional Interaction ◽  
Rnap Ii

ABSTRACT The general transcription factor TFIIB is required for accurate initiation, although the mechanism by which RNA polymerase II (RNAP II) identifies initiation sites is not well understood. Here we describe results from genetic and biochemical analyses of an altered form of yeast TFIIB containing an arginine-78 → cysteine (R78C) replacement in the “B-finger” domain. TFIIB R78C shifts start site selection downstream of normal and confers a cold-sensitive growth defect (Csm−). Suppression of the R78C Csm− phenotype identified a functional interaction between TFIIB and the Rpb2 subunit of RNAP II and defined a novel role for Rpb2 in start site selection. The rpb2 suppressor encodes a glycine-369 → serine (G369S) replacement, located in the “lobe” domain of Rpb2 and near the Rpb9 subunit, which was identified previously as an effector of start site selection. The Rpb2-Rpb9 “lobe-jaw” region of RNAP II is downstream of the catalytic center and distal to the site of RNAP II-TFIIB interaction. A TFIIB R78C mutant extract was defective for promoter-specific run-on transcription but yielded an altered pattern of abortive initiation products, indicating that the R78C defect does not preclude initiation. The sua7-3 rpb2-101 double mutant was sensitive to 6-azauracil in vivo and to nucleoside triphosphate substrate depletion in vitro. In the context of the recent X-ray structure of the yeast RNAP II-TFIIB complex, these results define a functional interaction between the B-finger domain of TFIIB and the distal lobe-jaw region of RNAP II and provide insight into the mechanism of start site selection.

scholarly journals Functional dissection of the catalytic mechanism of mammalian RNA polymerase II

2005 ◽  
Vol 83 (4) ◽  
pp. 497-504 ◽  
Author(s):  
Benoit Coulombe ◽  
Marie-France Langelier
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Catalytic Mechanism ◽  
Mutational Analysis ◽  
Structural Elements ◽  
Catalytic Mechanisms ◽  
Rnap Ii ◽  
Affinity Peptide

High resolution X-ray crystal structures of multisubunit RNA polymerases (RNAP) have contributed to our understanding of transcriptional mechanisms. They also provided a powerful guide for the design of experiments aimed at further characterizing the molecular stages of the transcription reaction. Our laboratory used tandem-affinity peptide purification in native conditions to isolate human RNAP II variants that had site-specific mutations in structural elements located strategically within the enzyme's catalytic center. Both in vitro and in vivo analyses of these mutants revealed novel features of the catalytic mechanisms involving this enzyme.Key words: RNA polymerase II, transcriptional mechanisms, mutational analysis, mRNA synthesis.

scholarly journals Structure of TFIIK for phosphorylation of CTD of RNA polymerase II

2021 ◽  
Vol 7 (15) ◽  
pp. eabd4420
Author(s):  
Trevor van Eeuwen ◽  
Tao Li ◽  
Hee Jong Kim ◽  
Jose J. Gorbea Colón ◽  
Mitchell I. Parker ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Activation Loop ◽  
Active Conformation ◽  
General Transcription Factor ◽  
Cryo Electron Microscopy ◽  
Proposed Model ◽  
Carboxyl Terminal ◽  
Catalytic Cleft

During transcription initiation, the general transcription factor TFIIH marks RNA polymerase II by phosphorylating Ser5 of the carboxyl-terminal domain (CTD) of Rpb1, which is followed by extensive modifications coupled to transcription elongation, mRNA processing, and histone dynamics. We have determined a 3.5-Å resolution cryo–electron microscopy (cryo-EM) structure of the TFIIH kinase module (TFIIK in yeast), which is composed of Kin28, Ccl1, and Tfb3, yeast homologs of CDK7, cyclin H, and MAT1, respectively. The carboxyl-terminal region of Tfb3 was lying at the edge of catalytic cleft of Kin28, where a conserved Tfb3 helix served to stabilize the activation loop in its active conformation. By combining the structure of TFIIK with the previous cryo-EM structure of the preinitiation complex, we extend the previously proposed model of the CTD path to the active site of TFIIK.

scholarly journals Amino Acid Substitutions in Yeast TFIIF Confer Upstream Shifts in Transcription Initiation and Altered Interaction with RNA Polymerase II

2004 ◽  
Vol 24 (24) ◽  
pp. 10975-10985 ◽  
Author(s):  
Mohamed A. Ghazy ◽  
Seth A. Brodie ◽  
Michelle L. Ammerman ◽  
Lynn M. Ziegler ◽  
Alfred S. Ponticelli
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Primer Extension ◽  
Site Directed Mutagenesis ◽  
Protein Encoding ◽  
Transcription Factor Iif ◽  
Growth Properties ◽  
Encoding Genes

ABSTRACT Transcription factor IIF (TFIIF) is required for transcription of protein-encoding genes by eukaryotic RNA polymerase II. In contrast to numerous studies establishing a role for higher eukaryotic TFIIF in multiple steps of the transcription cycle, relatively little has been reported regarding the functions of TFIIF in the yeast Saccharomyces cerevisiae. In this study, site-directed mutagenesis, plasmid shuffle complementation assays, and primer extension analyses were employed to probe the functional domains of the S. cerevisiae TFIIF subunits Tfg1 and Tfg2. Analyses of 35 Tfg1 alanine substitution mutants and 19 Tfg2 substitution mutants identified 5 mutants exhibiting altered properties in vivo. Primer extension analyses revealed that the conditional growth properties exhibited by the tfg1-E346A, tfg1-W350A, and tfg2-L59K mutants were associated with pronounced upstream shifts in transcription initiation in vivo. Analyses of double mutant strains demonstrated functional interactions between the Tfg1 mutations and mutations in Tfg2, TFIIB, and RNA polymerase II. Importantly, biochemical results demonstrated an altered interaction between mutant TFIIF protein and RNA polymerase II. These results provide direct evidence for the involvement of S. cerevisiae TFIIF in the mechanism of transcription start site utilization and support the view that a TFIIF-RNA polymerase II interaction is a determinant in this process.

scholarly journals The RNA Polymerase II Kinase Ctk1 Regulates Positioning of a 5′ Histone Methylation Boundary along Genes

2006 ◽  
Vol 27 (2) ◽  
pp. 721-731 ◽  
Author(s):  
Tiaojiang Xiao ◽  
Yoichiro Shibata ◽  
Bhargavi Rao ◽  
R. Nicholas Laribee ◽  
Rose O'Rourke ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Histone Deacetylation ◽  
H3k4 Methylation ◽  
H3k36 Methylation ◽  
Transcriptional Initiation ◽  
Spurious Transcription ◽  
Transcriptional Stress ◽  
Rnap Ii

ABSTRACT In yeast and other eukaryotes, the histone methyltransferase Set1 mediates methylation of lysine 4 on histone H3 (H3K4me). This modification marks the 5′ end of transcribed genes in a 5′-to-3′ tri- to di- to monomethyl gradient and promotes association of chromatin-remodeling and histone-modifying enzymes. Here we show that Ctk1, the serine 2 C-terminal domain (CTD) kinase for RNA polymerase II (RNAP II), regulates H3K4 methylation. We found that CTK1 deletion nearly abolished H3K4 monomethylation yet caused a significant increase in H3K4 di- and trimethylation. Both in individual genes and genome-wide, loss of CTK1 disrupted the H3K4 methylation patterns normally observed. H3K4me2 and H3K4me3 spread 3′ into the bodies of genes, while H3K4 monomethylation was diminished. These effects were dependent on the catalytic activity of Ctk1 but are independent of Set2-mediated H3K36 methylation. Furthermore, these effects are not due to spurious transcription initiation in the bodies of genes, to changes in RNAP II occupancy, to changes in serine 5 CTD phosphorylation patterns, or to “transcriptional stress.” These data show that Ctk1 acts to restrict the spread of H3K4 methylation through a mechanism that is independent of a general transcription defect. The evidence presented suggests that Ctk1 controls the maintenance of suppressive chromatin in the coding regions of genes by both promoting H3K36 methylation, which leads to histone deacetylation, and preventing the 3′ spread of H3K4 trimethylation, a mark associated with transcriptional initiation.

Sign in / Sign up

Export Citation Format

Share Document