scholarly journals Elongin B-Mediated Epigenetic Alteration of Viral Chromatin Correlates with Efficient Human Cytomegalovirus Gene Expression and Replication

mBio ◽  
2011 ◽  
Vol 2 (2) ◽  
Author(s):  
Jiwon Hwang ◽  
Ryan T. Saffert ◽  
Robert F. Kalejta
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Human Cytomegalovirus ◽  
Viral Gene ◽  
Epigenetic Mark ◽  
Protein Accumulation ◽  
Transcriptional Elongation ◽  
Histone H2b ◽  
Cellular Genes

ABSTRACTElongins B and C are members of complexes that increase the efficiency of transcriptional elongation by RNA polymerase II (RNAPII) and enhance the monoubiquitination of histone H2B, an epigenetic mark of actively transcribed genes. Here we show that, in addition to its role in facilitating transcription of the cellular genome, elongin B also enhances gene expression from the double-stranded DNA genome of human cytomegalovirus (HCMV), a pathogenic herpesvirus. Reducing the level of elongin B by small interfering RNA- or short hairpin RNA-mediated knockdown decreased viral mRNA expression, viral protein accumulation, viral DNA replication, and infectious virion production. Chromatin immunoprecipitation analysis indicated viral genome occupancy of the elongating form of RNAPII, and monoubiquitinated histone H2B was reduced in elongin B-deficient cells. These data suggest that, in addition to the previously documented epigenetic regulation of transcriptional initiation, HCMV also subverts cellular elongin B-mediated epigenetic mechanisms for enhancing transcriptional elongation to enhance viral gene expression and virus replication.IMPORTANCEThe genetic and epigenetic control of transcription initiation at both cellular and viral promoters is well documented. Recently, the epigenetic modification of histone H2B monoubiquitination throughout the bodies of cellular genes has been shown to enhance the elongation of RNA polymerase II-initiated transcripts. Mechanisms that might control the elongation of viral transcripts are less well studied. Here we show that, as with cellular genes, elongin B-mediated monoubiquitination of histone H2B also facilitates the transcriptional elongation of human cytomegalovirus genes. This and perhaps other epigenetic markings of actively transcribed regions may help in identifying viral genes expressed duringin vitrolatency or during natural infections of humans. Furthermore, this work identifies a novel, tractable model system to further study the regulation of transcriptional elongation in living cells.

scholarly journals HIV-1 Tat-associated RNA polymerase C-terminal domain kinase, CDK2, phosphorylates CDK7 and stimulates Tat-mediated transcription

2002 ◽  
Vol 364 (3) ◽  
pp. 649-657 ◽  
Author(s):  
Sergei NEKHAI ◽  
Meisheng ZHOU ◽  
Anne FERNANDEZ ◽  
William S. LANE ◽  
Ned J.C. LAMB ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Nuclear Extract ◽  
Viral Gene ◽  
Transcriptional Elongation ◽  
Rna Pol Ii ◽  
Hela Nuclear Extract ◽  
Pol Ii ◽  
Terminal Domain ◽  
Hiv 1

HIV-1 gene expression is regulated by a viral transactivator protein (Tat) which induces transcriptional elongation of HIV-1 long tandem repeat (LTR). This induction requires hyperphosphorylation of the C-terminal domain (CTD) repeats of RNA polymerase II (Pol II). To achieve CTD hyperphosphorylation, Tat stimulates CTD kinases associated with general transcription factors of the promoter complex, specifically TFIIH-associated CDK7 and positive transcription factor b-associated CDK9 (cyclin-dependent kinase 9). Other studies indicate that Tat may bind an additional CTD kinase that regulates the target-specific phosphorylation of RNA Pol II CTD. We previously reported that Tat-associated T-cell-derived kinase (TTK), purified from human primary T-cells, stimulates Tat-dependent transcription of HIV-1 LTR in vivo [Nekhai, Shukla, Fernandez, Kumar and Lamb (2000) Virology 266, 246–256]. In the work presented here, we characterized the components of TTK by biochemical fractionation and the function of TTK in transcription assays in vitro. TTK uniquely co-purified with CDK2 and not with either CDK9 or CDK7. Tat induced the TTK-associated CDK2 kinase to phosphorylate CTD, specifically at Ser-2 residues. The TTK fraction restored Tat-mediated transcription activation of HIV-1 LTR in a HeLa nuclear extract immunodepleted of CDK9, but not in the HeLa nuclear extract double-depleted of CDK9 and CDK7. Direct microinjection of the TTK fraction augmented Tat transactivation of HIV-1 LTR in human primary HS68 fibroblasts. The results argue that TTK-associated CDK2 may function to maintain target-specific phosphorylation of RNA Pol II that is essential for Tat transactivation of HIV-1 promoter. They are also consistent with the observed cell-cycle-specific induction of viral gene transactivation.

scholarly journals HSV-1 ICP22 Is a Selective Viral Repressor of Cellular RNA Polymerase II-Mediated Transcription Elongation

Vaccines ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1054
Author(s):  
Nur Firdaus Isa ◽  
Olivier Bensaude ◽  
Nadiah C. Aziz ◽  
Shona Murphy
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Elongation ◽  
Viral Gene ◽  
Elongation Factors ◽  
Pol Ii ◽  
Early Protein ◽  
Hsv 1

The Herpes Simplex Virus (HSV-1) immediate-early protein ICP22 interacts with cellular proteins to inhibit host cell gene expression and promote viral gene expression. ICP22 inhibits phosphorylation of Ser2 of the RNA polymerase II (pol II) carboxyl-terminal domain (CTD) and productive elongation of pol II. Here we show that ICP22 affects elongation of pol II through both the early-elongation checkpoint and the poly(A)-associated elongation checkpoint of a protein-coding gene model. Coimmunoprecipitation assays using tagged ICP22 expressed in human cells and pulldown assays with recombinant ICP22 in vitro coupled with mass spectrometry identify transcription elongation factors, including P-TEFb, additional CTD kinases and the FACT complex as interacting cellular factors. Using a photoreactive amino acid incorporated into ICP22, we found that L191, Y230 and C225 crosslink to both subunits of the FACT complex in cells. Our findings indicate that ICP22 interacts with critical elongation regulators to inhibit transcription elongation of cellular genes, which may be vital for HSV-1 pathogenesis. We also show that the HSV viral activator, VP16, has a region of structural similarity to the ICP22 region that interacts with elongation factors, suggesting a model where VP16 competes with ICP22 to deliver elongation factors to viral genes.

scholarly journals HSV-1 ICP22 is a selective viral repressor of cellular RNA polymerase II-mediated transcription elongation

2021 ◽  
Author(s):  
Nur Firdaus Isa ◽  
Olivier Bensaude ◽  
Nadiah C. Aziz ◽  
Shona Murphy
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Elongation ◽  
Viral Gene ◽  
Elongation Factors ◽  
Pol Ii ◽  
Early Protein ◽  
Hsv 1

The Herpes Simplex Virus (HSV-1) immediate early protein ICP22 interacts with cellular proteins to inhibit host cell gene expression and promote viral gene expression. ICP22 inhibits phosphorylation of Ser2 of the RNA polymerase II (pol II) carboxyl-terminal domain (CTD) and productive elongation of pol II. Here we show that ICP22 affects elongation of pol II through both the early-elongation checkpoint and the poly(A)-associated elongation checkpoint on a protein-coding gene model. Coimmunoprecipitation assays using tagged ICP22 expressed in human cells and pulldown assays with recombinant ICP22 in vitro coupled with mass spectrometry identify transcription elongation factors, including P-TEFb, additional CTD kinases and the FACT complex as interacting cellular factors. Using a photoreactive amino acid incorporated into ICP22, we found that L191, Y230 and C225 crosslink to both subunits of the FACT complex in cells.  Our findings indicate that ICP22 physically interacts with critical elongation regulators to inhibit transcription elongation of cellular genes, which may be vital for HSV-1 pathogenesis. We also show that the HSV viral activator, VP16 has a region of structural similarity to the ICP22 region that interacts with elongation factors, suggesting a model where VP16 competes with ICP22 to deliver elongation factors to viral genes.

scholarly journals Human Cytomegalovirus pUL79 Is an Elongation Factor of RNA Polymerase II for Viral Gene Transcription

2014 ◽  
Vol 10 (8) ◽  
pp. e1004350 ◽  
Author(s):  
Yi-Chieh Perng ◽  
Jessica A. Campbell ◽  
Deborah J. Lenschow ◽  
Dong Yu
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Gene Transcription ◽  
Human Cytomegalovirus ◽  
Elongation Factor ◽  
Viral Gene ◽  
Viral Gene Transcription

scholarly journals Human hHpr1/p84/Thoc1 Regulates Transcriptional Elongation and Physically Links RNA Polymerase II and RNA Processing Factors

2005 ◽  
Vol 25 (10) ◽  
pp. 4023-4033 ◽  
Author(s):  
Yanping Li ◽  
Xiaoling Wang ◽  
Xiaojing Zhang ◽  
David W. Goodrich
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Processing ◽  
Rna Splicing ◽  
Transcriptional Elongation ◽  
Intact Cells ◽  
Efficient Gene ◽  
Cellular Phenotypes ◽  
Processing Factors

ABSTRACT Cotranscriptional loading of RNA processing factors onto nascent RNA facilitates efficient gene expression. Mechanisms responsible for coupling transcription and RNA processing are not well defined, but the Saccharomyces cerevisiae TREX complex provides an example. TREX is composed of the subcomplex THO that associates with RNA polymerase II and is required for normal transcriptional elongation. THO associates with proteins involved in RNA splicing and export to form the larger TREX complex. Hence, assembly of TREX physically couples transcriptional elongation with RNA processing factors. Whether metazoan species with long, intron-containing genes utilize a similar mechanism has not been established. Here we show that human hHpr1/p84/Thoc1 associates with elongating RNA polymerase II and the RNA splicing and export factor UAP56 in intact cells. Depletion of hHpr1/p84/Thoc1 causes transcriptional elongation defects and associated cellular phenotypes similar to those observed in THO-deficient yeast. We conclude that hHpr1/p84/Thoc1 regulates transcriptional elongation and may participate in a protein complex functionally analogous to yeast TREX, physically linking elongating RNA polymerase II with RNA processing factors.

scholarly journals Control of Transcriptional Elongation by RNA Polymerase II: A Retrospective

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Kris Brannan ◽  
David L. Bentley
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Elongation ◽  
Transcriptional Elongation ◽  
Transcription Start ◽  
Control Of Gene Expression ◽  
Transcription Start Sites ◽  
Cellular Genes ◽  
Bottle Neck ◽  
Multicellular Organisms

The origins of our current understanding of control of transcription elongation lie in pioneering experiments that mapped RNA polymerase II on viral and cellular genes. These studies first uncovered the surprising excess of polymerase molecules that we now know to be situated at the at the 5′ ends of most genes in multicellular organisms. The pileup of pol II near transcription start sites reflects a ubiquitous bottle-neck that limits elongation right at the start of the transcription elongation. Subsequent seminal work identified conserved protein factors that positively and negatively control the flux of polymerase through this bottle-neck, and make a major contribution to control of gene expression.

scholarly journals Association of Herpes Simplex Virus Type 1 ICP8 and ICP27 Proteins with Cellular RNA Polymerase II Holoenzyme

2002 ◽  
Vol 76 (12) ◽  
pp. 5893-5904 ◽  
Author(s):  
Changhong Zhou ◽  
David M. Knipe
Keyword(s):  
Gene Expression ◽  
Herpes Simplex ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Gene Transcription ◽  
Late Gene ◽  
Viral Gene ◽  
Viral Genes ◽  
Simplex Virus ◽  
Rna Polymerase Ii Holoenzyme

ABSTRACT Herpes simplex virus 1 (HSV-1) infection causes the shutoff of host gene transcription and the induction of a transcriptional program of viral gene expression. Cellular RNA polymerase II is responsible for transcription of all the viral genes, but several viral proteins stimulate viral gene transcription. ICP4 is required for all delayed-early and late gene transcription, ICP0 stimulates transcription of viral genes, and ICP27 stimulates expression of some early genes and transcription of at least some late viral genes. The early DNA-binding protein, ICP8, also stimulates late gene transcription. We therefore investigated which HSV proteins interact with RNA polymerase II. Using immunoprecipitation and Western blotting methods, we observed the coprecipitation of ICP27 and ICP8 with RNA polymerase II holoenzyme. The association of ICP27 with RNA polymerase II was detectable as early as 3 h postinfection, while ICP8 association became evident by 5 h postinfection, and the association of both was independent of viral DNA synthesis. Infections with ICP27 gene mutant viruses revealed that ICP27 is required for the association of ICP8 with RNA polymerase II, while studies with ICP8 gene deletion mutants showed no apparent role for ICP8 in the association of ICP27 with RNA polymerase II. The association of ICP27 and ICP8 with RNA polymerase II holoenzyme appeared to be independent of nucleic acids. We hypothesize that the interaction of ICP27 with RNA polymerase II holoenzyme reflects its role in stimulating early and late gene expression and/or its role in inhibiting host transcription and that the interaction of ICP8 with RNA polymerase II holoenzyme reflects its role in stimulating late gene transcription.

Nutrient-regulated gene expression in eukaryotes

2006 ◽  
Vol 73 ◽  
pp. 85-96 ◽  
Author(s):  
Richard J. Reece ◽  
Laila Beynon ◽  
Stacey Holden ◽  
Amanda D. Hughes ◽  
Karine Rébora ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcriptional Control ◽  
Direct Interaction ◽  
Signalling Pathways ◽  
A Cell ◽  
One Step ◽  
Higher Eukaryotes ◽  
Regulated Gene Expression

The recognition of changes in environmental conditions, and the ability to adapt to these changes, is essential for the viability of cells. There are numerous well characterized systems by which the presence or absence of an individual metabolite may be recognized by a cell. However, the recognition of a metabolite is just one step in a process that often results in changes in the expression of whole sets of genes required to respond to that metabolite. In higher eukaryotes, the signalling pathway between metabolite recognition and transcriptional control can be complex. Recent evidence from the relatively simple eukaryote yeast suggests that complex signalling pathways may be circumvented through the direct interaction between individual metabolites and regulators of RNA polymerase II-mediated transcription. Biochemical and structural analyses are beginning to unravel these elegant genetic control elements.

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