The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Martin Teichmann - One of the best experts on this subject based on the ideXlab platform.
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Contributions of in vitro transcription to the understanding of human RNA Polymerase III transcription
Transcription, 2014Co-Authors: Hélène Dumay-odelot, S Durrieu-gaillard, L'emir El-ayoubi, Christian Parrot, Martin TeichmannAbstract:Human RNA Polymerase III transcribes small untranslated RNAs that contribute to the regulation of essential cellular processes, including transcription, RNA processing and translation. Analysis of this transcription system by in vitro transcription techniques has largely contributed to the discovery of its transcription factors and to the understanding of the regulation of human RNA Polymerase III transcription. Here we review some of the key steps that led to the identification of transcription factors and to the definition of minimal promoter sequences for human RNA Polymerase III transcription.
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cell growth and differentiation dependent regulation of RNA Polymerase III transcription
Cell Cycle, 2010Co-Authors: Helene Dumayodelot, Stephanie Durrieugaillard, Daniel Da Silva, Robert G Roeder, Martin TeichmannAbstract:RNA Polymerase III transcribes small untranslated RNAs that fulfill essential cellular functions in regulating transcription, RNA processing, translation and protein translocation. RNA Polymerase III transcription activity is tightly regulated during the cell cycle and coupled to growth control mechanisms. Furthermore, there are reports of changes in RNA Polymerase III transcription activity during cellular differentiation, including the discovery of a novel isoform of human RNA Polymerase III that has been shown to be specifically expressed in undifferentiated human H1 embryonic stem cells. Here, we review major regulatory mechanisms of RNA Polymerase III transcription during the cell cycle, cell growth and cell differentiation.
Olivier Lefebvre - One of the best experts on this subject based on the ideXlab platform.
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yeast RNA Polymerase III transcription factors and effectors
Biochimica et Biophysica Acta, 2013Co-Authors: Joel Acker, Christine Conesa, Olivier LefebvreAbstract:Abstract Recent data indicate that the well-defined transcription machinery of RNA Polymerase III (Pol III) is probably more complex than commonly thought. In this review, we describe the yeast basal transcription factors of Pol III and their involvements in the transcription cycle. We also present a list of proteins detected on genes transcribed by Pol III (class III genes) that might participate in the transcription process. Surprisingly, several of these proteins are involved in RNA Polymerase II transcription. Defining the role of these potential new effectors in Pol III transcription in vivo will be the challenge of the next few years. This article is part of a Special Issue entitled: Transcription by Odd Pols.
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RNA Polymerase III and class III transcription factors from Saccharomyces cerevisiae.
Methods in Enzymology, 2004Co-Authors: Janine Huet, Nathalie Manaud, Giorgio Dieci, Gérald Peyroche, Christine Conesa, Olivier Lefebvre, A. Ruet, Michel Riva, André SentenacAbstract:Publisher Summary RNA Polymerase III is specifically recruited at the transcription start sites via a cascade of protein-protein-DNA interactions involving various transcription factors. Remarkably, complex assemblies are formed that involve more than 25 polypeptides and cover the entire transcription units. The transcriptional components and the process of transcription complex formation on various class III genes have been best analyzed in Saccharomyces cerevisiae. This chapter describes the purification of yeast RNA Polymerase III and of yeast factors TFIIIA (transcription factor IIIA), TFIIIB, and TFIIIC. RNA Polymerase III and TFIIIC can be purified to near homogeneity as stable multisubunit assemblies. In contrast, TFIIIB can be easily dissociated into three components (TBP, TFIIIB, and B"). TFIIIA, TFIIIB and TBP can be obtained in active form as recombinant proteins made in Escherichia coli . Twenty components of the yeast class III transcription machinery have already been cloned and mutagenized.
Ian M. Willis - One of the best experts on this subject based on the ideXlab platform.
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Structural basis for RNA Polymerase III transcription repression by Maf1
Nature Structural & Molecular Biology, 2020Co-Authors: Matthias K. Vorländer, Florence Baudin, Robyn D. Moir, Rene Wetzel, Wim J. H. Hagen, Ian M. Willis, Christoph W. MüllerAbstract:Maf1 is a conserved inhibitor of RNA Polymerase III (Pol III) that influences phenotypes ranging from metabolic efficiency to lifespan. Here, we present a 3.3-A-resolution cryo-EM structure of yeast Maf1 bound to Pol III, establishing that Maf1 sequesters Pol III elements involved in transcription initiation and binds the mobile C34 winged helix 2 domain, sealing off the active site. The Maf1 binding site overlaps with that of TFIIIB in the preinitiation complex. A 3.3-A-resolution cryo-EM structure of yeast Maf1 bound to RNA Polymerase III (Pol III) explains the molecular mechanism for Pol III inhibition.
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Interaction between a complex of RNA Polymerase III subunits and the 70-kDa component of transcription factor IIIB.
Journal of Biological Chemistry, 1993Co-Authors: Michel Werner, Ian M. Willis, Nathalie Chaussivert, André SentenacAbstract:Abstract A system that detects the formation of complexes between different proteins by linking them to separate domains of the GAL4 transcription activator protein has been used to study protein-protein interactions between four essential and unique subunits of yeast RNA Polymerase III (C82, C53, C34 and C31), the 70-kDa component of the initiation transcription factor IIIB (TFIIIB70) and the TATA-binding protein. We found that C82, C34, and C31 are able to combine with each other in vivo and that C34 interacts with TFIIIB70. These results suggest that C34 and TFIIIB70 are specificity determinants of the RNA Polymerase III-TFIIIB interaction.
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RNA Polymerase III genes factors and transcriptional specificity
FEBS Journal, 1993Co-Authors: Ian M. WillisAbstract:Recent studies on RNA Polymerase III (pol III) gene transcription have provided a new awareness of the molecular complexity of this process. Fortunately, while the number of transcription components has been increasing, fundamental similarities have emerged regarding the function of eukaryotic promoter elements and the factors that bind them to form preinitiation complexes. Among these, the ability of transcription factor IIIB (TFIIIB) and pol III to transcribe the Saccharomyces cerevisiae U6 gene suggests that the concept of a minimal pol II promoter comprising a TATA box and an initiator region has a parallel in the pol III system. Furthermore, for each of the three classes of eukaryotic RNA Polymerase, the assembly of transcription preinitiation complexes and, to some extent, the nature of these complexes appears to be more similar than was previously anticipated.
Robert J. White - One of the best experts on this subject based on the ideXlab platform.
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RNA Polymerase I and RNA Polymerase III in Eukaryotes
Encyclopedia of Biological Chemistry, 2020Co-Authors: Robert J. WhiteAbstract:The nuclei of eukaryotic organisms contain at least three RNA Polymerases that transcribe the genome into RNA copies. These are large, multisubunit enzymes with several shared components. RNA Polymerase I is the most active of these enzymes and generates substantial amounts of ribosomal RNA in regions of the nucleus termed nucleoli. The main product of RNA Polymerase III is transfer RNA. Most cancers produce abnormally high amounts of ribosomal RNA and transfer RNA, and this is likely to contribute to aberrant cell growth. Key tumor suppressors reduce the output of RNA Polymerases I and III as a means of growth restraint.
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transcription by RNA Polymerase III more complex than we thought
Nature Reviews Genetics, 2011Co-Authors: Robert J. WhiteAbstract:RNA Polymerase III is highly specialized for the production of short non-coding RNAs. This Progress article discusses the implications of recent ChIP–seq studies that reveal unprecedented genome-wide detail and unanticipated complexities of RNA Polymerase III transcription, including tissue-specific transcriptional regulation and intriguing parallels to RNA Polymerase II. RNA Polymerase (Pol) III is highly specialized for the production of short non-coding RNAs. Once considered to be under relatively simple controls, recent studies using chromatin immunoprecipitation followed by sequencing (ChIP–seq) have revealed unexpected levels of complexity for Pol III regulation, including substantial cell-type selectivity and intriguing overlap with Pol II transcription. Here I describe these novel insights and consider their implications and the questions that remain.
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non coding RNA production by RNA Polymerase III is implicated in cancer
Nature Reviews Cancer, 2008Co-Authors: Lynne Marshall, Robert J. WhiteAbstract:RNA Polymerase III (Pol III) makes a variety of small non-coding RNAs, such as tRNA and 5S ribosomal RNA. Increased expression of pol III products is often observed in transformed cells. Much progress has been made in determining how Pol III-dependent transcription is regulated and how it increases in cancers, but the importance of this increase has not been clearly established. New evidence suggests that Pol III output can substantially affect transformation.
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Cell cycle regulation of RNA Polymerase III transcription.
Molecular and Cellular Biology, 1995Co-Authors: Robert J. White, Tanya M. Gottlieb, C S Downes, Stephen P. JacksonAbstract:Inactivation of the TATA-binding protein-containing complex TFIIIB contributes to the mitotic repression of RNA Polymerase III transcription, both in frogs and in humans (J. M. Gottesfeld, V. J. Wolf, T. Dang, D. J. Forbes, and P. Hartl, Science 263:81-84, 1994; R. J. White, T. M. Gottlieb, C. S. Downes, and S. P. Jackson, Mol. Cell. Biol. 15:1983-1992, 1995). Using extracts of synchronized proliferating HeLa cells, we show that TFIIIB activity remains low during the early part of G1 phase and increases only gradually as cells approach S phase. As a result, the transcription of all class III genes tested is significantly less active in early G1 than it is in S or G2 phase, both in vitro and in vivo. The increased activity of TFIIIB as cells progress through interphase appears to be due to changes in the TATA-binding protein-associated components of this complex. The data suggest that TFIIIB is an important target for the cell cycle regulation of RNA Polymerase III transcription during both mitosis and interphase of actively proliferating HeLa cells.
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Regulation of RNA Polymerase III transcription in response to Simian virus 40 transformation.
The EMBO Journal, 1990Co-Authors: Robert J. White, David Stott, Peter W. J. RigbyAbstract:Abstract Transcription by RNA Polymerase III of the B2 family of middle-repetitive elements is activated in response to transformation by a variety of agents, including DNA tumour viruses, RNA tumour viruses and chemical carcinogens. We have investigated the mechanism of activation in SV40-transformed cells and we find that the effect is due to an increase in the activity of the general class III transcription factor TFIIIC, achieved both by an increase in factor abundance and by a change in its phosphorylation state. SV40 transformation also stimulates transcription of other genes by RNA Polymerase III but the effect may be balanced by compensatory post-transcriptional changes. TFIIIC may mediate the stimulation of Polymerase III transcription by a range of transforming viruses.
Nouria Hernandez - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Human RNA Polymerase III Identifies Orthologues for Saccharomyces cerevisiae RNA Polymerase III Subunits
Molecular and Cellular Biology, 2002Co-Authors: Ping Hu, Si Wu, Chih-chi Yuan, Ryuji Kobayashi, Michael P. Myers, Nouria HernandezAbstract:Unlike Saccharomyces cerevisiae RNA Polymerase III, human RNA Polymerase III has not been entirely characterized. Orthologues of the yeast RNA Polymerase III subunits C128 and C37 remain unidentified, and for many of the other subunits, the available information is limited to database sequences with various degrees of similarity to the yeast subunits. We have purified an RNA Polymerase III complex and identified its components. We found that two RNA Polymerase III subunits, referred to as RPC8 and RPC9, displayed sequence similarity to the RNA Polymerase II RPB7 and RPB4 subunits, respectively. RPC8 and RPC9 associated with each other, paralleling the association of the RNA Polymerase II subunits, and were thus paralogues of RPB7 and RPB4. Furthermore, the complex contained a prominent 80-kDa polypeptide, which we called RPC5 and which corresponded to the human orthologue of the yeast C37 subunit despite limited sequence similarity. RPC5 associated with RPC53, the human orthologue of S. cerevisiae C53, paralleling the association of the S. cerevisiae C37 and C53 subunits, and was required for transcription from the type 2 VAI and type 3 human U6 promoters. Our results provide a characterization of human RNA Polymerase III and show that the RPC5 subunit is essential for transcription.
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The Largest Subunit of Human RNA Polymerase III Is Closely Related to the Largest Subunit of Yeast and Trypanosome RNA Polymerase III
Genome Research, 1997Co-Authors: Setareh Sepehri, Nouria HernandezAbstract:In both yeast and mammalian systems, considerable progress has been made toward the characterization of the transcription factors required for transcription by RNA Polymerase III. However, whereas in yeast all of the RNA Polymerase III subunits have been cloned, relatively little is known about the enzyme itself in higher eukaryotes. For example, no higher eukaryotic sequence corresponding to the largest RNA Polymerase III subunit is available. Here we describe the isolation of cDNAs that encode the largest subunit of human RNA Polymerase III, as suggested by the observations that (1) antibodies directed against the cloned protein immunoprecipitate an active enzyme whose sensitivity to different concentrations of alpha-amanitin is that expected for human RNA Polymerase III; and (2) depletion of transcription extracts with the same antibodies results in inhibition of transcription from an RNA Polymerase III, but not from an RNA Polymerase II, promoter. Sequence comparisons reveal that regions conserved in the RNA Polymerase I, II, and III largest subunits characterized so far are also conserved in the human RNA Polymerase III sequence, and thus probably perform similar functions for the human RNA Polymerase III enzyme.
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The cloned RNA Polymerase II transcription factor IID selects RNA Polymerase III to transcribe the human U6 gene in vitro.
Genes & Development, 1991Co-Authors: Susan M. Lobo, James Lister, Maureen L. Sullivan, Nouria HernandezAbstract:Although the human U2 and U6 snRNA genes are transcribed by different RNA Polymerases (i.e., RNA Polymerases II and III, respectively), their promoters are very similar in structure. Both contain a proximal sequence element (PSE) and an octamer motif-containing enhancer, and these elements are interchangeable between the two promoters. The RNA Polymerase III specificity of the U6 promoter is conferred by a single A/T-rich element located around position -25. Mutation of the A/T-rich region converts the U6 promoter into an RNA Polymerase II promoter, whereas insertion of the A/T-rich region into the U2 promoter converts that promoter into an RNA Polymerase III promoter. We show that this A/T-rich element can be replaced by a number of TATA boxes derived from mRNA promoters transcribed by RNA Polymerase II with little effect on RNA Polymerase III transcription. Furthermore, the cloned RNA Polymerase II transcription factor TFIID both binds to the U6 A/T-rich region and directs accurate RNA Polymerase III transcription in vitro. Mutations in the U6 A/T-rich region that convert the U6 promoter into an RNA Polymerase II promoter also abolish TFIID binding. Together, these observations suggest that in the human snRNA promoters, unlike in mRNA promoters, binding of TFIID directs the assembly of RNA Polymerase III transcription complexes, whereas the lack of TFIID binding results in the assembly of RNA Polymerase II snRNA transcription complexes.
