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Yague-Sanz C, Migeot V, Larochelle M, Bachand F, Wéry M, Morillon A, Hermand D. Chromatin remodeling by Pol II primes efficient Pol III transcription. Nat Commun 2023; 14:3587. [PMID: 37328480 PMCID: PMC10276017 DOI: 10.1038/s41467-023-39387-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 06/09/2023] [Indexed: 06/18/2023] Open
Abstract
The packaging of the genetic material into chromatin imposes the remodeling of this barrier to allow efficient transcription. RNA polymerase II activity is coupled with several histone modification complexes that enforce remodeling. How RNA polymerase III (Pol III) counteracts the inhibitory effect of chromatin is unknown. We report here a mechanism where RNA Polymerase II (Pol II) transcription is required to prime and maintain nucleosome depletion at Pol III loci and contributes to efficient Pol III recruitment upon re-initiation of growth from stationary phase in Fission yeast. The Pcr1 transcription factor participates in the recruitment of Pol II, which affects local histone occupancy through the associated SAGA complex and a Pol II phospho-S2 CTD / Mst2 pathway. These data expand the central role of Pol II in gene expression beyond mRNA synthesis.
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Affiliation(s)
- Carlo Yague-Sanz
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur, 5000, Belgium
| | - Valérie Migeot
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur, 5000, Belgium
| | - Marc Larochelle
- RNA Group, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, QC, J1E 4K8, Canada
| | - François Bachand
- RNA Group, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, QC, J1E 4K8, Canada
| | - Maxime Wéry
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, PSL Research University, Université Pierre et Marie Curie, CNRS UMR 3244, Paris, France
| | - Antonin Morillon
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, PSL Research University, Université Pierre et Marie Curie, CNRS UMR 3244, Paris, France
| | - Damien Hermand
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur, 5000, Belgium.
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2
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Gopaul D, Denby Wilkes C, Goldar A, Giordanengo Aiach N, Barrault MB, Novikova E, Soutourina J. Genomic analysis of Rad26 and Rad1-Rad10 reveals differences in their dependence on Mediator and RNA polymerase II. Genome Res 2022; 32:1516-1528. [PMID: 35738899 PMCID: PMC9435749 DOI: 10.1101/gr.276371.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 06/16/2022] [Indexed: 02/03/2023]
Abstract
Mediator is a conserved coregulator playing a key role in RNA polymerase (Pol) II transcription. Mediator also links transcription and nucleotide excision repair (NER) via a direct contact with Rad2/ERCC5(XPG) endonuclease. In this work, we analyzed the genome-wide distribution of Rad26/ERCC6(CSB) and Rad1-Rad10/ERCC4(XPF)-ERCC1, addressing the question of a potential link of these proteins with Mediator and Pol II in yeast Saccharomyces cerevisiae Our genomic analyses reveal that Rad1-Rad10 and Rad26 are present on the yeast genome in the absence of genotoxic stress, especially at highly transcribed regions, with Rad26 binding strongly correlating with that of Pol II. Moreover, we show that Rad1-Rad10 and Rad26 colocalize with Mediator at intergenic regions and physically interact with this complex. Using kin28 TFIIH mutant, we found that Mediator stabilization on core promoters leads to an increase in Rad1-Rad10 chromatin binding, whereas Rad26 occupancy follows mainly a decrease in Pol II transcription. Combined with multivariate analyses, our results show the relationships between Rad1-Rad10, Rad26, Mediator, and Pol II, modulated by the changes in binding dynamics of Mediator and Pol II transcription. In conclusion, we extend the Mediator link to Rad1-Rad10 and Rad26 NER proteins and reveal important differences in their dependence on Mediator and Pol II. Rad2 is the most dependent on Mediator, followed by Rad1-Rad10, whereas Rad26 is the most closely related to Pol II. Our work thus contributes to new concepts of the functional interplay between transcription and DNA repair machineries, which are relevant for human diseases including cancer and XP/CS syndromes.
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Affiliation(s)
- Diyavarshini Gopaul
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Cyril Denby Wilkes
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Arach Goldar
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Nathalie Giordanengo Aiach
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Marie-Bénédicte Barrault
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Elizaveta Novikova
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Julie Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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3
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Garrido-Godino AI, Cuevas-Bermúdez A, Gutiérrez-Santiago F, Mota-Trujillo MDC, Navarro F. The Association of Rpb4 with RNA Polymerase II Depends on CTD Ser5P Phosphatase Rtr1 and Influences mRNA Decay in Saccharomyces cerevisiae. Int J Mol Sci 2022; 23:2002. [PMID: 35216121 PMCID: PMC8875030 DOI: 10.3390/ijms23042002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 02/04/2023] Open
Abstract
Rtr1 is an RNA polymerase II (RNA pol II) CTD-phosphatase that influences gene expression during the transition from transcription initiation to elongation and during transcription termination. Rtr1 interacts with the RNA pol II and this interaction depends on the phosphorylation state of the CTD of Rpb1, which may influence dissociation of the heterodimer Rpb4/7 during transcription. In addition, Rtr1 was proposed as an RNA pol II import factor in RNA pol II biogenesis and participates in mRNA decay by autoregulating the turnover of its own mRNA. Our work shows that Rtr1 acts in RNA pol II assembly by mediating the Rpb4/7 association with the rest of the enzyme. RTR1 deletion alters RNA pol II assembly and increases the amount of RNA pol II associated with the chromatin that lacks Rpb4, decreasing Rpb4-mRNA imprinting and, consequently, increasing mRNA stability. Thus, Rtr1 interplays RNA pol II biogenesis and mRNA decay regulation. Our data also indicate that Rtr1 mediates mRNA decay regulation more broadly than previously proposed by cooperating with Rpb4. Interestingly, our data include new layers in the mechanisms of gene regulation and in the crosstalk between mRNA synthesis and decay by demonstrating how the association of Rpb4/7 to the RNA pol II influences mRNA decay.
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Affiliation(s)
- Ana I. Garrido-Godino
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
| | - Abel Cuevas-Bermúdez
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
| | - Francisco Gutiérrez-Santiago
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
| | - Maria del Carmen Mota-Trujillo
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
| | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain; (A.I.G.-G.); (A.C.-B.); (F.G.-S.); (M.d.C.M.-T.)
- Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain
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4
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Abstract
RNA polymerase III (Pol III) is a large multisubunit complex conserved in all eukaryotes that plays an essential role in producing a variety of short non-coding RNAs, such as tRNA, 5S rRNA and U6 snRNA transcripts. Pol III comprises of 17 subunits in both yeast and human with a 10-subunit core and seven peripheral subunits. Because of its size and complexity, Pol III has posed a formidable challenge to structural biologists. The first atomic cryogenic electron microscopy structure of yeast Pol III leading to the canonical view was reported in 2015. Within the last few years, the optimization of endogenous extract and purification procedure and the technical and methodological advances in cryogenic electron microscopy, together allow us to have a first look at the unprecedented details of human Pol III organization. Here, we look back on the structural studies of human Pol III and discuss them in the light of our current understanding of its role in eukaryotic transcription.
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Affiliation(s)
- Qianmin Wang
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| | - Ming Lei
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China.,State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Wu
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
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5
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Abstract
The innate immune system has numerous signal transduction pathways that lead to the production of type I interferons in response to exposure of cells to external stimuli. One of these pathways comprises RNA polymerase (Pol) III that senses common DNA viruses, such as cytomegalovirus, vaccinia, herpes simplex virus-1 and varicella zoster virus. This polymerase detects and transcribes viral genomic regions to generate AU-rich transcripts that bring to the induction of type I interferons. Remarkably, Pol III is also stimulated by foreign non-viral DNAs and expression of one of its subunits is induced by an RNA virus, the Sindbis virus. Moreover, a protein subunit of RNase P, which is known to associate with Pol III in initiation complexes, is induced by viral infection. Accordingly, alliance of the two tRNA enzymes in innate immunity merits a consideration.
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Affiliation(s)
- Nayef Jarrous
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Israel-Canada
| | - Alexander Rouvinski
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Israel-Canada.,The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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6
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Determinants of Replication-Fork Pausing at tRNA Genes in Saccharomyces cerevisiae. Genetics 2020; 214:825-838. [PMID: 32071194 DOI: 10.1534/genetics.120.303092] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 02/12/2020] [Indexed: 12/21/2022] Open
Abstract
Transfer RNA (tRNA) genes are widely studied sites of replication-fork pausing and genome instability in the budding yeast Saccharomyces cerevisiae tRNAs are extremely highly transcribed and serve as constitutive condensin binding sites. tRNA transcription by RNA polymerase III has previously been identified as stimulating replication-fork pausing at tRNA genes, but the nature of the block to replication has not been incontrovertibly demonstrated. Here, we describe a systematic, genome-wide analysis of the contributions of candidates to replication-fork progression at tDNAs in yeast: transcription factor binding, transcription, topoisomerase activity, condensin-mediated clustering, and Rad18-dependent DNA repair. We show that an asymmetric block to replication is maintained even when tRNA transcription is abolished by depletion of one or more subunits of RNA polymerase III. By contrast, analogous depletion of the essential transcription factor TFIIIB removes the obstacle to replication. Therefore, our data suggest that the RNA polymerase III transcription complex itself represents an asymmetric obstacle to replication even in the absence of RNA synthesis. We additionally demonstrate that replication-fork progression past tRNA genes is unaffected by the global depletion of condensin from the nucleus, and can be stimulated by the removal of topoisomerases or Rad18-dependent DNA repair pathways.
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7
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Molecular requirements for sensing of intracellular microbial nucleic acids by the innate immune system. Cytokine 2017; 98:4-14. [DOI: 10.1016/j.cyto.2016.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 10/11/2016] [Indexed: 12/24/2022]
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8
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Johnson KCM, Yu Y, Gao L, Eng RC, Wasteneys GO, Chen X, Li X. A partial loss-of-function mutation in an Arabidopsis RNA polymerase III subunit leads to pleiotropic defects. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2219-30. [PMID: 26865731 PMCID: PMC4809280 DOI: 10.1093/jxb/erw020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Plants employ five DNA-dependent RNA polymerases (Pols) in transcription. One of these polymerases, Pol III, has previously been reported to transcribe 5S rRNA, tRNAs, and a number of small RNAs. However, in-depth functional analysis is complicated by the fact that knockout mutations in Pol subunits are typically lethal. Here, we report the characterization of the first known viable Pol III subunit mutant,nrpc7-1 This mutant was originally isolated from a forward genetic screen designed to identify enhancers of the autoimmune mutantsnc1, which contains a gain-of-function mutation in a nucleotide-binding leucine-rich repeat (NLR) immune receptor-encoding gene. Thenrpc7-1mutation occurs in an intron-exon splice site and results in intron retention in someNRPC7transcripts. There is a global disruption in RNA equilibrium innrpc7-1, exemplified by the altered expression of a number of RNA molecules, some of which are not reported to be transcribed by Pol III. There are developmental defects associated with the mutation, as homozygous mutant plants are dwarf, have stunted roots and siliques, and possess serrated leaves. These defects are possibly due to altered small RNA stability or activity. Additionally, thenrpc7-1mutation confers anNLR-specific alternative splicing defect that correlates with enhanced disease resistance, highlighting the importance of alternative splicing in regulating NLR activity. Altogether, these results reveal novel roles for Pol III in maintaining RNA homeostasis, adjusting the expression of a diverse suite of genes, and indirectly modulating gene splicing. Future analyses using thenrpc7-1mutant will be instrumental in examining other unknown Pol III functions.
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Affiliation(s)
- Kaeli C M Johnson
- Department of Botany, University of British Columbia, Vancouver, V6T 1Z4, Canada Michael Smith Laboratories, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Yu Yu
- Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA
| | - Lei Gao
- Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA
| | - Ryan C Eng
- Department of Botany, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Geoffrey O Wasteneys
- Department of Botany, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Xuemei Chen
- Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA
| | - Xin Li
- Department of Botany, University of British Columbia, Vancouver, V6T 1Z4, Canada Michael Smith Laboratories, University of British Columbia, Vancouver, V6T 1Z4, Canada
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9
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Wei Y, Xu J, Zhang W, Wen Z, Liu F. RNA polymerase III component Rpc9 regulates hematopoietic stem and progenitor cell maintenance in zebrafish. Development 2016; 143:2103-10. [DOI: 10.1242/dev.126797] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 04/25/2016] [Indexed: 12/18/2022]
Abstract
Hematopoietic stem and progenitor cells (HSPCs) are capable of self-renewal and replenishing all lineages of blood cells throughout the lifetime and thus critical for tissue homeostasis. However, the mechanism regulating HSPC development is still incompletely understood. Here, we isolate a zebrafish mutant with defective T lymphopoiesis and positional cloning identifies that Rpc9, a component of DNA-directed RNA polymerase III (Pol III) complex, is responsible for the mutant phenotype. Further analysis shows that rpc9-deficiency leads to the impairment of HSPCs and their derivatives in zebrafish embryos. Excessive apoptosis is observed in the caudal hematopoietic tissue (CHT, the equivalent of fetal liver in mammals) of rpc9−/− embryos and the hematopoietic defects in rpc9−/− embryos can be fully rescued by suppression of p53. Thus, our work illustrate that Rpc9, a component of Pol III, plays an important tissue-specific role in HSPC maintenance during zebrafish embryogenesis and that it might be conserved across vertebrates including mammals.
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Affiliation(s)
- Yonglong Wei
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Xu
- State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, Division of Life Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Wenqing Zhang
- Key Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases of Guangdong Higher Education Institutes, Department of Cell Biology, Southern Medical University, Guangzhou 510515, China
| | - Zilong Wen
- State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, Division of Life Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Feng Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
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10
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Abstract
Reuter et al. show that Nab2, a poly(A)-binding protein important for correct poly(A) tail length and nuclear mRNA export, is present at all RNA polymerase III (RNAPIII) transcribed genes. Nab2 is required for the occupancy of RNAPIII and TFIIIB at target genes. RNA polymerase III (RNAPIII) synthesizes most small RNAs, the most prominent being tRNAs. Although the basic mechanism of RNAPIII transcription is well understood, recent evidence suggests that additional proteins play a role in RNAPIII transcription. Here, we discovered by a genome-wide approach that Nab2, a poly(A)-binding protein important for correct poly(A) tail length and nuclear mRNA export, is present at all RNAPIII transcribed genes. The occupancy of Nab2 at RNAPIII transcribed genes is dependent on transcription. Using a novel temperature-sensitive allele of NAB2, nab2-34, we show that Nab2 is required for the occupancy of RNAPIII and TFIIIB at target genes. Furthermore, Nab2 interacts with RNAPIII, TFIIIB, and RNAPIII transcripts. Importantly, impairment of Nab2 function causes an RNAPIII transcription defect in vivo and in vitro. Taken together, we establish Nab2, an important mRNA biogenesis factor, as a novel player required for RNAPIII transcription by stabilizing TFIIIB and RNAPIII at promoters.
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Affiliation(s)
- L Maximilian Reuter
- Institute of Biochemistry, Justus Liebig University Giessen, 35392 Giessen, Germany; Gene Center, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Dominik M Meinel
- Gene Center, Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Katja Sträßer
- Institute of Biochemistry, Justus Liebig University Giessen, 35392 Giessen, Germany; Gene Center, Ludwig-Maximilians-University Munich, 81377 Munich, Germany; Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-University Munich, 81377 Munich, Germany
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11
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Correct assembly of RNA polymerase II depends on the foot domain and is required for multiple steps of transcription in Saccharomyces cerevisiae. Mol Cell Biol 2013; 33:3611-26. [PMID: 23836886 DOI: 10.1128/mcb.00262-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Recent papers have provided insight into the cytoplasmic assembly of RNA polymerase II (RNA pol II) and its transport to the nucleus. However, little is known about the mechanisms governing its nuclear assembly, stability, degradation, and recycling. We demonstrate that the foot of RNA pol II is crucial for the assembly and stability of the complex, by ensuring the correct association of Rpb1 with Rpb6 and of the dimer Rpb4-Rpb7 (Rpb4/7). Mutations at the foot affect the assembly and stability of the enzyme, a defect that is offset by RPB6 overexpression, in coordination with Rpb1 degradation by an Asr1-independent mechanism. Correct assembly is a prerequisite for the proper maintenance of several transcription steps. In fact, assembly defects alter transcriptional activity and the amount of enzyme associated with the genes, affect C-terminal domain (CTD) phosphorylation, interfere with the mRNA-capping machinery, and possibly increase the amount of stalled RNA pol II. In addition, our data show that TATA-binding protein (TBP) occupancy does not correlate with RNA pol II occupancy or transcriptional activity, suggesting a functional relationship between assembly, Mediator, and preinitiation complex (PIC) stability. Finally, our data help clarify the mechanisms governing the assembly and stability of RNA pol II.
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12
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Abstract
The Caenorhabditis elegans pRb ortholog, LIN-35, functions in a wide range of cellular and developmental processes. This includes a role of LIN-35 in nutrient utilization by the intestine, which it carries out redundantly with SLR-2, a zinc-finger protein. This and other redundant functions of LIN-35 were identified in genetic screens for mutations that display synthetic phenotypes in conjunction with loss of lin-35. To explore the intestinal role of LIN-35, we conducted a genome-wide RNA-interference-feeding screen for suppressors of lin-35; slr-2 early larval arrest. Of the 26 suppressors identified, 17 fall into three functional classes: (1) ribosome biogenesis genes, (2) mitochondrial prohibitins, and (3) chromatin regulators. Further characterization indicates that different categories of suppressors act through distinct molecular mechanisms. We also tested lin-35; slr-2 suppressors, as well as suppressors of the synthetic multivulval phenotype, to determine the spectrum of lin-35-synthetic phenotypes that could be suppressed following inhibition of these genes. We identified 19 genes, most of which are evolutionarily conserved, that can suppress multiple unrelated lin-35-synthetic phenotypes. Our study reveals a network of genes broadly antagonistic to LIN-35 as well as genes specific to the role of LIN-35 in intestinal and vulval development. Suppressors of multiple lin-35 phenotypes may be candidate targets for anticancer therapies. Moreover, screening for suppressors of phenotypically distinct synthetic interactions, which share a common altered gene, may prove to be a novel and effective approach for identifying genes whose activities are most directly relevant to the core functions of the shared gene.
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Beckouët F, Mariotte-Labarre S, Peyroche G, Nogi Y, Thuriaux P. Rpa43 and its partners in the yeast RNA polymerase I transcription complex. FEBS Lett 2011; 585:3355-9. [PMID: 21983101 DOI: 10.1016/j.febslet.2011.09.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Revised: 08/29/2011] [Accepted: 09/06/2011] [Indexed: 10/17/2022]
Abstract
An Rpa43/Rpa14 stalk protrudes from RNA polymerase I (RNAPI), with homology to Rpb7/Rpb4 (RNAPII), Rpc25/Rpc17 (RNAPIII) and RpoE/RpoF (archaea). In fungi and vertebrates, Rpa43 contains hydrophilic domains forming about half of its size, but these domains lack in Schizosaccharomyces pombe and most other eukaryote lineages. In Saccharomyces cerevisiae, they can be lost with little or no growth effect, as shown by deletion mapping and by domain swapping with fission yeast, but genetically interact with rpa12Δ, rpa34Δ or rpa49Δ, lacking non-essential subunits important for transcript elongation. Two-hybrid data and other genetic evidence suggest that Rpa43 directly bind Spt5, an RNAPI elongation factor also acting in RNAPII-dependent transcription, and may also interact with the nucleosomal chaperone Spt6.
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Affiliation(s)
- Frédéric Beckouët
- CEA, iBiTec-S, Service de Biologie Intégrative & Génétique Moléculaire, F-91191 Gif-sur-Yvette, France
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14
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Park SH, Nguyen TN, Kirkham JK, Lee JH, Günzl A. Transcription by the multifunctional RNA polymerase I in Trypanosoma brucei functions independently of RPB7. Mol Biochem Parasitol 2011; 180:35-42. [PMID: 21816181 DOI: 10.1016/j.molbiopara.2011.06.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/10/2011] [Accepted: 06/13/2011] [Indexed: 10/18/2022]
Abstract
Trypanosoma brucei has a multifunctional RNA polymerase (pol) I that transcribes ribosomal gene units (RRNA) and units encoding its major cell surface proteins variant surface glycoprotein (VSG) and procyclin. Previous analysis of tandem affinity-purified, transcriptionally active RNA pol I identified ten subunits including an apparently trypanosomatid-specific protein termed RPA31. Another ortholog was identified in silico. No orthologs of the yeast subunit doublet RPA43/RPA14 have been identified yet. Instead, a recent report presented evidence that RPB7, the RNA pol II paralog of RPA43, is an RNA pol I subunit and essential for RRNA and VSG transcription in bloodstream form trypanosomes [18]. Revisiting this attractive hypothesis, we were unable to detect a stable interaction between RPB7 and RNA pol I in either reciprocal co-immunoprecipitation or tandem affinity purification. Furthermore, immunodepletion of RPB7 from extract virtually abolished RNA pol II transcription in vitro but had no effect on RRNA or VSG ES promoter transcription in the same reactions. Accordingly, chromatin immunoprecipitation analysis revealed cross-linking of RPB7 to known RNA pol II transcription units but not to the VSG ES promoter or to the 18S rRNA coding region. Interestingly, RPB7 did crosslink to the RRNA promoter but so did the RNA pol II-specific subunit RPB9 suggesting that RNA pol II is recruited to this promoter. Overall, our data led to the conclusion that RNA pol I transcription in T. brucei does not require the RNA pol II subunit RPB7.
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Affiliation(s)
- Sung Hee Park
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030-6403, USA
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15
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Kuranda K, François J, Palamarczyk G. The isoprenoid pathway and transcriptional response to its inhibitors in the yeastSaccharomyces cerevisiae. FEMS Yeast Res 2010; 10:14-27. [DOI: 10.1111/j.1567-1364.2009.00560.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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16
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17
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Structure-function analysis of RNA polymerases I and III. Curr Opin Struct Biol 2009; 19:740-5. [PMID: 19896367 DOI: 10.1016/j.sbi.2009.10.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 09/04/2009] [Accepted: 10/08/2009] [Indexed: 11/20/2022]
Abstract
Recent advances in elucidating the structure of yeast Pol I and III are based on a combination of X-ray crystal analysis, electron microscopy and homology modelling. They allow a better comparison of the three eukaryotic nuclear RNA polymerases, underscoring the most obvious difference existing between the three enzymes, which lies in the existence of additional Pol-I-specific and Pol-III-specific subunits. Their location on the cognate RNA polymerases is now fairly well known, suggesting precise hypotheses as to their function in transcription during initiation, elongation, termination and/or reinitiation. Unexpectedly, even though Pol I and III, but not Pol II, have an intrinsic RNA cleavage activity, it was found that TFIIS Pol II cleavage stimulation factor also played a general role in Pol III transcription.
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18
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Ablasser A, Bauernfeind F, Hartmann G, Latz E, Fitzgerald KA, Hornung V. RIG-I-dependent sensing of poly(dA:dT) through the induction of an RNA polymerase III-transcribed RNA intermediate. Nat Immunol 2009; 10:1065-72. [PMID: 19609254 PMCID: PMC3878616 DOI: 10.1038/ni.1779] [Citation(s) in RCA: 669] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Accepted: 07/13/2009] [Indexed: 12/24/2022]
Abstract
RNA is sensed by Toll-like receptor 7 (TLR7) and TLR8 or by the RNA helicases LGP2, Mda5 and RIG-I to trigger antiviral responses. Much less is known about sensors for DNA. Here we identify a novel DNA-sensing pathway involving RNA polymerase III and RIG-I. In this pathway, AT-rich double-stranded DNA (dsDNA) served as a template for RNA polymerase III and was transcribed into double-stranded RNA (dsRNA) containing a 5'-triphosphate moiety. Activation of RIG-I by this dsRNA induced production of type I interferon and activation of the transcription factor NF-kappaB. This pathway was important in the sensing of Epstein-Barr virus-encoded small RNAs, which were transcribed by RNA polymerase III and then triggered RIG-I activation. Thus, RNA polymerase III and RIG-I are pivotal in sensing viral DNA.
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Affiliation(s)
- Andrea Ablasser
- Institute for Clinical Chemistry and Pharmacology, University of Bonn, 53127 Bonn, Germany
| | - Franz Bauernfeind
- Institute for Clinical Chemistry and Pharmacology, University of Bonn, 53127 Bonn, Germany
| | - Gunther Hartmann
- Institute for Clinical Chemistry and Pharmacology, University of Bonn, 53127 Bonn, Germany
| | - Eicke Latz
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Katherine A. Fitzgerald
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Veit Hornung
- Institute for Clinical Chemistry and Pharmacology, University of Bonn, 53127 Bonn, Germany
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19
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Ghavi-Helm Y, Michaut M, Acker J, Aude JC, Thuriaux P, Werner M, Soutourina J. Genome-wide location analysis reveals a role of TFIIS in RNA polymerase III transcription. Genes Dev 2008; 22:1934-47. [PMID: 18628399 DOI: 10.1101/gad.471908] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
TFIIS is a transcription elongation factor that stimulates transcript cleavage activity of arrested RNA polymerase II (Pol II). Recent studies revealed that TFIIS has also a role in Pol II transcription initiation. To improve our understanding of TFIIS function in vivo, we performed genome-wide location analysis of this factor. Under normal growth conditions, TFIIS was detected on Pol II-transcribed genes, and TFIIS occupancy was well correlated with that of Pol II, indicating that TFIIS recruitment is not restricted to NTP-depleted cells. Unexpectedly, TFIIS was also detected on almost all Pol III-transcribed genes. TFIIS and Pol III occupancies correlated well genome-wide on this novel class of targets. In vivo, some dst1 mutants were partly defective in tRNA synthesis and showed a reduced Pol III occupancy at the restrictive temperature. In vitro transcription assays suggested that TFIIS may affect Pol III start site selection. These data provide strong in vivo and in vitro evidence in favor of a role of TFIIS as a general Pol III transcription factor.
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20
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Cieśla M, Towpik J, Graczyk D, Oficjalska-Pham D, Harismendy O, Suleau A, Balicki K, Conesa C, Lefebvre O, Boguta M. Maf1 is involved in coupling carbon metabolism to RNA polymerase III transcription. Mol Cell Biol 2007; 27:7693-702. [PMID: 17785443 PMCID: PMC2169064 DOI: 10.1128/mcb.01051-07] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 07/04/2007] [Accepted: 08/23/2007] [Indexed: 12/29/2022] Open
Abstract
RNA polymerase III (Pol III) produces essential components of the biosynthetic machinery, and therefore its activity is tightly coupled with cell growth and metabolism. In the yeast Saccharomyces cerevisiae, Maf1 is the only known global and direct Pol III transcription repressor which mediates numerous stress signals. Here we demonstrate that transcription regulation by Maf1 is not limited to stress but is important for the switch between fermentation and respiration. Under respiratory conditions, Maf1 is activated by dephosphorylation and imported into the nucleus. The transition from a nonfermentable carbon source to that of glucose induces Maf1 phosphorylation and its relocation to the cytoplasm. The absence of Maf1-mediated control of tRNA synthesis impairs cell viability in nonfermentable carbon sources. The respiratory phenotype of maf1-Delta allowed genetic suppression studies to dissect the mechanism of Maf1 action on the Pol III transcription apparatus. Moreover, in cells grown in a nonfermentable carbon source, Maf1 regulates the levels of different tRNAs to various extents. The differences in regulation may contribute to the physiological role of Maf1.
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Affiliation(s)
- Małgorzata Cieśla
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
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21
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Lotan R, Goler-Baron V, Duek L, Haimovich G, Choder M. The Rpb7p subunit of yeast RNA polymerase II plays roles in the two major cytoplasmic mRNA decay mechanisms. ACTA ACUST UNITED AC 2007; 178:1133-43. [PMID: 17875743 PMCID: PMC2064649 DOI: 10.1083/jcb.200701165] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The steady-state level of mRNAs is determined by the balance between their synthesis by RNA polymerase II (Pol II) and their decay. In the cytoplasm, mRNAs are degraded by two major pathways; one requires decapping and 5′ to 3′ exonuclease activity and the other involves 3′ to 5′ degradation. Rpb7p is a Pol II subunit that shuttles between the nucleus and the cytoplasm. Here, we show that Rpb7p is involved in the two mRNA decay pathways and possibly couples them. Rpb7p stimulates the deadenylation stage required for execution of both pathways. Additionally, Rpb7p is both an active component of the P bodies, where decapping and 5′ to 3′ degradation occur, and is capable of affecting the P bodies function. Moreover, Rpb7p interacts with the decapping regulator Pat1p in a manner important for the mRNA decay machinery. Rpb7p is also involved in the second pathway, as it stimulates 3′ to 5′ degradation. Our genetic analyses suggest that Rpb7p plays two distinct roles in mRNA decay, which can both be uncoupled from Rpb7p's role in transcription. Thus, Rpb7p plays pivotal roles in determining mRNA levels.
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Affiliation(s)
- Rona Lotan
- Department of Molecular Microbiology, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
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22
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Naji S, Grünberg S, Thomm M. The RPB7 orthologue E' is required for transcriptional activity of a reconstituted archaeal core enzyme at low temperatures and stimulates open complex formation. J Biol Chem 2007; 282:11047-57. [PMID: 17311916 DOI: 10.1074/jbc.m611674200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RNA polymerases from Archaea and Eukaryotes consist of a core enzyme associated with a dimeric E'F (Rpb7/Rpb4) subcomplex but the functional contribution of the two subunit subcomplexes to the transcription process is poorly understood. Here we report the reconstitution of the 11-subunit RNA polymerase and of the core enzyme from the hyperthermophilic Archaeon Pyrococcus furiosus. The core enzyme showed significant activity between 70 and 80 degrees C but was almost inactive at 60 degrees C. E' stimulated the activity of the core enzyme at 60 degrees C, dramatically suggesting an important role of this subunit at low growth temperatures. Subunit F did not contribute significantly to catalytic activity. Permanganate footprinting at low temperatures dissected the contributions of the core enzyme, subunit E', and of archaeal TFE to open complex formation. Opening in the -2 and -4 region could be achieved by the core enzyme, subunit E' stimulated bubble formation in general and opening at the upstream end of the transcription bubble was preferably stimulated by TFE. Analyses of the kinetic stabilities of open complexes revealed an unexpected E'-independent role of TFE in the stabilization of open complexes.
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Affiliation(s)
- Souad Naji
- Lehrstuhl für Mikrobiologie und Archaeenzentrum, Universität Regensburg, 93053 Regensburg, Germany
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23
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Zaros C, Briand JF, Boulard Y, Labarre-Mariotte S, Garcia-Lopez MC, Thuriaux P, Navarro F. Functional organization of the Rpb5 subunit shared by the three yeast RNA polymerases. Nucleic Acids Res 2006; 35:634-47. [PMID: 17179178 PMCID: PMC1802627 DOI: 10.1093/nar/gkl686] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 07/30/2006] [Accepted: 09/07/2006] [Indexed: 12/05/2022] Open
Abstract
Rpb5, a subunit shared by the three yeast RNA polymerases, combines a eukaryotic N-terminal module with a globular C-end conserved in all non-bacterial enzymes. Conditional and lethal mutants of the moderately conserved eukaryotic module showed that its large N-terminal helix and a short motif at the end of the module are critical in vivo. Lethal or conditional mutants of the C-terminal globe altered the binding of Rpb5 to Rpb1-beta25/26 (prolonging the Bridge helix) and Rpb1-alpha44/47 (ahead of the Switch 1 loop and binding Rpb5 in a two-hybrid assay). The large intervening segment of Rpb1 is held across the DNA Cleft by Rpb9, consistent with the synergy observed for rpb5 mutants and rpb9Delta or its RNA polymerase I rpa12Delta counterpart. Rpb1-beta25/26, Rpb1-alpha44/45 and the Switch 1 loop were only found in Rpb5-containing polymerases, but the Bridge and Rpb1-alpha46/47 helix bundle were universally conserved. We conclude that the main function of the dual Rpb5-Rpb1 binding and the Rpb9-Rpb1 interaction is to hold the Bridge helix, the Rpb1-alpha44/47 helix bundle and the Switch 1 loop into a closely packed DNA-binding fold around the transcription bubble, in an organization shared by the two other nuclear RNA polymerases and by the archaeal and viral enzymes.
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Affiliation(s)
- Cécile Zaros
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - Jean-François Briand
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - Yves Boulard
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - Sylvie Labarre-Mariotte
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - M. Carmen Garcia-Lopez
- Department Biología Experimental—Area de Genética (ED.B3) Universidad de Jaén Paraje lasLagunillas E-23071 Jaén, SPAIN
| | - Pierre Thuriaux
- Service de Biochimie & Génétique Moléculaire.Bâtiment 144 CEA-Saclay, F-91191, Gif-sur-Yvette, CEDEX, France
| | - Francisco Navarro
- Department Biología Experimental—Area de Genética (ED.B3) Universidad de Jaén Paraje lasLagunillas E-23071 Jaén, SPAIN
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24
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Selitrennik M, Duek L, Lotan R, Choder M. Nucleocytoplasmic shuttling of the Rpb4p and Rpb7p subunits of Saccharomyces cerevisiae RNA polymerase II by two pathways. EUKARYOTIC CELL 2006; 5:2092-103. [PMID: 17056745 PMCID: PMC1694818 DOI: 10.1128/ec.00288-06] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Rpb4p and Rpb7p are subunits of the RNA polymerase II of Saccharomyces cerevisiae that form a dissociable heterodimeric complex. Whereas the only reported function of Rpb7p is related to transcription, Rpb4p has been found to also act in mRNA export and in the major mRNA decay pathway that operates in the cytoplasm, thus raising the possibility that Rpb4p links between the nuclear and cytoplasmic processes. Here we show that both Rpb4p and Rpb7p shuttle between the nucleus and the cytoplasm. Shuttling kinetics of the two proteins are similar as long as their interaction is possible, suggesting that they shuttle as a heterodimer. Under normal conditions, shuttling of Rpb4p and Rpb7p depends on ongoing transcription. However, during severe stresses of heat shock, ethanol, and starvation, the two proteins shuttle via a transcription-independent pathway. Thus, Rpb4p and Rpb7p shuttle via two pathways, depending on environmental conditions.
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Affiliation(s)
- Michael Selitrennik
- Department of Molecular Microbiology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel 31096
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25
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Jasiak AJ, Armache KJ, Martens B, Jansen RP, Cramer P. Structural biology of RNA polymerase III: subcomplex C17/25 X-ray structure and 11 subunit enzyme model. Mol Cell 2006; 23:71-81. [PMID: 16818233 DOI: 10.1016/j.molcel.2006.05.013] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 04/27/2006] [Accepted: 05/08/2006] [Indexed: 01/22/2023]
Abstract
We obtained an 11 subunit model of RNA polymerase (Pol) III by combining a homology model of the nine subunit core enzyme with a new X-ray structure of the subcomplex C17/25. Compared to Pol II, Pol III shows a conserved active center for RNA synthesis but a structurally different upstream face for specific initiation complex assembly during promoter selection. The Pol III upstream face includes a HRDC domain in subunit C17 that is translated by 35 A and rotated by 150 degrees compared to its Pol II counterpart. The HRDC domain is essential in vivo, folds independently in vitro, and, unlike other HRDC domains, shows no indication of nucleic acid binding. Thus, the HRDC domain is a functional module that could account for the role of C17 in Pol III promoter-specific initiation. During elongation, C17/25 may bind Pol III transcripts emerging from the adjacent exit pore, because the subcomplex binds to tRNA in vitro.
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Affiliation(s)
- Anna J Jasiak
- Department of Chemistry and Biochemistry, Gene Center, Ludwig-Maximilians-University of Munich, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
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26
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Proshkina GM, Shematorova EK, Proshkin SA, Zaros C, Thuriaux P, Shpakovski GV. Ancient origin, functional conservation and fast evolution of DNA-dependent RNA polymerase III. Nucleic Acids Res 2006; 34:3615-24. [PMID: 16877568 PMCID: PMC1540719 DOI: 10.1093/nar/gkl421] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
RNA polymerase III contains seventeen subunits in yeasts (Saccharomyces cerevisiae and Schizosaccharomyces pombe) and in human cells. Twelve of them are akin to the core RNA polymerase I or II. The five other are RNA polymerase III-specific and form the functionally distinct groups Rpc31-Rpc34-Rpc82 and Rpc37-Rpc53. Currently sequenced eukaryotic genomes revealed significant homology to these seventeen subunits in Fungi, Animals, Plants and Amoebozoans. Except for subunit Rpc31, this also extended to the much more distantly related genomes of Alveolates and Excavates, indicating that the complex subunit organization of RNA polymerase III emerged at a very early stage of eukaryotic evolution. The Sch.pombe subunits were expressed in S.cerevisiae null mutants and tested for growth. Ten core subunits showed heterospecific complementation, but the two largest catalytic subunits (Rpc1 and Rpc2) and all five RNA polymerase III-specific subunits (Rpc82, Rpc53, Rpc37, Rpc34 and Rpc31) were non-functional. Three highly conserved RNA polymerase III-specific domains were found in the twelve-subunit core structure. They correspond to the Rpc17-Rpc25 dimer, involved in transcription initiation, to an N-terminal domain of the largest subunit Rpc1 important to anchor Rpc31, Rpc34 and Rpc82, and to a C-terminal domain of Rpc1 that presumably holds Rpc37, Rpc53 and their Rpc11 partner.
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Affiliation(s)
| | | | | | - Cécile Zaros
- Laboratoire de Physiogénomique, Service de Biochimie & Génétique MoléculaireBâtiment 144, CEA/Saclay, F-91191 Gif-sur-Yvette, cedex, France
| | - Pierre Thuriaux
- Laboratoire de Physiogénomique, Service de Biochimie & Génétique MoléculaireBâtiment 144, CEA/Saclay, F-91191 Gif-sur-Yvette, cedex, France
- Correspondence may also be addressed to Pierre Thuriaux. Tel: 33 1 69 08 35 86; Fax: 33 1 69 08 47 12;
| | - George V. Shpakovski
- To whom correspondence should be addressed. Tel: +7 495 3306583; Fax: +7 495 3357103;
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