1
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Shekhar AC, Wu WJ, Chen HT. Mutational and biophysical analyses reveal a TFIIIC binding region in the TFIIF-related Rpc53 subunit of RNA polymerase III. J Biol Chem 2023; 299:104859. [PMID: 37230389 PMCID: PMC10404625 DOI: 10.1016/j.jbc.2023.104859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/27/2023] Open
Abstract
The TFIIF-like Rpc53/Rpc37 heterodimer of RNA polymerase (pol) III is involved in various stages of transcription. The C-terminal region of Rpc53 dimerizes with Rpc37 to anchor on the lobe domain of the pol III cleft. However, structural and functional features of the Rpc53 N-terminal region had not been characterized previously. Here, we conducted site-directed alanine replacement mutagenesis on the Rpc53 N-terminus, generating yeast strains that exhibited a cold-sensitive growth defect and severely compromised pol III transcriptional activity. Circular dichroism and NMR spectroscopy revealed a highly disordered 57-amino acid polypeptide in the Rpc53 N-terminus. This polypeptide is a versatile protein-binding module displaying nanomolar-level binding affinities for Rpc37 and the Tfc4 subunit of the transcription initiation factor TFIIIC. Accordingly, we denote this Rpc53 N-terminus polypeptide as the TFIIIC-binding region or CBR. Alanine replacements in the CBR significantly reduced its binding affinity for Tfc4, highlighting its functional importance to cell growth and transcription in vitro. Our study reveals the functional basis for Rpc53's CBR in assembly of the pol III transcription initiation complex.
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Affiliation(s)
- Arvind Chandra Shekhar
- Molecular and Cell Biology, Taiwan International Graduate Program, Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, R.O.C.; Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, R.O.C
| | - Wen-Jin Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, R.O.C
| | - Hung-Ta Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, R.O.C..
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2
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Shekhar AC, Sun YE, Khoo SK, Lin YC, Malau E, Chang WH, Chen HT. Site-directed biochemical analyses reveal that the switchable C-terminus of Rpc31 contributes to RNA polymerase III transcription initiation. Nucleic Acids Res 2023; 51:4223-4236. [PMID: 36484109 PMCID: PMC10201443 DOI: 10.1093/nar/gkac1163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/14/2022] [Accepted: 11/23/2022] [Indexed: 08/23/2023] Open
Abstract
Rpc31 is a subunit in the TFIIE-related Rpc82/34/31 heterotrimeric subcomplex of Saccharomyces cerevisiae RNA polymerase III (pol III). Structural analyses of pol III have indicated that the N-terminal region of Rpc31 anchors on Rpc82 and further interacts with the polymerase core and stalk subcomplex. However, structural and functional information for the C-terminal region of Rpc31 is sparse. We conducted a mutational analysis on Rpc31, which uncovered a functional peptide adjacent to the highly conserved Asp-Glu-rich acidic C-terminus. This C-terminal peptide region, termed 'pre-acidic', is important for optimal cell growth, tRNA synthesis, and stable association of Rpc31 in the pre-initiation complex (PIC). Our site-directed photo-cross-linking to map protein interactions within the PIC reveal that this pre-acidic region specifically targets Rpc34 during transcription initiation, but also interacts with the DNA entry surface in free pol III. Thus, we have uncovered a switchable Rpc31 C-terminal region that functions in an initiation-specific protein interaction for pol III transcription.
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Affiliation(s)
| | - Yuan-En Sun
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, R.O.C
| | - Seok-Kooi Khoo
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, R.O.C
| | - Yu-Chun Lin
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, R.O.C
| | | | - Wei-Hau Chang
- Institute of Chemistry, Academia Sinica, Taiwan, R.O.C
| | - Hung-Ta Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, R.O.C
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3
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Knockdown NRPC2, 3, 8, NRPABC1 and NRPABC2 Affects RNAPIII Activity and Disrupts Seed Development in Arabidopsis. Int J Mol Sci 2021; 22:ijms222111314. [PMID: 34768744 PMCID: PMC8583208 DOI: 10.3390/ijms222111314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/16/2022] Open
Abstract
RNA polymerase III (RNAPIII) contains 17 subunits forming 4 functional domains that control the different stages of RNAPIII transcription and are dedicated to the synthesis of small RNAs such as 5S rRNA and tRNAs. Here, we identified 23 genes encoding these subunits in Arabidopsis (Arabidopsis thaliana) and further analyzed 5 subunits (NRPC2, NRPC3, NRPC8, NRPABC1, and NRPABC2) encoded by 6 genes with different expression patterns and belonging to different sub-complexes. The knockdown of these genes repressed the expression of 5S rRNA and tRNAs, causing seed developmental arrest at different stages. Among these knockdown mutants, RNA-seq analysis revealed 821 common differentially expressed genes (DEGs), significantly enriched in response to stress, abscisic acid, cytokinins, and the jasmonic acid signaling pathway. Weighted gene co-expression network analysis (WGCNA) revealed several hub genes involved in embryo development, carbohydrate metabolic and lipid metabolic processes. We identified numerous unique DEGs between the mutants belonging to pathways, including cell proliferation, ribosome biogenesis, cell death, and tRNA metabolic processes. Thus, NRPC2, NRPC3, NRPC8, NRPABC1, and NRPABC2 control seed development in Arabidopsis by influencing RNAPIII activity and, thus, hormone signaling. Reduced expression of these subunit genes causes an insufficient accumulation of the total RNAPIII, leading to the phenotypes observed following the genetic knockdown of these subunits.
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4
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Participation of TFIIIB Subunit Brf1 in Transcription Regulation in the Human Pathogen Leishmania major. Genes (Basel) 2021; 12:genes12020280. [PMID: 33669344 PMCID: PMC7920299 DOI: 10.3390/genes12020280] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/02/2021] [Accepted: 02/11/2021] [Indexed: 12/24/2022] Open
Abstract
In yeast and higher eukaryotes, transcription factor TFIIIB is required for accurate initiation of transcription by RNA Polymerase III (Pol III), which synthesizes transfer RNAs (tRNAs), 5S ribosomal RNA (rRNA), and other essential RNA molecules. TFIIIB is composed of three subunits: B double prime 1 (Bdp1), TATA-binding protein (TBP), and TFIIB-related factor 1 (Brf1). Here, we report the molecular characterization of Brf1 in Leishmania major (LmBrf1), a parasitic protozoan that shows distinctive transcription characteristics, including the apparent absence of Pol III general transcription factors TFIIIA and TFIIIC. Although single-knockout parasites of LmBrf1 were obtained, attempts to generate LmBrf1-null mutants were unsuccessful, which suggests that LmBrf1 is essential in promastigotes of L. major. Notably, Northern blot analyses showed that the half-lives of the messenger RNAs (mRNAs) from LmBrf1 and other components of the Pol III transcription machinery (Bdp1 and Pol III subunit RPC1) are very similar (~40 min). Stabilization of these transcripts was observed in stationary-phase parasites. Chromatin immunoprecipitation (ChIP) experiments showed that LmBrf1 binds to tRNA, small nuclear RNA (snRNA), and 5S rRNA genes. Unexpectedly, the results also indicated that LmBrf1 associates to the promoter region of the 18S rRNA genes and to three Pol II-dependent regions here analyzed. Tandem affinity purification and mass spectrometry analyses allowed the identification of a putative TFIIIC subunit. Moreover, several proteins involved in transcription by all three RNA polymerases co-purified with the tagged version of LmBrf1.
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5
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Yamada N, Rossi MJ, Farrell N, Pugh BF, Mahony S. Alignment and quantification of ChIP-exo crosslinking patterns reveal the spatial organization of protein-DNA complexes. Nucleic Acids Res 2020; 48:11215-11226. [PMID: 32747934 PMCID: PMC7672471 DOI: 10.1093/nar/gkaa618] [Citation(s) in RCA: 2] [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: 12/09/2019] [Revised: 06/25/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022] Open
Abstract
The ChIP-exo assay precisely delineates protein-DNA crosslinking patterns by combining chromatin immunoprecipitation with 5' to 3' exonuclease digestion. Within a regulatory complex, the physical distance of a regulatory protein to DNA affects crosslinking efficiencies. Therefore, the spatial organization of a protein-DNA complex could potentially be inferred by analyzing how crosslinking signatures vary between its subunits. Here, we present a computational framework that aligns ChIP-exo crosslinking patterns from multiple proteins across a set of coordinately bound regulatory regions, and which detects and quantifies protein-DNA crosslinking events within the aligned profiles. By producing consistent measurements of protein-DNA crosslinking strengths across multiple proteins, our approach enables characterization of relative spatial organization within a regulatory complex. Applying our approach to collections of ChIP-exo data, we demonstrate that it can recover aspects of regulatory complex spatial organization at yeast ribosomal protein genes and yeast tRNA genes. We also demonstrate the ability to quantify changes in protein-DNA complex organization across conditions by applying our approach to analyze Drosophila Pol II transcriptional components. Our results suggest that principled analyses of ChIP-exo crosslinking patterns enable inference of spatial organization within protein-DNA complexes.
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Affiliation(s)
- Naomi Yamada
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Matthew J Rossi
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Nina Farrell
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - B Franklin Pugh
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Shaun Mahony
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
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6
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Fu C, Liu X, Li X, Huo P, Ge J, Hou Y, Yang W, Zhang J, Zhang L, Zhao D, Ma C, Liu J. BRF Negatively Regulates Thermotolerance Defect of fes1a in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2020; 11:171. [PMID: 32210987 PMCID: PMC7077510 DOI: 10.3389/fpls.2020.00171] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
FES1A is a heat shock protein 70 binding protein. Mutation of FES1A leads to a defect in thermotolerance of Arabidopsis; however, independent fes1a mutants exhibit a range in the extent of thermosensitivity. Here, we found that BRF2, a gene adjacent to FES1A and encoding a component of transcription factor IIIB, affects the thermosensitivity of fes1a mutants. Knockout of BRF2 suppressed fes1a thermosensitivity, while overexpression of BRF2 increased thermosensitivity of fes1a. BRF2 in fes1a mutants regulates the transcriptional strength of RNA Polymerase II and accumulation of heat shock proteins and eventually affects the thermotolerance of fes1a. There is a cross-talking between RNA Pol III and Pol II. The cross-talking is initiated by BRF, magnified by the mutation of FES1A, and finally has an effect on thermotolerance.
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Affiliation(s)
- Can Fu
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Xiaxia Liu
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Xuezhi Li
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Panfei Huo
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jingjing Ge
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Yanfei Hou
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Wenwen Yang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jingxia Zhang
- Cotton Research Center, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Limin Zhang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Dazhong Zhao
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Changle Ma
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jian Liu
- College of Life Sciences, Shandong Normal University, Jinan, China
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7
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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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8
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Multiple direct interactions of TBP with the MYC oncoprotein. Nat Struct Mol Biol 2019; 26:1035-1043. [DOI: 10.1038/s41594-019-0321-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 09/25/2019] [Indexed: 01/07/2023]
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9
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Khoo SK, Wu CC, Lin YC, Chen HT. The TFIIE-related Rpc82 subunit of RNA polymerase III interacts with the TFIIB-related transcription factor Brf1 and the polymerase cleft for transcription initiation. Nucleic Acids Res 2019; 46:1157-1166. [PMID: 29177422 PMCID: PMC5814912 DOI: 10.1093/nar/gkx1179] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 11/16/2017] [Indexed: 11/13/2022] Open
Abstract
Rpc82 is a TFIIE-related subunit of the eukaryotic RNA polymerase III (pol III) complex. Rpc82 contains four winged-helix (WH) domains and a C-terminal coiled-coil domain. Structural resolution of the pol III complex indicated that Rpc82 anchors on the clamp domain of the pol III cleft to interact with the duplex DNA downstream of the transcription bubble. However, whether Rpc82 interacts with a transcription factor is still not known. Here, we report that a structurally disordered insertion in the third WH domain of Rpc82 is important for cell growth and in vitro transcription activity. Site-specific photo-crosslinking analysis indicated that the WH3 insertion interacts with the TFIIB-related transcription factor Brf1 within the pre-initiation complex (PIC). Moreover, crosslinking and hydroxyl radical probing analyses revealed Rpc82 interactions with the upstream DNA and the protrusion and wall domains of the pol III cleft. Our genetic and biochemical analyses thus provide new molecular insights into the function of Rpc82 in pol III transcription.
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Affiliation(s)
- Seok-Kooi Khoo
- Institute of Molecular Biology, Academia Sinica, 128 Sec. 2 Academia Rd., Taipei 115, Taiwan, R.O.C
| | - Chih-Chien Wu
- Institute of Molecular Biology, Academia Sinica, 128 Sec. 2 Academia Rd., Taipei 115, Taiwan, R.O.C
| | - Yu-Chun Lin
- Institute of Molecular Biology, Academia Sinica, 128 Sec. 2 Academia Rd., Taipei 115, Taiwan, R.O.C
| | - Hung-Ta Chen
- Institute of Molecular Biology, Academia Sinica, 128 Sec. 2 Academia Rd., Taipei 115, Taiwan, R.O.C
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10
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Román-Carraro FC, Florencio-Martínez LE, Romero-Meza G, Nepomuceno-Mejía T, Carrero JC, Arroyo R, Ortega-López J, Manning-Cela RG, Martínez-Calvillo S. TFIIIB Subunit Bdp1 Participates in RNA Polymerase III Transcription in the Protozoan Parasite Leishmania major. BIOMED RESEARCH INTERNATIONAL 2019; 2019:1425281. [PMID: 31058184 PMCID: PMC6463643 DOI: 10.1155/2019/1425281] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 03/13/2019] [Indexed: 01/03/2023]
Abstract
Leishmania major, a protozoan parasite that diverged early from the main eukaryotic lineage, exhibits unusual mechanisms of gene expression. Little is known in this organism about the transcription factors involved in the synthesis of tRNA, 5S rRNA, and snRNAs, transcribed by RNA Polymerase III (Pol III). Here we identify and characterize the TFIIIB subunit Bdp1 in L. major (LmBdp1). Bdp1 plays key roles in Pol III transcription initiation in other organisms, as it participates in Pol III recruitment and promoter opening. In silico analysis showed that LmBdp1 contains the typical extended SANT domain as well as other Bdp1 conserved regions. Nevertheless, LmBdp1 also displays distinctive features, including the presence of only one aromatic residue in the N-linker region. We were not able to produce null mutants of LmBdp1 by homologous recombination, as the obtained double replacement cell line contained an extra copy of LmBdp1, indicating that LmBdp1 is essential for the viability of L. major promastigotes. Notably, the mutant cell line showed reduced levels of the LmBdp1 protein, and its growth was significantly decreased in relation to wild-type cells. Nuclear run-on assays demonstrated that Pol III transcription was affected in the mutant cell line, and ChIP experiments showed that LmBdp1 binds to 5S rRNA, tRNA, and snRNA genes. Thus, our results indicate that LmBdp1 is an essential protein required for Pol III transcription in L. major.
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Affiliation(s)
- Fiordaliso C. Román-Carraro
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
| | - Luis E. Florencio-Martínez
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
| | - Gabriela Romero-Meza
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
| | - Tomás Nepomuceno-Mejía
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
| | - Julio C. Carrero
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, CP 04510, Mexico
| | - Rossana Arroyo
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Ciudad de México, CP 07360, Mexico
| | - Jaime Ortega-López
- Departamento de Biotecnología y Bioingeniería, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Ciudad de México, CP 07360, Mexico
| | - Rebeca G. Manning-Cela
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Ciudad de México, CP 07360, Mexico
| | - Santiago Martínez-Calvillo
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Col. Los Reyes Iztacala, Tlalnepantla, Estado de México, CP 54090, Mexico
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11
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Mishra S, Maraia RJ. RNA polymerase III subunits C37/53 modulate rU:dA hybrid 3' end dynamics during transcription termination. Nucleic Acids Res 2019; 47:310-327. [PMID: 30407541 PMCID: PMC6326807 DOI: 10.1093/nar/gky1109] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/22/2018] [Indexed: 12/18/2022] Open
Abstract
RNA polymerase (RNAP) III synthesizes tRNAs and other transcripts, and mutations to its subunits cause human disorders. The RNAP III subunit-heterodimer C37/53 functions in initiation, elongation and in termination-associated reinitiation with subunit C11. C37/53 is related to heterodimers associated with RNAPs I and II, and C11 is related to TFIIS and Rpa12.2, the active site RNA 3' cleavage factors for RNAPs II and I. Critical to termination is stability of the RNA:DNA hybrid bound in the active center, which is loose for RNAP III relative to other RNAPs. Here, we examined RNAP III lacking C37/53/C11 and various reconstituted forms during termination. First, we established a minimal terminator as 5T and 3A on the non-template and template DNA strands, respectively. We demonstrate that C11 stimulates termination, and does so independently of its RNA cleavage activity. We found that C37/53 sensitizes RNAP III termination to RNA:DNA hybrid strength and promotes RNA 3' end pairing/annealing with the template. The latter counteracts C11-insensitive arrest in the proximal part of the oligo(T)-tract, promoting oligo(rU:dA) extension toward greater hybrid instability and RNA release. The data also indicate that RNA 3' end engagement with the active site is a determinant of termination. Broader implications are also discussed.
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Affiliation(s)
- Saurabh Mishra
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Richard J Maraia
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
- Commissioned Corps, U.S. Public Health Service, Rockville, MD 20852, USA
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12
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Greber BJ, Nogales E. The Structures of Eukaryotic Transcription Pre-initiation Complexes and Their Functional Implications. Subcell Biochem 2019; 93:143-192. [PMID: 31939151 DOI: 10.1007/978-3-030-28151-9_5] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Transcription is a highly regulated process that supplies living cells with coding and non-coding RNA molecules. Failure to properly regulate transcription is associated with human pathologies, including cancers. RNA polymerase II is the enzyme complex that synthesizes messenger RNAs that are then translated into proteins. In spite of its complexity, RNA polymerase requires a plethora of general transcription factors to be recruited to the transcription start site as part of a large transcription pre-initiation complex, and to help it gain access to the transcribed strand of the DNA. This chapter reviews the structure and function of these eukaryotic transcription pre-initiation complexes, with a particular emphasis on two of its constituents, the multisubunit complexes TFIID and TFIIH. We also compare the overall architecture of the RNA polymerase II pre-initiation complex with those of RNA polymerases I and III, involved in transcription of ribosomal RNA and non-coding RNAs such as tRNAs and snRNAs, and discuss the general, conserved features that are applicable to all eukaryotic RNA polymerase systems.
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Affiliation(s)
- Basil J Greber
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA.
- Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Eva Nogales
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA
- Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
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13
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Structural visualization of RNA polymerase III transcription machineries. Cell Discov 2018; 4:40. [PMID: 30083386 PMCID: PMC6066478 DOI: 10.1038/s41421-018-0044-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 06/04/2018] [Accepted: 06/06/2018] [Indexed: 12/19/2022] Open
Abstract
RNA polymerase III (Pol III) transcription initiation requires the action of the transcription factor IIIB (TFIIIB) and is highly regulated. Here, we determine the structures of Pol III pre-initiation complexes (PICs) using single particle cryo-electron microscopy (cryo-EM). We observe stable Pol III-TFIIIB complexes using nucleic acid scaffolds mimicking various functional states, in which TFIIIB tightly encircles the upstream promoter DNA. There is an intricate interaction between TFIIIB and Pol III, which stabilizes the winged-helix domains of the C34 subunit of Pol III over the active site cleft. The architecture of Pol III PIC more resembles that of the Pol II PIC than the Pol I PIC. In addition, we also obtain a 3D reconstruction of Pol III in complex with TFIIIB using the elongation complex (EC) scaffold, shedding light on the mechanism of facilitated recycling of Pol III prior to transcription re-initiation.
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14
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Engel C, Neyer S, Cramer P. Distinct Mechanisms of Transcription Initiation by RNA Polymerases I and II. Annu Rev Biophys 2018; 47:425-446. [DOI: 10.1146/annurev-biophys-070317-033058] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA polymerases I and II (Pol I and Pol II) are the eukaryotic enzymes that catalyze DNA-dependent synthesis of ribosomal RNA and messenger RNA, respectively. Recent work shows that the transcribing forms of both enzymes are similar and the fundamental mechanisms of RNA chain elongation are conserved. However, the mechanisms of transcription initiation and its regulation differ between Pol I and Pol II. Recent structural studies of Pol I complexes with transcription initiation factors provided insights into how the polymerase recognizes its specific promoter DNA, how it may open DNA, and how initiation may be regulated. Comparison with the well-studied Pol II initiation system reveals a distinct architecture of the initiation complex and visualizes promoter- and gene-class-specific aspects of transcription initiation. On the basis of new structural studies, we derive a model of the Pol I transcription cycle and provide a molecular movie of Pol I transcription that can be used for teaching.
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Affiliation(s)
- Christoph Engel
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Current affiliation: Institute of Biochemistry, Genetics and Microbiology, University of Regensburg, 93053 Regensburg, Germany
| | - Simon Neyer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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15
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Molecular mechanism of promoter opening by RNA polymerase III. Nature 2018; 553:295-300. [PMID: 29345638 PMCID: PMC5777638 DOI: 10.1038/nature25440] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/08/2017] [Indexed: 01/03/2023]
Abstract
RNA polymerase III (Pol III) assembles together with transcription factor IIIB (TFIIIB) on different promoter types to initiate the transcription of small, structured RNAs. Here, we present structures of Pol III pre-initiation complexes comprising the 17-subunit Pol III and hetero-trimeric transcription factor TFIIIB with subunits TATA-binding protein (TBP), B-related factor 1 (Brf1) and B double prime 1 (Bdp1) bound to a natural promoter in different functional states. Electron cryo-microscopy (cryo-EM) reconstructions varying from 3.7 Å to 5.5 Å resolution include two early intermediates in which the DNA duplex is closed, an open DNA complex and an initially transcribing complex with RNA in the active site. Our structures reveal an extremely tight and multivalent interaction of TFIIIB with promoter DNA and explain how TFIIIB recruits Pol III. TFIIIB and Pol III subunit C37 together activate the intrinsic transcription factor-like activity of the Pol III-specific heterotrimer to initiate melting of double-stranded DNA in a mechanism similar as used in the Pol II system.
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16
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Ramsay EP, Vannini A. Structural rearrangements of the RNA polymerase III machinery during tRNA transcription initiation. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:285-294. [PMID: 29155071 DOI: 10.1016/j.bbagrm.2017.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/07/2017] [Accepted: 11/11/2017] [Indexed: 01/03/2023]
Abstract
RNA polymerase III catalyses the synthesis of tRNAs in eukaryotic organisms. Through combined biochemical and structural characterisation, multiple auxiliary factors have been identified alongside RNA Polymerase III as critical in both facilitating and regulating transcription. Together, this machinery forms dynamic multi-protein complexes at tRNA genes which are required for polymerase recruitment, DNA opening and initiation and elongation of the tRNA transcripts. Central to the function of these complexes is their ability to undergo multiple conformational changes and rearrangements that regulate each step. Here, we discuss the available biochemical and structural data on the structural plasticity of multi-protein complexes involved in RNA Polymerase III transcriptional initiation and facilitated re-initiation during tRNA synthesis. Increasingly, structural information is becoming available for RNA polymerase III and its functional complexes, allowing for a deeper understanding of tRNA transcriptional initiation. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena.
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MESH Headings
- Animals
- Eukaryotic Cells/metabolism
- Humans
- Models, Genetic
- Multiprotein Complexes/metabolism
- Promoter Regions, Genetic/genetics
- Protein Subunits
- RNA Polymerase III/chemistry
- RNA Polymerase III/metabolism
- RNA, Transfer/biosynthesis
- RNA, Transfer/genetics
- RNA, Transfer, Amino Acid-Specific/biosynthesis
- RNA, Transfer, Amino Acid-Specific/genetics
- Transcription Elongation, Genetic
- Transcription Factors/genetics
- Transcription Initiation, Genetic
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17
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Functions of the TFIIE-Related Tandem Winged-Helix Domain of Rpc34 in RNA Polymerase III Initiation and Elongation. Mol Cell Biol 2018; 38:MCB.00105-17. [PMID: 29180511 DOI: 10.1128/mcb.00105-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 11/22/2017] [Indexed: 12/18/2022] Open
Abstract
Rpc34 is a subunit of the Rpc82/34/31 subcomplex residing on the DNA-binding cleft of RNA polymerase (Pol) III. Rpc34 contains a structurally flexible N-terminal tandem winged-helix (tWH) domain related to the TFIIE transcription factor. While the second WH (WH2) fold of the tWH domain is known to function in DNA melting activity during transcription initiation, the functional role of the WH1 fold is unknown. In this study, we generated a series of new Rpc34 tWH mutants conferring a cold-sensitive growth phenotype. We found that the tWH mutations severely compromised in vitro transcription activity due to destabilization of the preinitiation complex (PIC). Site-specific protein photo-cross-linking analysis indicated that the tWH domain persistently interacts with protein subunits of the Pol III cleft in the PIC and the ternary elongation complex (TEC). Furthermore, purified Pol III proteins with tWH mutations also showed reduced efficiency in RNA elongation. Our study results suggest that the tWH domain is an important protein module above the Pol III cleft that integrates protein and nucleic acid interactions for initiation and elongation.
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18
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Willis IM, Moir RD. Signaling to and from the RNA Polymerase III Transcription and Processing Machinery. Annu Rev Biochem 2018; 87:75-100. [PMID: 29328783 DOI: 10.1146/annurev-biochem-062917-012624] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA polymerase (Pol) III has a specialized role in transcribing the most abundant RNAs in eukaryotic cells, transfer RNAs (tRNAs), along with other ubiquitous small noncoding RNAs, many of which have functions related to the ribosome and protein synthesis. The high energetic cost of producing these RNAs and their central role in protein synthesis underlie the robust regulation of Pol III transcription in response to nutrients and stress by growth regulatory pathways. Downstream of Pol III, signaling impacts posttranscriptional processes affecting tRNA function in translation and tRNA cleavage into smaller fragments that are increasingly attributed with novel cellular activities. In this review, we consider how nutrients and stress control Pol III transcription via its factors and its negative regulator, Maf1. We highlight recent work showing that the composition of the tRNA population and the function of individual tRNAs is dynamically controlled and that unrestrained Pol III transcription can reprogram central metabolic pathways.
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Affiliation(s)
- Ian M Willis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA; , .,Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Robyn D Moir
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA; ,
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19
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Liu Q, Wang J, Zhao Y, Li CI, Stengel KR, Acharya P, Johnston G, Hiebert SW, Shyr Y. Identification of active miRNA promoters from nuclear run-on RNA sequencing. Nucleic Acids Res 2017; 45:e121. [PMID: 28460090 PMCID: PMC5737662 DOI: 10.1093/nar/gkx318] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 04/13/2017] [Indexed: 12/27/2022] Open
Abstract
The genome-wide identification of microRNA transcription start sites (miRNA TSSs) is essential for understanding how miRNAs are regulated in development and disease. In this study, we developed mirSTP (mirna transcription Start sites Tracking Program), a probabilistic model for identifying active miRNA TSSs from nascent transcriptomes generated by global run-on sequencing (GRO-seq) and precision run-on sequencing (PRO-seq). MirSTP takes advantage of characteristic bidirectional transcription signatures at active TSSs in GRO/PRO-seq data, and provides accurate TSS prediction for human intergenic miRNAs at a high resolution. MirSTP performed better than existing generalized and experiment specific methods, in terms of the enrichment of various promoter-associated marks. MirSTP analysis of 27 human cell lines in 183 GRO-seq and 28 PRO-seq experiments identified TSSs for 480 intergenic miRNAs, indicating a wide usage of alternative TSSs. By integrating predicted miRNA TSSs with matched ENCODE transcription factor (TF) ChIP-seq data, we connected miRNAs into the transcriptional circuitry, which provides a valuable source for understanding the complex interplay between TF and miRNA. With mirSTP, we not only predicted TSSs for 72 miRNAs, but also identified 12 primary miRNAs with significant RNA polymerase pausing alterations after JQ1 treatment; each miRNA was further validated through BRD4 binding to its predicted promoter. MirSTP is available at http://bioinfo.vanderbilt.edu/mirSTP/.
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Affiliation(s)
- Qi Liu
- Center for Quantitative Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN 37203, USA
| | - Jing Wang
- Center for Quantitative Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yue Zhao
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Chung-I Li
- Department of Statistics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Kristy R Stengel
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Pankaj Acharya
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Gretchen Johnston
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Scott W Hiebert
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yu Shyr
- Center for Quantitative Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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20
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Jee YH, Sowada N, Markello TC, Rezvani I, Borck G, Baron J. BRF1 mutations in a family with growth failure, markedly delayed bone age, and central nervous system anomalies. Clin Genet 2016; 91:739-747. [PMID: 27748960 DOI: 10.1111/cge.12887] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/06/2016] [Accepted: 10/10/2016] [Indexed: 12/20/2022]
Abstract
Linear growth failure can be caused by many different genetic abnormalities. In many cases, the genetic defect affects not only the growth plate, causing short stature but also other organs/tissues causing additional clinical abnormalities. A 10-year old boy was evaluated for impaired postnatal linear growth (height 113.3 cm, -4.6 SDS), a bone age that was delayed by 5 years, dysmorphic facies, cognitive impairment, and central nervous system anomalies. His younger brother, presented only with growth failure at 10 months of age. Exome sequencing identified compound heterozygous variants in the gene encoding RNA polymerase III transcription initiation factor 90 kDa subunit (BRF1) in both affected siblings: a missense mutation (c.875 C > G:p.P292R) and a frameshift mutation (c.551delG:p.C184Sfs). The frameshift mutation is expected to lead to nonsense-mediated mRNA decay (NMD) and/or to protein truncation. Expression of BRF1 with the P292R missense mutation failed to rescue yeast lacking BRF1. The findings confirm a previous report showing that biallelic mutations in BRF1 cause cerebellar-facial-dental syndrome. Our findings also help define the growth phenotype, indicating that the linear growth failure can become clinically evident before the neurological abnormalities and that a severely delayed bone age may serve as a diagnostic clue.
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Affiliation(s)
- Y H Jee
- Section on Growth and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - N Sowada
- Institute of Human Genetics, University of Ulm, Ulm, Germany
| | - T C Markello
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - I Rezvani
- Section of Pediatric Endocrinology and Diabetes, Department of Pediatrics, St. Christopher's Hospital of Children, Philadelphia, PA, USA
| | - G Borck
- Institute of Human Genetics, University of Ulm, Ulm, Germany
| | - J Baron
- Section on Growth and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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21
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Abstract
The structures of RNA Polymerase (Pol) II pre-initiation complexes (PIC) have recently been determined at near-atomic resolution, elucidating unprecedented mechanistic details of promoter opening during transcription initiation. The key structural features of promoter opening are summarized here. Structural knowledge of Pol I and III PIC is also briefly discussed.
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Affiliation(s)
- Yan Han
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Yuan He
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA,CONTACT Yan Han , Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
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22
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Kang JJ, Kang YS, Stumph WE. TFIIIB subunit locations on U6 gene promoter DNA mapped by site-specific protein-DNA photo-cross-linking. FEBS Lett 2016; 590:1488-97. [PMID: 27112515 DOI: 10.1002/1873-3468.12185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 11/05/2022]
Abstract
RNA polymerase III-transcribed U6 snRNA genes have gene-external promoters that contain TATA boxes. U6 TATA sequences are bound by TFIIIB that in Drosophila contains the three subunits TBP, Brf1, and Bdp1. The overall structure of TFIIIB is still not well understood. We have therefore studied the mode of TFIIIB binding to DNA by site-specific protein-DNA photo-cross-linking. The results indicate that a portion of Brf1 is sandwiched between Bdp1 and TBP upstream of the TATA box. Furthermore, Bdp1 traverses the DNA under the N-terminal stirrup of TBP to interact with the DNA (and very likely Brf1) downstream of the TATA sequence.
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Affiliation(s)
- Jin Joo Kang
- Department of Chemistry and Biochemistry, San Diego State University, CA, USA
| | - Yoon Soon Kang
- Department of Chemistry and Biochemistry, San Diego State University, CA, USA
| | - William E Stumph
- Department of Chemistry and Biochemistry, San Diego State University, CA, USA
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23
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Hoffmann NA, Jakobi AJ, Vorländer MK, Sachse C, Müller CW. Transcribing RNA polymerase III observed by electron cryomicroscopy. FEBS J 2016; 283:2811-9. [PMID: 27059519 PMCID: PMC5053293 DOI: 10.1111/febs.13732] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 03/26/2016] [Accepted: 04/04/2016] [Indexed: 12/21/2022]
Abstract
Electron cryomicroscopy reconstructions of elongating RNA polymerase (Pol) III at 3.9 Å resolution and of unbound Pol III (apo Pol III) in two distinct conformations at 4.6 Å and 4.7 Å resolution allow the construction of complete atomic models of Pol III and provide new functional insights into the adaption of Pol III to fulfill its specific transcription tasks.
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Affiliation(s)
- Niklas A Hoffmann
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
| | - Arjen J Jakobi
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
| | - Matthias K Vorländer
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
| | - Carsten Sachse
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
| | - Christoph W Müller
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Heidelberg, Germany
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24
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Hoffmann NA, Jakobi AJ, Moreno-Morcillo M, Glatt S, Kosinski J, Hagen WJH, Sachse C, Müller CW. Molecular structures of unbound and transcribing RNA polymerase III. Nature 2015; 528:231-6. [PMID: 26605533 PMCID: PMC4681132 DOI: 10.1038/nature16143] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/13/2015] [Indexed: 12/11/2022]
Abstract
Transcription of genes encoding small structured RNAs such as transfer RNAs, spliceosomal U6 small nuclear RNA and ribosomal 5S RNA is carried out by RNA polymerase III (Pol III), the largest yet structurally least characterized eukaryotic RNA polymerase. Here we present the cryo-electron microscopy structures of the Saccharomyces cerevisiae Pol III elongating complex at 3.9 Å resolution and the apo Pol III enzyme in two different conformations at 4.6 and 4.7 Å resolution, respectively, which allow the building of a 17-subunit atomic model of Pol III. The reconstructions reveal the precise orientation of the C82-C34-C31 heterotrimer in close proximity to the stalk. The C53-C37 heterodimer positions residues involved in transcription termination close to the non-template DNA strand. In the apo Pol III structures, the stalk adopts different orientations coupled with closed and open conformations of the clamp. Our results provide novel insights into Pol III-specific transcription and the adaptation of Pol III towards its small transcriptional targets.
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Affiliation(s)
- Niklas A. Hoffmann
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Arjen J. Jakobi
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, Notkestr. 85, 22607 Hamburg, Germany
| | - Maria Moreno-Morcillo
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Sebastian Glatt
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Jan Kosinski
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Wim J. H. Hagen
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Carsten Sachse
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Correspondence and requests for materials should be addressed to C.S. () or C.W.M. ()
| | - Christoph W. Müller
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Correspondence and requests for materials should be addressed to C.S. () or C.W.M. ()
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25
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Affiliation(s)
- Richard J Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland 20892-2425, USA
| | - Keshab Rijal
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland 20892-2425, USA
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26
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BRF1, a subunit of RNA polymerase III transcription factor TFIIIB, is essential for cell growth of Trypanosoma brucei. Parasitology 2015; 142:1563-73. [PMID: 26337955 DOI: 10.1017/s0031182015001122] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
RNA polymerase III (Pol III) synthesizes small RNA molecules that are essential for cell viability. Accurate initiation of transcription by Pol III requires general transcription factor TFIIIB, which is composed of three subunits: TFIIB-related factor BRF1, TATA-binding protein and BDP1. Here we report the molecular characterization of BRF1 in Trypanosoma brucei (TbBRF1), a parasitic protozoa that shows distinctive transcription characteristics. In silico analysis allowed the detection in TbBRF1 of the three conserved domains located in the N-terminal region of all BRF1 orthologues, namely a zinc ribbon motif and two cyclin repeats. Homology modelling suggested that, similarly to other BRF1 and TFIIB proteins, the TbBRF1 cyclin repeats show the characteristic structure of five α-helices per repeat, connected by a short random-coiled linker. As expected for a transcription factor, TbBRF1 was localized in the nucleus. Knock-down of TbBRF1 by RNA interference (RNAi) showed that this protein is essential for the viability of procyclic forms of T. brucei, since ablation of TbBRF1 led to growth arrest of the parasites. Nuclear run-on and quantitative real-time PCR analyses demonstrated that transcription of all the Pol III-dependent genes analysed was reduced, at different levels, after RNAi induction.
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27
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A Region of Bdp1 Necessary for Transcription Initiation That Is Located within the RNA Polymerase III Active Site Cleft. Mol Cell Biol 2015; 35:2831-40. [PMID: 26055328 DOI: 10.1128/mcb.00263-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 06/01/2015] [Indexed: 02/02/2023] Open
Abstract
The RNA polymerase III (Pol III)-specific transcription factor Bdp1 is crucial to Pol III recruitment and promoter opening in transcription initiation, yet structural information is sparse. To examine its protein-binding targets within the preinitiation complex at the residue level, photoreactive amino acids were introduced into Saccharomyces cerevisiae Bdp1. Mutations within the highly conserved SANT domain cross-linked to the transcription factor IIB (TFIIB)-related transcription factor Brf1, consistent with the findings of previous studies. In addition, we identified an essential N-terminal region that cross-linked with the Pol III catalytic subunit C128 as well as Brf1. Closer examination revealed that this region interacted with the C128 N-terminal region, the N-terminal half of Brf1, and the C-terminal domain of the C37 subunit, together positioning this region within the active site cleft of the preinitiation complex. With our functional data, our analyses identified an essential region of Bdp1 that is positioned within the active site cleft of Pol III and necessary for transcription initiation.
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28
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Borck G, Hög F, Dentici ML, Tan PL, Sowada N, Medeira A, Gueneau L, Thiele H, Kousi M, Lepri F, Wenzeck L, Blumenthal I, Radicioni A, Schwarzenberg TL, Mandriani B, Fischetto R, Morris-Rosendahl DJ, Altmüller J, Reymond A, Nürnberg P, Merla G, Dallapiccola B, Katsanis N, Cramer P, Kubisch C. BRF1 mutations alter RNA polymerase III-dependent transcription and cause neurodevelopmental anomalies. Genome Res 2015; 25:155-66. [PMID: 25561519 PMCID: PMC4315290 DOI: 10.1101/gr.176925.114] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 11/26/2014] [Indexed: 01/11/2023]
Abstract
RNA polymerase III (Pol III) synthesizes tRNAs and other small noncoding RNAs to regulate protein synthesis. Dysregulation of Pol III transcription has been linked to cancer, and germline mutations in genes encoding Pol III subunits or tRNA processing factors cause neurogenetic disorders in humans, such as hypomyelinating leukodystrophies and pontocerebellar hypoplasia. Here we describe an autosomal recessive disorder characterized by cerebellar hypoplasia and intellectual disability, as well as facial dysmorphic features, short stature, microcephaly, and dental anomalies. Whole-exome sequencing revealed biallelic missense alterations of BRF1 in three families. In support of the pathogenic potential of the discovered alleles, suppression or CRISPR-mediated deletion of brf1 in zebrafish embryos recapitulated key neurodevelopmental phenotypes; in vivo complementation showed all four candidate mutations to be pathogenic in an apparent isoform-specific context. BRF1 associates with BDP1 and TBP to form the transcription factor IIIB (TFIIIB), which recruits Pol III to target genes. We show that disease-causing mutations reduce Brf1 occupancy at tRNA target genes in Saccharomyces cerevisiae and impair cell growth. Moreover, BRF1 mutations reduce Pol III-related transcription activity in vitro. Taken together, our data show that BRF1 mutations that reduce protein activity cause neurodevelopmental anomalies, suggesting that BRF1-mediated Pol III transcription is required for normal cerebellar and cognitive development.
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Affiliation(s)
- Guntram Borck
- Institute of Human Genetics, University of Ulm, 89081 Ulm, Germany;
| | - Friederike Hög
- Gene Center Munich and Department of Biochemistry, Center for Integrated Protein Science CIPSM, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | | | - Perciliz L Tan
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27710, USA
| | - Nadine Sowada
- Institute of Human Genetics, University of Ulm, 89081 Ulm, Germany
| | - Ana Medeira
- Serviço de Genética, Departamento de Pediatria, Hospital S. Maria, CHLN, 1649-035 Lisboa, Portugal
| | - Lucie Gueneau
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany
| | - Maria Kousi
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27710, USA
| | | | - Larissa Wenzeck
- Gene Center Munich and Department of Biochemistry, Center for Integrated Protein Science CIPSM, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Ian Blumenthal
- Molecular Neurogenetics Unit and Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Antonio Radicioni
- Department of Experimental Medicine, Sapienza University, 00161 Rome, Italy
| | | | - Barbara Mandriani
- IRCCS Casa Sollievo Della Sofferenza, Medical Genetics Unit, 71013 San Giovanni Rotondo, Italy; PhD Program, Molecular Genetics applied to Medical Sciences, University of Brescia, 25121 Brescia, Italy
| | - Rita Fischetto
- U.O. Malattie Metaboliche PO Giovanni XXIII, AOU Policlinico Consorziale, 70120 Bari, Italy
| | | | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany; Institute for Human Genetics, University of Cologne, 50931 Cologne, Germany
| | - Alexandre Reymond
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Giuseppe Merla
- IRCCS Casa Sollievo Della Sofferenza, Medical Genetics Unit, 71013 San Giovanni Rotondo, Italy
| | | | - Nicholas Katsanis
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27710, USA
| | - Patrick Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, 37077 Göttingen, Germany
| | - Christian Kubisch
- Institute of Human Genetics, University of Ulm, 89081 Ulm, Germany; Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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29
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Knutson BA, Luo J, Ranish J, Hahn S. Architecture of the Saccharomyces cerevisiae RNA polymerase I Core Factor complex. Nat Struct Mol Biol 2014; 21:810-6. [PMID: 25132180 PMCID: PMC4219626 DOI: 10.1038/nsmb.2873] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 07/16/2014] [Indexed: 12/31/2022]
Abstract
Core Factor (CF) is a conserved RNA polymerase (Pol) I general transcription factor and is comprised of Rrn6, Rrn11, and the TFIIB-related subunit Rrn7. CF binds TBP, Pol I, and the regulatory factors Rrn3 and UAF. We used chemical crosslinking-mass spectrometry (CXMS) to determine the molecular architecture of CF and its interactions with TBP. The CF subunits assemble through an interconnected network of interactions between five structural domains that are conserved in orthologous subunits of the human Pol I factor SL1. The crosslinking-derived model was validated through a series of genetic and biochemical assays. Our combined results show the architecture of CF and the functions of the CF subunits in assembly of the complex. We extend these findings to model how CF assembles into the Pol I preinitiation complex, providing new insight into the roles of CF, TBP and Rrn3.
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Affiliation(s)
- Bruce A Knutson
- 1] Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA. [2]
| | - Jie Luo
- Institute for Systems Biology, Seattle, Washington, USA
| | | | - Steven Hahn
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
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