1
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Midha T, Kolomeisky AB, Igoshin OA. Linear-Decoupling Enables Accurate Speed and Accuracy Predictions for Copolymerization Processes. J Phys Chem Lett 2024; 15:9361-9368. [PMID: 39240239 DOI: 10.1021/acs.jpclett.4c02132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2024]
Abstract
Biological processes exhibit remarkable accuracy and speed and can be theoretically explored through various approaches. The Markov-chain copolymerization theory, describing polymer growth kinetics as a Markov chain, provides an exact set of equations to solve for error and speed. Still, due to nonlinearity, these equations are hard to solve. Alternatively, the enzyme-kinetics approach, which formulates a set of linear equations, simplifies the biological processes as transitions between discrete chemical states, but generally, it might not be accurate. Here, we show that the enzyme-kinetic approach can lead to inaccurate fluxes, even for first-order polymerization processes. To address the problem, we propose a simplified linear-decoupling approximation for steady-state probabilities of higher-order copolymer chains under biologically relevant conditions. Our findings demonstrate that the stationary speed and error rate obtained from the linear-decoupling method align closely with exact values from the Markov-chain (nonlinear) approximation. Extending the technique to higher-order processes with proofreading and internal states shows that it works equally well to describe trade-offs between speed and accuracy for DNA replication and transcription elongation. Our work underscores the proposed linear-decoupling approximation's efficacy in addressing the nonlinear behavior of the Markov-chain approach and the enzyme-kinetic approach's limitations, ensuring accurate predictions for high-fidelity biological processes.
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Affiliation(s)
- Tripti Midha
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Anatoly B Kolomeisky
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Oleg A Igoshin
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
- Department of Biosciences, Rice University, Houston, Texas 77005, United States
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2
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Mäkinen JJ, Rosenqvist P, Virta P, Metsä-Ketelä M, Belogurov GA. Probing the nucleobase selectivity of RNA polymerases with dual-coding substrates. J Biol Chem 2024:107755. [PMID: 39260691 DOI: 10.1016/j.jbc.2024.107755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 08/27/2024] [Accepted: 08/30/2024] [Indexed: 09/13/2024] Open
Abstract
Formycin A (FOR) and Pyrazofurin A (PYR) are nucleoside analogues with antiviral and antitumor properties. They are known to interfere with nucleic acid metabolism, but their direct effect on transcription is less understood. We explored how RNA polymerases (RNAPs) from bacteria, mitochondria, and viruses utilize FOR, PYR, and oxidized purine nucleotides. All tested polymerases incorporated FOR in place of adenine and PYR in place of uridine. FOR also exhibited surprising dual-coding behavior, functioning as a cytosine substitute, particularly for viral RNAP. In contrast, 8-oxoadenine and 8-oxoguanine were incorporated in place of uridine in addition to their canonical Watson-Crick codings. Our data suggest that the interconversion of canonical anti- and alternative syn-conformers underlies dual-coding abilities of FOR and oxidized purines. Structurally distinct RNAPs displayed varying abilities to utilize syn-conformers during transcription. By examining base pairings that led to substrate incorporation and the entire spectrum of geometrically compatible pairings, we have gained new insights into the nucleobase selection processes employed by structurally diverse RNAPs. These insights may pave the way for advancements in antiviral therapies.
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Affiliation(s)
- Janne J Mäkinen
- University of Turku, Department of Life Technologies, FIN-20014 Turku, Finland
| | - Petja Rosenqvist
- Department of Chemistry, University of Turku, FIN-20500 Turku, Finland
| | - Pasi Virta
- Department of Chemistry, University of Turku, FIN-20500 Turku, Finland
| | - Mikko Metsä-Ketelä
- University of Turku, Department of Life Technologies, FIN-20014 Turku, Finland
| | - Georgiy A Belogurov
- University of Turku, Department of Life Technologies, FIN-20014 Turku, Finland.
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3
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Fang C, Huang K, Wu X, Zhang H, Gu Z, Wang J, Zhang Y. Transcription elongation of the plant RNA polymerase IV is prone to backtracking. SCIENCE ADVANCES 2024; 10:eadq3087. [PMID: 39178250 PMCID: PMC11343019 DOI: 10.1126/sciadv.adq3087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 07/22/2024] [Indexed: 08/25/2024]
Abstract
RNA polymerase IV (Pol IV) forms a complex with RNA-directed RNA polymerase 2 (RDR2) to produce double-stranded RNA (dsRNA) precursors essential for plant gene silencing. In the "backtracking-triggered RNA channeling" model, Pol IV backtracks and delivers its transcript's 3' terminus to RDR2, which synthesizes dsRNA. However, the mechanisms underlying Pol IV backtracking and RNA protection from cleavage are unclear. Here, we determined cryo-electron microscopy structures of Pol IV elongation complexes at four states of its nucleotide addition cycle (NAC): posttranslocation, guanosine triphosphate-bound, pretranslocation, and backtracked states. The structures reveal that Pol IV maintains an open DNA cleft and kinked bridge helix in all NAC states, loosely interacts with the nucleoside triphosphate substrate, and barely contacts proximal backtracked nucleotides. Biochemical data indicate that Pol IV is inefficient in forward translocation and RNA cleavage. These findings suggest that Pol IV transcription elongation is prone to backtracking and incapable of RNA hydrolysis, ensuring efficient dsRNA production by Pol IV-RDR2.
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Affiliation(s)
- Chengli Fang
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Kun Huang
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Xiaoxian Wu
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hongwei Zhang
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zhanxi Gu
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiawei Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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4
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Zhang X, Xu J, Hu J, Zhang S, Hao Y, Zhang D, Qian H, Wang D, Fu XD. Cockayne Syndrome Linked to Elevated R-Loops Induced by Stalled RNA Polymerase II during Transcription Elongation. Nat Commun 2024; 15:6031. [PMID: 39019869 PMCID: PMC11255242 DOI: 10.1038/s41467-024-50298-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 07/04/2024] [Indexed: 07/19/2024] Open
Abstract
Mutations in the Cockayne Syndrome group B (CSB) gene cause cancer in mice, but premature aging and severe neurodevelopmental defects in humans. CSB, a member of the SWI/SNF family of chromatin remodelers, plays diverse roles in regulating gene expression and transcription-coupled nucleotide excision repair (TC-NER); however, these functions do not explain the distinct phenotypic differences observed between CSB-deficient mice and humans. During investigating Cockayne Syndrome-associated genome instability, we uncover an intrinsic mechanism that involves elongating RNA polymerase II (RNAPII) undergoing transient pauses at internal T-runs where CSB is required to propel RNAPII forward. Consequently, CSB deficiency retards RNAPII elongation in these regions, and when coupled with G-rich sequences upstream, exacerbates genome instability by promoting R-loop formation. These R-loop prone motifs are notably abundant in relatively long genes related to neuronal functions in the human genome, but less prevalent in the mouse genome. These findings provide mechanistic insights into differential impacts of CSB deficiency on mice versus humans and suggest that the manifestation of the Cockayne Syndrome phenotype in humans results from the progressive evolution of mammalian genomes.
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Affiliation(s)
- Xuan Zhang
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA
| | - Jun Xu
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
- Genetics and Metabolism Department, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jing Hu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Sitao Zhang
- National Institute of Biological Sciences,7 Science Park Road, Beijing, China
| | - Yajing Hao
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- China National Center for Bioinformation, Beijing, China
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Dongyang Zhang
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA
| | - Hao Qian
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Dong Wang
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA.
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA.
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA.
| | - Xiang-Dong Fu
- Westlake Laboratory of Life Sciences and Biomedicine, School of Life Sciences and School of Medicine, Westlake University, Hangzhou, Zhejiang, China.
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5
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Sekine SI, Ehara H, Kujirai T, Kurumizaka H. Structural perspectives on transcription in chromatin. Trends Cell Biol 2024; 34:211-224. [PMID: 37596139 DOI: 10.1016/j.tcb.2023.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/17/2023] [Accepted: 07/24/2023] [Indexed: 08/20/2023]
Abstract
In eukaryotes, all genetic processes take place in the cell nucleus, where DNA is packaged as chromatin in 'beads-on-a-string' nucleosome arrays. RNA polymerase II (RNAPII) transcribes protein-coding and many non-coding genes in this chromatin environment. RNAPII elongates RNA while passing through multiple nucleosomes and maintaining the integrity of the chromatin structure. Recent structural studies have shed light on the detailed mechanisms of this process, including how transcribing RNAPII progresses through a nucleosome and reassembles it afterwards, and how transcription elongation factors, chromatin remodelers, and histone chaperones participate in these processes. Other studies have also illuminated the crucial role of nucleosomes in preinitiation complex assembly and transcription initiation. In this review we outline these advances and discuss future perspectives.
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Affiliation(s)
- Shun-Ichi Sekine
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
| | - Haruhiko Ehara
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Tomoya Kujirai
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Hitoshi Kurumizaka
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
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6
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Xie G, Du X, Hu H, Du J. Molecular mechanisms of the RNA polymerases in plant RNA-directed DNA methylation. Trends Biochem Sci 2024; 49:247-256. [PMID: 38072749 DOI: 10.1016/j.tibs.2023.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 11/16/2023] [Accepted: 11/21/2023] [Indexed: 03/10/2024]
Abstract
In plants, two atypical DNA-dependent RNA polymerases, RNA polymerase IV (Pol IV) and Pol V, and an RNA-DEPENDENT RNA POLYMERASE 2 (RDR2) together produce noncoding RNAs (ncRNAs) to guide the plant-specific RNA-directed DNA methylation (RdDM). Although both Pol IV and Pol V have evolved from the canonical Pol II, they have adapted to different roles in RdDM. The mechanisms of their adaptation are key to understanding plant DNA methylation and the divergent evolution of polymerases. In this review, we summarize insights that have emerged from recent structural studies of Pol IV, Pol V, and RDR2 and discuss their structural features critical for efficient ncRNA production in RdDM.
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Affiliation(s)
- Guohui Xie
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xuan Du
- Department of Biochemistry and Molecular Biology, International Cancer Center, Shenzhen University Medical School, Shenzhen 518060, China
| | - Hongmiao Hu
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Jiamu Du
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China; Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen 518055, China.
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7
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Chen Y, Cramer P. RNA polymerase II elongation factors use conserved regulatory mechanisms. Curr Opin Struct Biol 2024; 84:102766. [PMID: 38181687 DOI: 10.1016/j.sbi.2023.102766] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 01/07/2024]
Abstract
RNA polymerase II (Pol II) transcription is regulated by many elongation factors. Among these factors, TFIIF, PAF-RTF1, ELL and Elongin stimulate mRNA chain elongation by Pol II. Cryo-EM structures of Pol II complexes with these elongation factors now reveal some general principles on how elongation factors bind Pol II and how they stimulate transcription. All four elongation factors contact Pol II at domains external 2 and protrusion, whereas TFIIF and ELL additionally bind the Pol II lobe. All factors apparently stabilize cleft-flanking elements, whereas RTF1 and Elongin additionally approach the active site with a latch element and may influence catalysis or translocation. Due to the shared binding sites on Pol II, factor binding is mutually exclusive, and thus it remains to be studied what determines which elongation factors bind at a certain gene and under which condition.
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Affiliation(s)
- Ying Chen
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany.
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany.
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8
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Duan B, Qiu C, Lockless SW, Sze SH, Kaplan CD. Higher-order epistasis within Pol II trigger loop haplotypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.20.576280. [PMID: 38293233 PMCID: PMC10827151 DOI: 10.1101/2024.01.20.576280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
RNA polymerase II (Pol II) has a highly conserved domain, the trigger loop (TL), that controls transcription fidelity and speed. We previously probed pairwise genetic interactions between residues within and surrounding the TL and identified widespread incompatibility between TLs of different species when placed in the Saccharomyces cerevisiae Pol II context, indicating epistasis between the TL and its surrounding context. We sought to understand the nature of this incompatibility and probe higher order epistasis internal to the TL. We have employed deep mutational scanning with selected natural TL variants ("haplotypes"), and all possible intermediate substitution combinations between them and the yeast Pol II TL. We identified both positive and negative higher-order residue interactions within example TL haplotypes. Intricate higher-order epistasis formed by TL residues was sometimes only apparent from analysis of intermediate genotypes, emphasizing complexity of epistatic interactions. Furthermore, we distinguished TL substitutions with distinct classes of epistatic patterns, suggesting specific TL residues that potentially influence TL evolution. Our examples of complex residue interactions suggest possible pathways for epistasis to facilitate Pol II evolution.
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Affiliation(s)
- Bingbing Duan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
| | - Chenxi Qiu
- Department of Genetics, Harvard Medical School, Boston, MA 02215
| | - Steve W Lockless
- Department of Biology, Texas A&M University, College Station, TX 77843
| | - Sing-Hoi Sze
- Department of Computer Science & Engineering, Texas A&M University, College Station, TX 77843
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843
| | - Craig D Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
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9
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Sarsam RD, Xu J, Lahiri I, Gong W, Li Q, Oh J, Zhou Z, Hou P, Chong J, Hao N, Li S, Wang D, Leschziner AE. Elf1 promotes Rad26's interaction with lesion-arrested Pol II for transcription-coupled repair. Proc Natl Acad Sci U S A 2024; 121:e2314245121. [PMID: 38194460 PMCID: PMC10801861 DOI: 10.1073/pnas.2314245121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 11/27/2023] [Indexed: 01/11/2024] Open
Abstract
Transcription-coupled nucleotide excision repair (TC-NER) is a highly conserved DNA repair pathway that removes bulky lesions in the transcribed genome. Cockayne syndrome B protein (CSB), or its yeast ortholog Rad26, has been known for decades to play important roles in the lesion-recognition steps of TC-NER. Another conserved protein ELOF1, or its yeast ortholog Elf1, was recently identified as a core transcription-coupled repair factor. How Rad26 distinguishes between RNA polymerase II (Pol II) stalled at a DNA lesion or other obstacles and what role Elf1 plays in this process remains unknown. Here, we present cryo-EM structures of Pol II-Rad26 complexes stalled at different obstacles that show that Rad26 uses a common mechanism to recognize a stalled Pol II, with additional interactions when Pol II is arrested at a lesion. A cryo-EM structure of lesion-arrested Pol II-Rad26 bound to Elf1 revealed that Elf1 induces further interactions between Rad26 and a lesion-arrested Pol II. Biochemical and genetic data support the importance of the interplay between Elf1 and Rad26 in TC-NER initiation. Together, our results provide important mechanistic insights into how two conserved transcription-coupled repair factors, Rad26/CSB and Elf1/ELOF1, work together at the initial lesion recognition steps of transcription-coupled repair.
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Affiliation(s)
- Reta D. Sarsam
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA92093
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA92093
| | - Indrajit Lahiri
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA92093
| | - Wenzhi Gong
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA70803
| | - Qingrong Li
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA92093
| | - Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA92093
| | - Zhen Zhou
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA92093
| | - Peini Hou
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA92093
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA92093
| | - Nan Hao
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA92093
| | - Shisheng Li
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA70803
| | - Dong Wang
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA92093
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA92093
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA92093
| | - Andres E. Leschziner
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA92093
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA92093
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10
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Schwank K, Schmid C, Fremter T, Engel C, Milkereit P, Griesenbeck J, Tschochner H. Features of yeast RNA polymerase I with special consideration of the lobe binding subunits. Biol Chem 2023; 404:979-1002. [PMID: 37823775 DOI: 10.1515/hsz-2023-0184] [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: 04/14/2023] [Accepted: 07/13/2023] [Indexed: 10/13/2023]
Abstract
Ribosomal RNAs (rRNAs) are structural components of ribosomes and represent the most abundant cellular RNA fraction. In the yeast Saccharomyces cerevisiae, they account for more than 60 % of the RNA content in a growing cell. The major amount of rRNA is synthesized by RNA polymerase I (Pol I). This enzyme transcribes exclusively the rRNA gene which is tandemly repeated in about 150 copies on chromosome XII. The high number of transcribed rRNA genes, the efficient recruitment of the transcription machinery and the dense packaging of elongating Pol I molecules on the gene ensure that enough rRNA is generated. Specific features of Pol I and of associated factors confer promoter selectivity and both elongation and termination competence. Many excellent reviews exist about the state of research about function and regulation of Pol I and how Pol I initiation complexes are assembled. In this report we focus on the Pol I specific lobe binding subunits which support efficient, error-free, and correctly terminated rRNA synthesis.
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Affiliation(s)
- Katrin Schwank
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Catharina Schmid
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Tobias Fremter
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Christoph Engel
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Philipp Milkereit
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Joachim Griesenbeck
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
| | - Herbert Tschochner
- Regensburg Center of Biochemistry (RCB), Universität Regensburg, D-93053 Regensburg, Germany
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11
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Cavallaro M, Wang Y, Hebenstreit D, Dutta R. Bayesian inference of polymerase dynamics over the exclusion process. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221469. [PMID: 37538742 PMCID: PMC10394410 DOI: 10.1098/rsos.221469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 07/12/2023] [Indexed: 08/05/2023]
Abstract
Transcription is a complex phenomenon that permits the conversion of genetic information into phenotype by means of an enzyme called RNA polymerase, which erratically moves along and scans the DNA template. We perform Bayesian inference over a paradigmatic mechanistic model of non-equilibrium statistical physics, i.e. the asymmetric exclusion processes in the hydrodynamic limit, assuming a Gaussian process prior for the polymerase progression rate as a latent variable. Our framework allows us to infer the speed of polymerases during transcription given their spatial distribution, while avoiding the explicit inversion of the system's dynamics. The results, which show processing rates strongly varying with genomic position and minor role of traffic-like congestion, may have strong implications for the understanding of gene expression.
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Affiliation(s)
- Massimo Cavallaro
- Mathematics Institute, University of Warwick, Coventry, UK
- School of Life Sciences, University of Warwick, Coventry, UK
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, UK
| | - Yuexuan Wang
- Institute of Applied Statistics, Johannes Kepler Universität, Linz, Austria
| | | | - Ritabrata Dutta
- Department of Statistics, University of Warwick, Coventry, UK
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12
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Midha T, Mallory JD, Kolomeisky AB, Igoshin OA. Synergy among Pausing, Intrinsic Proofreading, and Accessory Proteins Results in Optimal Transcription Speed and Tolerable Accuracy. J Phys Chem Lett 2023; 14:3422-3429. [PMID: 37010247 DOI: 10.1021/acs.jpclett.3c00345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Cleavage of dinucleotides after the misincorporational pauses serves as a proofreading mechanism that increases transcriptional elongation accuracy. The accuracy is further improved by accessory proteins such as GreA and TFIIS. However, it is not clear why RNAP pauses and why cleavage-factor-assisted proofreading is necessary despite transcriptional errors in vitro being of the same order as those in downstream translation. Here, we developed a chemical-kinetic model that incorporates most relevant features of transcriptional proofreading and uncovers how the balance between speed and accuracy is achieved. We found that long pauses are essential for high accuracy, whereas cleavage-factor-stimulated proofreading optimizes speed. Moreover, in comparison to the cleavage of a single nucleotide or three nucleotides, RNAP backtracking and dinucleotide cleavage improve both speed and accuracy. Our results thereby show how the molecular mechanism and the kinetic parameters of the transcriptional process were evolutionarily optimized to achieve maximal speed and tolerable accuracy.
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Affiliation(s)
- Tripti Midha
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Joel D Mallory
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Anatoly B Kolomeisky
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Oleg A Igoshin
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
- Department of Biosciences, Rice University, Houston, Texas 77005, United States
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13
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Duan B, Qiu C, Sze SH, Kaplan C. Widespread epistasis shapes RNA Polymerase II active site function and evolution. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.27.530048. [PMID: 36909581 PMCID: PMC10002619 DOI: 10.1101/2023.02.27.530048] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Multi-subunit RNA Polymerases (msRNAPs) are responsible for transcription in all kingdoms of life. At the heart of these msRNAPs is an ultra-conserved active site domain, the trigger loop (TL), coordinating transcription speed and fidelity by critical conformational changes impacting multiple steps in substrate selection, catalysis, and translocation. Previous studies have observed several different types of genetic interactions between eukaryotic RNA polymerase II (Pol II) TL residues, suggesting that the TL's function is shaped by functional interactions of residues within and around the TL. The extent of these interaction networks and how they control msRNAP function and evolution remain to be determined. Here we have dissected the Pol II TL interaction landscape by deep mutational scanning in Saccharomyces cerevisiae Pol II. Through analysis of over 15000 alleles, representing all single mutants, a rationally designed subset of double mutants, and evolutionarily observed TL haplotypes, we identify interaction networks controlling TL function. Substituting residues creates allele-specific networks and propagates epistatic effects across the Pol II active site. Furthermore, the interaction landscape further distinguishes alleles with similar growth phenotypes, suggesting increased resolution over the previously reported single mutant phenotypic landscape. Finally, co-evolutionary analyses reveal groups of co-evolving residues across Pol II converge onto the active site, where evolutionary constraints interface with pervasive epistasis. Our studies provide a powerful system to understand the plasticity of RNA polymerase mechanism and evolution, and provide the first example of pervasive epistatic landscape in a highly conserved and constrained domain within an essential enzyme.
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Affiliation(s)
- Bingbing Duan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
| | - Chenxi Qiu
- Department of Genetics, Harvard Medical School, Boston, MA 02215
| | - Sing-Hoi Sze
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX 77843
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843
| | - Craig Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
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14
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Zhang Y, Han W, Wang L, Wang H, Jia Q, Chen T, Wang S, Li M. Correlative Escherichia coli Transcription Rate and Bubble Conformation Remodeled by NusA and NusG. J Phys Chem B 2023; 127:2909-2917. [PMID: 36977198 DOI: 10.1021/acs.jpcb.2c08771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Transcription is highly regulated by a variety of transcription factors, among which NusA and NusG act contradictorily in Escherichia coli (E. coli) that NusA stabilizes a paused RNA polymerase (RNAP) and NusG suppresses it. The mechanism of the NusA and NusG regulations on RNAP transcription has been addressed, but their effect on the conformational changes of the transcription bubble correlated with transcription kinetics remains elusive. By using single-molecule magnetic trap, we identify a reduction in the transcription rate of ∼40% events by NusA. Although the rest ∼60% of transcription events exhibit unaffected transcription rates, a NusA-enhanced standard deviation of the transcription rate is observed. NusA remodeling also increases the extent of DNA unwinding in the transcription bubble by 1-2 base pairs, which can be reduced by NusG. The NusG remodeling is more significant on the RNAP molecules with reduced transcription rates rather than those without. Our results provide a quantitative view on the mechanisms of transcriptional regulation by NusA and NusG factors.
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Affiliation(s)
- Yuqiong Zhang
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631, China
- Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Weijing Han
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Lisha Wang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Hao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qi Jia
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Tongsheng Chen
- MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631, China
- Guangdong Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631, China
| | - Shuang Wang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Ming Li
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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15
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Wee LM, Tong AB, Florez Ariza AJ, Cañari-Chumpitaz C, Grob P, Nogales E, Bustamante CJ. A trailing ribosome speeds up RNA polymerase at the expense of transcript fidelity via force and allostery. Cell 2023; 186:1244-1262.e34. [PMID: 36931247 PMCID: PMC10135430 DOI: 10.1016/j.cell.2023.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 11/14/2022] [Accepted: 02/06/2023] [Indexed: 03/18/2023]
Abstract
In prokaryotes, translation can occur on mRNA that is being transcribed in a process called coupling. How the ribosome affects the RNA polymerase (RNAP) during coupling is not well understood. Here, we reconstituted the E. coli coupling system and demonstrated that the ribosome can prevent pausing and termination of RNAP and double the overall transcription rate at the expense of fidelity. Moreover, we monitored single RNAPs coupled to ribosomes and show that coupling increases the pause-free velocity of the polymerase and that a mechanical assisting force is sufficient to explain the majority of the effects of coupling. Also, by cryo-EM, we observed that RNAPs with a terminal mismatch adopt a backtracked conformation, while a coupled ribosome allosterically induces these polymerases toward a catalytically active anti-swiveled state. Finally, we demonstrate that prolonged RNAP pausing is detrimental to cell viability, which could be prevented by polymerase reactivation through a coupled ribosome.
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Affiliation(s)
- Liang Meng Wee
- QB3-Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA
| | - Alexander B Tong
- QB3-Berkeley, Berkeley, CA, USA; Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Alfredo Jose Florez Ariza
- QB3-Berkeley, Berkeley, CA, USA; Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA
| | - Cristhian Cañari-Chumpitaz
- QB3-Berkeley, Berkeley, CA, USA; Department of Chemistry, University of California Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA
| | - Patricia Grob
- QB3-Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - Eva Nogales
- QB3-Berkeley, Berkeley, CA, USA; Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Carlos J Bustamante
- QB3-Berkeley, Berkeley, CA, USA; Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA; Department of Chemistry, University of California Berkeley, Berkeley, CA, USA; Department of Physics, University of California Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA; Kavli Energy Nanoscience Institute, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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16
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Johnson GE, Parker DJ, Lalanne JB, Parker ML, Li GW. BaM-seq and TBaM-seq, highly multiplexed and targeted RNA-seq protocols for rapid, low-cost library generation from bacterial samples. NAR Genom Bioinform 2023; 5:lqad017. [PMID: 36879903 PMCID: PMC9985320 DOI: 10.1093/nargab/lqad017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/13/2023] [Accepted: 02/27/2023] [Indexed: 03/07/2023] Open
Abstract
The ability to profile transcriptomes and characterize global gene expression changes has been greatly enabled by the development of RNA sequencing technologies (RNA-seq). However, the process of generating sequencing-compatible cDNA libraries from RNA samples can be time-consuming and expensive, especially for bacterial mRNAs which lack poly(A)-tails that are often used to streamline this process for eukaryotic samples. Compared to the increasing throughput and decreasing cost of sequencing, library preparation has had limited advances. Here, we describe bacterial-multiplexed-seq (BaM-seq), an approach that enables simple barcoding of many bacterial RNA samples that decreases the time and cost of library preparation. We also present targeted-bacterial-multiplexed-seq (TBaM-seq) that allows for differential expression analysis of specific gene panels with over 100-fold enrichment in read coverage. In addition, we introduce the concept of transcriptome redistribution based on TBaM-seq that dramatically reduces the required sequencing depth while still allowing for quantification of both highly and lowly abundant transcripts. These methods accurately measure gene expression changes with high technical reproducibility and agreement with gold standard, lower throughput approaches. Together, use of these library preparation protocols allows for fast, affordable generation of sequencing libraries.
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Affiliation(s)
- Grace E Johnson
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Darren J Parker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jean-Benoit Lalanne
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mirae L Parker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Computational & Systems Biology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gene-Wei Li
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
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17
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Obermeyer S, Stöckl R, Schnekenburger T, Kapoor H, Stempfl T, Schwartz U, Grasser KD. TFIIS Is Crucial During Early Transcript Elongation for Transcriptional Reprogramming in Response to Heat Stress. J Mol Biol 2023; 435:167917. [PMID: 36502880 DOI: 10.1016/j.jmb.2022.167917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/01/2022] [Accepted: 12/04/2022] [Indexed: 12/13/2022]
Abstract
In addition to the stage of transcriptional initiation, the production of mRNAs is regulated during elongation. Accordingly, the synthesis of mRNAs by RNA polymerase II (RNAPII) in the chromatin context is modulated by various transcript elongation factors. TFIIS is an elongation factor that stimulates the transcript cleavage activity of RNAPII to reactivate stalled elongation complexes at barriers to transcription including nucleosomes. Since Arabidopsis tfIIs mutants grow normally under standard conditions, we have exposed them to heat stress (HS), revealing that tfIIs plants are highly sensitive to elevated temperatures. Transcriptomic analyses demonstrate that particularly HS-induced genes are expressed at lower levels in tfIIs than in wildtype. Mapping the distribution of elongating RNAPII uncovered that in tfIIs plants RNAPII accumulates at the +1 nucleosome of genes that are upregulated upon HS. The promoter-proximal RNAPII accumulation in tfIIs under HS conditions conforms to that observed upon inhibition of the RNAPII transcript cleavage activity. Further analysis of the RNAPII accumulation downstream of transcriptional start sites illustrated that RNAPII stalling occurs at +1 nucleosomes that are depleted in the histone variant H2A.Z upon HS. Therefore, assistance of early transcript elongation by TFIIS is required for reprogramming gene expression to establish plant thermotolerance.
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Affiliation(s)
- Simon Obermeyer
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Richard Stöckl
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Tobias Schnekenburger
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Henna Kapoor
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Thomas Stempfl
- Center of Excellence for Fluorescent Bioanalytics (KFB), University of Regensburg, Am Biopark 9, D-93053 Regensburg, Germany
| | - Uwe Schwartz
- NGS Analysis Centre, Biology and Pre-Clinical Medicine, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
| | - Klaus D Grasser
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany.
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18
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Unarta IC, Goonetilleke EC, Wang D, Huang X. Nucleotide addition and cleavage by RNA polymerase II: Coordination of two catalytic reactions using a single active site. J Biol Chem 2022; 299:102844. [PMID: 36581202 PMCID: PMC9860460 DOI: 10.1016/j.jbc.2022.102844] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 12/19/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
RNA polymerase II (Pol II) incorporates complementary ribonucleotides into the growing RNA chain one at a time via the nucleotide addition cycle. The nucleotide addition cycle, however, is prone to misincorporation of noncomplementary nucleotides. Thus, to ensure transcriptional fidelity, Pol II backtracks and then cleaves the misincorporated nucleotides. These two reverse reactions, nucleotide addition and cleavage, are catalyzed in the same active site of Pol II, which is different from DNA polymerases or other endonucleases. Recently, substantial progress has been made to understand how Pol II effectively performs its dual role in the same active site. Our review highlights these recent studies and provides an overall model of the catalytic mechanisms of Pol II. In particular, RNA extension follows the two-metal-ion mechanism, and several Pol II residues play important roles to facilitate the catalysis. In sharp contrast, the cleavage reaction is independent of any Pol II residues. Interestingly, Pol II relies on its residues to recognize the misincorporated nucleotides during the backtracking process, prior to cleavage. In this way, Pol II efficiently compartmentalizes its two distinct catalytic functions using the same active site. Lastly, we also discuss a new perspective on the potential third Mg2+ in the nucleotide addition and intrinsic cleavage reactions.
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Affiliation(s)
- Ilona Christy Unarta
- Department of Chemistry, Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eshani C Goonetilleke
- Department of Chemistry, Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Dong Wang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA; Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California, USA; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA.
| | - Xuhui Huang
- Department of Chemistry, Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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19
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Mitra P, Banerjee S, Khandavalli C, Deshmukh AS. The role of Toxoplasma TFIIS-like protein in the early stages of mRNA transcription. Biochim Biophys Acta Gen Subj 2022; 1866:130240. [PMID: 36058424 DOI: 10.1016/j.bbagen.2022.130240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/25/2022] [Accepted: 08/28/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND The mRNA transcription is a multistep process involving distinct sets of proteins associated with RNA polymerase II (RNAPII) through various stages. Recent studies have highlighted the role of RNAPII-associated proteins in facilitating the assembly of functional complexes in a crowded nuclear milieu. RNAPII dynamics and gene expression regulation have been primarily studied in model eukaryotes like yeasts and mammals and remain largely unchartered in protozoan parasites like Toxoplasma gondii, where considerable gene expression changes accompany stage differentiations. Here we report a key modulator of RNAPII activity, TFIIS in Toxoplasma gondii (TgTFIIS). METHODS A Pull-down assay demonstrated that TgTFIIS binds to RNAPII subunit TgRPB1. Truncation mutants of TFIIS help us define the regions critical for its binding to TgRPB1. Co-immunoprecipitation analysis confirmed the interaction between the native TgTFIIS and TgRPB1. Confocal microscopy revealed a predominantly nuclear localization. Native TgTFIIS was able to bind promoter DNA which was consistent with the CHIP results. RESULTS TgTFIIS complements initiation defects in yeast mutants, and the regions implicated in RNAPII binding appeared essential for this function. Interestingly, the C-terminal zinc finger domain necessary for its potential elongation function is dispensable for TgRPB1 binding. TgTFIIS was found to be associated with the promoter region along with its association with the ORF on an RNAPII transcribed gene. CONCLUSION The observations were in line with the potential role of TgTFIIS in early events of RNAPII transcription in addition to elongation. GENERAL SIGNIFICANCE The study elucidates the potential role of RNAPII-associated proteins in multiple steps of transcription.
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Affiliation(s)
- Pallabi Mitra
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India.
| | - Sneha Banerjee
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Chittiraju Khandavalli
- DBT-National Institute of Animal Biotechnology, Hyderabad, India; Dept. of Graduate Studies, Regional Centre for Biotechnology, Faridabad, Haryana, India
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20
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Kor R, Mohammad-Rafiee F. Theoretical study of RNA-polymerase behavior considering the backtracking state. SOFT MATTER 2022; 18:5979-5988. [PMID: 35920142 DOI: 10.1039/d2sm00232a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The dynamical behavior of the RNA polymerase in the transcription process is vital to gene expression. During the transcription process, the 3' end of the transcribed RNA can be dislocated from the active site of the enzyme and as a result, the RNA polymerase goes to the backtracked state. Here, we develop a theoretical model to study the transcription process considering the backtracking state. We aim at describing the behavior of the enzyme in the backtracking state in the presence of an external force, which leads to two possibilities: (i) rescuing from the backtracking state and, (ii) the arresting of the enzyme. We study the probability and the rate of the mentioned processes. In addition, we find that entering the backtracking state behaves like the Brownian ratchet mechanism. This model could shed some light on the modeling of the transcription process and further studies on the energy landscape of the backtracking channel and the gene regulation.
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Affiliation(s)
- Razieh Kor
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
| | - Farshid Mohammad-Rafiee
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
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21
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Farnung L, Ochmann M, Garg G, Vos SM, Cramer P. Structure of a backtracked hexasomal intermediate of nucleosome transcription. Mol Cell 2022; 82:3126-3134.e7. [PMID: 35858621 DOI: 10.1016/j.molcel.2022.06.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/17/2022] [Accepted: 06/21/2022] [Indexed: 10/17/2022]
Abstract
During gene transcription, RNA polymerase II (RNA Pol II) passes nucleosomes with the help of various elongation factors. Here, we show that RNA Pol II achieves efficient nucleosome passage when the human elongation factors DSIF, PAF1 complex (PAF), RTF1, SPT6, and TFIIS are present. The cryo-EM structure of an intermediate of the nucleosome passage shows a partially unraveled hexasome that lacks the proximal H2A-H2B dimer and interacts with the RNA Pol II jaw, DSIF, and the CTR9trestle helix. RNA Pol II adopts a backtracked state with the RNA 3' end dislodged from the active site and bound in the RNA Pol II pore. Additional structures and biochemical data show that human TFIIS enters the RNA Pol II pore and stimulates the cleavage of the backtracked RNA and nucleosome passage.
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Affiliation(s)
- Lucas Farnung
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany.
| | - Moritz Ochmann
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - Gaurika Garg
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - Seychelle M Vos
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - Patrick Cramer
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany.
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22
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Todorovic M, Rivollier P, Wong AAWL, Wang Z, Pryyma A, Nguyen TT, Newell KC, Froelich J, Perrin DM. Rationally Designed Amanitins Achieve Enhanced Cytotoxicity. J Med Chem 2022; 65:10357-10376. [PMID: 35696491 DOI: 10.1021/acs.jmedchem.1c02226] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
For 70 years, α-amanitin, the most cytotoxic peptide in its class, has been without a synthetic rival; through synthesis, we address the structure-activity relationships to inform the design of new amatoxins and disclose analogues that are more cytotoxic than the natural product when evaluated on CHO, HEK293, and HeLa cells, whereas on liver-derived HepG2 cells, the same toxins show diminished cytotoxicity.
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Affiliation(s)
- Mihajlo Todorovic
- Chemistry Department, 2036 Main Mall, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T-1Z1, Canada
| | - Paul Rivollier
- Chemistry Department, 2036 Main Mall, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T-1Z1, Canada
| | - Antonio A W L Wong
- Chemistry Department, 2036 Main Mall, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T-1Z1, Canada
| | - Zhou Wang
- Chemistry Department, 2036 Main Mall, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T-1Z1, Canada
| | - Alla Pryyma
- Chemistry Department, 2036 Main Mall, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T-1Z1, Canada
| | - Tuan Trung Nguyen
- Chemistry Department, 2036 Main Mall, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T-1Z1, Canada
| | - Kayla C Newell
- Chemistry Department, 2036 Main Mall, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T-1Z1, Canada
| | - Juliette Froelich
- Chemistry Department, 2036 Main Mall, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T-1Z1, Canada
| | - David M Perrin
- Chemistry Department, 2036 Main Mall, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T-1Z1, Canada
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23
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RNA polymerase I (Pol I) lobe-binding subunit Rpa12.2 promotes RNA cleavage and proofreading. J Biol Chem 2022; 298:101862. [PMID: 35341765 PMCID: PMC9108883 DOI: 10.1016/j.jbc.2022.101862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 03/13/2022] [Accepted: 03/17/2022] [Indexed: 11/23/2022] Open
Abstract
Elongating nuclear RNA polymerases (Pols) frequently pause, backtrack, and are then reactivated by endonucleolytic cleavage. Pol backtracking and RNA cleavage are also crucial for proofreading, which contributes to transcription fidelity. RNA polymerase I (Pol I) of the yeast Saccharomyces cerevisiae synthesizes exclusively 35S rRNA, the precursor transcript of mature ribosomal 5.8S, 18S, and 25S rRNA. Pol I contains the specific heterodimeric subunits Rpa34.5/49 and subunit Rpa12.2, which have been implicated in RNA cleavage and elongation activity, respectively. These subunits are associated with the Pol I lobe structure and encompass different structural domains, but the contribution of these domains to RNA elongation is unclear. Here, we used Pol I mutants or reconstituted Pol I enzymes to study the effects of these subunits and/or their distinct domains on RNA cleavage, backtracking, and transcription fidelity in defined in vitro systems. Our findings suggest that the presence of the intact C-terminal domain of Rpa12.2 is sufficient to support the cleavage reaction, but that the N-terminal domains of Rpa12.2 and the heterodimer facilitate backtracking and RNA cleavage. Since both N-terminal and C-terminal domains of Rpa12.2 were also required to faithfully incorporate NTPs in the growing RNA chain, efficient backtracking and RNA cleavage might be a prerequisite for transcription fidelity. We propose that RNA Pols containing efficient RNA cleavage activity are able to add and remove nucleotides until the matching nucleotide supports RNA chain elongation, whereas cleavage-deficient enzymes can escape this proofreading process by incorporating incorrect nucleotides.
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24
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Yang C, Fujiwara R, Kim HJ, Basnet P, Zhu Y, Colón JJG, Steimle S, Garcia BA, Kaplan CD, Murakami K. Structural visualization of de novo transcription initiation by Saccharomyces cerevisiae RNA polymerase II. Mol Cell 2022; 82:660-676.e9. [PMID: 35051353 PMCID: PMC8818039 DOI: 10.1016/j.molcel.2021.12.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 11/04/2021] [Accepted: 12/15/2021] [Indexed: 02/05/2023]
Abstract
Previous structural studies of the initiation-elongation transition of RNA polymerase II (pol II) transcription have relied on the use of synthetic oligonucleotides, often artificially discontinuous to capture pol II in the initiating state. Here, we report multiple structures of initiation complexes converted de novo from a 33-subunit yeast pre-initiation complex (PIC) through catalytic activities and subsequently stalled at different template positions. We determine that PICs in the initially transcribing complex (ITC) can synthesize a transcript of ∼26 nucleotides before transitioning to an elongation complex (EC) as determined by the loss of general transcription factors (GTFs). Unexpectedly, transition to an EC was greatly accelerated when an ITC encountered a downstream EC stalled at promoter proximal regions and resulted in a collided head-to-end dimeric EC complex. Our structural analysis reveals a dynamic state of TFIIH, the largest of GTFs, in PIC/ITC with distinct functional consequences at multiple steps on the pathway to elongation.
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Affiliation(s)
- Chun Yang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A
| | - Rina Fujiwara
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Hee Jong Kim
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA,Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Pratik Basnet
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Yunye Zhu
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Jose J. Gorbea Colón
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Stefan Steimle
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A
| | - Benjamin A. Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Craig D. Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Kenji Murakami
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Lead contact,Correspondence to:
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25
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Oh J, Jia T, Xu J, Chong J, Dervan PB, Wang D. RNA polymerase II trapped on a molecular treadmill: Structural basis of persistent transcriptional arrest by a minor groove DNA binder. Proc Natl Acad Sci U S A 2022; 119:e2114065119. [PMID: 35022237 PMCID: PMC8784135 DOI: 10.1073/pnas.2114065119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/07/2021] [Indexed: 02/06/2023] Open
Abstract
Elongating RNA polymerase II (Pol II) can be paused or arrested by a variety of obstacles. These obstacles include DNA lesions, DNA-binding proteins, and small molecules. Hairpin pyrrole-imidazole (Py-Im) polyamides bind to the minor groove of DNA in a sequence-specific manner and induce strong transcriptional arrest. Remarkably, this Py-Im-induced Pol II transcriptional arrest is persistent and cannot be rescued by transcription factor TFIIS. In contrast, TFIIS can effectively rescue the transcriptional arrest induced by a nucleosome barrier. The structural basis of Py-Im-induced transcriptional arrest and why TFIIS cannot rescue this arrest remain elusive. Here we determined the X-ray crystal structures of four distinct Pol II elongation complexes (Pol II ECs) in complex with hairpin Py-Im polyamides as well as of the hairpin Py-Im polyamides-dsDNA complex. We observed that the Py-Im oligomer directly interacts with RNA Pol II residues, introduces compression of the downstream DNA duplex, prevents Pol II forward translocation, and induces Pol II backtracking. These results, together with biochemical studies, provide structural insight into the molecular mechanism by which Py-Im blocks transcription. Our structural study reveals why TFIIS fails to promote Pol II bypass of Py-Im-induced transcriptional arrest.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Tiezheng Jia
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Peter B Dervan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125;
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093;
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
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26
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Gong P. Within and Beyond the Nucleotide Addition Cycle of Viral RNA-dependent RNA Polymerases. Front Mol Biosci 2022; 8:822218. [PMID: 35083282 PMCID: PMC8784604 DOI: 10.3389/fmolb.2021.822218] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 12/21/2021] [Indexed: 11/13/2022] Open
Abstract
Nucleotide addition cycle (NAC) is a fundamental process utilized by nucleic acid polymerases when carrying out nucleic acid biosynthesis. An induced-fit mechanism is usually taken by these polymerases upon NTP/dNTP substrate binding, leading to active site closure and formation of a phosphodiester bond. In viral RNA-dependent RNA polymerases, the post-chemistry translocation is stringently controlled by a structurally conserved motif, resulting in asymmetric movement of the template-product duplex. This perspective focuses on viral RdRP NAC and related mechanisms that have not been structurally clarified to date. Firstly, RdRP movement along the template strand in the absence of catalytic events may be relevant to catalytic complex dissociation or proofreading. Secondly, pyrophosphate or non-cognate NTP-mediated cleavage of the product strand 3′-nucleotide can also play a role in reactivating paused or arrested catalytic complexes. Furthermore, non-cognate NTP substrates, including NTP analog inhibitors, can not only alter NAC when being misincorporated, but also impact on subsequent NACs. Complications and challenges related to these topics are also discussed.
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Affiliation(s)
- Peng Gong
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
- Drug Discovery Center for Infectious Diseases, Nankai University, Tianjin, China
- *Correspondence: Peng Gong,
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27
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Pilsl M, Engel C. Structural Studies of Eukaryotic RNA Polymerase I Using Cryo-Electron Microscopy. Methods Mol Biol 2022; 2533:71-80. [PMID: 35796983 PMCID: PMC9761920 DOI: 10.1007/978-1-0716-2501-9_5] [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] [Indexed: 06/15/2023]
Abstract
Technical advances have pushed the resolution limit of single-particle cryo-electron microscopy (cryo-EM) throughout the past decade and made the technique accessible to a wide range of samples. Among them, multisubunit DNA-dependent RNA polymerases (Pols) are a prominent example. This review aims at briefly summarizing the architecture and structural adaptations of Pol I, highlighting the importance of cryo-electron microscopy in determining the structures of transcription complexes.
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Affiliation(s)
- Michael Pilsl
- Regensburg Center for Biochemistry (RCB), University of Regensburg, Regensburg, Germany
| | - Christoph Engel
- Regensburg Center for Biochemistry (RCB), University of Regensburg, Regensburg, Germany.
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28
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Huang K, Wu XX, Fang CL, Xu ZG, Zhang HW, Gao J, Zhou CM, You LL, Gu ZX, Mu WH, Feng Y, Wang JW, Zhang Y. Pol IV and RDR2: A two-RNA-polymerase machine that produces double-stranded RNA. Science 2021; 374:1579-1586. [DOI: 10.1126/science.abj9184] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Kun Huang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao-Xian Wu
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Cheng-Li Fang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhou-Geng Xu
- University of Chinese Academy of Sciences, Beijing 100049, China
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hong-Wei Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Gao
- University of Chinese Academy of Sciences, Beijing 100049, China
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Chuan-Miao Zhou
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Lin-Lin You
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhan-Xi Gu
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wen-Hui Mu
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Yu Feng
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jia-Wei Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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29
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Palo MZ, Zhu J, Mishanina TV, Landick R. Conserved Trigger Loop Histidine of RNA Polymerase II Functions as a Positional Catalyst Primarily through Steric Effects. Biochemistry 2021; 60:3323-3336. [PMID: 34705427 DOI: 10.1021/acs.biochem.1c00528] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In all domains of life, multisubunit RNA polymerases (RNAPs) catalyze both the extension of mRNA transcripts by nucleotide addition and the hydrolysis of RNA, which enables proofreading by removal of misincorporated nucleotides. A highly conserved catalytic module within RNAPs called the trigger loop (TL) functions as the key controller of these activities. The TL is proposed to act as a positional catalyst of phosphoryl transfer and transcript cleavage via electrostatic and steric contacts with substrates in its folded helical form. The function of a near-universally conserved TL histidine that contacts NTP phosphates is of particular interest. Despite its exceptional conservation, substitutions of the TL His with Gln support efficient catalysis in bacterial and yeast RNAPs. Unlike bacterial TLs, which contain a nearby Arg, the TL His is the only acid-base catalyst candidate in the eukaryotic RNAPII TL. Nonetheless, replacement of the TL His with Leu is reported to support cell growth in yeast, suggesting that even hydrogen bonding and polarity at this position may be dispensable for efficient catalysis by RNAPII. To test how a TL His-to-Leu substitution affects the enzymatic functions of RNAPII, we compared its rates of nucleotide addition, pyrophosphorolysis, and RNA hydrolysis to those of the wild-type RNAPII enzyme. The His-to-Leu substitution slightly reduced rates of phosphoryl transfer with little if any effect on intrinsic transcript cleavage. These findings indicate that the highly conserved TL His is neither an obligate acid-base catalyst nor a polar contact for NTP phosphates but instead functions as a positional catalyst mainly through steric effects.
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Affiliation(s)
- Michael Z Palo
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Junqiao Zhu
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Tatiana V Mishanina
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.,Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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30
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Abstract
The ongoing Covid-19 pandemic has spurred research in the biology of the nidovirus severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Much focus has been on the viral RNA synthesis machinery due to its fundamental role in viral propagation. The central and essential enzyme of the RNA synthesis process, the RNA-dependent RNA polymerase (RdRp), functions in conjunction with a coterie of viral-encoded enzymes that mediate crucial nucleic acid transactions. Some of these enzymes share common features with other RNA viruses, while others play roles unique to nidoviruses or CoVs. The RdRps are proven targets for viral pathogens, and many of the other nucleic acid processing enzymes are promising targets. The purpose of this review is to summarize recent advances in our understanding of the mechanisms of RNA synthesis in CoVs. By reflecting on these studies, we hope to emphasize the remaining gaps in our knowledge. The recent onslaught of structural information related to SARS-CoV-2 RNA synthesis, in combination with previous structural, genetic and biochemical studies, have vastly improved our understanding of how CoVs replicate and process their genomic RNA. Structural biology not only provides a blueprint for understanding the function of the enzymes and cofactors in molecular detail, but also provides a basis for drug design and optimization. The concerted efforts of researchers around the world, in combination with the renewed urgency toward understanding this deadly family of viruses, may eventually yield new and improved antivirals that provide relief to the current global devastation.
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Affiliation(s)
- Brandon Malone
- The Rockefeller University, New York, New York, United States
| | | | - Seth A Darst
- The Rockefeller University, New York, New York, United States.
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31
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Zhao D, Liu W, Chen K, Wu Z, Yang H, Xu Y. Structure of the human RNA polymerase I elongation complex. Cell Discov 2021; 7:97. [PMID: 34671025 PMCID: PMC8528822 DOI: 10.1038/s41421-021-00335-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 09/06/2021] [Indexed: 01/29/2023] Open
Abstract
Eukaryotic RNA polymerase I (Pol I) transcribes ribosomal DNA and generates RNA for ribosome synthesis. Pol I accounts for the majority of cellular transcription activity and dysregulation of Pol I transcription leads to cancers and ribosomopathies. Despite extensive structural studies of yeast Pol I, structure of human Pol I remains unsolved. Here we determined the structures of the human Pol I in the pre-translocation, post-translocation, and backtracked states at near-atomic resolution. The single-subunit peripheral stalk lacks contacts with the DNA-binding clamp and is more flexible than the two-subunit stalk in yeast Pol I. Compared to yeast Pol I, human Pol I possesses a more closed clamp, which makes more contacts with DNA. The Pol I structure in the post-cleavage backtracked state shows that the C-terminal zinc ribbon of RPA12 inserts into an open funnel and facilitates “dinucleotide cleavage” on mismatched DNA–RNA hybrid. Critical disease-associated mutations are mapped on Pol I regions that are involved in catalysis and complex organization. In summary, the structures provide new sights into human Pol I complex organization and efficient proofreading.
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Affiliation(s)
- Dan Zhao
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai, China
| | - Weida Liu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai, China
| | - Ke Chen
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai, China
| | - Zihan Wu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai, China
| | - Huirong Yang
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai, China.
| | - Yanhui Xu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai, China. .,The International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology of China, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China. .,Human Phenome Institute, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China. .,State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot, Inner Mongolia, China.
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32
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Xu J, Chong J, Wang D. Strand-specific effect of Rad26 and TFIIS in rescuing transcriptional arrest by CAG trinucleotide repeat slip-outs. Nucleic Acids Res 2021; 49:7618-7627. [PMID: 34197619 PMCID: PMC8287942 DOI: 10.1093/nar/gkab573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/08/2021] [Accepted: 06/21/2021] [Indexed: 02/03/2023] Open
Abstract
Transcription induced CAG repeat instability is associated with fatal neurological disorders. Genetic approaches found transcription-coupled nucleotide excision repair (TC-NER) factor CSB protein and TFIIS play critical roles in modulating the repeat stability. Here, we took advantage of an in vitro reconstituted yeast transcription system to investigate the underlying mechanism of RNA polymerase II (Pol II) transcriptional pausing/stalling by CAG slip-out structures and the functions of TFIIS and Rad26, the yeast ortholog of CSB, in modulating transcriptional arrest. We identified length-dependent and strand-specific mechanisms that account for CAG slip-out induced transcriptional arrest. We found substantial R-loop formation for the distal transcriptional pausing induced by template strand (TS) slip-out, but not non-template strand (NTS) slip-out. In contrast, Pol II backtracking was observed at the proximal transcriptional pausing sites induced by both NTS and TS slip-out blockage. Strikingly, we revealed that Rad26 and TFIIS can stimulate bypass of NTS CAG slip-out, but not TS slip-out induced distal pausing. Our biochemical results provide new insights into understanding the mechanism of CAG slip-out induced transcriptional pausing and functions of transcription factors in modulating transcription-coupled CAG repeat instability, which may pave the way for developing potential strategies for the treatment of repeat sequence associated human diseases.
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Affiliation(s)
- Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, USA
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, USA
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
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33
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Transcriptional processing of an unnatural base pair by eukaryotic RNA polymerase II. Nat Chem Biol 2021; 17:906-914. [PMID: 34140682 PMCID: PMC8319059 DOI: 10.1038/s41589-021-00817-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 05/10/2021] [Indexed: 02/05/2023]
Abstract
The development of unnatural base pairs (UBPs) has greatly increased the information storage capacity of DNA, allowing for transcription of unnatural RNA by the heterologously expressed T7 RNA polymerase (RNAP) in Escherichia coli. However, little is known about how UBPs are transcribed by cellular RNA polymerases. Here, we investigated how synthetic unnatural nucleotides, NaM and TPT3, are recognized by eukaryotic RNA polymerase II (Pol II) and found that Pol II is able to selectively recognize UBPs with high fidelity when dTPT3 is in the template strand and rNaMTP acts as the nucleotide substrate. Our structural analysis and molecular dynamics simulation provide structural insights into transcriptional processing of UBPs in a stepwise manner. Intriguingly, we identified a novel 3'-RNA binding site after rNaM addition, termed the swing state. These results may pave the way for future studies in the design of transcription and translation strategies in higher organisms with expanded genetic codes.
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34
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Matinkhoo K, Wong AAWL, Hambira CM, Kato B, Wei C, Müller C, Hechler T, Braun A, Gallo F, Pahl A, Perrin DM. Design, Synthesis, and Biochemical Evaluation of Alpha-Amanitin Derivatives Containing Analogs of the trans-Hydroxyproline Residue for Potential Use in Antibody-Drug Conjugates. Chemistry 2021; 27:10282-10292. [PMID: 34058032 DOI: 10.1002/chem.202101373] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Indexed: 01/08/2023]
Abstract
Alpha-amanitin, an extremely toxic bicyclic octapeptide extracted from the death-cap mushroom, Amanita phalloides, is a highly selective allosteric inhibitor of RNA polymerase II. Following on growing interest in using this toxin as a payload in antibody-drug conjugates, herein we report the synthesis and biochemical evaluation of several new derivatives of this toxin to probe the role of the trans-hydroxyproline (Hyp), which is known to be critical for toxicity. This structure activity relationship (SAR) study represents the first of its kind to use various Hyp-analogs to alter the conformational and H-bonding properties of Hyp in amanitin.
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Affiliation(s)
- Kaveh Matinkhoo
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Antonio A W L Wong
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Chido M Hambira
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Brandon Kato
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Charlie Wei
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Christoph Müller
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - Torsten Hechler
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - Alexandra Braun
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - Francesca Gallo
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - Andreas Pahl
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - David M Perrin
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
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35
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Structure of human RNA polymerase III elongation complex. Cell Res 2021; 31:791-800. [PMID: 33674783 PMCID: PMC8249397 DOI: 10.1038/s41422-021-00472-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/06/2021] [Indexed: 01/31/2023] Open
Abstract
RNA polymerase III (Pol III) transcribes essential structured small RNAs, such as tRNAs, 5S rRNA and U6 snRNA. The transcriptional activity of Pol III is tightly controlled and its dysregulation is associated with human diseases, such as cancer. Human Pol III has two isoforms with difference only in one of its subunits RPC7 (α and β). Despite structural studies of yeast Pol III, structure of human Pol III remains unsolved. Here, we determined the structures of 17-subunit human Pol IIIα complex in the backtracked and post-translocation states, respectively. Human Pol III contains a generally conserved catalytic core, similar to that of yeast counterpart, and structurally unique RPC3-RPC6-RPC7 heterotrimer and RPC10. The N-ribbon of TFIIS-like RPC10 docks on the RPC4-RPC5 heterodimer and the C-ribbon inserts into the funnel of Pol III in the backtracked state but is more flexible in the post-translocation state. RPC7 threads through the heterotrimer and bridges the stalk and Pol III core module. The winged helix 1 domain of RPC6 and the N-terminal region of RPC7α stabilize each other and may prevent Maf1-mediated repression of Pol III activity. The C-terminal FeS cluster of RPC6 coordinates a network of interactions that mediate core-heterotrimer contacts and stabilize Pol III. Our structural analysis sheds new light on the molecular mechanism of human Pol IIIα-specific transcriptional regulation and provides explanations for upregulated Pol III activity in RPC7α-dominant cancer cells.
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36
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Yan L, Yang Y, Li M, Zhang Y, Zheng L, Ge J, Huang YC, Liu Z, Wang T, Gao S, Zhang R, Huang YY, Guddat LW, Gao Y, Rao Z, Lou Z. Coupling of N7-methyltransferase and 3'-5' exoribonuclease with SARS-CoV-2 polymerase reveals mechanisms for capping and proofreading. Cell 2021; 184:3474-3485.e11. [PMID: 34143953 PMCID: PMC8142856 DOI: 10.1016/j.cell.2021.05.033] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/20/2021] [Accepted: 05/19/2021] [Indexed: 12/16/2022]
Abstract
The capping of mRNA and the proofreading play essential roles in SARS-CoV-2 replication and transcription. Here, we present the cryo-EM structure of the SARS-CoV-2 replication-transcription complex (RTC) in a form identified as Cap(0)-RTC, which couples a co-transcriptional capping complex (CCC) composed of nsp12 NiRAN, nsp9, the bifunctional nsp14 possessing an N-terminal exoribonuclease (ExoN) and a C-terminal N7-methyltransferase (N7-MTase), and nsp10 as a cofactor of nsp14. Nsp9 and nsp12 NiRAN recruit nsp10/nsp14 into the Cap(0)-RTC, forming the N7-CCC to yield cap(0) (7MeGpppA) at 5' end of pre-mRNA. A dimeric form of Cap(0)-RTC observed by cryo-EM suggests an in trans backtracking mechanism for nsp14 ExoN to facilitate proofreading of the RNA in concert with polymerase nsp12. These results not only provide a structural basis for understanding co-transcriptional modification of SARS-CoV-2 mRNA but also shed light on how replication fidelity in SARS-CoV-2 is maintained.
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Affiliation(s)
- Liming Yan
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yunxiang Yang
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Mingyu Li
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Ying Zhang
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Litao Zheng
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China; School of Life Sciences, Tsinghua University, Beijing, China
| | - Ji Ge
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yucen C Huang
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Zhenyu Liu
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Tao Wang
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Shan Gao
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China
| | - Ran Zhang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuanyun Y Huang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Luke W Guddat
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Yan Gao
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
| | - Zihe Rao
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, China; School of Life Sciences, Tsinghua University, Beijing, China; State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences and College of Pharmacy, Nankai University, Tianjin, China; National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; Guangzhou Laboratory, Guangzhou, China.
| | - Zhiyong Lou
- MOE Key Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing, China; Guangzhou Laboratory, Guangzhou, China.
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Nicholls RA, Wojdyr M, Joosten RP, Catapano L, Long F, Fischer M, Emsley P, Murshudov GN. The missing link: covalent linkages in structural models. Acta Crystallogr D Struct Biol 2021; 77:727-745. [PMID: 34076588 PMCID: PMC8171067 DOI: 10.1107/s2059798321003934] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/13/2021] [Indexed: 11/10/2022] Open
Abstract
Covalent linkages between constituent blocks of macromolecules and ligands have been subject to inconsistent treatment during the model-building, refinement and deposition process. This may stem from a number of sources, including difficulties with initially detecting the covalent linkage, identifying the correct chemistry, obtaining an appropriate restraint dictionary and ensuring its correct application. The analysis presented herein assesses the extent of problems involving covalent linkages in the Protein Data Bank (PDB). Not only will this facilitate the remediation of existing models, but also, more importantly, it will inform and thus improve the quality of future linkages. By considering linkages of known type in the CCP4 Monomer Library (CCP4-ML), failure to model a covalent linkage is identified to result in inaccurate (systematically longer) interatomic distances. Scanning the PDB for proximal atom pairs that do not have a corresponding type in the CCP4-ML reveals a large number of commonly occurring types of unannotated potential linkages; in general, these may or may not be covalently linked. Manual consideration of the most commonly occurring cases identifies a number of genuine classes of covalent linkages. The recent expansion of the CCP4-ML is discussed, which has involved the addition of over 16 000 and the replacement of over 11 000 component dictionaries using AceDRG. As part of this effort, the CCP4-ML has also been extended using AceDRG link dictionaries for the aforementioned linkage types identified in this analysis. This will facilitate the identification of such linkage types in future modelling efforts, whilst concurrently easing the process involved in their application. The need for a universal standard for maintaining link records corresponding to covalent linkages, and references to the associated dictionaries used during modelling and refinement, following deposition to the PDB is emphasized. The importance of correctly modelling covalent linkages is demonstrated using a case study, which involves the covalent linkage of an inhibitor to the main protease in various viral species, including SARS-CoV-2. This example demonstrates the importance of properly modelling covalent linkages using a comprehensive restraint dictionary, as opposed to just using a single interatomic distance restraint or failing to model the covalent linkage at all.
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Affiliation(s)
- Robert A. Nicholls
- Structural Studies, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Marcin Wojdyr
- Global Phasing Limited, Sheraton House, Castle Park, Cambridge CB3 0AX, United Kingdom
| | - Robbie P. Joosten
- Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
- Oncode Institute, The Netherlands
| | - Lucrezia Catapano
- Structural Studies, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
- Randall Centre for Cell and Molecular Biophysics, Faculty of Life Sciences and Medicine, King’s College London, London SE1 9RT, United Kingdom
| | - Fei Long
- Structural Studies, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Marcus Fischer
- Chemical Biology and Therapeutics and Structural Biology, St Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105-3678, USA
| | - Paul Emsley
- Structural Studies, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Garib N. Murshudov
- Structural Studies, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
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38
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Xu J, Chong J, Wang D. Opposite roles of transcription elongation factors Spt4/5 and Elf1 in RNA polymerase II transcription through B-form versus non-B DNA structures. Nucleic Acids Res 2021; 49:4944-4953. [PMID: 33877330 PMCID: PMC8136819 DOI: 10.1093/nar/gkab240] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/21/2021] [Accepted: 04/06/2021] [Indexed: 12/18/2022] Open
Abstract
Transcription elongation can be affected by numerous types of obstacles, such as nucleosome, pausing sequences, DNA lesions and non-B-form DNA structures. Spt4/5 and Elf1 are conserved transcription elongation factors that promote RNA polymerase II (Pol II) bypass of nucleosome and pausing sequences. Importantly, genetic studies have shown that Spt4/5 plays essential roles in the transcription of expanded nucleotide repeat genes associated with inherited neurological diseases. Here, we investigate the function of Spt4/5 and Elf1 in the transcription elongation of CTG•CAG repeat using an in vitro reconstituted yeast transcription system. We found that Spt4/5 helps Pol II transcribe through the CTG•CAG tract duplex DNA, which is in good agreement with its canonical roles in stimulating transcription elongation. In sharp contrast, surprisingly, we revealed that Spt4/5 greatly inhibits Pol II transcriptional bypass of CTG and CAG slip-out structures. Furthermore, we demonstrated that transcription elongation factor Elf1 individually and cooperatively with Spt4/5 inhibits Pol II bypass of the slip-out structures. This study uncovers the important functional interplays between template DNA structures and the function of transcription elongation factors. This study also expands our understanding of the functions of Spt4/5 and Elf1 in transcriptional processing of trinucleotide repeat DNA.
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Affiliation(s)
- Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
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39
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Malone B, Chen J, Wang Q, Llewellyn E, Choi YJ, Olinares PDB, Cao X, Hernandez C, Eng ET, Chait BT, Shaw DE, Landick R, Darst SA, Campbell EA. Structural basis for backtracking by the SARS-CoV-2 replication-transcription complex. Proc Natl Acad Sci U S A 2021; 118:e2102516118. [PMID: 33883267 PMCID: PMC8126829 DOI: 10.1073/pnas.2102516118] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Backtracking, the reverse motion of the transcriptase enzyme on the nucleic acid template, is a universal regulatory feature of transcription in cellular organisms but its role in viruses is not established. Here we present evidence that backtracking extends into the viral realm, where backtracking by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-dependent RNA polymerase (RdRp) may aid viral transcription and replication. Structures of SARS-CoV-2 RdRp bound to the essential nsp13 helicase and RNA suggested the helicase facilitates backtracking. We use cryo-electron microscopy, RNA-protein cross-linking, and unbiased molecular dynamics simulations to characterize SARS-CoV-2 RdRp backtracking. The results establish that the single-stranded 3' segment of the product RNA generated by backtracking extrudes through the RdRp nucleoside triphosphate (NTP) entry tunnel, that a mismatched nucleotide at the product RNA 3' end frays and enters the NTP entry tunnel to initiate backtracking, and that nsp13 stimulates RdRp backtracking. Backtracking may aid proofreading, a crucial process for SARS-CoV-2 resistance against antivirals.
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Affiliation(s)
- Brandon Malone
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065
| | - James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065
| | - Qi Wang
- D. E. Shaw Research, New York, NY 10036
| | - Eliza Llewellyn
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065
| | - Young Joo Choi
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, 10065
| | - Xinyun Cao
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Carolina Hernandez
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027
| | - Edward T Eng
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, 10065
| | - David E Shaw
- D. E. Shaw Research, New York, NY 10036
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065;
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065;
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40
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Malone B, Chen J, Wang Q, Llewellyn E, Choi YJ, Olinares PDB, Cao X, Hernandez C, Eng ET, Chait BT, Shaw DE, Landick R, Darst SA, Campbell EA. Structural basis for backtracking by the SARS-CoV-2 replication-transcription complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.03.13.435256. [PMID: 33758867 PMCID: PMC7987028 DOI: 10.1101/2021.03.13.435256] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Backtracking, the reverse motion of the transcriptase enzyme on the nucleic acid template, is a universal regulatory feature of transcription in cellular organisms but its role in viruses is not established. Here we present evidence that backtracking extends into the viral realm, where backtracking by the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) may aid viral transcription and replication. Structures of SARS-CoV-2 RdRp bound to the essential nsp13 helicase and RNA suggested the helicase facilitates backtracking. We use cryo-electron microscopy, RNA-protein crosslinking, and unbiased molecular dynamics simulations to characterize SARS-CoV-2 RdRp backtracking. The results establish that the single-stranded 3'-segment of the product-RNA generated by backtracking extrudes through the RdRp NTP-entry tunnel, that a mismatched nucleotide at the product-RNA 3'-end frays and enters the NTP-entry tunnel to initiate backtracking, and that nsp13 stimulates RdRp backtracking. Backtracking may aid proofreading, a crucial process for SARS-CoV-2 resistance against antivirals.
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Affiliation(s)
- Brandon Malone
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
- These authors contributed equally: Brandon Malone, James Chen
| | - James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
- These authors contributed equally: Brandon Malone, James Chen
| | - Qi Wang
- D. E. Shaw Research, New York, NY 10036 USA
| | - Eliza Llewellyn
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Young Joo Choi
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Paul Dominic B. Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, 10065 USA
| | - Xinyun Cao
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Carolina Hernandez
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027 USA
| | - Edward T. Eng
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027 USA
| | - Brian T. Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, 10065 USA
| | - David E. Shaw
- D. E. Shaw Research, New York, NY 10036 USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032 USA
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Seth A. Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Elizabeth A. Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
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41
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Berkyurek AC, Furlan G, Lampersberger L, Beltran T, Weick E, Nischwitz E, Cunha Navarro I, Braukmann F, Akay A, Price J, Butter F, Sarkies P, Miska EA. The RNA polymerase II subunit RPB-9 recruits the integrator complex to terminate Caenorhabditis elegans piRNA transcription. EMBO J 2021; 40:e105565. [PMID: 33533030 PMCID: PMC7917558 DOI: 10.15252/embj.2020105565] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 12/14/2020] [Accepted: 12/19/2020] [Indexed: 01/03/2023] Open
Abstract
PIWI-interacting RNAs (piRNAs) are genome-encoded small RNAs that regulate germ cell development and maintain germline integrity in many animals. Mature piRNAs engage Piwi Argonaute proteins to silence complementary transcripts, including transposable elements and endogenous genes. piRNA biogenesis mechanisms are diverse and remain poorly understood. Here, we identify the RNA polymerase II (RNA Pol II) core subunit RPB-9 as required for piRNA-mediated silencing in the nematode Caenorhabditis elegans. We show that rpb-9 initiates heritable piRNA-mediated gene silencing at two DNA transposon families and at a subset of somatic genes in the germline. We provide genetic and biochemical evidence that RPB-9 is required for piRNA biogenesis by recruiting the Integrator complex at piRNA genes, hence promoting transcriptional termination. We conclude that, as a part of its rapid evolution, the piRNA pathway has co-opted an ancient machinery for high-fidelity transcription.
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Affiliation(s)
- Ahmet C Berkyurek
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Giulia Furlan
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Lisa Lampersberger
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Toni Beltran
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
| | - Eva‐Maria Weick
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Present address:
Structural Biology ProgramSloan Kettering InstituteMemorial Sloan Kettering Cancer CenterNew YorkNYUSA
| | - Emily Nischwitz
- Quantitative ProteomicsInstitute of Molecular BiologyMainzGermany
| | - Isabela Cunha Navarro
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Fabian Braukmann
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Alper Akay
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
- Present address:
School of Biological SciencesUniversity of East AngliaNorwich, NorfolkUK
| | - Jonathan Price
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Falk Butter
- Quantitative ProteomicsInstitute of Molecular BiologyMainzGermany
| | - Peter Sarkies
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
| | - Eric A Miska
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
- Wellcome Sanger InstituteWellcome Trust Genome CampusCambridgeUK
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42
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Wang Q, Li S, Wan F, Xu Y, Wu Z, Cao M, Lan P, Lei M, Wu J. Structural insights into transcriptional regulation of human RNA polymerase III. Nat Struct Mol Biol 2021; 28:220-227. [PMID: 33558766 DOI: 10.1038/s41594-021-00557-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 12/29/2020] [Indexed: 01/30/2023]
Abstract
RNA polymerase III (Pol III) synthesizes structured, essential small RNAs, such as transfer RNA, 5S ribosomal RNA and U6 small nuclear RNA. Pol III, the largest nuclear RNA polymerase, is composed of a conserved core region and eight constitutive regulatory subunits, but how these factors jointly regulate Pol III transcription remains unclear. Here, we present cryo-EM structures of human Pol III in both apo and elongating states, which unveil both an orchestrated movement during the apo-to-elongating transition and an unexpected apo state in which the RPC7 subunit tail occupies the DNA-RNA-binding cleft of Pol III, suggesting that RPC7 plays important roles in both autoinhibition and transcription initiation. The structures also reveal a proofreading mechanism for the TFIIS-like subunit RPC10, which stably retains its catalytic position in the secondary channel, explaining the high fidelity of Pol III transcription. Our work provides an integrated picture of the mechanism of Pol III transcription regulation.
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Affiliation(s)
- Qianmin Wang
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| | - Shaobai Li
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| | - Futang Wan
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| | - Youwei Xu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Zhenfang Wu
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| | - Mi Cao
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| | - Pengfei Lan
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Shanghai Institute of Precision Medicine, Shanghai, China.
| | - Ming Lei
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Shanghai Institute of Precision Medicine, Shanghai, China. .,Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Jian Wu
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Shanghai Institute of Precision Medicine, Shanghai, China.
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43
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Cryo-EM structures of human RNA polymerase III in its unbound and transcribing states. Nat Struct Mol Biol 2021; 28:210-219. [PMID: 33558764 PMCID: PMC7610652 DOI: 10.1038/s41594-020-00555-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 12/21/2020] [Indexed: 01/30/2023]
Abstract
RNA polymerase III (Pol III) synthesizes transfer RNAs and other short, essential RNAs. Human Pol III misregulation is linked to tumor transformation, neurodegenerative and developmental disorders, and increased sensitivity to viral infections. Here, we present cryo-electron microscopy structures at 2.8 to 3.3 Å resolution of transcribing and unbound human Pol III. We observe insertion of the TFIIS-like subunit RPC10 into the polymerase funnel, providing insights into how RPC10 triggers transcription termination. Our structures resolve elements absent from Saccharomyces cerevisiae Pol III such as the winged-helix domains of RPC5 and an iron-sulfur cluster, which tethers the heterotrimer subcomplex to the core. The cancer-associated RPC7α isoform binds the polymerase clamp, potentially interfering with Pol III inhibition by tumor suppressor MAF1, which may explain why overexpressed RPC7α enhances tumor transformation. Finally, the human Pol III structure allows mapping of disease-related mutations and may contribute to the development of inhibitors that selectively target Pol III for therapeutic interventions.
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44
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Noe Gonzalez M, Blears D, Svejstrup JQ. Causes and consequences of RNA polymerase II stalling during transcript elongation. Nat Rev Mol Cell Biol 2021; 22:3-21. [PMID: 33208928 DOI: 10.1038/s41580-020-00308-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2020] [Indexed: 02/07/2023]
Abstract
The journey of RNA polymerase II (Pol II) as it transcribes a gene is anything but a smooth ride. Transcript elongation is discontinuous and can be perturbed by intrinsic regulatory barriers, such as promoter-proximal pausing, nucleosomes, RNA secondary structures and the underlying DNA sequence. More substantial blocking of Pol II translocation can be caused by other physiological circumstances and extrinsic obstacles, including other transcribing polymerases, the replication machinery and several types of DNA damage, such as bulky lesions and DNA double-strand breaks. Although numerous different obstacles cause Pol II stalling or arrest, the cell somehow distinguishes between them and invokes different mechanisms to resolve each roadblock. Resolution of Pol II blocking can be as straightforward as temporary backtracking and transcription elongation factor S-II (TFIIS)-dependent RNA cleavage, or as drastic as premature transcription termination or degradation of polyubiquitylated Pol II and its associated nascent RNA. In this Review, we discuss the current knowledge of how these different Pol II stalling contexts are distinguished by the cell, how they overlap with each other, how they are resolved and how, when unresolved, they can cause genome instability.
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Affiliation(s)
- Melvin Noe Gonzalez
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Daniel Blears
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK.
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
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45
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Huynh MT, Yadav SP, Reese JC, Lee TH. Nucleosome Dynamics during Transcription Elongation. ACS Chem Biol 2020; 15:3133-3142. [PMID: 33263994 DOI: 10.1021/acschembio.0c00617] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The nucleosome is the basic packing unit of the eukaryotic genome. Dynamic interactions between DNA and histones in the nucleosome are the molecular basis of gene accessibility regulation that governs the kinetics of various DNA-templated processes such as transcription elongation by RNA Polymerase II (Pol II). On the basis of single-molecule FRET measurements with chemically modified histones, we investigated the nucleosome dynamics during transcription elongation and how it is affected by histone acetylation at H3 K56 and the histone chaperone Nap1, both of which can affect DNA-histone interactions. We observed that H3K56 acetylation dramatically shortens the pause duration of Pol II near the entry region of the nucleosome, while Nap1 induces no noticeable difference. We also found that the elongation rate of Pol II through the nucleosome is unaffected by the acetylation or Nap1. These results indicate that H3K56 acetylation facilitates Pol II translocation through the nucleosome by assisting paused Pol II to resume and that Nap1 does not affect Pol II progression. Following transcription, only a small fraction of nucleosomes remain intact, which is unaffected by H3K56 acetylation or Nap1. These results suggest that (i) spontaneous nucleosome opening enables Pol II progression, (ii) Pol II mediates nucleosome reassembly very inefficiently, and (iii) Nap1 in the absence of other factors does not promote nucleosome disassembly or reassembly during transcription.
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46
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Abstract
Gene transcription by RNA polymerase II (Pol II) is the first step in the expression of the eukaryotic genome and a focal point for cellular regulation during development, differentiation, and responses to the environment. Two decades after the determination of the structure of Pol II, the mechanisms of transcription have been elucidated with studies of Pol II complexes with nucleic acids and associated proteins. Here we provide an overview of the nearly 200 available Pol II complex structures and summarize how these structures have elucidated promoter-dependent transcription initiation, promoter-proximal pausing and release of Pol II into active elongation, and the mechanisms that Pol II uses to navigate obstacles such as nucleosomes and DNA lesions. We predict that future studies will focus on how Pol II transcription is interconnected with chromatin transitions, RNA processing, and DNA repair.
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Affiliation(s)
- Sara Osman
- 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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47
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Chen J, Malone B, Llewellyn E, Grasso M, Shelton PM, Olinares PDB, Maruthi K, Eng ET, Vatandaslar H, Chait BT, Kapoor TM, Darst SA, Campbell EA. Structural Basis for Helicase-Polymerase Coupling in the SARS-CoV-2 Replication-Transcription Complex. Cell 2020; 182:1560-1573.e13. [PMID: 32783916 PMCID: PMC7386476 DOI: 10.1016/j.cell.2020.07.033] [Citation(s) in RCA: 309] [Impact Index Per Article: 77.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/10/2020] [Accepted: 07/22/2020] [Indexed: 01/21/2023]
Abstract
SARS-CoV-2 is the causative agent of the 2019-2020 pandemic. The SARS-CoV-2 genome is replicated and transcribed by the RNA-dependent RNA polymerase holoenzyme (subunits nsp7/nsp82/nsp12) along with a cast of accessory factors. One of these factors is the nsp13 helicase. Both the holo-RdRp and nsp13 are essential for viral replication and are targets for treating the disease COVID-19. Here we present cryoelectron microscopic structures of the SARS-CoV-2 holo-RdRp with an RNA template product in complex with two molecules of the nsp13 helicase. The Nidovirales order-specific N-terminal domains of each nsp13 interact with the N-terminal extension of each copy of nsp8. One nsp13 also contacts the nsp12 thumb. The structure places the nucleic acid-binding ATPase domains of the helicase directly in front of the replicating-transcribing holo-RdRp, constraining models for nsp13 function. We also observe ADP-Mg2+ bound in the nsp12 N-terminal nidovirus RdRp-associated nucleotidyltransferase domain, detailing a new pocket for anti-viral therapy development.
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Affiliation(s)
- James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Brandon Malone
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Eliza Llewellyn
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA
| | - Michael Grasso
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Patrick M.M. Shelton
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Paul Dominic B. Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Kashyap Maruthi
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Edward T. Eng
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Hasan Vatandaslar
- Institute of Molecular Health Sciences, ETH Zürich, 8093 Zürich, Switzerland
| | - Brian T. Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Tarun M. Kapoor
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Seth A. Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA,Corresponding author
| | - Elizabeth A. Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY 10065, USA,Corresponding author
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48
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Chen J, Malone B, Llewellyn E, Grasso M, Shelton PMM, Olinares PDB, Maruthi K, Eng E, Vatandaslar H, Chait BT, Kapoor T, Darst SA, Campbell EA. Structural basis for helicase-polymerase coupling in the SARS-CoV-2 replication-transcription complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32676607 PMCID: PMC7359531 DOI: 10.1101/2020.07.08.194084] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
SARS-CoV-2 is the causative agent of the 2019-2020 pandemic. The SARS-CoV-2 genome is replicated-transcribed by the RNA-dependent RNA polymerase holoenzyme (subunits nsp7/nsp82/nsp12) along with a cast of accessory factors. One of these factors is the nsp13 helicase. Both the holo-RdRp and nsp13 are essential for viral replication and are targets for treating the disease COVID-19. Here we present cryo-electron microscopic structures of the SARS-CoV-2 holo-RdRp with an RNA template-product in complex with two molecules of the nsp13 helicase. The Nidovirus-order-specific N-terminal domains of each nsp13 interact with the N-terminal extension of each copy of nsp8. One nsp13 also contacts the nsp12-thumb. The structure places the nucleic acid-binding ATPase domains of the helicase directly in front of the replicating-transcribing holo-RdRp, constraining models for nsp13 function. We also observe ADP-Mg2+ bound in the nsp12 N-terminal nidovirus RdRp-associated nucleotidyltransferase domain, detailing a new pocket for anti-viral therapeutic development.
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Affiliation(s)
- James Chen
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Brandon Malone
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Eliza Llewellyn
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Michael Grasso
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, 10065 USA
| | - Patrick M M Shelton
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, 10065 USA
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, 10065 USA
| | - Kashyap Maruthi
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027 USA
| | - Ed Eng
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027 USA
| | - Hasan Vatandaslar
- Institute of Molecular Health Sciences, ETH Zurich, 8093 Zürich, Switzerland
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, 10065 USA
| | - Tarun Kapoor
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, 10065 USA
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, 10065 USA
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49
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Cheung PPH, Jiang B, Booth GT, Chong TH, Unarta IC, Wang Y, Suarez GD, Wang J, Lis JT, Huang X. Identifying Transcription Error-Enriched Genomic Loci Using Nuclear Run-on Circular-Sequencing Coupled with Background Error Modeling. J Mol Biol 2020; 432:3933-3949. [PMID: 32325070 DOI: 10.1016/j.jmb.2020.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 01/30/2023]
Abstract
RNA polymerase transcribes certain genomic loci with higher errors rates. These transcription error-enriched genomic loci (TEELs) have implications in disease. Current deep-sequencing methods cannot distinguish TEELs from post-transcriptional modifications, stochastic transcription errors, and technical noise, impeding efforts to elucidate the mechanisms linking TEELs to disease. Here, we describe background error model-coupled precision nuclear run-on circular-sequencing (EmPC-seq) to discern genomic regions enriched for transcription misincorporations. EmPC-seq innovatively combines a nuclear run-on assay for capturing nascent RNA before post-transcriptional modifications, a circular-sequencing step that sequences the same nascent RNA molecules multiple times to improve accuracy, and a statistical model for distinguishing error-enriched regions among stochastic polymerase errors. Applying EmPC-seq to the ribosomal RNA transcriptome, we show that TEELs of RNA polymerase I are not randomly distributed but clustered together, with higher error frequencies at nascent transcript 3' ends. Our study establishes a reliable method of identifying TEELs with nucleotide precision, which can help elucidate their molecular origins.
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Affiliation(s)
- Peter Pak-Hang Cheung
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China; Department of Chemistry, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Biaobin Jiang
- Division of Life Science, Department of Chemical and Biological Engineering, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong; The HKUST Jockey Club Institute for Advanced Study (IAS), The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Gregory T Booth
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Tin Hang Chong
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China
| | - Ilona Christy Unarta
- Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Yuqing Wang
- Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Gianmarco D Suarez
- Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Jiguang Wang
- Division of Life Science, Department of Chemical and Biological Engineering, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA; The HKUST Jockey Club Institute for Advanced Study (IAS), The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
| | - Xuhui Huang
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China; Department of Chemistry, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong; Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
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50
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Antosz W, Deforges J, Begcy K, Bruckmann A, Poirier Y, Dresselhaus T, Grasser KD. Critical Role of Transcript Cleavage in Arabidopsis RNA Polymerase II Transcriptional Elongation. THE PLANT CELL 2020; 32:1449-1463. [PMID: 32152189 PMCID: PMC7203918 DOI: 10.1105/tpc.19.00891] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/10/2020] [Accepted: 03/05/2020] [Indexed: 05/14/2023]
Abstract
Transcript elongation factors associate with elongating RNA polymerase II (RNAPII) to control the efficiency of mRNA synthesis and consequently modulate plant growth and development. Encountering obstacles during transcription such as nucleosomes or particular DNA sequences may cause backtracking and transcriptional arrest of RNAPII. The elongation factor TFIIS stimulates the intrinsic transcript cleavage activity of the polymerase, which is required for efficient rescue of backtracked/arrested RNAPII. A TFIIS mutant variant (TFIISmut) lacks the stimulatory activity to promote RNA cleavage, but instead efficiently inhibits unstimulated transcript cleavage by RNAPII. We could not recover viable Arabidopsis (Arabidopsis thaliana) tfIIs plants constitutively expressing TFIISmut. Induced, transient expression of TFIISmut in tfIIs plants provoked severe growth defects, transcriptomic changes and massive, transcription-related redistribution of elongating RNAPII within transcribed regions toward the transcriptional start site. The predominant site of RNAPII accumulation overlapped with the +1 nucleosome, suggesting that upon inhibition of RNA cleavage activity, RNAPII arrest prevalently occurs at this position. In the presence of TFIISmut, the amount of RNAPII was reduced, which could be reverted by inhibiting the proteasome, indicating proteasomal degradation of arrested RNAPII. Our findings suggest that polymerase backtracking/arrest frequently occurs in plant cells, and RNAPII-reactivation is essential for correct transcriptional output and proper growth/development.
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Affiliation(s)
- Wojciech Antosz
- Department of Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93040 Regensburg, Germany
| | - Jules Deforges
- Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Kevin Begcy
- Environmental Horticulture Department, University of Florida, Gainesville, Florida 32611
| | - Astrid Bruckmann
- Department for Biochemistry I, Biochemistry Centre, University of Regensburg, D-93040 Regensburg, Germany
| | - Yves Poirier
- Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Thomas Dresselhaus
- Department of Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93040 Regensburg, Germany
| | - Klaus D Grasser
- Department of Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93040 Regensburg, Germany
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