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Gapińska M, Zajko W, Skowronek K, Figiel M, Krawczyk P, Egorov A, Dziembowski A, Johansson MO, Nowotny M. Structure-functional characterization of Lactococcus AbiA phage defense system. Nucleic Acids Res 2024; 52:4723-4738. [PMID: 38587192 PMCID: PMC11077055 DOI: 10.1093/nar/gkae230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 02/01/2024] [Accepted: 03/20/2024] [Indexed: 04/09/2024] Open
Abstract
Bacterial reverse transcriptases (RTs) are a large and diverse enzyme family. AbiA, AbiK and Abi-P2 are abortive infection system (Abi) RTs that mediate defense against bacteriophages. What sets Abi RTs apart from other RT enzymes is their ability to synthesize long DNA products of random sequences in a template- and primer-independent manner. Structures of AbiK and Abi-P2 representatives have recently been determined, but there are no structural data available for AbiA. Here, we report the crystal structure of Lactococcus AbiA polymerase in complex with a single-stranded polymerization product. AbiA comprises three domains: an RT-like domain, a helical domain that is typical for Abi polymerases, and a higher eukaryotes and prokaryotes nucleotide-binding (HEPN) domain that is common for many antiviral proteins. AbiA forms a dimer that distinguishes it from AbiK and Abi-P2, which form trimers/hexamers. We show the DNA polymerase activity of AbiA in an in vitro assay and demonstrate that it requires the presence of the HEPN domain which is enzymatically inactive. We validate our biochemical and structural results in vivo through bacteriophage infection assays. Finally, our in vivo results suggest that AbiA-mediated phage defense may not rely on AbiA-mediated cell death.
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Affiliation(s)
- Marta Gapińska
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Weronika Zajko
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Krzysztof Skowronek
- Biophysics Core Facility, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Małgorzata Figiel
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Paweł S Krawczyk
- Laboratory of RNA Biology, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Artyom A Egorov
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Andrzej Dziembowski
- Laboratory of RNA Biology, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Marcus J O Johansson
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland
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Chaban A, Minakhin L, Goldobina E, Bae B, Hao Y, Borukhov S, Putzeys L, Boon M, Kabinger F, Lavigne R, Makarova KS, Koonin EV, Nair SK, Tagami S, Severinov K, Sokolova ML. Tail-tape-fused virion and non-virion RNA polymerases of a thermophilic virus with an extremely long tail. Nat Commun 2024; 15:317. [PMID: 38182597 PMCID: PMC10770324 DOI: 10.1038/s41467-023-44630-z] [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: 05/15/2023] [Accepted: 12/19/2023] [Indexed: 01/07/2024] Open
Abstract
Thermus thermophilus bacteriophage P23-45 encodes a giant 5,002-residue tail tape measure protein (TMP) that defines the length of its extraordinarily long tail. Here, we show that the N-terminal portion of P23-45 TMP is an unusual RNA polymerase (RNAP) homologous to cellular RNAPs. The TMP-fused virion RNAP transcribes pre-early phage genes, including a gene that encodes another, non-virion RNAP, that transcribes early and some middle phage genes. We report the crystal structures of both P23-45 RNAPs. The non-virion RNAP has a crab-claw-like architecture. By contrast, the virion RNAP adopts a unique flat structure without a clamp. Structure and sequence comparisons of the P23-45 RNAPs with other RNAPs suggest that, despite the extensive functional differences, the two P23-45 RNAPs originate from an ancient gene duplication in an ancestral phage. Our findings demonstrate striking adaptability of RNAPs that can be attained within a single virus species.
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Affiliation(s)
- Anastasiia Chaban
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205, Russia
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, 69117, Germany
| | - Leonid Minakhin
- Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, 19107, USA
| | - Ekaterina Goldobina
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205, Russia
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland
| | - Brain Bae
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Yue Hao
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Sergei Borukhov
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine at Stratford, Stratford, NJ, 08084-1489, USA
| | - Leena Putzeys
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven, 3001, Belgium
| | - Maarten Boon
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven, 3001, Belgium
| | - Florian Kabinger
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, 37077, Germany
| | - Rob Lavigne
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven, 3001, Belgium
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Satish K Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Shunsuke Tagami
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
| | - Konstantin Severinov
- Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA.
- Institute of Molecular Genetics National Kurchatov Center, Moscow, 123182, Russia.
| | - Maria L Sokolova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205, Russia.
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, 37077, Germany.
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3
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Maksimov IV, Shein MY, Burkhanova GF. RNA Interference in Plant Protection from Fungal and Oomycete Infection. APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s0003683822100106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
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4
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Cui R, Li H, Zhao J, Li X, Gan J, Ma J. Structural insights into the dual activities of the two-barrel RNA polymerase QDE-1. Nucleic Acids Res 2022; 50:10169-10186. [PMID: 36039765 PMCID: PMC9508822 DOI: 10.1093/nar/gkac727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/01/2022] [Accepted: 08/27/2022] [Indexed: 11/19/2022] Open
Abstract
Neurospora crassa protein QDE-1, a member of the two-barrel polymerase superfamily, possesses both DNA- and RNA-dependent RNA polymerase (DdRP and RdRP) activities. The dual activities are essential for the production of double-stranded RNAs (dsRNAs), the precursors of small interfering RNAs (siRNAs) in N. crassa. Here, we report five complex structures of N-terminal truncated QDE-1 (QDE-1ΔN), representing four different reaction states: DNA/RNA-templated elongation, the de novo initiation of RNA synthesis, the first step of nucleotide condensation during de novo initiation and initial NTP loading. The template strand is aligned by a bridge-helix and double-psi beta-barrels 2 (DPBB2), the RNA product is held by DPBB1 and the slab domain. The DNA template unpairs with the RNA product at position –7, but the RNA template remains paired. The NTP analog coordinates with cations and is precisely positioned at the addition site by a rigid trigger loop and a proline-containing loop in the active center. The unique C-terminal tail from the QDE-1 dimer partner inserts into the substrate-binding cleft and plays regulatory roles in RNA synthesis. Collectively, this work elucidates the conserved mechanisms for DNA/RNA-dependent dual activities by QDE-1 and other two-barrel polymerase superfamily members.
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Affiliation(s)
- Ruixue Cui
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Hao Li
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jin Zhao
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Xuhang Li
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jianhua Gan
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jinbiao Ma
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
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Du X, Yang Z, Ariza AJF, Wang Q, Xie G, Li S, Du J. Structure of plant RNA-DEPENDENT RNA POLYMERASE 2, an enzyme involved in small interfering RNA production. THE PLANT CELL 2022; 34:2140-2149. [PMID: 35188193 PMCID: PMC9134047 DOI: 10.1093/plcell/koac067] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
In plants, the biogenesis of small interfering RNA (siRNA) requires a family of RNA-dependent RNA polymerases that convert single-stranded RNA (ssRNA) into double-stranded RNA (dsRNA), which is subsequently cleaved into defined lengths by Dicer endonucleases. Here, we determined the structure of maize (Zea mays) RNA-DEPENDENT RNA POLYMERASE 2 (ZmRDR2) in the closed and open conformations. The core catalytic region of ZmRDR2 possesses the canonical DNA-dependent RNA polymerase (DdRP) catalytic sites, pointing to a shared RNA production mechanism between DdRPs and plant RDR-family proteins. Apo-ZmRDR2 adopts a highly compact structure, representing an inactive closed conformation. By contrast, adding RNA induced a significant conformational change in the ZmRDR2 Head domain that opened the RNA binding tunnel, suggesting this is an active elongation conformation of ZmRDR2. Overall, our structural studies trapped both the active and inactive conformations of ZmRDR2, providing insights into the molecular mechanism of dsRNA synthesis during plant siRNA production.
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Affiliation(s)
- Xuan Du
- Department of Biochemistry and Molecular Biology, International Cancer Center, Shenzhen University Health Science Center, Shenzhen 518060, China
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Zhenlin Yang
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA
- 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 Science, Southern University of Science and Technology, Shenzhen 518055, China
| | - Alfredo Jose Florez Ariza
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720, USA
- Biophysics Graduate Group, University of California, Berkeley, California 94720, USA
| | - Qian Wang
- 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 Science, Southern University of Science and Technology, Shenzhen 518055, China
| | - 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 Science, Southern University of Science and Technology, Shenzhen 518055, China
| | - Sisi Li
- Department of Biochemistry and Molecular Biology, International Cancer Center, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - 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 Science, Southern University of Science and Technology, Shenzhen 518055, China
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Fukudome A, Singh J, Mishra V, Reddem E, Martinez-Marquez F, Wenzel S, Yan R, Shiozaki M, Yu Z, Wang JCY, Takagi Y, Pikaard CS. Structure and RNA template requirements of Arabidopsis RNA-DEPENDENT RNA POLYMERASE 2. Proc Natl Acad Sci U S A 2021; 118:e2115899118. [PMID: 34903670 PMCID: PMC8713982 DOI: 10.1073/pnas.2115899118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2021] [Indexed: 01/18/2023] Open
Abstract
RNA-dependent RNA polymerases play essential roles in RNA-mediated gene silencing in eukaryotes. In Arabidopsis, RNA-DEPENDENT RNA POLYMERASE 2 (RDR2) physically interacts with DNA-dependent NUCLEAR RNA POLYMERASE IV (Pol IV) and their activities are tightly coupled, with Pol IV transcriptional arrest, induced by the nontemplate DNA strand, somehow enabling RDR2 to engage Pol IV transcripts and generate double-stranded RNAs. The double-stranded RNAs are then released from the Pol IV-RDR2 complex and diced into short-interfering RNAs that guide RNA-directed DNA methylation and silencing. Here we report the structure of full-length RDR2, at an overall resolution of 3.1 Å, determined by cryoelectron microscopy. The N-terminal region contains an RNA-recognition motif adjacent to a positively charged channel that leads to a catalytic center with striking structural homology to the catalytic centers of multisubunit DNA-dependent RNA polymerases. We show that RDR2 initiates 1 to 2 nt internal to the 3' ends of its templates and can transcribe the RNA of an RNA/DNA hybrid, provided that 9 or more nucleotides are unpaired at the RNA's 3' end. Using a nucleic acid configuration that mimics the arrangement of RNA and DNA strands upon Pol IV transcriptional arrest, we show that displacement of the RNA 3' end occurs as the DNA template and nontemplate strands reanneal, enabling RDR2 transcription. These results suggest a model in which Pol IV arrest and backtracking displaces the RNA 3' end as the DNA strands reanneal, allowing RDR2 to engage the RNA and synthesize the complementary strand.
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Affiliation(s)
- Akihito Fukudome
- HHMI, Indiana University, Bloomington, IN 47405
- Department of Biology, Indiana University, Bloomington, IN 47405
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405
| | - Jasleen Singh
- Department of Biology, Indiana University, Bloomington, IN 47405
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405
| | - Vibhor Mishra
- HHMI, Indiana University, Bloomington, IN 47405
- Department of Biology, Indiana University, Bloomington, IN 47405
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405
| | - Eswar Reddem
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 47405
| | - Francisco Martinez-Marquez
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 47405
| | - Sabine Wenzel
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 47405
| | - Rui Yan
- CryoEM Facility, Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147
| | - Momoko Shiozaki
- CryoEM Facility, Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147
| | - Zhiheng Yu
- CryoEM Facility, Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147
| | - Joseph Che-Yen Wang
- Indiana University Electron Microscopy Center, Indiana University, Bloomington, IN 47405
| | - Yuichiro Takagi
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 47405;
| | - Craig S Pikaard
- HHMI, Indiana University, Bloomington, IN 47405;
- Department of Biology, Indiana University, Bloomington, IN 47405
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405
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7
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Lei L, Burton ZF. Early Evolution of Transcription Systems and Divergence of Archaea and Bacteria. Front Mol Biosci 2021; 8:651134. [PMID: 34026831 PMCID: PMC8131849 DOI: 10.3389/fmolb.2021.651134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
DNA template-dependent multi-subunit RNA polymerases (RNAPs) found in all three domains of life and some viruses are of the two-double-Ψ-β-barrel (DPBB) type. The 2-DPBB protein format is also found in some RNA template-dependent RNAPs and a major replicative DNA template-dependent DNA polymerase (DNAP) from Archaea (PolD). The 2-DPBB family of RNAPs and DNAPs probably evolved prior to the last universal common cellular ancestor (LUCA). Archaeal Transcription Factor B (TFB) and bacterial σ factors include homologous strings of helix-turn-helix units. The consequences of TFB-σ homology are discussed in terms of the evolution of archaeal and bacterial core promoters. Domain-specific DPBB loop inserts functionally connect general transcription factors to the RNAP active site. Archaea appear to be more similar to LUCA than Bacteria. Evolution of bacterial σ factors from TFB appears to have driven divergence of Bacteria from Archaea, splitting the prokaryotic domains.
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Affiliation(s)
- Lei Lei
- Department of Biology, University of New England, Biddeford, ME, United States
| | - Zachary F Burton
- Department of Biochemistry and Molecular Biology, Michigan State University, E. Lansing, MI, United States
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Sauguet L. The Extended "Two-Barrel" Polymerases Superfamily: Structure, Function and Evolution. J Mol Biol 2019; 431:4167-4183. [PMID: 31103775 DOI: 10.1016/j.jmb.2019.05.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 01/14/2023]
Abstract
DNA and RNA polymerases (DNAP and RNAP) play central roles in genome replication, maintenance and repair, as well as in the expression of genes through their transcription. Multisubunit RNAPs carry out transcription and are represented, without exception, in all cellular life forms as well as in nucleo-cytoplasmic DNA viruses. Since their discovery, multisubunit RNAPs have been the focus of intense structural and functional studies revealing that they all share a well-conserved active-site region called the two-barrel catalytic core. The two-barrel core hosts the polymerase active site, which is located at the interface between two double-psi β-barrel domains that contribute distinct amino acid residues to the active site in an asymmetrical fashion. Recently, sequencing and structural studies have added a surprising variety of DNA and RNA to the two-barrel superfamily, including the archaeal replicative DNAP (PolD), which extends the family to DNA-dependent DNAPs involved in replication. While all these polymerases share a minimal core that must have been present in their common ancestor, the two-barrel polymerase superfamily now encompasses a remarkable diversity of enzymes, including DNA-dependent RNAPs, RNA-dependent RNAPs, and DNA-dependent DNAPs, which participate in critical biological processes such as DNA transcription, DNA replication, and gene silencing. The present review will discuss both common features and differences among the extended two-barrel polymerase superfamily, focusing on the newly discovered members. Comparing their structures provides insights into the molecular mechanisms evolved by the contemporary two-barrel polymerases to accomplish their different biological functions.
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Affiliation(s)
- Ludovic Sauguet
- Institut Pasteur, Unité de Dynamique Structurale des Macromolécules, 75015 Paris, France.
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Pinzón N, Bertrand S, Subirana L, Busseau I, Escrivá H, Seitz H. Functional lability of RNA-dependent RNA polymerases in animals. PLoS Genet 2019; 15:e1007915. [PMID: 30779744 PMCID: PMC6396948 DOI: 10.1371/journal.pgen.1007915] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 03/01/2019] [Accepted: 12/24/2018] [Indexed: 11/18/2022] Open
Abstract
RNA interference (RNAi) requires RNA-dependent RNA polymerases (RdRPs) in many eukaryotes, and RNAi amplification constitutes the only known function for eukaryotic RdRPs. Yet in animals, classical model organisms can elicit RNAi without possessing RdRPs, and only nematode RNAi was shown to require RdRPs. Here we show that RdRP genes are much more common in animals than previously thought, even in insects, where they had been assumed not to exist. RdRP genes were present in the ancestors of numerous clades, and they were subsequently lost at a high frequency. In order to probe the function of RdRPs in a deuterostome (the cephalochordate Branchiostoma lanceolatum), we performed high-throughput analyses of small RNAs from various Branchiostoma developmental stages. Our results show that Branchiostoma RdRPs do not appear to participate in RNAi: we did not detect any candidate small RNA population exhibiting classical siRNA length or sequence features. Our results show that RdRPs have been independently lost in dozens of animal clades, and even in a clade where they have been conserved (cephalochordates) their function in RNAi amplification is not preserved. Such a dramatic functional variability reveals an unexpected plasticity in RNA silencing pathways. RNA interference (RNAi) is a conserved gene regulation system in eukaryotes. In non-animal eukaryotes, it necessitates RNA-dependent RNA polymerases (“RdRPs”). Among animals, only nematodes appear to require RdRPs for RNAi. Yet additional animal clades have RdRPs and it is assumed that they participate in RNAi. Here, we find that RdRPs are much more common in animals than previously thought, but their genes were independently lost in many lineages. Focusing on a species with RdRP genes (a cephalochordate), we found that it does not use them for RNAi. While RNAi is the only known function for eukaryotic RdRPs, our results suggest additional roles. Eukaryotic RdRPs thus have a complex evolutionary history in animals, with frequent independent losses and apparent functional diversification.
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Affiliation(s)
- Natalia Pinzón
- Institut de Génétique Humaine, UMR 9002 CNRS and université de Montpellier, 141, rue de la Cardonille, 34396 Montpellier CEDEX 5, France
| | - Stéphanie Bertrand
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins, BIOM, F-66650 Banyuls-sur-Mer, France
| | - Lucie Subirana
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins, BIOM, F-66650 Banyuls-sur-Mer, France
| | - Isabelle Busseau
- Institut de Génétique Humaine, UMR 9002 CNRS and université de Montpellier, 141, rue de la Cardonille, 34396 Montpellier CEDEX 5, France
| | - Hector Escrivá
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins, BIOM, F-66650 Banyuls-sur-Mer, France
| | - Hervé Seitz
- Institut de Génétique Humaine, UMR 9002 CNRS and université de Montpellier, 141, rue de la Cardonille, 34396 Montpellier CEDEX 5, France
- * E-mail:
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RNA Interference: A Natural Immune System of Plants to Counteract Biotic Stressors. Cells 2019; 8:cells8010038. [PMID: 30634662 PMCID: PMC6356646 DOI: 10.3390/cells8010038] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/01/2019] [Accepted: 01/07/2019] [Indexed: 02/06/2023] Open
Abstract
During plant-pathogen interactions, plants have to defend the living transposable elements from pathogens. In response to such elements, plants activate a variety of defense mechanisms to counteract the aggressiveness of biotic stressors. RNA interference (RNAi) is a key biological process in plants to inhibit gene expression both transcriptionally and post-transcriptionally, using three different groups of proteins to resist the virulence of pathogens. However, pathogens trigger an anti-silencing mechanism through the expression of suppressors to block host RNAi. The disruption of the silencing mechanism is a virulence strategy of pathogens to promote infection in the invaded hosts. In this review, we summarize the RNA silencing pathway, anti-silencing suppressors, and counter-defenses of plants to viral, fungal, and bacterial pathogens.
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Koonin EV. Evolution of RNA- and DNA-guided antivirus defense systems in prokaryotes and eukaryotes: common ancestry vs convergence. Biol Direct 2017; 12:5. [PMID: 28187792 PMCID: PMC5303251 DOI: 10.1186/s13062-017-0177-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/06/2017] [Indexed: 12/18/2022] Open
Abstract
Abstract Complementarity between nucleic acid molecules is central to biological information transfer processes. Apart from the basal processes of replication, transcription and translation, complementarity is also employed by multiple defense and regulatory systems. All cellular life forms possess defense systems against viruses and mobile genetic elements, and in most of them some of the defense mechanisms involve small guide RNAs or DNAs that recognize parasite genomes and trigger their inactivation. The nucleic acid-guided defense systems include prokaryotic Argonaute (pAgo)-centered innate immunity and CRISPR-Cas adaptive immunity as well as diverse branches of RNA interference (RNAi) in eukaryotes. The archaeal pAgo machinery is the direct ancestor of eukaryotic RNAi that, however, acquired additional components, such as Dicer, and enormously diversified through multiple duplications. In contrast, eukaryotes lack any heritage of the CRISPR-Cas systems, conceivably, due to the cellular toxicity of some Cas proteins that would get activated as a result of operon disruption in eukaryotes. The adaptive immunity function in eukaryotes is taken over partly by the PIWI RNA branch of RNAi and partly by protein-based immunity. In this review, I briefly discuss the interplay between homology and analogy in the evolution of RNA- and DNA-guided immunity, and attempt to formulate some general evolutionary principles for this ancient class of defense systems. Reviewers This article was reviewed by Mikhail Gelfand and Bojan Zagrovic.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA.
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Majumdar R, Rajasekaran K, Cary JW. RNA Interference (RNAi) as a Potential Tool for Control of Mycotoxin Contamination in Crop Plants: Concepts and Considerations. FRONTIERS IN PLANT SCIENCE 2017; 8:200. [PMID: 28261252 PMCID: PMC5306134 DOI: 10.3389/fpls.2017.00200] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 02/02/2017] [Indexed: 05/20/2023]
Abstract
Mycotoxin contamination in food and feed crops is a major concern worldwide. Fungal pathogens of the genera Aspergillus. Fusarium, and Penicillium are a major threat to food and feed crops due to production of mycotoxins such as aflatoxins, 4-deoxynivalenol, patulin, and numerous other toxic secondary metabolites that substantially reduce the value of the crop. While host resistance genes are frequently used to introgress disease resistance into elite germplasm, either through traditional breeding or transgenic approaches, such resistance is often compromised by the evolving pathogen over time. RNAi-based host-induced gene silencing of key genes required by the pathogen for optimal growth, virulence and/or toxin production, can serve as an alternative, pre-harvest approach for disease control. RNAi represents a robust and efficient tool that can be used in a highly targeted, tissue specific manner to combat mycotoxigenic fungi infecting crop plants. Successful transgenic RNAi implementation depends on several factors including (1) designing vectors to produce double-stranded RNAs (dsRNAs) that will generate small interfering RNA (siRNA) species for optimal gene silencing and reduced potential for off-target effects; (2) availability of ample target siRNAs at the infection site; (3) efficient uptake of siRNAs by the fungus; (4) siRNA half-life and (5) amplification of the silencing effect. This review provides a critical and comprehensive evaluation of the published literature on the use of RNAi-based approaches to control mycotoxin contamination in crop plants. It also examines experimental strategies used to better understand the mode of action of RNAi with the aim of eliminating mycotoxin contamination, thereby improving food and feed safety.
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