1
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Yao Z, Jin H, Li C, Ma W, Zhang W, Lin Y. Knockdown of Dcr1 and Dcr2 limits the lethal effect of C-factor in Chilo suppressalis. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2023; 113:e22004. [PMID: 36780173 DOI: 10.1002/arch.22004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/13/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Dicer is a highly conserved ribonuclease in evolution. It belongs to the RNase III family and can specifically recognize and cleave double-stranded RNA (dsRNA). In this study, the genome and transcriptome of Chilo suppressalis were analyzed, and it was found that there were two members in the Dicer family, named Dcr1 and Dcr2. The dsRNAs of Dcr1 and Dcr2 genes were synthesized and fed to C. suppressalis larvae. The C-factor of C. suppressalis was selected as the marker gene. The results showed that both Dcr1 and Dcr2 genes were significantly knocked down. The larval mortality was significantly reduced by 43.50% (p < 0.05) after feeding on dsC-factor and dsDcr1. The transcription levels of C-factor genes were significantly increased by 33.95% (p < 0.05) and 32.94% (p < 0.05) when the larvae fed with dsDcr2 + dsC-factor for 72 h and 96 h, respectively. Furthermore, the mortality was significantly decreased by 79% (p < 0.05) after feeding dsC-factor and dsDcr2. These findings imply that Dcr1 can decrease the lethal effect of C-factor gene but cannot affect its RNAi efficiency and Dcr2 can decrease the lethal effect of C-factor gene by inhibiting RNAi efficiency.
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Affiliation(s)
- Zhuotian Yao
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Huihui Jin
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Changyan Li
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Weihua Ma
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Wei Zhang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yongjun Lin
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, Hubei, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
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2
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Aderounmu AM, Aruscavage PJ, Kolaczkowski B, Bass BL. Ancestral protein reconstruction reveals evolutionary events governing variation in Dicer helicase function. eLife 2023; 12:e85120. [PMID: 37068011 PMCID: PMC10159624 DOI: 10.7554/elife.85120] [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: 11/23/2022] [Accepted: 04/14/2023] [Indexed: 04/18/2023] Open
Abstract
Antiviral defense in ecdysozoan invertebrates requires Dicer with a helicase domain capable of ATP hydrolysis. But despite well-conserved ATPase motifs, human Dicer is incapable of ATP hydrolysis, consistent with a muted role in antiviral defense. To investigate this enigma, we used ancestral protein reconstruction to resurrect Dicer's helicase in animals and trace the evolutionary trajectory of ATP hydrolysis. Biochemical assays indicated ancient Dicer possessed ATPase function, that like extant invertebrate Dicers, is stimulated by dsRNA. Analyses revealed that dsRNA stimulates ATPase activity by increasing ATP affinity, reflected in Michaelis constants. Deuterostome Dicer-1 ancestor, while exhibiting lower dsRNA affinity, retained some ATPase activity; importantly, ATPase activity was undetectable in the vertebrate Dicer-1 ancestor, which had even lower dsRNA affinity. Reverting residues in the ATP hydrolysis pocket was insufficient to rescue hydrolysis, but additional substitutions distant from the pocket rescued vertebrate Dicer-1's ATPase function. Our work suggests Dicer lost ATPase function in the vertebrate ancestor due to loss of ATP affinity, involving motifs distant from the active site, important for coupling dsRNA binding to the active conformation. By competing with Dicer for viral dsRNA, RIG-I-like receptors important for interferon signaling may have allowed or actively caused loss of ATPase function.
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Affiliation(s)
| | | | - Bryan Kolaczkowski
- Department of Microbiology and Cell Science, University of FloridaGainesvilleUnited States
| | - Brenda L Bass
- Department of Biochemistry, University of UtahSalt Lake CityUnited States
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3
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Wong MRE, Lim KH, Hee EXY, Chen H, Kuick CH, Jet AS, Chang KTE, Sulaiman NS, Low SY, Hartono S, Tran ANT, Ahamed SH, Lam CMJ, Soh SY, Hannan KM, Hannan RD, Coupland LA, Loh AHP. Targeting Mutant Dicer Tumorigenesis in Pleuropulmonary Blastoma via Inhibition of RNA Polymerase I. Transl Res 2023:S1931-5244(23)00041-5. [PMID: 36921796 DOI: 10.1016/j.trsl.2023.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 02/23/2023] [Accepted: 03/07/2023] [Indexed: 03/14/2023]
Abstract
DICER1 mutations predispose to increased risk for various cancers, particularly pleuropulmonary blastoma (PPB), the commonest lung malignancy of childhood. There is a paucity of directly actionable molecular targets as these tumors are driven by loss-of-function mutations of DICER1. Therapeutic development for PPB is further limited by a lack of biologically and physiologically-representative disease models. Given recent evidence of Dicer's role as a haploinsufficient tumor suppressor regulating RNA polymerase I (Pol I), Pol I inhibition could abrogate mutant Dicer-mediated accumulation of stalled polymerases to trigger apoptosis. Hence, we developed a novel sub-pleural orthotopic PPB patient-derived xenograft (PDX) model that retained both RNase IIIa and IIIb hotspot mutations and recapitulated the cardiorespiratory physiology of intra-thoracic disease, and with it evaluated the tolerability and efficacy of first-in-class Pol I inhibitor CX-5461. In PDX tumors, CX-5461 significantly reduced H3K9 di-methylation and increased nuclear p53 expression, within 24 hours' exposure. Following treatment at the maximum tolerated dosing regimen (12 doses, 30mg/kg), tumors were smaller and less hemorrhagic than controls, with significantly decreased cellular proliferation, and increased apoptosis. As demonstrated in a novel intra-thoracic tumor model of PPB, Pol I inhibition with CX-5461 could be a tolerable and clinically-feasible therapeutic strategy for mutant Dicer tumors, inducing anti-tumor effects by decreasing H3K9 methylation and enhancing p53-mediated apoptosis.
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Affiliation(s)
- Megan Rui En Wong
- VIVA-KKH Paediatric Brain and Solid Tumour Programme, Children's Blood and Cancer Centre, KK Women's and Children's Hospital, Singapore 229899
| | - Kia Hui Lim
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
| | - Esther Xuan Yi Hee
- VIVA-KKH Paediatric Brain and Solid Tumour Programme, Children's Blood and Cancer Centre, KK Women's and Children's Hospital, Singapore 229899
| | - Huiyi Chen
- Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, Singapore 229899
| | - Chik Hong Kuick
- Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, Singapore 229899
| | - Aw Sze Jet
- Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, Singapore 229899
| | - Kenneth Tou En Chang
- VIVA-KKH Paediatric Brain and Solid Tumour Programme, Children's Blood and Cancer Centre, KK Women's and Children's Hospital, Singapore 229899; Department of Pathology and Laboratory Medicine, KK Women's and Children's Hospital, Singapore 229899; Duke-NUS School of Medicine, Singapore 169857
| | - Nurfarhanah Syed Sulaiman
- VIVA-KKH Paediatric Brain and Solid Tumour Programme, Children's Blood and Cancer Centre, KK Women's and Children's Hospital, Singapore 229899; Department of Neurology, National Neuroscience Institute, Singapore 308433
| | - Sharon Yy Low
- VIVA-KKH Paediatric Brain and Solid Tumour Programme, Children's Blood and Cancer Centre, KK Women's and Children's Hospital, Singapore 229899; Department of Neurology, National Neuroscience Institute, Singapore 308433; Duke-NUS School of Medicine, Singapore 169857
| | - Septian Hartono
- Department of Oncologic Imaging, National Cancer Centre Singapore, Singapore 169610
| | - Anh Nguyen Tuan Tran
- Department of Oncologic Imaging, National Cancer Centre Singapore, Singapore 169610
| | - Summaiyya Hanum Ahamed
- Duke-NUS School of Medicine, Singapore 169857; Department of Diagnostic and Interventional Imaging, KK Women's and Children's Hospital, Singapore 229899
| | - Ching Mei Joyce Lam
- Duke-NUS School of Medicine, Singapore 169857; Department of Paediatric Subspecialties Haematology/Oncology Service, KK Women's and Children's Hospital, Singapore 229899
| | - Shui Yen Soh
- VIVA-KKH Paediatric Brain and Solid Tumour Programme, Children's Blood and Cancer Centre, KK Women's and Children's Hospital, Singapore 229899; Duke-NUS School of Medicine, Singapore 169857; Department of Paediatric Subspecialties Haematology/Oncology Service, KK Women's and Children's Hospital, Singapore 229899
| | - Katherine M Hannan
- Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, the Australian National University, Canberra, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Ross D Hannan
- Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, the Australian National University, Canberra, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, VIC, Australia; Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Lucy A Coupland
- Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, the Australian National University, Canberra, Australia
| | - Amos Hong Pheng Loh
- VIVA-KKH Paediatric Brain and Solid Tumour Programme, Children's Blood and Cancer Centre, KK Women's and Children's Hospital, Singapore 229899; Duke-NUS School of Medicine, Singapore 169857; Department of Paediatric Surgery, KK Women's and Children's Hospital, Singapore 229899.
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4
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Torrez RM, Ohi MD, Garner AL. Structural Insights into the Advances and Mechanistic Understanding of Human Dicer. Biochemistry 2023; 62:1-16. [PMID: 36534787 DOI: 10.1021/acs.biochem.2c00570] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The RNase III endoribonuclease Dicer was discovered to be associated with cleavage of double-stranded RNA in 2001. Since then, many advances in our understanding of Dicer function have revealed that the enzyme plays a major role not only in microRNA biology but also in multiple RNA interference-related pathways. Yet, there is still much to be learned regarding Dicer structure-function in relation to how Dicer and Dicer-like enzymes initiate their cleavage reaction and release the desired RNA product. This Perspective describes the latest advances in Dicer structural studies, expands on what we have learned from this data, and outlines key gaps in knowledge that remain to be addressed. More specifically, we focus on human Dicer and highlight the intermediate processing steps where there is a lack of structural data to understand how the enzyme traverses from pre-cleavage to cleavage-competent states. Understanding these details is necessary to model Dicer's function as well as develop more specific microRNA-targeted therapeutics for the treatment of human diseases.
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Affiliation(s)
- Rachel M Torrez
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109, United States
| | - Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
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5
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A Tale of Two Lobsters—Transcriptomic Analysis Reveals a Potential Gap in the RNA Interference Pathway in the Tropical Rock Lobster Panulirus ornatus. Int J Mol Sci 2022; 23:ijms231911752. [PMID: 36233053 PMCID: PMC9569428 DOI: 10.3390/ijms231911752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/28/2022] [Accepted: 09/28/2022] [Indexed: 11/25/2022] Open
Abstract
RNA interference (RNAi) has been widely utilised in many invertebrate models since its discovery, and in a majority of instances presents as a highly efficient and potent gene silencing mechanism. This is emphasized in crustaceans with almost all taxa having the capacity to trigger effective silencing, with a notable exception in the spiny lobsters where repeated attempts at dsRNA induced RNAi have demonstrated extremely ineffective gene knockdown. A comparison of the core RNAi machinery in transcriptomic data from spiny lobsters (Panulirus ornatus) and the closely related slipper lobsters (Thenus australiensis, where silencing is highly effective) revealed that both lobsters possess all proteins involved in the small interfering and microRNA pathways, and that there was little difference at both the sequence and domain architecture level. Comparing the expression of these genes however demonstrated that T. australiensis had significantly higher expression in the transcripts encoding proteins which directly interact with dsRNA when compared to P. ornatus, validated via qPCR. These results suggest that low expression of the core RNAi genes may be hindering the silencing response in P. ornatus, and suggest that it may be critical to enhance the expression of these genes to induce efficient silencing in spiny lobsters.
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6
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Riva V, Garbelli A, Casiraghi F, Arena F, Trivisani CI, Gagliardi A, Bini L, Schroeder M, Maffia A, Sabbioneda S, Maga G. Novel alternative ribonucleotide excision repair pathways in human cells by DDX3X and specialized DNA polymerases. Nucleic Acids Res 2021; 48:11551-11565. [PMID: 33137198 PMCID: PMC7672437 DOI: 10.1093/nar/gkaa948] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 10/02/2020] [Accepted: 10/08/2020] [Indexed: 01/02/2023] Open
Abstract
Removal of ribonucleotides (rNMPs) incorporated into the genome by the ribonucleotide excision repair (RER) is essential to avoid genetic instability. In eukaryotes, the RNaseH2 is the only known enzyme able to incise 5' of the rNMP, starting the RER process, which is subsequently carried out by replicative DNA polymerases (Pols) δ or ϵ, together with Flap endonuclease 1 (Fen-1) and DNA ligase 1. Here, we show that the DEAD-box RNA helicase DDX3X has RNaseH2-like activity and can support fully reconstituted in vitro RER reactions, not only with Pol δ but also with the repair Pols β and λ. Silencing of DDX3X causes accumulation of rNMPs in the cellular genome. These results support the existence of alternative RER pathways conferring high flexibility to human cells in responding to the threat posed by rNMPs incorporation.
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Affiliation(s)
- Valentina Riva
- Institute of Molecular Genetics IGM-CNR 'Luigi Luca Cavalli-Sforza', via Abbiategrasso 207, I-27100 Pavia, Italy
| | - Anna Garbelli
- Institute of Molecular Genetics IGM-CNR 'Luigi Luca Cavalli-Sforza', via Abbiategrasso 207, I-27100 Pavia, Italy
| | - Federica Casiraghi
- Institute of Molecular Genetics IGM-CNR 'Luigi Luca Cavalli-Sforza', via Abbiategrasso 207, I-27100 Pavia, Italy
| | - Francesca Arena
- Institute of Molecular Genetics IGM-CNR 'Luigi Luca Cavalli-Sforza', via Abbiategrasso 207, I-27100 Pavia, Italy
| | - Claudia Immacolata Trivisani
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via A. De Gasperi 2, I-53100 Siena, Italy
| | - Assunta Gagliardi
- Department of Life Sciences, Via A. Moro 2, University of Siena, I-53100 Siena, Italy
| | - Luca Bini
- Department of Life Sciences, Via A. Moro 2, University of Siena, I-53100 Siena, Italy
| | - Martina Schroeder
- Kathleen Lonsdale Institute for Human Health Research, Biology Department, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Antonio Maffia
- Institute of Molecular Genetics IGM-CNR 'Luigi Luca Cavalli-Sforza', via Abbiategrasso 207, I-27100 Pavia, Italy
| | - Simone Sabbioneda
- Institute of Molecular Genetics IGM-CNR 'Luigi Luca Cavalli-Sforza', via Abbiategrasso 207, I-27100 Pavia, Italy
| | - Giovanni Maga
- Institute of Molecular Genetics IGM-CNR 'Luigi Luca Cavalli-Sforza', via Abbiategrasso 207, I-27100 Pavia, Italy
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7
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Genetic Insight into the Domain Structure and Functions of Dicer-Type Ribonucleases. Int J Mol Sci 2021; 22:ijms22020616. [PMID: 33435485 PMCID: PMC7827160 DOI: 10.3390/ijms22020616] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/12/2022] Open
Abstract
Ribonuclease Dicer belongs to the family of RNase III endoribonucleases, the enzymes that specifically hydrolyze phosphodiester bonds found in double-stranded regions of RNAs. Dicer enzymes are mostly known for their essential role in the biogenesis of small regulatory RNAs. A typical Dicer-type RNase consists of a helicase domain, a domain of unknown function (DUF283), a PAZ (Piwi-Argonaute-Zwille) domain, two RNase III domains, and a double-stranded RNA binding domain; however, the domain composition of Dicers varies among species. Dicer and its homologues developed only in eukaryotes; nevertheless, the two enzymatic domains of Dicer, helicase and RNase III, display high sequence similarity to their prokaryotic orthologs. Evolutionary studies indicate that a combination of the helicase and RNase III domains in a single protein is a eukaryotic signature and is supposed to be one of the critical events that triggered the consolidation of the eukaryotic RNA interference. In this review, we provide the genetic insight into the domain organization and structure of Dicer proteins found in vertebrate and invertebrate animals, plants and fungi. We also discuss, in the context of the individual domains, domain deletion variants and partner proteins, a variety of Dicers’ functions not only related to small RNA biogenesis pathways.
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8
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Overexpression and purification of Dicer and accessory proteins for biochemical and structural studies. Methods 2017; 126:54-65. [PMID: 28723582 DOI: 10.1016/j.ymeth.2017.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/04/2017] [Accepted: 07/14/2017] [Indexed: 12/19/2022] Open
Abstract
The Dicer family of ribonucleases plays a key role in small RNA-based regulatory pathways by generating short dsRNA fragments that modulate expression of endogenous genes, or protect the host from invasive nucleic acids. Beginning with its initial discovery, biochemical characterization of Dicer has provided insight about its catalytic properties. However, a comprehensive understanding of how Dicer's domains contribute to substrate-specific recognition and catalysis is lacking. One reason for this void is the lack of high-resolution structural information for a metazoan Dicer in the apo- or substrate-bound state. Both biochemical and structural studies are facilitated by large amounts of highly purified, active protein, and Dicer enzymes have historically been recalcitrant to overexpression and purification. Here we describe optimized procedures for the large-scale expression of Dicer in baculovirus-infected insect cells. We then outline a three-step protocol for the purification of large amounts (3-4mg of Dicer per liter of insect cell culture) of highly purified and active Dicer protein, suitable for biochemical and structural studies. Our methods are general and are extended to enable overexpression, purification and biochemical characterization of accessory dsRNA binding proteins that interact with Dicer and modulate its catalytic activity.
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9
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Molecular mechanisms of Dicer: endonuclease and enzymatic activity. Biochem J 2017; 474:1603-1618. [PMID: 28473628 PMCID: PMC5415849 DOI: 10.1042/bcj20160759] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 12/12/2022]
Abstract
The enzyme Dicer is best known for its role as a riboendonuclease in the small RNA pathway. In this canonical role, Dicer is a critical regulator of the biogenesis of microRNA and small interfering RNA, as well as a growing number of additional small RNAs derived from various sources. Emerging evidence demonstrates that Dicer's endonuclease role extends beyond the generation of small RNAs; it is also involved in processing additional endogenous and exogenous substrates, and is becoming increasingly implicated in regulating a variety of other cellular processes, outside of its endonuclease function. This review will describe the canonical and newly identified functions of Dicer.
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10
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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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11
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Koonin EV. Origin of eukaryotes from within archaea, archaeal eukaryome and bursts of gene gain: eukaryogenesis just made easier? Philos Trans R Soc Lond B Biol Sci 2016; 370:20140333. [PMID: 26323764 PMCID: PMC4571572 DOI: 10.1098/rstb.2014.0333] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The origin of eukaryotes is a fundamental, forbidding evolutionary puzzle. Comparative genomic analysis clearly shows that the last eukaryotic common ancestor (LECA) possessed most of the signature complex features of modern eukaryotic cells, in particular the mitochondria, the endomembrane system including the nucleus, an advanced cytoskeleton and the ubiquitin network. Numerous duplications of ancestral genes, e.g. DNA polymerases, RNA polymerases and proteasome subunits, also can be traced back to the LECA. Thus, the LECA was not a primitive organism and its emergence must have resulted from extensive evolution towards cellular complexity. However, the scenario of eukaryogenesis, and in particular the relationship between endosymbiosis and the origin of eukaryotes, is far from being clear. Four recent developments provide new clues to the likely routes of eukaryogenesis. First, evolutionary reconstructions suggest complex ancestors for most of the major groups of archaea, with the subsequent evolution dominated by gene loss. Second, homologues of signature eukaryotic proteins, such as actin and tubulin that form the core of the cytoskeleton or the ubiquitin system, have been detected in diverse archaea. The discovery of this ‘dispersed eukaryome’ implies that the archaeal ancestor of eukaryotes was a complex cell that might have been capable of a primitive form of phagocytosis and thus conducive to endosymbiont capture. Third, phylogenomic analyses converge on the origin of most eukaryotic genes of archaeal descent from within the archaeal evolutionary tree, specifically, the TACK superphylum. Fourth, evidence has been presented that the origin of the major archaeal phyla involved massive acquisition of bacterial genes. Taken together, these findings make the symbiogenetic scenario for the origin of eukaryotes considerably more plausible and the origin of the organizational complexity of eukaryotic cells more readily explainable than they appeared until recently.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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12
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Jakob L, Treiber T, Treiber N, Gust A, Kramm K, Hansen K, Stotz M, Wankerl L, Herzog F, Hannus S, Grohmann D, Meister G. Structural and functional insights into the fly microRNA biogenesis factor Loquacious. RNA (NEW YORK, N.Y.) 2016; 22:383-396. [PMID: 26769856 PMCID: PMC4748816 DOI: 10.1261/rna.055426.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 12/02/2015] [Indexed: 06/05/2023]
Abstract
In the microRNA (miRNA) pathway, Dicer processes precursors to mature miRNAs. For efficient processing, double-stranded RNA-binding proteins support Dicer proteins. In flies, Loquacious (Loqs) interacts with Dicer1 (dmDcr1) to facilitate miRNA processing. Here, we have solved the structure of the third double-stranded RNA-binding domain (dsRBD) of Loqs and define specific structural elements that interact with dmDcr1. In addition, we show that the linker preceding dsRBD3 contributes significantly to dmDcr1 binding. Furthermore, our structural work demonstrates that the third dsRBD of Loqs forms homodimers. Mutations in the dimerization interface abrogate dmDcr1 interaction. Loqs, however, binds to dmDcr1 as a monomer using the identified dimerization surface, which suggests that Loqs might form dimers under conditions where dmDcr1 is absent or not accessible. Since critical sequence elements are conserved, we suggest that dimerization might be a general feature of dsRBD proteins in gene silencing.
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Affiliation(s)
- Leonhard Jakob
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Thomas Treiber
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Nora Treiber
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Alexander Gust
- Department of Microbiology and Archaea Centre, Laboratory of Single-Molecule Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Kevin Kramm
- Department of Microbiology and Archaea Centre, Laboratory of Single-Molecule Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Kerrin Hansen
- Intana Bioscience GmbH, 82152 Planegg, Martinsried, Germany
| | - Mathias Stotz
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Ludwig Wankerl
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Franz Herzog
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-University, 81377 München, Germany
| | - Stefan Hannus
- Intana Bioscience GmbH, 82152 Planegg, Martinsried, Germany
| | - Dina Grohmann
- Department of Microbiology and Archaea Centre, Laboratory of Single-Molecule Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Gunter Meister
- Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
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Singh B, Poças-Fonseca MJ, Johri BN, Satyanarayana T. Thermophilic molds: Biology and applications. Crit Rev Microbiol 2016; 42:985-1006. [DOI: 10.3109/1040841x.2015.1122572] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Unzippers, resolvers and sensors: a structural and functional biochemistry tale of RNA helicases. Int J Mol Sci 2015; 16:2269-93. [PMID: 25622248 PMCID: PMC4346836 DOI: 10.3390/ijms16022269] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 01/09/2015] [Accepted: 01/12/2015] [Indexed: 12/28/2022] Open
Abstract
The centrality of RNA within the biological world is an irrefutable fact that currently attracts increasing attention from the scientific community. The panoply of functional RNAs requires the existence of specific biological caretakers, RNA helicases, devoted to maintain the proper folding of those molecules, resolving unstable structures. However, evolution has taken advantage of the specific position and characteristics of RNA helicases to develop new functions for these proteins, which are at the interface of the basic processes for transference of information from DNA to proteins. RNA helicases are involved in many biologically relevant processes, not only as RNA chaperones, but also as signal transducers, scaffolds of molecular complexes, and regulatory elements. Structural biology studies during the last decade, founded in X-ray crystallography, have characterized in detail several RNA-helicases. This comprehensive review summarizes the structural knowledge accumulated in the last two decades within this family of proteins, with special emphasis on the structure-function relationships of the most widely-studied families of RNA helicases: the DEAD-box, RIG-I-like and viral NS3 classes.
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