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Seetharaman A, Galagali H, Linarte E, Liu MHX, Cohen JD, Chetal K, Sadreyev R, Tate AJ, Montgomery TA, Ruvkun G. Caenorhabditis elegans SynMuv B gene activity is down-regulated during a viral infection to enhance RNA interference. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.12.603258. [PMID: 39071373 PMCID: PMC11275910 DOI: 10.1101/2024.07.12.603258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Small RNA pathways regulate eukaryotic antiviral defense. Many of the Caenorhabditis elegans mutations that were identified based on their enhanced RNAi, the synMuv B genes, also emerged from unrelated genetic screens for increased growth factor signaling. The dozen synMuv B genes encode homologues of the mammalian dREAM complex found in nearly all animals and plants, which includes the lin-35 /retinoblastoma oncogene. We show that a set of highly induced mRNAs in synMuv B mutants is congruent with mRNAs induced by Orsay RNA virus infection of C. elegans . In wild type animals, a combination of a synMuv A mutation and a synMuv B mutation are required for the Muv phenotype of increased growth factor signaling. But we show that Orsay virus infection of a single synMuv A mutant can induce a Muv phenotype, unlike the uninfected single synMuv A mutant. This suggests that decreased synMuv B activity, which activates the antiviral RNAi pathway, is a defense response to viral infection. Small RNA deep sequencing analysis of various dREAM complex mutants uncovers distinct siRNA profiles indicative of such an siRNA response. We conclude that the synMuv B mutants maintain an antiviral readiness state even in the absence of actual infection. The enhanced RNAi and conservation of the dREAM complex mutants suggests new therapeutic avenues to boost antiviral defenses.
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2
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Dejima K, Imae R, Suehiro Y, Yoshida K, Mitani S. An endomembrane zinc transporter negatively regulates systemic RNAi in Caenorhabditis elegans. iScience 2023; 26:106930. [PMID: 37305693 PMCID: PMC10250833 DOI: 10.1016/j.isci.2023.106930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/18/2023] [Accepted: 05/16/2023] [Indexed: 06/13/2023] Open
Abstract
Double-stranded RNA (dsRNA) regulates gene expression in a sequence-dependent manner. In Caenorhabditis elegans, dsRNA spreads through the body and leads to systemic RNA silencing. Although several genes involved in systemic RNAi have been genetically identified, molecules that mediate systemic RNAi remain largely unknown. Here, we identified ZIPT-9, a C. elegans homolog of ZIP9/SLC39A9, as a broad-spectrum negative regulator of systemic RNAi. We showed that RSD-3, SID-3, and SID-5 genetically act in parallel for efficient RNAi, and that zipt-9 mutants suppress the RNAi defects of all the mutants. Analysis of a complete set of deletion mutants for SLC30 and SLC39 family genes revealed that only zipt-9 mutants showed altered RNAi activity. Based on these results and our analysis using transgenic Zn2+ reporters, we propose that ZIPT-9-dependent Zn2+ homeostasis, rather than overall cytosolic Zn2+, modulates systemic RNAi activity. Our findings reveal a previously unknown function of zinc transporters in negative RNAi regulation.
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Affiliation(s)
- Katsufumi Dejima
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Rieko Imae
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Yuji Suehiro
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Keita Yoshida
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Shohei Mitani
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
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3
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The Caenorhabditis elegans ARIP-4 DNA helicase couples mitochondrial surveillance to immune, detoxification, and antiviral pathways. Proc Natl Acad Sci U S A 2022; 119:e2215966119. [PMID: 36445965 PMCID: PMC9894117 DOI: 10.1073/pnas.2215966119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Surveillance of Caenorhabditis elegans mitochondrial status is coupled to defense responses such as drug detoxification, immunity, antiviral RNA interference (RNAi), and regulation of life span. A cytochrome p540 detoxification gene, cyp-14A4, is specifically activated by mitochondrial dysfunction. The nuclear hormone receptor NHR-45 and the transcriptional Mediator component MDT-15/MED15 are required for the transcriptional activation of cyp-14A4 by mitochondrial mutations, gene inactivations, or toxins. A genetic screen for mutations that fail to activate this cytochrome p450 gene upon drug or mutation-induced mitochondrial dysfunction identified a DNA helicase ARIP-4 that functions in concert with the NHR-45 transcriptional regulatory cascade. In response to mitochondrial dysfunction, ARIP-4 and NHR-45 protein interaction is enhanced, and they relocalize from the nuclear periphery to the interior of intestinal nuclei. NHR-45/ARIP-4 also regulates the transcriptional activation of the eol-1 gene that encodes a decapping enzyme required for enhanced RNAi and transgene silencing of mitochondrial mutants. In the absence of arip-4, animals were more susceptible to the mitochondrial inhibitor antimycin. Thus, ARIP-4 serves as a transcriptional coactivator of NHR-45 to promote this defense response. A null mutation in arip-4 extends the life span and health span of both wild type and a mitochondrial mutant, suggesting that the activation of detoxification pathways is deleterious to health when the mitochondrial dysfunction is caused by mutation that cannot be cytochrome p450-detoxified. Thus, arip-4 acts in a pathway that couples mitochondrial surveillance to the activation of downstream immunity, detoxification, and RNAi responses.
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4
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Braun M, Shoshani S, Teixeira J, Mellul Shtern A, Miller M, Granot Z, Fischer SE, Garcia SMA, Tabach Y. Asymmetric inheritance of RNA toxicity in C. elegans expressing CTG repeats. iScience 2022; 25:104246. [PMID: 35494247 PMCID: PMC9051633 DOI: 10.1016/j.isci.2022.104246] [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: 11/30/2021] [Revised: 03/01/2022] [Accepted: 04/07/2022] [Indexed: 11/18/2022] Open
Abstract
Nucleotide repeat expansions are a hallmark of over 40 neurodegenerative diseases and cause RNA toxicity and multisystemic symptoms that worsen with age. Through an unclear mechanism, RNA toxicity can trigger severe disease manifestation in infants if the repeats are inherited from their mother. Here we use Caenorhabditis elegans bearing expanded CUG repeats to show that this asymmetric intergenerational inheritance of toxicity contributes to disease pathogenesis. In addition, we show that this mechanism is dependent on small RNA pathways with maternal repeat-derived small RNAs causing transcriptomic changes in the offspring, reduced motility, and shortened lifespan. We rescued the toxicity phenotypes in the offspring by perturbing the RNAi machinery in the affected hermaphrodites. This points to a novel mechanism linking maternal bias and the RNAi machinery and suggests that toxic RNA is transmitted to offspring, causing disease phenotypes through intergenerational epigenetic inheritance. Maternal origin of expanded CUG repeats induces RNA toxicity in Caenorhabditis elegans offspring Offspring of affected hermaphrodites show molecular and phenotypic disease phenotypes The RNAi machinery is directly related to the maternal inheritance of RNA toxicity Altering the RNAi machinery in affected hermaphrodites rescues toxicity in offspring
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Affiliation(s)
- Maya Braun
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Shachar Shoshani
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Joana Teixeira
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790 Finland
| | - Anna Mellul Shtern
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Maya Miller
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Zvi Granot
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Sylvia E.J. Fischer
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Susana M.D. A. Garcia
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790 Finland
- Corresponding author
| | - Yuval Tabach
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
- Corresponding author
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5
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Saber S, Snyder M, Rajaei M, Baer CF. Mutation, selection, and the prevalence of the Caenorhabditis elegans heat-sensitive mortal germline phenotype. G3 (BETHESDA, MD.) 2022; 12:jkac063. [PMID: 35311992 PMCID: PMC9073675 DOI: 10.1093/g3journal/jkac063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 03/10/2022] [Indexed: 11/17/2022]
Abstract
Caenorhabditis elegans strains with the heat-sensitive mortal germline phenotype become progressively sterile over the course of a few tens of generations when maintained at temperatures near the upper range of C. elegans' tolerance. Mortal germline is transgenerationally heritable, and proximately under epigenetic control. Previous studies have suggested that mortal germline presents a relatively large mutational target and that mortal germline is not uncommon in natural populations of C. elegans. The mortal germline phenotype is not monolithic. Some strains exhibit a strong mortal germline phenotype, in which individuals invariably become sterile over a few generations, whereas other strains show a weaker (less penetrant) phenotype in which the onset of sterility is slower and more stochastic. We present results in which we (1) quantify the rate of mutation to the mortal germline phenotype and (2) quantify the frequency of mortal germline in a collection of 95 wild isolates. Over the course of ∼16,000 meioses, we detected one mutation to a strong mortal germline phenotype, resulting in a point estimate of the mutation rate UMrt≈ 6×10-5/genome/generation. We detected no mutations to a weak mortal germline phenotype. Six out of 95 wild isolates have a strong mortal germline phenotype, and although quantification of the weak mortal germline phenotype is inexact, the weak mortal germline phenotype is not rare in nature. We estimate a strength of selection against mutations conferring the strong mortal germline phenotype s¯≈0.1%, similar to selection against mutations affecting competitive fitness. The appreciable frequency of weak mortal germline variants in nature combined with the low mutation rate suggests that mortal germline may be maintained by balancing selection.
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Affiliation(s)
- Sayran Saber
- Department of Biology, University of Florida, Gainesville, FL 32611-8525, USA
| | - Michael Snyder
- Department of Biology, University of Florida, Gainesville, FL 32611-8525, USA
| | - Moein Rajaei
- Department of Biology, University of Florida, Gainesville, FL 32611-8525, USA
| | - Charles F Baer
- Department of Biology, University of Florida, Gainesville, FL 32611-8525, USA
- University of Florida Genetics Institute, Gainesville, FL 32610, USA
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Tsouris A, Schacherer J, Ishchuk OP. RNA Interference (RNAi ) as a Tool for High-Resolution Phenotypic Screening of the Pathogenic Yeast Candida glabrata. Methods Mol Biol 2022; 2477:313-330. [PMID: 35524125 DOI: 10.1007/978-1-0716-2257-5_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
After its discovery RNA interference (RNAi) has become a powerful tool to study gene functions in different organisms. RNAi has been applied at genome-wide scale and can be nowadays performed using high-throughput automated systems (robotics). The simplest RNAi process requires the expression of two genes (Dicer and Argonaute) to function. To initiate the silencing, constructs generating either double-strand RNA or antisense RNA are required. Recently, RNAi was reconstituted by expressing Saccharomyces castellii genes in the human pathogenic yeast Candida glabrata and was used to identify new genes related to the virulence of this pathogen.In this chapter, we describe a method to make the C. glabrata pathogenic yeast competent for RNAi and to use RNA silencing as a tool for low- or high-resolution phenotypic screening in this species.
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Affiliation(s)
- Andreas Tsouris
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - Joseph Schacherer
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
- Institut Universitaire de France (IUF), Paris, France
| | - Olena P Ishchuk
- Department of Biology and Biological Engineering, Systems and Synthetic Biology, Chalmers University of Technology, Gothenburg, Sweden.
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The nuclear ubiquitin ligase adaptor SPOP is a conserved regulator of C9orf72 dipeptide toxicity. Proc Natl Acad Sci U S A 2021; 118:2104664118. [PMID: 34593637 DOI: 10.1073/pnas.2104664118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2021] [Indexed: 12/29/2022] Open
Abstract
A hexanucleotide repeat expansion in the C9orf72 gene is the most common cause of inherited amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Unconventional translation of the C9orf72 repeat produces dipeptide repeat proteins (DPRs). Previously, we showed that the DPRs PR50 and GR50 are highly toxic when expressed in Caenorhabditis elegans, and this toxicity depends on nuclear localization of the DPR. In an unbiased genome-wide RNA interference (RNAi) screen for suppressors of PR50 toxicity, we identified 12 genes that consistently suppressed either the developmental arrest and/or paralysis phenotype evoked by PR50 expression. All of these genes have vertebrate homologs, and 7 of 12 contain predicted nuclear localization signals. One of these genes was spop-1, the C. elegans homolog of SPOP, a nuclear localized E3 ubiquitin ligase adaptor only found in metazoans. SPOP is also required for GR50 toxicity and functions in a genetic pathway that includes cul-3, which is the canonical E3 ligase partner for SPOP Genetic or pharmacological inhibition of SPOP in mammalian primary spinal cord motor neurons suppressed DPR toxicity without affecting DPR expression levels. Finally, we find that knockdown of bromodomain proteins in both C. elegans and mammalian neurons, which are known SPOP ubiquitination targets, suppresses the protective effect of SPOP inhibition. Together, these data suggest a model in which SPOP promotes the DPR-dependent ubiquitination and degradation of BRD proteins. We speculate the pharmacological manipulation of this pathway, which is currently underway for multiple cancer subtypes, could also represent an entry point for therapeutic intervention to treat C9orf72 FTD/ALS.
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Rzepnikowska W, Kochański A. Models for IGHMBP2-associated diseases: an overview and a roadmap for the future. Neuromuscul Disord 2021; 31:1266-1278. [PMID: 34785121 DOI: 10.1016/j.nmd.2021.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/16/2021] [Accepted: 08/06/2021] [Indexed: 12/13/2022]
Abstract
Models are practical tools with which to establish the basic aspects of a diseases. They allow systematic research into the significance of mutations, of cellular and molecular pathomechanisms, of therapeutic options and of functions of diseases associated proteins. Thus, disease models are an integral part of the study of enigmatic proteins such as immunoglobulin mu-binding protein 2 (IGHMBP2). IGHMBP2 has been well defined as a helicase, however there is little known about its role in cellular processes. Notably, it is unclear why changes in such an abundant protein lead to specific neuronal disorders including spinal muscular atrophy with respiratory distress type 1 (SMARD1) and Charcot-Marie-Tooth type 2S (CMT2S). SMARD1 is caused by a loss of motor neurons in the spinal cord that results in muscle atrophy and is accompanied by rapid respiratory failure. In contrast, CMT2S manifests as a severe neuropathy, but typically without critical breathing problems. Here, we present the clinical manifestation of IGHMBP2 mutations, function of protein and models that may be used for the study of IGHMBP2-associated disorders. We highlight the strengths and weaknesses of specific models and discuss the orthologs of IGHMBP2 that are found in different systems with regard to their similarity to human IGHMBP2.
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Affiliation(s)
- Weronika Rzepnikowska
- Neuromuscular Unit, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw 02-106, Poland.
| | - Andrzej Kochański
- Neuromuscular Unit, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw 02-106, Poland
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9
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Replication stress promotes cell elimination by extrusion. Nature 2021; 593:591-596. [PMID: 33953402 DOI: 10.1038/s41586-021-03526-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 04/09/2021] [Indexed: 01/21/2023]
Abstract
Cell extrusion is a mechanism of cell elimination that is used by organisms as diverse as sponges, nematodes, insects and mammals1-3. During extrusion, a cell detaches from a layer of surrounding cells while maintaining the continuity of that layer4. Vertebrate epithelial tissues primarily eliminate cells by extrusion, and the dysregulation of cell extrusion has been linked to epithelial diseases, including cancer1,5. The mechanisms that drive cell extrusion remain incompletely understood. Here, to analyse cell extrusion by Caenorhabditis elegans embryos3, we conducted a genome-wide RNA interference screen, identified multiple cell-cycle genes with S-phase-specific function, and performed live-imaging experiments to establish how those genes control extrusion. Extruding cells experience replication stress during S phase and activate a replication-stress response via homologues of ATR and CHK1. Preventing S-phase entry, inhibiting the replication-stress response, or allowing completion of the cell cycle blocked cell extrusion. Hydroxyurea-induced replication stress6,7 triggered ATR-CHK1- and p53-dependent cell extrusion from a mammalian epithelial monolayer. We conclude that cell extrusion induced by replication stress is conserved among animals and propose that this extrusion process is a primordial mechanism of cell elimination with a tumour-suppressive function in mammals.
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10
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Mao K, Breen P, Ruvkun G. Mitochondrial dysfunction induces RNA interference in C. elegans through a pathway homologous to the mammalian RIG-I antiviral response. PLoS Biol 2020; 18:e3000996. [PMID: 33264285 PMCID: PMC7735679 DOI: 10.1371/journal.pbio.3000996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 12/14/2020] [Accepted: 11/09/2020] [Indexed: 12/27/2022] Open
Abstract
RNA interference (RNAi) is an antiviral pathway common to many eukaryotes that detects and cleaves foreign nucleic acids. In mammals, mitochondrially localized proteins such as mitochondrial antiviral signaling (MAVS), retinoic acid-inducible gene I (RIG-I), and melanoma differentiation-associated protein 5 (MDA5) mediate antiviral responses. Here, we report that mitochondrial dysfunction in Caenorhabditis elegans activates RNAi-directed silencing via induction of a pathway homologous to the mammalian RIG-I helicase viral response pathway. The induction of RNAi also requires the conserved RNA decapping enzyme EOL-1/DXO. The transcriptional induction of eol-1 requires DRH-1 as well as the mitochondrial unfolded protein response (UPRmt). Upon mitochondrial dysfunction, EOL-1 is concentrated into foci that depend on the transcription of mitochondrial RNAs that may form double-stranded RNA (dsRNA), as has been observed in mammalian antiviral responses. Enhanced RNAi triggered by mitochondrial dysfunction is necessary for the increase in longevity that is induced by mitochondrial dysfunction. Surveillance of mitochondrial dysfunction in the nematode Caenorhabditis elegans triggers the activation of an RNA interference pathway to mediate antiviral defense, in a manner homologous to the mammalian RIG-I helicase viral response pathway.
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Affiliation(s)
- Kai Mao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Peter Breen
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gary Ruvkun
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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11
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Penagos-Puig A, Furlan-Magaril M. Heterochromatin as an Important Driver of Genome Organization. Front Cell Dev Biol 2020; 8:579137. [PMID: 33072761 PMCID: PMC7530337 DOI: 10.3389/fcell.2020.579137] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022] Open
Abstract
Heterochromatin is a constituent of eukaryotic genomes with functions spanning from gene expression silencing to constraining DNA replication and repair. Inside the nucleus, heterochromatin segregates spatially from euchromatin and is localized preferentially toward the nuclear periphery and surrounding the nucleolus. Despite being an abundant nuclear compartment, little is known about how heterochromatin regulates and participates in the mechanisms driving genome organization. Here, we review pioneer and recent evidence that explores the functional role of heterochromatin in the formation of distinct chromatin compartments and how failure of the molecular mechanisms forming heterochromatin leads to disarray of genome conformation and disease.
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Affiliation(s)
- Andrés Penagos-Puig
- Department of Molecular Genetics, Institute of Cellular Physiology, National Autonomous University of Mexico, Mexico City, Mexico
| | - Mayra Furlan-Magaril
- Department of Molecular Genetics, Institute of Cellular Physiology, National Autonomous University of Mexico, Mexico City, Mexico
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12
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Harnessing the power of genetics: fast forward genetics in Caenorhabditis elegans. Mol Genet Genomics 2020; 296:1-20. [PMID: 32888055 DOI: 10.1007/s00438-020-01721-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 08/27/2020] [Indexed: 12/23/2022]
Abstract
Forward genetics is a powerful tool to unravel molecular mechanisms of diverse biological processes. The success of genetic screens primarily relies on the ease of genetic manipulation of an organism and the availability of a plethora of genetic tools. The roundworm Caenorhabditis elegans has been one of the favorite models for genetic studies due to its hermaphroditic lifestyle, ease of maintenance, and availability of various genetic manipulation tools. The strength of C. elegans genetics is highlighted by the leading role of this organism in the discovery of several conserved biological processes. In this review, the principles and strategies for forward genetics in C. elegans are discussed. Further, the recent advancements that have drastically accelerated the otherwise time-consuming process of mutation identification, making forward genetic screens a method of choice for understanding biological functions, are discussed. The emphasis of the review has been on providing practical and conceptual pointers for designing genetic screens that will identify mutations, specifically disrupting the biological processes of interest.
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13
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Houri-Zeevi L, Korem Kohanim Y, Antonova O, Rechavi O. Three Rules Explain Transgenerational Small RNA Inheritance in C. elegans. Cell 2020; 182:1186-1197.e12. [PMID: 32841602 PMCID: PMC7479518 DOI: 10.1016/j.cell.2020.07.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/21/2020] [Accepted: 07/17/2020] [Indexed: 02/06/2023]
Abstract
Experiences trigger transgenerational small RNA-based responses in C. elegans nematodes. Dedicated machinery ensures that heritable effects are reset, but how the responses segregate in the population is unknown. We show that isogenic individuals differ dramatically in the persistence of transgenerational responses. By examining lineages of more than 20,000 worms, three principles emerge: (1) The silencing each mother initiates is distributed evenly among her descendants; heritable RNAi dissipates but is uniform in every generation. (2) Differences between lineages arise because the mothers that initiate heritable responses stochastically assume different "inheritance states" that determine the progeny's fate. (3) The likelihood that an RNAi response would continue to be inherited increases the more generations it lasts. The inheritance states are determined by HSF-1, which regulates silencing factors and, accordingly, small RNA levels. We found that, based on the parents' inheritance state, the descendants' developmental rate in response to stress can be predicted.
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Affiliation(s)
- Leah Houri-Zeevi
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Yael Korem Kohanim
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Olga Antonova
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
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Puleo N, Lamitina T. The conserved multi-functional nuclear protein dss-1/Sem1 is required for C9orf72-associated ALS/FTD dipeptide toxicity. MICROPUBLICATION BIOLOGY 2020; 2020. [PMID: 32550521 PMCID: PMC7266659 DOI: 10.17912/micropub.biology.000262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Noah Puleo
- University of Pittsburgh, Depts. of Pediatrics and Cell Biology
| | - Todd Lamitina
- University of Pittsburgh, Depts. of Pediatrics and Cell Biology
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15
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Kordyukova M, Sokolova O, Morgunova V, Ryazansky S, Akulenko N, Glukhov S, Kalmykova A. Nuclear Ccr4-Not mediates the degradation of telomeric and transposon transcripts at chromatin in the Drosophila germline. Nucleic Acids Res 2020; 48:141-156. [PMID: 31724732 PMCID: PMC7145718 DOI: 10.1093/nar/gkz1072] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 10/28/2019] [Accepted: 10/30/2019] [Indexed: 01/05/2023] Open
Abstract
Ccr4-Not is a highly conserved complex involved in cotranscriptional RNA surveillance pathways in yeast. In Drosophila, Ccr4-Not is linked to the translational repression of miRNA targets and the posttranscriptional control of maternal mRNAs during oogenesis and embryonic development. Here, we describe a new role for the Ccr4-Not complex in nuclear RNA metabolism in the Drosophila germline. Ccr4 depletion results in the accumulation of transposable and telomeric repeat transcripts in the fraction of chromatin-associated RNA; however, it does not affect small RNA levels or the heterochromatin state of the target loci. Nuclear targets of Ccr4 mainly comprise active full-length transposable elements (TEs) and telomeric and subtelomeric repeats. Moreover, Ccr4-Not foci localize at telomeres in a Piwi-dependent manner, suggesting a functional relationship between these pathways. Indeed, we detected interactions between the components of the Ccr4-Not complex and piRNA machinery, which indicates that these pathways cooperate in the nucleus to recognize and degrade TE transcripts at transcription sites. These data reveal a new layer of transposon control in the germline, which is critical for the maintenance of genome integrity.
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Affiliation(s)
- Maria Kordyukova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Olesya Sokolova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Valeriya Morgunova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Sergei Ryazansky
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Natalia Akulenko
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Sergey Glukhov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Alla Kalmykova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
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16
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Caenorhabditis elegans ADAR editing and the ERI-6/7/MOV10 RNAi pathway silence endogenous viral elements and LTR retrotransposons. Proc Natl Acad Sci U S A 2020; 117:5987-5996. [PMID: 32123111 PMCID: PMC7084138 DOI: 10.1073/pnas.1919028117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Silencing of transposable elements and viruses is critical for the maintenance of genome integrity, cellular homeostasis, and organismal health. Here we describe multiple factors that control different types of transposable elements, providing insight into how they are regulated. We also identify stress response pathways that are triggered upon misregulation of these transposable elements. The conservation of these factors and pathways in human suggests that our studies in Caenorhabditis elegans can provide general insight into the regulation of and response to transposable elements and viruses. Endogenous retroviruses and long terminal repeat (LTR) retrotransposons are mobile genetic elements that are closely related to retroviruses. Desilenced endogenous retroviruses are associated with human autoimmune disorders and neurodegenerative diseases. Caenorhabditis elegans and related Caenorhabditis spp. contain LTR retrotransposons and, as described here, numerous integrated viral genes including viral envelope genes that are part of LTR retrotransposons. We found that both LTR retrotransposons and endogenous viral elements are silenced by ADARs [adenosine deaminases acting on double-stranded RNA (dsRNA)] together with the endogenous RNA interference (RNAi) factor ERI-6/7, a homolog of MOV10 helicase, a retrotransposon and retrovirus restriction factor in human. siRNAs corresponding to integrated viral genes and LTR retrotransposons, but not to DNA transposons, are dependent on the ADARs and ERI-6/7. siRNAs corresponding to palindromic repeats are independent of the ADARs and ERI-6/7, and are in fact increased in adar- and eri-6/7–defective mutants because of an antiviral RNAi response to dsRNA. Silencing of LTR retrotransposons is dependent on downstream RNAi factors and P granule components but is independent of the viral sensor DRH-1/RIG-I and the nuclear Argonaute NRDE-3. The activation of retrotransposons in the ADAR- and ERI-6/7/MOV10–defective mutant is associated with the induction of the unfolded protein response (UPR), a common response to viral infection. The overlap between genes induced upon viral infection and infection with intracellular pathogens and genes coexpressed with retrotransposons suggests that there is a common response to different types of foreign elements that includes a response to proteotoxicity presumably caused by the burden of replicating pathogens and expressed retrotransposons.
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17
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Newman MA, Ji F, Fischer SEJ, Anselmo A, Sadreyev RI, Ruvkun G. The surveillance of pre-mRNA splicing is an early step in C. elegans RNAi of endogenous genes. Genes Dev 2018; 32:670-681. [PMID: 29739806 PMCID: PMC6004069 DOI: 10.1101/gad.311514.118] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 04/03/2018] [Indexed: 01/03/2023]
Abstract
Here, Newman et al. provide insight into the role of mRNA splicing in C. elegans RNAi and show that viable null mutations in U1 and U2 snRNP-specific splicing factor genes cause defects in RNAi. They also demonstrate that RNAi targeted transcripts are tightly bound to spliceosomes, which suggests multiple layers of regulation by the spliceosome at early steps of small RNA-mediated gene silencing. RNAi pathways detect and silence foreign nucleic acids such as viruses as well as endogenous genes in many species. The phylogenetic profile across eukaryotes of proteins that mediate key steps in RNAi is correlated with the profiles of multiple mRNA splicing proteins and with intron number, suggesting that RNAi may surveil mRNA splicing to detect the divergent or absent introns of viruses. Here we examine the role of mRNA splicing in Caenorhabditis elegans RNAi. We found that viable null mutations in U1 and U2 small nuclear ribonucleic protein (snRNP)-specific splicing factor genes cause defects in RNAi. The U1A ortholog rnp-2 is required for normal ERGO-1 Argonaute class 26G siRNA biogenesis, trans-splicing of the eri-6/7 transcript, and targeting of poorly conserved gene transcripts by WAGO Argonaute class 22G siRNAs. We found that gene transcripts engaged by the siRNA-generating machinery are poorly conserved, possess few introns, and often have introns that are divergent from introns with strong consensus splicing sites found in highly conserved genes. We present biochemical evidence that RNAi targeted transcripts are tightly bound to spliceosomes. These findings suggest multiple layers of regulation by the spliceosome at early steps of small RNA-mediated gene silencing.
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Affiliation(s)
- Martin A Newman
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Fei Ji
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Sylvia E J Fischer
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Anthony Anselmo
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Ruslan I Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Gary Ruvkun
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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18
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Shiu PK, Hunter CP. Early Developmental Exposure to dsRNA Is Critical for Initiating Efficient Nuclear RNAi in C. elegans. Cell Rep 2017; 18:2969-2978. [PMID: 28329688 DOI: 10.1016/j.celrep.2017.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 12/21/2016] [Accepted: 02/28/2017] [Indexed: 11/17/2022] Open
Abstract
RNAi has enabled researchers to study the function of many genes. However, it is not understood why some RNAi experiments succeed while others do not. Here, we show in C. elegans that pharyngeal muscle is resistant to RNAi when initially exposed to double-stranded RNA (dsRNA) by feeding but sensitive to RNAi in the next generation. Investigating this observation, we find that pharyngeal muscle cells as well as vulval muscle cells require nuclear rather than cytoplasmic RNAi. Further, we find in these cell types that nuclear RNAi silencing is most efficiently triggered during early development, defining a critical period for initiating nuclear RNAi. Finally, using heat-shock-induced dsRNA expression, we show that synMuv B class mutants act in part to extend this critical window. The synMuv-B-dependent early-development-associated critical period for initiating nuclear RNAi suggests that mechanisms that restrict developmental plasticity may also restrict the initiation of nuclear RNAi.
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Affiliation(s)
- Philip K Shiu
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Craig P Hunter
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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19
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Silencing of Repetitive DNA Is Controlled by a Member of an Unusual Caenorhabditis elegans Gene Family. Genetics 2017; 207:529-545. [PMID: 28801529 DOI: 10.1534/genetics.117.300134] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/10/2017] [Indexed: 01/08/2023] Open
Abstract
Repetitive DNA sequences are subject to gene silencing in various animal species. Under specific circumstances repetitive DNA sequences can escape such silencing. For example, exogenously added, extrachromosomal DNA sequences that are stably inherited in multicopy repetitive arrays in the nematode Caenorhabditis elegans are frequently silenced in the germline, whereas such silencing often does not occur in the soma. This indicates that somatic cells might utilize factors that prevent repetitive DNA silencing. Indeed, such "antisilencing" factors have been revealed through genetic screens that identified mutant loci in which repetitive transgenic arrays are aberrantly silenced in the soma. We describe here a novel locus, pals-22 (for protein containing ALS2CR12 signature), required to prevent silencing of repetitive transgenes in neurons and other somatic tissue types. pals-22 deficiency also severely impacts animal vigor and confers phenotypes reminiscent of accelerated aging. We find that pals-22 is a member of a large family of divergent genes (39 members), defined by homology to the ALS2CR12 protein family. While gene family members are highly divergent, they show striking patterns of chromosomal clustering. The family expansion appears C. elegans-specific and has not occurred to the same extent in other nematode species for which genome sequences are available. The transgene-silencing phenotype observed upon loss of PALS-22 protein depends on the biogenesis of small RNAs. We speculate that the pals gene family may be part of a species-specific cellular defense mechanism.
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20
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Paces J, Nic M, Novotny T, Svoboda P. Literature review of baseline information to support the risk assessment of RNAi‐based GM plants. ACTA ACUST UNITED AC 2017. [PMCID: PMC7163844 DOI: 10.2903/sp.efsa.2017.en-1246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jan Paces
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
| | | | | | - Petr Svoboda
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
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21
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Brönner C, Salvi L, Zocco M, Ugolini I, Halic M. Accumulation of RNA on chromatin disrupts heterochromatic silencing. Genome Res 2017; 27:1174-1183. [PMID: 28404620 PMCID: PMC5495069 DOI: 10.1101/gr.216986.116] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 04/11/2017] [Indexed: 12/13/2022]
Abstract
Long noncoding RNAs (lncRNAs) play a conserved role in regulating gene expression, chromatin dynamics, and cell differentiation. They serve as a platform for RNA interference (RNAi)–mediated heterochromatin formation or DNA methylation in many eukaryotic organisms. We found in Schizosaccharomyces pombe that heterochromatin is lost at transcribed regions in the absence of RNA degradation. We show that heterochromatic RNAs are retained on chromatin, form DNA:RNA hybrids, and need to be degraded by the Ccr4-Not complex or RNAi to maintain heterochromatic silencing. The Ccr4-Not complex is localized to chromatin independently of H3K9me and degrades chromatin-associated transcripts, which is required for transcriptional silencing. Overexpression of heterochromatic RNA, but not euchromatic RNA, leads to chromatin localization and loss of silencing of a distant ade6 reporter in wild-type cells. Our results demonstrate that chromatin-bound RNAs disrupt heterochromatin organization and need to be degraded in a process of heterochromatin formation.
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Affiliation(s)
- Cornelia Brönner
- Department of Biochemistry, Gene Center, University of Munich (LMU), 81377 Munich, Germany
| | - Luca Salvi
- Department of Biochemistry, Gene Center, University of Munich (LMU), 81377 Munich, Germany
| | - Manuel Zocco
- Department of Biochemistry, Gene Center, University of Munich (LMU), 81377 Munich, Germany
| | - Ilaria Ugolini
- Department of Biochemistry, Gene Center, University of Munich (LMU), 81377 Munich, Germany
| | - Mario Halic
- Department of Biochemistry, Gene Center, University of Munich (LMU), 81377 Munich, Germany
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22
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Sugiyama T, Thillainadesan G, Chalamcharla VR, Meng Z, Balachandran V, Dhakshnamoorthy J, Zhou M, Grewal SIS. Enhancer of Rudimentary Cooperates with Conserved RNA-Processing Factors to Promote Meiotic mRNA Decay and Facultative Heterochromatin Assembly. Mol Cell 2016; 61:747-759. [PMID: 26942678 DOI: 10.1016/j.molcel.2016.01.029] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 12/22/2015] [Accepted: 01/27/2016] [Indexed: 12/21/2022]
Abstract
Erh1, the fission yeast homolog of Enhancer of rudimentary, is implicated in meiotic mRNA elimination during vegetative growth, but its function is poorly understood. We show that Erh1 and the RNA-binding protein Mmi1 form a stoichiometric complex, called the Erh1-Mmi1 complex (EMC), to promote meiotic mRNA decay and facultative heterochromatin assembly. To perform these functions, EMC associates with two distinct complexes, Mtl1-Red1 core (MTREC) and CCR4-NOT. Whereas MTREC facilitates assembly of heterochromatin islands coating meiotic genes silenced by the nuclear exosome, CCR4-NOT promotes RNAi-dependent heterochromatin domain (HOOD) formation at EMC-target loci. CCR4-NOT also assembles HOODs at retrotransposons and regulated genes containing cryptic introns. We find that CCR4-NOT facilitates HOOD assembly through its association with the conserved Pir2/ARS2 protein, and also maintains rDNA integrity and silencing by promoting heterochromatin formation. Our results reveal connections among Erh1, CCR4-NOT, Pir2/ARS2, and RNAi, which target heterochromatin to regulate gene expression and protect genome integrity.
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Affiliation(s)
- Tomoyasu Sugiyama
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, MD 20892, USA
| | - Gobi Thillainadesan
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, MD 20892, USA
| | - Venkata R Chalamcharla
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, MD 20892, USA
| | - Zhaojing Meng
- Laboratory of Proteomics and Analytical Technologies, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Vanivilasini Balachandran
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, MD 20892, USA
| | - Jothy Dhakshnamoorthy
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, MD 20892, USA
| | - Ming Zhou
- Laboratory of Proteomics and Analytical Technologies, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Shiv I S Grewal
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, MD 20892, USA.
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23
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Le HH, Looney M, Strauss B, Bloodgood M, Jose AM. Tissue homogeneity requires inhibition of unequal gene silencing during development. J Cell Biol 2016; 214:319-31. [PMID: 27458132 PMCID: PMC4970325 DOI: 10.1083/jcb.201601050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 06/29/2016] [Indexed: 11/22/2022] Open
Abstract
Multicellular organisms can generate and maintain homogenous populations of cells that make up individual tissues. However, cellular processes that can disrupt homogeneity and how organisms overcome such disruption are unknown. We found that ∼100-fold differences in expression from a repetitive DNA transgene can occur between intestinal cells in Caenorhabditis elegans These differences are caused by gene silencing in some cells and are actively suppressed by parental and zygotic factors such as the conserved exonuclease ERI-1. If unsuppressed, silencing can spread between some cells in embryos but can be repeat specific and independent of other homologous loci within each cell. Silencing can persist through DNA replication and nuclear divisions, disrupting uniform gene expression in developed animals. Analysis at single-cell resolution suggests that differences between cells arise during early cell divisions upon unequal segregation of an initiator of silencing. Our results suggest that organisms with high repetitive DNA content, which include humans, could use similar developmental mechanisms to achieve and maintain tissue homogeneity.
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Affiliation(s)
- Hai H Le
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Monika Looney
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Benjamin Strauss
- Center for Advanced Study of Language, University of Maryland, College Park, MD 20742
| | - Michael Bloodgood
- Center for Advanced Study of Language, University of Maryland, College Park, MD 20742
| | - Antony M Jose
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
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24
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Nagy AI, Vázquez-Manrique RP, Lopez M, Christov CP, Sequedo MD, Herzog M, Herlihy AE, Bodak M, Gatsi R, Baylis HA. IP3 signalling regulates exogenous RNAi in Caenorhabditis elegans. EMBO Rep 2015; 16:341-50. [PMID: 25608529 DOI: 10.15252/embr.201439585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
RNA interference (RNAi) is a widespread and widely exploited phenomenon. Here, we show that changing inositol 1,4,5-trisphosphate (IP3) signalling alters RNAi sensitivity in Caenorhabditis elegans. Reducing IP3 signalling enhances sensitivity to RNAi in a broad range of genes and tissues. Conversely up-regulating IP3 signalling decreases sensitivity. Tissue-specific rescue experiments suggest IP3 functions in the intestine. We also exploit IP3 signalling mutants to further enhance the sensitivity of RNAi hypersensitive strains. These results demonstrate that conserved cell signalling pathways can modify RNAi responses, implying that RNAi responses may be influenced by an animal's physiology or environment.
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Affiliation(s)
- Anikó I Nagy
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Rafael P Vázquez-Manrique
- Research Group in Molecular, Cellular and Genomic Biomedicine, Health Research Institute-La Fe, Valencia, Spain Centre for Biomedical Network Research on Rare Diseases (CIBERER), Valencia, Spain
| | - Marie Lopez
- Department of Zoology, University of Cambridge, Cambridge, UK
| | | | - María Dolores Sequedo
- Research Group in Molecular, Cellular and Genomic Biomedicine, Health Research Institute-La Fe, Valencia, Spain Centre for Biomedical Network Research on Rare Diseases (CIBERER), Valencia, Spain
| | - Mareike Herzog
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Anna E Herlihy
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Maxime Bodak
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Roxani Gatsi
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Howard A Baylis
- Department of Zoology, University of Cambridge, Cambridge, UK
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25
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Abstract
Transgenesis in model organisms is necessary to determine the function, expression, and subcellular localization of gene products. In Caenorhabditis elegans, injected DNA can be propagated as multicopy extrachromosomal arrays but transgenes in arrays are mosaic, over-expressed in some tissues and silenced in the germline. Here, a method to insert a transgene into a specific genomic location called Mos1-mediated single-copy insertion (MosSCI) is described. Single-copy insertion allows transgene expression at levels that approximate endogenous gene expression as well as expression in the germline.
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