1
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Knudsen-Palmer DR, Raman P, Ettefa F, De Ravin L, Jose AM. Target-specific requirements for RNA interference can arise through restricted RNA amplification despite the lack of specialized pathways. eLife 2024; 13:RP97487. [PMID: 39161220 PMCID: PMC11335349 DOI: 10.7554/elife.97487] [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] [Indexed: 08/21/2024] Open
Abstract
Since double-stranded RNA (dsRNA) is effective for silencing a wide variety of genes, all genes are typically considered equivalent targets for such RNA interference (RNAi). Yet, loss of some regulators of RNAi in the nematode Caenorhabditis elegans can selectively impair the silencing of some genes. Here, we show that such selective requirements can be explained by an intersecting network of regulators acting on genes with differences in their RNA metabolism. In this network, the Maelstrom domain-containing protein RDE-10, the intrinsically disordered protein MUT-16, and the Argonaute protein NRDE-3 work together so that any two are required for silencing one somatic gene, but each is singly required for silencing another somatic gene, where only the requirement for NRDE-3 can be overcome by enhanced dsRNA processing. Quantitative models and their exploratory simulations led us to find that (1) changing cis-regulatory elements of the target gene can reduce the dependence on NRDE-3, (2) animals can recover from silencing in non-dividing cells, and (3) cleavage and tailing of mRNAs with UG dinucleotides, which makes them templates for amplifying small RNAs, are enriched within 'pUG zones' matching the dsRNA. Similar crosstalk between pathways and restricted amplification could result in apparently selective silencing by endogenous RNAs.
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Affiliation(s)
- Daphne R Knudsen-Palmer
- Department of Cell Biology and Molecular Genetics, Biological Sciences Graduate Program, University of MarylandCollege ParkUnited States
| | - Pravrutha Raman
- Department of Cell Biology and Molecular Genetics, Biological Sciences Graduate Program, University of MarylandCollege ParkUnited States
| | - Farida Ettefa
- Department of Cell Biology and Molecular Genetics, Biological Sciences Graduate Program, University of MarylandCollege ParkUnited States
| | - Laura De Ravin
- Department of Cell Biology and Molecular Genetics, Biological Sciences Graduate Program, University of MarylandCollege ParkUnited States
| | - Antony M Jose
- Department of Cell Biology and Molecular Genetics, Biological Sciences Graduate Program, University of MarylandCollege ParkUnited States
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2
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Ow MC, Nishiguchi MA, Dar AR, Butcher RA, Hall SE. RNAi-dependent expression of sperm genes in ADL chemosensory neurons is required for olfactory responses in Caenorhabditis elegans. Front Mol Biosci 2024; 11:1396587. [PMID: 39055986 PMCID: PMC11269235 DOI: 10.3389/fmolb.2024.1396587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/11/2024] [Indexed: 07/28/2024] Open
Abstract
Environmental conditions experienced early in the life of an animal can result in gene expression changes later in its life history. We have previously shown that C. elegans animals that experienced the developmentally arrested and stress resistant dauer stage (postdauers) retain a cellular memory of early-life stress that manifests during adulthood as genome-wide changes in gene expression, chromatin states, and altered life history traits. One consequence of developmental reprogramming in C. elegans postdauer adults is the downregulation of osm-9 TRPV channel gene expression in the ADL chemosensory neurons resulting in reduced avoidance to a pheromone component, ascr#3. This altered response to ascr#3 requires the principal effector of the somatic nuclear RNAi pathway, the Argonaute (AGO) NRDE-3. To investigate the role of the somatic nuclear RNAi pathway in regulating the developmental reprogramming of ADL due to early-life stress, we profiled the mRNA transcriptome of control and postdauer ADL in wild-type and nrde-3 mutant adults. We found 711 differentially expressed (DE) genes between control and postdauer ADL neurons, 90% of which are dependent upon NRDE-3. Additionally, we identified a conserved sequence that is enriched in the upstream regulatory sequences of the NRDE-3-dependent differentially expressed genes. Surprisingly, 214 of the ADL DE genes are considered "germline-expressed", including 21 genes encoding the Major Sperm Proteins and two genes encoding the sperm-specific PP1 phosphatases, GSP-3 and GSP-4. Loss of function mutations in gsp-3 resulted in both aberrant avoidance and attraction behaviors. We also show that an AGO pseudogene, Y49F6A.1 (wago-11), is expressed in ADL and is required for ascr#3 avoidance. Overall, our results suggest that small RNAs and reproductive genes program the ADL mRNA transcriptome during their developmental history and highlight a nexus between neuronal and reproductive networks in calibrating animal neuroplasticity.
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Affiliation(s)
- Maria C. Ow
- Biology Department, Syracuse University, Syracuse, NY, United States
| | | | - Abdul Rouf Dar
- Department of Chemistry, University of Florida, Gainesville, FL, United States
| | - Rebecca A. Butcher
- Department of Chemistry, University of Florida, Gainesville, FL, United States
| | - Sarah E. Hall
- Biology Department, Syracuse University, Syracuse, NY, United States
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3
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Knudsen-Palmer DR, Raman P, Ettefa F, De Ravin L, Jose AM. Target-specific requirements for RNA interference can arise through restricted RNA amplification despite the lack of specialized pathways. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.07.527351. [PMID: 36798330 PMCID: PMC9934570 DOI: 10.1101/2023.02.07.527351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Since double-stranded RNA (dsRNA) is effective for silencing a wide variety of genes, all genes are typically considered equivalent targets for such RNA interference (RNAi). Yet, loss of some regulators of RNAi in the nematode C. elegans can selectively impair the silencing of some genes. Here we show that such selective requirements can be explained by an intersecting network of regulators acting on genes with differences in their RNA metabolism. In this network, the Maelstrom domain-containing protein RDE-10, the intrinsically disordered protein MUT-16, and the Argonaute protein NRDE-3 work together so that any two are required for silencing one somatic gene, but each is singly required for silencing another somatic gene, where only the requirement for NRDE-3 can be overcome by enhanced dsRNA processing. Quantitative models and their exploratory simulations led us to find that (1) changing cis-regulatory elements of the target gene can reduce the dependence on NRDE-3, (2) animals can recover from silencing in non-dividing cells and (3) cleavage and tailing of mRNAs with UG dinucleotides, which makes them templates for amplifying small RNAs, is enriched within 'pUG zones' matching the dsRNA. Similar crosstalk between pathways and restricted amplification could result in apparently selective silencing by endogenous RNAs.
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Affiliation(s)
- Daphne R. Knudsen-Palmer
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
| | - Pravrutha Raman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
- Current address: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Farida Ettefa
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
- Current address: Institute for Systems Genetics, New York University School of Medicine, New York, NY, USA
| | - Laura De Ravin
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
| | - Antony M. Jose
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
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4
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Chen S, Liu W, Xiong L, Tao Z, Zhao D. Tissue-specific silencing of integrated transgenes achieved through endogenous RNA interference in Caenorhabditis elegans. RNA Biol 2024; 21:1-10. [PMID: 38531838 DOI: 10.1080/15476286.2024.2332856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2024] [Indexed: 03/28/2024] Open
Abstract
Transgene silencing is a common phenomenon observed in Caenorhabditis elegans, particularly in the germline, but the precise mechanisms underlying this process remain elusive. Through an analysis of the transcription factors profile of C. elegans, we discovered that the expression of several transgenic reporter lines exhibited tissue-specific silencing, specifically in the intestine of C. elegans. Notably, this silencing could be reversed in mutants defective in endogenous RNA interference (RNAi). Further investigation using knock-in strains revealed that these intestine-silent genes were indeed expressed in vivo, indicating that the organism itself regulates the intestine-specific silencing. This tissue-specific silencing appears to be mediated through the endo-RNAi pathway, with the main factors of this pathway, mut-2 and mut-16, are significantly enriched in the intestine. Additionally, histone modification factors, such as met-2, are involved in this silencing mechanism. Given the crucial role of the intestine in reproduction alongside the germline, the transgene silencing observed in the intestine reflects the self-protective mechanisms employed by the organisms. In summary, our study proposed that compared to other tissues, the transgenic silencing of intestine is specifically regulated by the endo-RNAi pathway.
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Affiliation(s)
- Siyu Chen
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Institute of Sport, Exercise & Health, Tianjin University of Sport, Tianjin, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Weihong Liu
- Intelligent Perception Lab, Hanwang Technology Co. Ltd, Beijing, China
| | - Lei Xiong
- Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, Cambridge, MA, USA
- The Broad Institute of Harvard and MIT, Cambridge, MA, USA
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhiju Tao
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Di Zhao
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Institute of Sport, Exercise & Health, Tianjin University of Sport, Tianjin, China
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5
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Lažetić V, Batachari LE, Russell AB, Troemel ER. Similarities in the induction of the intracellular pathogen response in Caenorhabditis elegans and the type I interferon response in mammals. Bioessays 2023; 45:e2300097. [PMID: 37667453 PMCID: PMC10694843 DOI: 10.1002/bies.202300097] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 09/06/2023]
Abstract
Although the type-I interferon (IFN-I) response is considered vertebrate-specific, recent findings about the Intracellular Pathogen Response (IPR) in nematode Caenorhabditis elegans indicate that there are similarities between these two transcriptional immunological programs. The IPR is induced during infection with natural intracellular fungal and viral pathogens of the intestine and promotes resistance against these pathogens. Similarly, the IFN-I response is induced by viruses and other intracellular pathogens and promotes resistance against infection. Whether the IPR and the IFN-I response evolved in a divergent or convergent manner is an unanswered and exciting question, which could be addressed by further studies of immunity against intracellular pathogens in C. elegans and other simple host organisms. Here we highlight similar roles played by RIG-I-like receptors, purine metabolism enzymes, proteotoxic stressors, and transcription factors to induce the IPR and IFN-I response, as well as the similar consequences of these defense programs on organismal development.
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Affiliation(s)
- Vladimir Lažetić
- School of Biological SciencesUniversity of California, San DiegoLa JollaCaliforniaUSA
- Department of Biological SciencesThe George Washington UniversityWashingtonDCUSA
| | - Lakshmi E. Batachari
- School of Biological SciencesUniversity of California, San DiegoLa JollaCaliforniaUSA
| | - Alistair B. Russell
- School of Biological SciencesUniversity of California, San DiegoLa JollaCaliforniaUSA
| | - Emily R. Troemel
- School of Biological SciencesUniversity of California, San DiegoLa JollaCaliforniaUSA
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6
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Sarkies P. Planting the seeds for a forest of RNAi pathways. PLoS Biol 2023; 21:e3002279. [PMID: 37585418 PMCID: PMC10431632 DOI: 10.1371/journal.pbio.3002279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023] Open
Abstract
Cells from most eukaryotic species make several different types of small interfering RNAs. Pioneering work in plants, published in PLOS Biology almost 20 years ago, established a framework to understand how multiple RNA interference pathways can regulate the genome in parallel.
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Affiliation(s)
- Peter Sarkies
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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7
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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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8
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Desbois M, Pak JS, Opperman KJ, Giles AC, Grill B. Optimized protocol for in vivo affinity purification proteomics and biochemistry using C. elegans. STAR Protoc 2023; 4:102262. [PMID: 37294631 PMCID: PMC10323129 DOI: 10.1016/j.xpro.2023.102262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 06/11/2023] Open
Abstract
We present an optimized protocol for in vivo affinity purification proteomics and biochemistry using the model organism C. elegans. We describe steps for target tagging, large-scale culture, affinity purification using a cryomill, mass spectrometry and validation of candidate binding proteins. Our approach has proven successful for identifying protein-protein interactions and signaling networks with verified functional relevance. Our protocol is also suitable for biochemical evaluation of protein-protein interactions in vivo. For complete details on the use and execution of this protocol, please refer to Crawley et al.,1 Giles et al.,2 and Desbois et al.3.
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Affiliation(s)
- Muriel Desbois
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Joseph S Pak
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Karla J Opperman
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Andrew C Giles
- Division of Medical Sciences, University of Northern British Columbia, Prince George, BC V2N 4Z9 Canada
| | - Brock Grill
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Pediatrics, University of Washington Medical School, Seattle, WA 98101, USA; Department of Pharmacology, University of Washington Medical School, Seattle, WA 98101, USA.
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9
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Sanchez-Briñas A, Duran-Ruiz C, Astola A, Arroyo MM, Raposo FG, Valle A, Bolivar J. ZNF330/NOA36 interacts with HSPA1 and HSPA8 and modulates cell cycle and proliferation in response to heat shock in HEK293 cells. Biol Direct 2023; 18:26. [PMID: 37254218 DOI: 10.1186/s13062-023-00384-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 05/20/2023] [Indexed: 06/01/2023] Open
Abstract
BACKGROUND The human genome contains nearly 20.000 protein-coding genes, but there are still more than 6,000 proteins poorly characterized. Among them, ZNF330/NOA36 stand out because it is a highly evolutionarily conserved nucleolar zinc-finger protein found in the genome of ancient animal phyla like sponges or cnidarians, up to humans. Firstly described as a human autoantigen, NOA36 is expressed in all tissues and human cell lines, and it has been related to apoptosis in human cells as well as in muscle morphogenesis and hematopoiesis in Drosophila. Nevertheless, further research is required to better understand the roles of this highly conserved protein. RESULTS Here, we have investigated possible interactors of human ZNF330/NOA36 through affinity-purification mass spectrometry (AP-MS). Among them, NOA36 interaction with HSPA1 and HSPA8 heat shock proteins was disclosed and further validated by co-immunoprecipitation. Also, "Enhancer of Rudimentary Homolog" (ERH), a protein involved in cell cycle regulation, was detected in the AP-MS approach. Furthermore, we developed a NOA36 knockout cell line using CRISPR/Cas9n in HEK293, and we found that the cell cycle profile was modified, and proliferation decreased after heat shock in the knocked-out cells. These differences were not due to a different expression of the HSPs genes detected in the AP-MS after inducing stress. CONCLUSIONS Our results indicate that NOA36 is necessary for proliferation recovery in response to thermal stress to achieve a regular cell cycle profile, likely by interaction with HSPA1 and HSPA8. Further studies would be required to disclose the relevance of NOA36-EHR interaction in this context.
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Affiliation(s)
- Alejandra Sanchez-Briñas
- Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus Universitario de Puerto Real, University of Cadiz, Puerto Real, Cadiz, 11510, Spain
| | - Carmen Duran-Ruiz
- Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus Universitario de Puerto Real, University of Cadiz, Puerto Real, Cadiz, 11510, Spain
- Biomedical Research and Innovation Institute of Cadiz (INiBICA), Cadiz, Spain
| | - Antonio Astola
- Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus Universitario de Puerto Real, University of Cadiz, Puerto Real, Cadiz, 11510, Spain
- Institute of Biomolecules (INBIO), University of Cadiz, Cadiz, Spain
| | - Marta Marina Arroyo
- Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus Universitario de Puerto Real, University of Cadiz, Puerto Real, Cadiz, 11510, Spain
| | - Fátima G Raposo
- Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus Universitario de Puerto Real, University of Cadiz, Puerto Real, Cadiz, 11510, Spain
| | - Antonio Valle
- Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus Universitario de Puerto Real, University of Cadiz, Puerto Real, Cadiz, 11510, Spain
- Institute of Viticulture and Agri-Food Research (IVAGRO) - International Campus of Excellence (ceiA3), University of Cadiz, Cadiz, Spain
| | - Jorge Bolivar
- Department of Biomedicine, Biotechnology and Public Health-Biochemistry and Molecular Biology, Campus Universitario de Puerto Real, University of Cadiz, Puerto Real, Cadiz, 11510, Spain.
- Institute of Biomolecules (INBIO), University of Cadiz, Cadiz, Spain.
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10
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Iwama RE, Moran Y. Origins and diversification of animal innate immune responses against viral infections. Nat Ecol Evol 2023; 7:182-193. [PMID: 36635343 DOI: 10.1038/s41559-022-01951-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 11/11/2022] [Indexed: 01/14/2023]
Abstract
Immune systems are of pivotal importance to any living organism on Earth, as they protect the organism against deleterious effects of viral infections. Though the current knowledge about these systems is still biased towards the immune response in vertebrates, some studies have focused on the identification and characterization of components of invertebrate antiviral immune systems. Two classic model organisms, the insect Drosophila melanogaster and the nematode Caenorhabditis elegans, were instrumental in the discovery of several important components of the innate immune system, such as the Toll-like receptors and the RNA interference pathway. However, these two model organisms provide only a limited view of the evolutionary history of the immune system, as they both are ecdysozoan protostomes. Recent functional studies in non-classic models such as unicellular holozoans (for example, choanoflagellates), lophotrochozoans (for example, oysters) and cnidarians (for example, sea anemones) have added crucial information for understanding the evolution of antiviral systems, as they revealed unexpected ancestral complexity. This Review aims to summarize this information and present the ancestral nature of the antiviral immune response in animals. We also discuss lineage-specific adaptations and future perspectives for the comparative study of the innate immune system that are essential for understanding its evolution.
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Affiliation(s)
- Rafael E Iwama
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Yehu Moran
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, Hebrew University of Jerusalem, Jerusalem, Israel.
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11
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Karin O, Miska EA, Simons BD. Epigenetic inheritance of gene silencing is maintained by a self-tuning mechanism based on resource competition. Cell Syst 2023; 14:24-40.e11. [PMID: 36657390 PMCID: PMC7614883 DOI: 10.1016/j.cels.2022.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/05/2022] [Accepted: 12/12/2022] [Indexed: 01/19/2023]
Abstract
Biological systems can maintain memories over long timescales, with examples including memories in the brain and immune system. It is unknown how functional properties of memory systems, such as memory persistence, can be established by biological circuits. To address this question, we focus on transgenerational epigenetic inheritance in Caenorhabditis elegans. In response to a trigger, worms silence a target gene for multiple generations, resisting strong dilution due to growth and reproduction. Silencing may also be maintained indefinitely upon selection according to silencing levels. We show that these properties imply the fine-tuning of biochemical rates in which the silencing system is positioned near the transition to bistability. We demonstrate that this behavior is consistent with a generic mechanism based on competition for synthesis resources, which leads to self-organization around a critical state with broad silencing timescales. The theory makes distinct predictions and offers insights into the design principles of long-term memory systems.
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Affiliation(s)
- Omer Karin
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge, CB3 0WA, UK; Wellcome Trust, Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, CB2 1QN, UK; Department of Mathematics, Imperial College London, London, SW7 2AZ, UK.
| | - Eric A Miska
- Wellcome Trust, Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, CB2 1QN, UK; Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK; Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge CB10 1SA, UK
| | - Benjamin D Simons
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge, CB3 0WA, UK; Wellcome Trust, Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, CB2 1QN, UK; Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge, CB2 0AW, UK.
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12
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Quévillon Huberdeau M, Shah VN, Nahar S, Neumeier J, Houle F, Bruckmann A, Gypas F, Nakanishi K, Großhans H, Meister G, Simard MJ. A specific type of Argonaute phosphorylation regulates binding to microRNAs during C. elegans development. Cell Rep 2022; 41:111822. [PMID: 36516777 PMCID: PMC10436268 DOI: 10.1016/j.celrep.2022.111822] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 09/22/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022] Open
Abstract
Argonaute proteins are at the core of the microRNA-mediated gene silencing pathway essential for animals. In C. elegans, the microRNA-specific Argonautes ALG-1 and ALG-2 regulate multiple processes required for proper animal developmental timing and viability. Here we identified a phosphorylation site on ALG-1 that modulates microRNA association. Mutating ALG-1 serine 642 into a phospho-mimicking residue impairs microRNA binding and causes embryonic lethality and post-embryonic phenotypes that are consistent with alteration of microRNA functions. Monitoring microRNA levels in alg-1 phosphorylation mutant animals shows that microRNA passenger strands increase in abundance but are not preferentially loaded into ALG-1, indicating that the miRNA binding defects could lead to microRNA duplex accumulation. Our genetic and biochemical experiments support protein kinase A (PKA) KIN-1 as the putative kinase that phosphorylates ALG-1 serine 642. Our data indicate that PKA triggers ALG-1 phosphorylation to regulate its microRNA association during C. elegans development.
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Affiliation(s)
- Miguel Quévillon Huberdeau
- CHU de Québec-Université Laval Research Center (Oncology Division), Québec City, QC G1R 3S3, Canada; Université Laval Cancer Research Centre, Québec City, QC G1R 3S3, Canada
| | - Vivek Nilesh Shah
- CHU de Québec-Université Laval Research Center (Oncology Division), Québec City, QC G1R 3S3, Canada; Université Laval Cancer Research Centre, Québec City, QC G1R 3S3, Canada
| | - Smita Nahar
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Julia Neumeier
- Regensburg Center for Biochemistry (RCB), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - François Houle
- CHU de Québec-Université Laval Research Center (Oncology Division), Québec City, QC G1R 3S3, Canada; Université Laval Cancer Research Centre, Québec City, QC G1R 3S3, Canada
| | - Astrid Bruckmann
- Regensburg Center for Biochemistry (RCB), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Foivos Gypas
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Kotaro Nakanishi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, Columbus, OH 43210, USA
| | - Helge Großhans
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; University of Basel, 4056 Basel, Switzerland
| | - Gunter Meister
- Regensburg Center for Biochemistry (RCB), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany
| | - Martin J Simard
- CHU de Québec-Université Laval Research Center (Oncology Division), Québec City, QC G1R 3S3, Canada; Université Laval Cancer Research Centre, Québec City, QC G1R 3S3, Canada.
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13
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Tsai HY, Cheng HT, Tsai YT. Biogenesis of C. elegans spermatogenesis small RNAs is initiated by a zc3h12a-like ribonuclease. SCIENCE ADVANCES 2022; 8:eabm0699. [PMID: 35947655 PMCID: PMC9365287 DOI: 10.1126/sciadv.abm0699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Small RNAs regulate spermatogenesis across species ranging from Caenorhabditis elegans to humans. In C. elegans, two Argonaute proteins, ALG-3 and ALG-4, and their associated alg-3/4 26G-small RNAs are essential for spermiogenesis at 25°C. The alg-3/4 26G-small RNAs are antisense to their target mRNAs and produced by the RNA-dependent RNA polymerase, RRF-3. However, it remains unclear how the RNA templates for RRF-3 are generated and which cellular processes are affected by alg-3/4 26G-small RNAs. Here, we demonstrate a previously unidentified zc3h12a-like ribonuclease protein, NYN-3, in alg-3/4 26G-small RNAs biogenesis. NYN-3 is not only required for proper abundance of alg-3/4 26G-small RNAs but also crosslinked to their targeted mRNAs before RRF-3 from ePAR-CLIP-seq. Bioinformatics analysis was then used to parse the 26G-small RNA-targeted genes into functional subclasses. Collectively, these findings implicate NYN-3 as an initiator of alg-3/4 26G-small RNA generation.
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Affiliation(s)
- Hsin-Yue Tsai
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
- Center of Precision Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Hsian-Tang Cheng
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Yi-Ting Tsai
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, No. 7 Chung-Shan South Road, Taipei 10002, Taiwan
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14
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Cockrum CS, Strome S. Maternal H3K36 and H3K27 HMTs protect germline development via regulation of the transcription factor LIN-15B. eLife 2022; 11:77951. [PMID: 35920536 PMCID: PMC9348848 DOI: 10.7554/elife.77951] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 07/18/2022] [Indexed: 12/05/2022] Open
Abstract
Maternally synthesized products play critical roles in the development of offspring. A premier example is the Caenorhabditis elegans H3K36 methyltransferase MES-4, which is essential for germline survival and development in offspring. How maternal MES-4 protects the germline is not well understood, but its role in H3K36 methylation hinted that it may regulate gene expression in primordial germ cells (PGCs). We tested this hypothesis by profiling transcripts from nascent germlines (PGCs and their descendants) dissected from wild-type and mes-4 mutant (lacking maternal and zygotic MES-4) larvae. mes-4 nascent germlines displayed downregulation of some germline genes, upregulation of some somatic genes, and dramatic upregulation of hundreds of genes on the X chromosome. We demonstrated that upregulation of one or more genes on the X is the cause of germline death by generating and analyzing mes-4 mutants that inherited different endowments of X chromosome(s). Intriguingly, removal of the THAP transcription factor LIN-15B from mes-4 mutants reduced X misexpression and prevented germline death. lin-15B is X-linked and misexpressed in mes-4 PGCs, identifying it as a critical target for MES-4 repression. The above findings extend to the H3K27 methyltransferase MES-2/3/6, the C. elegans version of polycomb repressive complex 2. We propose that maternal MES-4 and PRC2 cooperate to protect germline survival by preventing synthesis of germline-toxic products encoded by genes on the X chromosome, including the key transcription factor LIN-15B.
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Affiliation(s)
- Chad Steven Cockrum
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States
| | - Susan Strome
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States
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15
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Carro MDLM, Grimson A, Cohen PE. Small RNAs and their protein partners in animal meiosis. Curr Top Dev Biol 2022; 151:245-279. [PMID: 36681472 DOI: 10.1016/bs.ctdb.2022.06.001] [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] [Indexed: 01/25/2023]
Abstract
Meiosis is characterized by highly regulated transitions in gene expression that require diverse mechanisms of gene regulation. For example, in male mammals, transcription undergoes a global shut-down in early prophase I of meiosis, followed by increasing transcriptional activity into pachynema. Later, as spermiogenesis proceeds, the histones bound to DNA are replaced with transition proteins, which are themselves replaced with protamines, resulting in a highly condensed nucleus with repressed transcriptional activity. In addition, two specialized gene silencing events take place during prophase I: meiotic silencing of unsynapsed chromatin (MSUC), and the sex chromatin specific mechanism, meiotic sex chromosome inactivation (MSCI). Notably, conserved roles for the RNA binding protein (RBP) machinery that functions with small non-coding RNAs have been described as participating in these meiosis-specific mechanisms, suggesting that RNA-mediated gene regulation is critical for fertility in many species. Here, we review roles of small RNAs and their associated RBPs in meiosis-related processes such as centromere function, silencing of unpaired chromatin and meiotic recombination. We will discuss the emerging evidence of non-canonical functions of these components in meiosis.
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Affiliation(s)
- María de Las Mercedes Carro
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, United States; Cornell Reproductive Sciences Center (CoRe), Cornell University, Ithaca, NY, United States
| | - Andrew Grimson
- Cornell Reproductive Sciences Center (CoRe), Cornell University, Ithaca, NY, United States; Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY, United States.
| | - Paula E Cohen
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, United States; Cornell Reproductive Sciences Center (CoRe), Cornell University, Ithaca, NY, United States.
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16
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Hsu TY, Hsu LN, Chen SY, Juang BT. MUT-7 Provides Molecular Insight into the Werner Syndrome Exonuclease. Cells 2021; 10:cells10123457. [PMID: 34943966 PMCID: PMC8700014 DOI: 10.3390/cells10123457] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/01/2021] [Accepted: 12/05/2021] [Indexed: 11/24/2022] Open
Abstract
Werner syndrome (WS) is a rare recessive genetic disease characterized by premature aging. Individuals with this disorder develop normally during childhood, but their physiological conditions exacerbate the aging process in late adolescence. WS is caused by mutation of the human WS gene (WRN), which encodes two main domains, a 3′-5′ exonuclease and a 3′-5′ helicase. Caenorhabditis elegans expresses human WRN orthologs as two different proteins: MUT-7, which has a 3′-5′ exonuclease domain, and C. elegans WRN-1 (CeWRN-1), which has only helicase domains. These unique proteins dynamically regulate olfactory memory in C. elegans, providing insight into the molecular roles of WRN domains in humans. In this review, we specifically focus on characterizing the function of MUT-7 in small interfering RNA (siRNA) synthesis in the cytoplasm and the roles of siRNA in directing nuclear CeWRN-1 loading onto a heterochromatin complex to induce negative feedback regulation. Further studies on the different contributions of the 3′-5′ exonuclease and helicase domains in the molecular mechanism will provide clues to the accelerated aging processes in WS.
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Affiliation(s)
- Tsung-Yuan Hsu
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan;
- Department of Cell and Tissue Biology, University of California, 513 Parnassus, San Francisco, CA 94143, USA
| | - Ling-Nung Hsu
- Occupational Safety and Health Office, Fu Jen Catholic University Hospital, New Taipei City 243, Taiwan;
| | - Shih-Yu Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan;
| | - Bi-Tzen Juang
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan;
- Center for Intelligent Drug Systems and Smart Bio-Devices (IDS2B), National Chiao Tung University, Hsinchu 300, Taiwan
- Correspondence:
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17
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Shukla A, Perales R, Kennedy S. piRNAs coordinate poly(UG) tailing to prevent aberrant and perpetual gene silencing. Curr Biol 2021; 31:4473-4485.e3. [PMID: 34428467 DOI: 10.1016/j.cub.2021.07.076] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 06/03/2021] [Accepted: 07/28/2021] [Indexed: 11/16/2022]
Abstract
Noncoding RNAs have emerged as mediators of transgenerational epigenetic inheritance (TEI) in a number of organisms. A robust example of such RNA-directed TEI is the inheritance of gene-silencing states following RNA interference (RNAi) in the metazoan C. elegans. During RNAi inheritance, gene silencing is transmitted by a self-perpetuating cascade of siRNA-directed poly(UG) tailing of mRNA fragments (pUGylation), followed by siRNA synthesis from poly(UG)-tailed mRNA templates (termed pUG RNA/siRNA cycling). Despite the self-perpetuating nature of pUG RNA/siRNA cycling, RNAi inheritance is finite, suggesting that systems likely exist to prevent indefinite RNAi-triggered gene silencing. Here we show that, in the absence of Piwi-interacting RNAs (piRNAs), an animal-specific class of small noncoding RNA, RNAi-based gene silencing can become essentially permanent, lasting at near 100% penetrance for more than 5 years and hundreds of generations. This perpetual gene silencing is mediated by continuous pUG RNA/siRNA cycling. Further, we find that piRNAs coordinate endogenous RNAi pathways to prevent germline-expressed genes, which are not normally subjected to TEI, from entering a state of continual and irreversible epigenetic silencing also mediated by continuous maintenance of pUG RNA/siRNA cycling. Together, our results show that one function of C. elegans piRNAs is to insulate germline-expressed genes from aberrant and runaway inactivation by the pUG RNA/siRNA epigenetic inheritance system.
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Affiliation(s)
- Aditi Shukla
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, MA 02115, USA; Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Roberto Perales
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, MA 02115, USA; Shape Therapeutics, Seattle, WA 98109, USA
| | - Scott Kennedy
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, MA 02115, USA.
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18
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Li K, Zheng J, Wirawan M, Trinh NM, Fedorova O, Griffin PR, Pyle AM, Luo D. Insights into the structure and RNA-binding specificity of Caenorhabditis elegans Dicer-related helicase 3 (DRH-3). Nucleic Acids Res 2021; 49:9978-9991. [PMID: 34403472 PMCID: PMC8464030 DOI: 10.1093/nar/gkab712] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 07/31/2021] [Accepted: 08/03/2021] [Indexed: 12/17/2022] Open
Abstract
DRH-3 is critically involved in germline development and RNA interference (RNAi) facilitated chromosome segregation via the 22G-siRNA pathway in Caenorhabditis elegans. DRH-3 has similar domain architecture to RIG-I-like receptors (RLRs) and belongs to the RIG-I-like RNA helicase family. The molecular understanding of DRH-3 and its function in endogenous RNAi pathways remains elusive. In this study, we solved the crystal structures of the DRH-3 N-terminal domain (NTD) and the C-terminal domains (CTDs) in complex with 5'-triphosphorylated RNAs. The NTD of DRH-3 adopts a distinct fold of tandem caspase activation and recruitment domains (CARDs) structurally similar to the CARDs of RIG-I and MDA5, suggesting a signaling function in the endogenous RNAi biogenesis. The CTD preferentially recognizes 5'-triphosphorylated double-stranded RNAs bearing the typical features of secondary siRNA transcripts. The full-length DRH-3 displays unique structural dynamics upon binding to RNA duplexes that differ from RIG-I or MDA5. These features of DRH-3 showcase the evolutionary divergence of the Dicer and RLR family of helicases.
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Affiliation(s)
- Kuohan Li
- Lee Kong Chian School of Medicine, Nanyang Technological University, EMB 03-07, 59 Nanyang Drive 636921, Singapore.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, EMB 06-01, 59 Nanyang Drive 636921, Singapore
| | - Jie Zheng
- The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Melissa Wirawan
- Lee Kong Chian School of Medicine, Nanyang Technological University, EMB 03-07, 59 Nanyang Drive 636921, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, EMB 06-01, 59 Nanyang Drive 636921, Singapore
| | - Nguyen Mai Trinh
- Lee Kong Chian School of Medicine, Nanyang Technological University, EMB 03-07, 59 Nanyang Drive 636921, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, EMB 06-01, 59 Nanyang Drive 636921, Singapore
| | - Olga Fedorova
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.,Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | | | - Anna M Pyle
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.,Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Dahai Luo
- Lee Kong Chian School of Medicine, Nanyang Technological University, EMB 03-07, 59 Nanyang Drive 636921, Singapore.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, EMB 06-01, 59 Nanyang Drive 636921, Singapore
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19
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Wahba L, Hansen L, Fire AZ. An essential role for the piRNA pathway in regulating the ribosomal RNA pool in C. elegans. Dev Cell 2021; 56:2295-2312.e6. [PMID: 34388368 PMCID: PMC8387450 DOI: 10.1016/j.devcel.2021.07.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/11/2021] [Accepted: 07/15/2021] [Indexed: 01/08/2023]
Abstract
Piwi-interacting RNAs (piRNAs) are RNA effectors with key roles in maintaining genome integrity and promoting fertility in metazoans. In Caenorhabditis elegans loss of piRNAs leads to a transgenerational sterility phenotype. The plethora of piRNAs and their ability to silence transcripts with imperfect complementarity have raised several (non-exclusive) models for the underlying drivers of sterility. Here, we report the extranuclear and transferable nature of the sterility driver, its suppression via mutations disrupting the endogenous RNAi and poly-uridylation machinery, and copy-number amplification at the ribosomal DNA locus. In piRNA-deficient animals, several small interfering RNA (siRNA) populations become increasingly overabundant in the generations preceding loss of germline function, including ribosomal siRNAs (risiRNAs). A concomitant increase in uridylated sense rRNA fragments suggests that poly-uridylation may potentiate RNAi-mediated gene silencing of rRNAs. We conclude that loss of the piRNA machinery allows for unchecked amplification of siRNA populations, originating from abundant highly structured RNAs, to deleterious levels.
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Affiliation(s)
- Lamia Wahba
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Loren Hansen
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew Z Fire
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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20
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Mayya VK, Flamand MN, Lambert AM, Jafarnejad SM, Wohlschlegel JA, Sonenberg N, Duchaine TF. microRNA-mediated translation repression through GYF-1 and IFE-4 in C. elegans development. Nucleic Acids Res 2021; 49:4803-4815. [PMID: 33758928 PMCID: PMC8136787 DOI: 10.1093/nar/gkab162] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/24/2021] [Accepted: 03/17/2021] [Indexed: 12/11/2022] Open
Abstract
microRNA (miRNA)-mediated gene silencing is enacted through the recruitment of effector proteins that direct translational repression or degradation of mRNA targets, but the relative importance of their activities for animal development remains unknown. Our concerted proteomic surveys identified the uncharacterized GYF-domain encoding protein GYF-1 and its direct interaction with IFE-4, the ortholog of the mammalian translation repressor 4EHP, as key miRNA effector proteins in Caenorhabditis elegans. Recruitment of GYF-1 protein to mRNA reporters in vitro or in vivo leads to potent translation repression without affecting the poly(A) tail or impinging on mRNA stability. Loss of gyf-1 is synthetic lethal with hypomorphic alleles of embryonic miR-35-42 and larval (L4) let-7 miRNAs, which is phenocopied through engineered mutations in gyf-1 that abolish interaction with IFE-4. GYF-1/4EHP function is cascade-specific, as loss of gyf-1 had no noticeable impact on the functions of other miRNAs, including lin-4 and lsy-6. Overall, our findings reveal the first direct effector of miRNA-mediated translational repression in C. elegans and its physiological importance for the function of several, but likely not all miRNAs.
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Affiliation(s)
- Vinay K Mayya
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
| | - Mathieu N Flamand
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
| | - Alice M Lambert
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
| | - Seyed Mehdi Jafarnejad
- Patrick G. Johnston Centre for Cancer Research, Queen's University of Belfast, Belfast BT9 7AE UK
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Nahum Sonenberg
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
| | - Thomas F Duchaine
- Goodman Cancer Research Center, McGill University, Montréal H3G 1Y6, Canada.,Department of Biochemistry, McGill University, Montréal H3G 1Y6, Canada
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21
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Werner A, Clark JE, Samaranayake C, Casement J, Zinad HS, Sadeq S, Al-Hashimi S, Smith M, Kotaja N, Mattick JS. Widespread formation of double-stranded RNAs in testis. Genome Res 2021; 31:1174-1186. [PMID: 34158368 PMCID: PMC8256860 DOI: 10.1101/gr.265603.120] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/02/2021] [Indexed: 12/27/2022]
Abstract
The testis transcriptome is highly complex and includes RNAs that potentially hybridize to form double-stranded RNA (dsRNA). We isolated dsRNA using the monoclonal J2 antibody and deep-sequenced the enriched samples from testes of juvenile Dicer1 knockout mice, age-matched controls, and adult animals. Comparison of our data set with recently published data from mouse liver revealed that the dsRNA transcriptome in testis is markedly different from liver: In testis, dsRNA-forming transcripts derive from mRNAs including promoters and immediate downstream regions, whereas in somatic cells they originate more often from introns and intergenic transcription. The genes that generate dsRNA are significantly expressed in isolated male germ cells with particular enrichment in pachytene spermatocytes. dsRNA formation is lower on the sex (X and Y) chromosomes. The dsRNA transcriptome is significantly less complex in juvenile mice as compared to adult controls and, possibly as a consequence, the knockout of Dicer1 has only a minor effect on the total number of transcript peaks associated with dsRNA. The comparison between dsRNA-associated genes in testis and liver with a reported set of genes that produce endogenous siRNAs reveals a significant overlap in testis but not in liver. Testis dsRNAs also significantly associate with natural antisense genes-again, this feature is not observed in liver. These findings point to a testis-specific mechanism involving natural antisense transcripts and the formation of dsRNAs that feed into the RNA interference pathway, possibly to mitigate the mutagenic impacts of recombination and transposon mobilization.
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Affiliation(s)
- Andreas Werner
- Biosciences Institute, Medical School, Newcastle University, Newcastle, NE2 4HH, United Kingdom
| | - James E Clark
- Biosciences Institute, Medical School, Newcastle University, Newcastle, NE2 4HH, United Kingdom
| | - Calum Samaranayake
- Biosciences Institute, Medical School, Newcastle University, Newcastle, NE2 4HH, United Kingdom
| | - John Casement
- Bioinformatics Support Unit, Medical School, Newcastle University, Newcastle, NE2 4HH, United Kingdom
| | - Hany S Zinad
- Biosciences Institute, Medical School, Newcastle University, Newcastle, NE2 4HH, United Kingdom
| | - Shaymaa Sadeq
- Biosciences Institute, Medical School, Newcastle University, Newcastle, NE2 4HH, United Kingdom
- Fallujah College of Medicine, Al-Fallujah University, Al-Fallujah, 9Q4V+H3, Iraq
| | - Surar Al-Hashimi
- Biosciences Institute, Medical School, Newcastle University, Newcastle, NE2 4HH, United Kingdom
| | - Martin Smith
- CHU Sainte-Justine Research Centre, Montreal, QC H3T 1C5, Canada
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Montreal, Montreal, QC H3T 1C5, Canada
| | - Noora Kotaja
- Institute of Biomedicine, University of Turku, Turku, FIN-20520, Finland
| | - John S Mattick
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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22
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Iqbal S, Jones MGK, Fosu-Nyarko J. RNA interference of an orthologue of Dicer of Meloidogyne incognita alludes to the gene's importance in nematode development. Sci Rep 2021; 11:11156. [PMID: 34045504 PMCID: PMC8160347 DOI: 10.1038/s41598-021-90363-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 05/04/2021] [Indexed: 12/13/2022] Open
Abstract
Dicers and dicer-like enzymes play an essential role in small RNA processing in eukaryotes. Nematodes are thought to encode one dicer, DCR-1; only that for Caenorhabditis spp. is well-characterised. Using genomic sequences of eight root-knot nematodes (Meloidogyne spp.), we identified putative coding sequences typical of eukaryotic DICERS. We noted that the primary and secondary structures of DICERS they encode were different for different Meloidogyne species and even for isolates of the same species, suggesting paralogy for the gene. One of the genes for M. incognita (Midcr-1.1) expressed in eggs, juvenile stage 2 and adults, with the highest expression in the adult females. All the Meloidogyne DICERS had seven major domains typical of those for Caenorhabditis spp. and humans with very similar protein folding. RNAi of Midcr-1.1 in J2s using seven dsRNAs, each based on sequences encoding the domains, induced mild paralysis but measurable knockdown was detected in J2s treated with five of the dsRNAs. For four of the dsRNAs, the RNAi effect lasted and reduced the nematode’s infectivity. Also, host plant delivery of dsRNAs complementary to coding sequences of the Dicer Dimerisation domain impaired development, reducing nematode infection by 71%. These results confirm the importance of the gene to nematode health.
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Affiliation(s)
- Sadia Iqbal
- Crop Biotechnology Research Group, College of Science, Health, Engineering and Education, WA State Agricultural Biotechnology Centre, Murdoch University, Perth, Australia.
| | - Michael G K Jones
- Crop Biotechnology Research Group, College of Science, Health, Engineering and Education, WA State Agricultural Biotechnology Centre, Murdoch University, Perth, Australia
| | - John Fosu-Nyarko
- Crop Biotechnology Research Group, College of Science, Health, Engineering and Education, WA State Agricultural Biotechnology Centre, Murdoch University, Perth, Australia.
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23
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Abstract
Memories encoded in the parent's brain should not be able to transfer to the progeny. This assumption, which is compatible with the tenets of modern neuroscience and genetics, is challenged by new insights regarding inheritance of transgenerational epigenetic responses. Here we reflect on new discoveries regarding "molecular memories" in light of older and scandalous work on "Memory transfer" spearheaded by James V. McConnell and Georges Ungar. While the history of this field is filled with controversies, mechanisms for transmission of information across generations are being elucidated in different organisms. Most strikingly, it is now clear that in Caenorhabditis elegans nematodes, somatic responses can control gene activity in descendants via heritable small RNA molecules, and that this type of inheritance is tightly regulated by dedicated machinery. In this perspective we will focus mostly on studies conducted using C. elegans, and examine recent work on the connection between small RNAs in the nervous system and germline. We will discuss the evidence for the inheritance of brain-orchestrated behavior, and its possible significance.
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Affiliation(s)
- Eric A Miska
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, United Kingdom; Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom; Department of Genetics, University of Cambridge, Cambridge, United Kingdom.
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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24
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Houri-Zeevi L, Teichman G, Gingold H, Rechavi O. Stress resets ancestral heritable small RNA responses. eLife 2021; 10:e65797. [PMID: 33729152 PMCID: PMC8021399 DOI: 10.7554/elife.65797] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/15/2021] [Indexed: 12/15/2022] Open
Abstract
Transgenerational inheritance of small RNAs challenges basic concepts of heredity. In Caenorhabditis elegans nematodes, small RNAs are transmitted across generations to establish a transgenerational memory trace of ancestral environments and distinguish self-genes from non-self-elements. Carryover of aberrant heritable small RNA responses was shown to be maladaptive and to lead to sterility. Here, we show that various types of stress (starvation, high temperatures, and high osmolarity) induce resetting of ancestral small RNA responses and a genome-wide reduction in heritable small RNA levels. We found that mutants that are defective in various stress pathways exhibit irregular RNAi inheritance dynamics even in the absence of stress. Moreover, we discovered that resetting of ancestral RNAi responses is specifically orchestrated by factors that function in the p38 MAPK pathway and the transcription factor SKN-1/Nrf2. Stress-dependent termination of small RNA inheritance could protect from run-on of environment-irrelevant heritable gene regulation.
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Affiliation(s)
- Leah Houri-Zeevi
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv UniversityTel AvivIsrael
| | - Guy Teichman
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv UniversityTel AvivIsrael
| | - Hila Gingold
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv UniversityTel AvivIsrael
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv UniversityTel AvivIsrael
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25
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Okabe E, Uno M, Kishimoto S, Nishida E. Intertissue small RNA communication mediates the acquisition and inheritance of hormesis in Caenorhabditis elegans. Commun Biol 2021; 4:207. [PMID: 33594200 PMCID: PMC7886853 DOI: 10.1038/s42003-021-01692-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/12/2021] [Indexed: 12/16/2022] Open
Abstract
Environmental conditions can cause phenotypic changes, part of which can be inherited by subsequent generations via soma-to-germline communication. However, the signaling molecules or pathways that mediate intertissue communication remain unclear. Here, we show that intertissue small RNA communication systems play a key role in the acquisition and inheritance of hormesis effects – stress-induced stress resistance – in Caenorhabditis elegans. The miRNA-processing enzyme DRSH-1 is involved in both the acquisition and the inheritance of hormesis, whereas worm-specific Argonaute (WAGO) proteins, which function with endo-siRNAs, are involved only in its inheritance. Further analyses demonstrate that the miRNA production system in the neuron and the small RNA transport machinery in the intestine are both essential for its acquisition and that both the transport of small RNAs in the germline and the germline Argonaute HRDE-1 complex are required for its inheritance. Our results thus demonstrate that overlapping and distinct roles of small RNA systems in the acquisition and inheritance of hormesis effects. Okabe et al. show that the miRNA production system in the neuron and the small RNA transport machinery in the intestine are required for the acquisition of hormesis. For its inheritance, both the transport of small RNAs in the germline and the germline Argonaute HRDE-1 complex are needed, highlighting distinct contribution of small RNA systems to hormesis.
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Affiliation(s)
- Emiko Okabe
- RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima Minamimachi, Chuo-ku, Kobe, 650-0047, Japan.,Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Masaharu Uno
- RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima Minamimachi, Chuo-ku, Kobe, 650-0047, Japan. .,Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
| | - Saya Kishimoto
- RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima Minamimachi, Chuo-ku, Kobe, 650-0047, Japan.,Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Eisuke Nishida
- RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima Minamimachi, Chuo-ku, Kobe, 650-0047, Japan.,Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
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26
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Haskell D, Zinovyeva A. KH domain containing RNA-binding proteins coordinate with microRNAs to regulate Caenorhabditis elegans development. G3 (BETHESDA, MD.) 2021; 11:jkab013. [PMID: 33585875 PMCID: PMC8022929 DOI: 10.1093/g3journal/jkab013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/23/2020] [Indexed: 11/13/2022]
Abstract
MicroRNAs (miRNAs) and RNA-binding proteins (RBPs) regulate gene expression at the post-transcriptional level, but the extent to which these key regulators of gene expression coordinate their activities and the precise mechanisms of this coordination are not well understood. RBPs often have recognizable RNA binding domains that correlate with specific protein function. Recently, several RBPs containing K homology (KH) RNA binding domains were shown to work with miRNAs to regulate gene expression, raising the possibility that KH domains may be important for coordinating with miRNA pathways in gene expression regulation. To ascertain whether additional KH domain proteins functionally interact with miRNAs during Caenorhabditis elegans development, we knocked down twenty-four genes encoding KH-domain proteins in several miRNA sensitized genetic backgrounds. Here, we report that a majority of the KH domain-containing genes genetically interact with multiple miRNAs and Argonaute alg-1. Interestingly, two KH domain genes, predicted splicing factors sfa-1 and asd-2, genetically interacted with all of the miRNA mutants tested, whereas other KH domain genes showed genetic interactions only with specific miRNAs. Our domain architecture and phylogenetic relationship analyses of the C. elegans KH domain-containing proteins revealed potential groups that may share both structure and function. Collectively, we show that many C. elegans KH domain RBPs functionally interact with miRNAs, suggesting direct or indirect coordination between these two classes of post-transcriptional gene expression regulators.
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Affiliation(s)
- Dustin Haskell
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Anna Zinovyeva
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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27
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Placentino M, de Jesus Domingues AM, Schreier J, Dietz S, Hellmann S, de Albuquerque BFM, Butter F, Ketting RF. Intrinsically disordered protein PID-2 modulates Z granules and is required for heritable piRNA-induced silencing in the Caenorhabditis elegans embryo. EMBO J 2021; 40:e105280. [PMID: 33231880 PMCID: PMC7849312 DOI: 10.15252/embj.2020105280] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 09/25/2020] [Accepted: 10/02/2020] [Indexed: 12/12/2022] Open
Abstract
In Caenorhabditis elegans, the piRNA (21U RNA) pathway is required to establish proper gene regulation and an immortal germline. To achieve this, PRG-1-bound 21U RNAs trigger silencing mechanisms mediated by RNA-dependent RNA polymerase (RdRP)-synthetized 22G RNAs. This silencing can become PRG-1-independent and heritable over many generations, a state termed RNA-induced epigenetic gene silencing (RNAe). How and when RNAe is established, and how it is maintained, is not known. We show that maternally provided 21U RNAs can be sufficient for triggering RNAe in embryos. Additionally, we identify PID-2, a protein containing intrinsically disordered regions (IDRs), as a factor required for establishing and maintaining RNAe. PID-2 interacts with two newly identified and partially redundant eTudor domain-containing proteins, PID-4 and PID-5. PID-5 has an additional domain related to the X-prolyl aminopeptidase APP-1, and binds APP-1, implicating potential N-terminal proteolysis in RNAe. All three proteins are required for germline immortality, localize to perinuclear foci, affect size and appearance of RNA inheritance-linked Z granules, and are required for balancing of 22G RNA populations. Overall, our study identifies three new proteins with crucial functions in C. elegans small RNA silencing.
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Affiliation(s)
- Maria Placentino
- Biology of Non‐coding RNA GroupInstitute of Molecular Biology (IMB)MainzGermany
- International PhD Programme on Gene Regulation, Epigenetics & Genome StabilityMainzGermany
| | | | - Jan Schreier
- Biology of Non‐coding RNA GroupInstitute of Molecular Biology (IMB)MainzGermany
- International PhD Programme on Gene Regulation, Epigenetics & Genome StabilityMainzGermany
| | - Sabrina Dietz
- International PhD Programme on Gene Regulation, Epigenetics & Genome StabilityMainzGermany
- Quantitative Proteomics GroupInstitute of Molecular Biology (IMB)MainzGermany
| | - Svenja Hellmann
- Biology of Non‐coding RNA GroupInstitute of Molecular Biology (IMB)MainzGermany
| | - Bruno FM de Albuquerque
- Biology of Non‐coding RNA GroupInstitute of Molecular Biology (IMB)MainzGermany
- Graduate Program in Areas of Basic and Applied BiologyUniversity of PortoPortoPortugal
| | - Falk Butter
- Quantitative Proteomics GroupInstitute of Molecular Biology (IMB)MainzGermany
| | - René F Ketting
- Biology of Non‐coding RNA GroupInstitute of Molecular Biology (IMB)MainzGermany
- Institute of Developmental Biology and NeurobiologyJohannses Gutenberg UniversityMainzGermany
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Hagen J, Sarkies P, Selkirk ME. Lentiviral transduction facilitates RNA interference in the nematode parasite Nippostrongylus brasiliensis. PLoS Pathog 2021; 17:e1009286. [PMID: 33497411 PMCID: PMC7864396 DOI: 10.1371/journal.ppat.1009286] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 02/05/2021] [Accepted: 01/06/2021] [Indexed: 12/16/2022] Open
Abstract
Animal-parasitic nematodes have thus far been largely refractory to genetic manipulation, and methods employed to effect RNA interference (RNAi) have been ineffective or inconsistent in most cases. We describe here a new approach for genetic manipulation of Nippostrongylus brasiliensis, a widely used laboratory model of gastrointestinal nematode infection. N. brasiliensis was successfully transduced with Vesicular Stomatitis Virus glycoprotein G (VSV-G)-pseudotyped lentivirus. The virus was taken up via the nematode intestine, RNA reverse transcribed into proviral DNA, and transgene transcripts produced stably in infective larvae, which resulted in expression of the reporter protein mCherry. Improved transgene expression was achieved by incorporating the C. elegans hlh11 promoter and the tbb2 3´-UTR into viral constructs. MicroRNA-adapted short hairpin RNAs delivered in this manner were processed correctly and resulted in partial knockdown of β-tubulin isotype-1 (tbb-iso-1) and secreted acetylcholinesterase B (ache-B). The system was further refined by lentiviral delivery of double stranded RNAs, which acted as a trigger for RNAi following processing and generation of 22G-RNAs. Virus-encoded sequences were detectable in F1 eggs and third stage larvae, demonstrating that proviral DNA entered the germline and was heritable. Lentiviral transduction thus provides a new means for genetic manipulation of parasitic nematodes, including gene silencing and expression of exogenous genes. The complex life cycle of parasitic nematodes makes them very difficult to manipulate genetically, and methods to delete or silence genes which are routinely used in other organisms are ineffective in most species of nematodes which infect animals. This has hindered attempts to understand the function of defined genes and proteins, and their roles in development and interaction of nematode parasites with their host. We show here that foreign genetic material can be introduced into a widely used laboratory model of intestinal nematode infection by using a viral vector. The vector was modified to improve transgene expression, and a reporter protein expressed by transduced nematode larvae in vitro. We subsequently utilised the viral vector to deliver double stranded RNA molecules to the larvae. These molecules were processed along known pathways, resulting in partial knockdown of two test genes. This system represents a new means of genetically manipulating nematode parasites, and will aid in understanding their complex biology, in addition to defining new targets for control of infection.
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Affiliation(s)
- Jana Hagen
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Peter Sarkies
- MRC London Institute of Medical Sciences, Imperial College London, London, United Kingdom
| | - Murray E. Selkirk
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail:
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29
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Chaves DA, Dai H, Li L, Moresco JJ, Oh ME, Conte D, Yates JR, Mello CC, Gu W. The RNA phosphatase PIR-1 regulates endogenous small RNA pathways in C. elegans. Mol Cell 2020; 81:546-557.e5. [PMID: 33378643 DOI: 10.1016/j.molcel.2020.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 11/25/2020] [Accepted: 12/01/2020] [Indexed: 12/12/2022]
Abstract
Eukaryotic cells regulate 5'-triphosphorylated RNAs (ppp-RNAs) to promote cellular functions and prevent recognition by antiviral RNA sensors. For example, RNA capping enzymes possess triphosphatase domains that remove the γ phosphates of ppp-RNAs during RNA capping. Members of the closely related PIR-1 (phosphatase that interacts with RNA and ribonucleoprotein particle 1) family of RNA polyphosphatases remove both the β and γ phosphates from ppp-RNAs. Here, we show that C. elegans PIR-1 dephosphorylates ppp-RNAs made by cellular RNA-dependent RNA polymerases (RdRPs) and is required for the maturation of 26G-RNAs, Dicer-dependent small RNAs that regulate thousands of genes during spermatogenesis and embryogenesis. PIR-1 also regulates the CSR-1 22G-RNA pathway and has critical functions in both somatic and germline development. Our findings suggest that PIR-1 modulates both Dicer-dependent and Dicer-independent Argonaute pathways and provide insight into how cells and viruses use a conserved RNA phosphatase to regulate and respond to ppp-RNA species.
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Affiliation(s)
- Daniel A Chaves
- Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA; Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Hui Dai
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, USA
| | - Lichao Li
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, USA
| | - James J Moresco
- Center for Genetics of Host Defense, UT Southwestern Medical Center, Dallas, TX, USA
| | - Myung Eun Oh
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, USA
| | - Darryl Conte
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - John R Yates
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA
| | - Craig C Mello
- Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA; RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Weifeng Gu
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, USA.
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30
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Lev I, Rechavi O. Germ Granules Allow Transmission of Small RNA-Based Parental Responses in the "Germ Plasm". iScience 2020; 23:101831. [PMID: 33305186 PMCID: PMC7718480 DOI: 10.1016/j.isci.2020.101831] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In the recent decade small RNA-based inheritance has been implicated in a variety of transmitted physiological responses to the environment. In Caenorhabditis elegans, heritable small RNAs rely on RNA-dependent RNA polymerases, RNA-processing machinery, chromatin modifiers, and argonauts for their biogenesis and gene-regulatory effects. Importantly, many of these factors reside in evolutionary conserved germ granules that are required for maintaining germ cell identity and gene expression. Recent literature demonstrated that transient disturbance to the stability of the germ granules leads to changes in the pools of heritable small RNAs and the physiology of the progeny. In this piece, we discuss the heritable consequences of transient destabilization of germ granules and elaborate on the various small RNA-related processes that act in the germ granules. We further propose that germ granules may serve as environment sensors that translate environmental changes to inheritable small RNA-based responses.
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Affiliation(s)
- Itamar Lev
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
- Department of Neurobiology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
| | - 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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31
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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: 11] [Impact Index Per Article: 2.8] [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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32
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Dai H, Gu W. Small RNA Plays Important Roles in Virus-Host Interactions. Viruses 2020; 12:E1271. [PMID: 33171824 PMCID: PMC7695165 DOI: 10.3390/v12111271] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/30/2020] [Accepted: 11/05/2020] [Indexed: 12/12/2022] Open
Abstract
Non-coding small RNAs play important roles in virus-host interactions. For hosts, small RNAs can serve as sensors in antiviral pathways including RNAi and CRISPR; for viruses, small RNAs can be involved in viral transcription and replication. This paper covers several recent discoveries on small RNA mediated virus-host interactions, and focuses on influenza virus cap-snatching and a few important virus sensors including PIR-1, RIG-I like protein DRH-1 and piRNAs. The paper also discusses recent advances in mammalian antiviral RNAi.
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Affiliation(s)
| | - Weifeng Gu
- Department of Molecular, Cell and Systems Biology, University of California, Riverside 900 University Avenue, Riverside, CA 92521, USA;
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33
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Abstract
A diversity of gene regulatory mechanisms drives the changes in gene expression required for animal development. Here, we discuss the developmental roles of a class of gene regulatory factors composed of a core protein subunit of the Argonaute family and a 21-26-nucleotide RNA cofactor. These represent ancient regulatory complexes, originally evolved to repress genomic parasites such as transposons, viruses and retroviruses. However, over the course of evolution, small RNA-guided pathways have expanded and diversified, and they play multiple roles across all eukaryotes. Pertinent to this review, Argonaute and small RNA-mediated regulation has acquired numerous functions that affect all aspects of animal life. The regulatory function is provided by the Argonaute protein and its interactors, while the small RNA provides target specificity, guiding the Argonaute to a complementary RNA. C. elegans has 19 different, functional Argonautes, defining distinct yet interconnected pathways. Each Argonaute binds a relatively well-defined class of small RNA with distinct molecular properties. A broad classification of animal small RNA pathways distinguishes between two groups: (i) the microRNA pathway is involved in repressing relatively specific endogenous genes and (ii) the other small RNA pathways, which effectively act as a genomic immune system to primarily repress expression of foreign or "non-self" RNA while maintaining correct endogenous gene expression. microRNAs play prominent direct roles in all developmental stages, adult physiology and lifespan. The other small RNA pathways act primarily in the germline, but their impact extends far beyond, into embryogenesis and adult physiology, and even to subsequent generations. Here, we review the mechanisms and developmental functions of the diverse small RNA pathways of C. elegans.
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Affiliation(s)
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria.
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34
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Rogers AK, Phillips CM. A Small-RNA-Mediated Feedback Loop Maintains Proper Levels of 22G-RNAs in C. elegans. Cell Rep 2020; 33:108279. [PMID: 33086057 PMCID: PMC7603289 DOI: 10.1016/j.celrep.2020.108279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 08/27/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
RNA interference (RNAi) is an essential regulatory mechanism in all animals. In Caenorhabditis elegans, several classes of small RNAs act to silence or license expression of mRNA targets. ERI-6/7 is required for the production of some endogenous small interfering RNAs (siRNAs) and acts as a negative regulator of the exogenous RNAi pathway. We find that the genomic locus encoding eri-6/7 contains two distinct regions that are targeted by endogenous siRNAs. Loss of these siRNAs disrupts eri-6/7 mRNA expression, resulting in increased production of siRNAs from other small RNA pathways because these pathways compete with eri-6/7-dependent transcripts for access to the downstream siRNA amplification machinery. Thus, the pathway acts like a small-RNA-mediated feedback loop to ensure homeostasis of gene expression by small RNA pathways. Similar feedback loops that maintain chromatin homeostasis have been identified in yeast and Drosophila melanogaster, suggesting an evolutionary conservation of feedback mechanisms in gene regulatory pathways.
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Affiliation(s)
- Alicia K Rogers
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Carolyn M Phillips
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
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35
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Purification and Characterization of Double-Stranded Nucleic Acid-Dependent ATPase Activities of Tagged Dicer-Related Helicase 1 and its Short Isoform in Caenorhabditis elegans. Genes (Basel) 2020; 11:genes11070734. [PMID: 32630243 PMCID: PMC7397212 DOI: 10.3390/genes11070734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/25/2020] [Accepted: 06/30/2020] [Indexed: 02/08/2023] Open
Abstract
The Dicer-related helicases (DRHs) are members of a helicase subfamily, and mammalian DRHs such as retinoic acid-inducible gene-I (RIG-I), are involved in antiviral immunity. Caenorhabditis elegans DRH-1 and DRH-3 play crucial roles in antiviral function and chromosome segregation, respectively. Although intrinsic double-stranded RNA-dependent ATP-hydrolyzing activity has been observed in the recombinant DRH-3 protein prepared from Escherichia coli, there are no reports of biochemical studies of the nematode RIG-I homolog DRH-1. In this study, the secondary structure prediction by JPred4 revealed that DRH-1 and DRH-3 had distinct N-terminal regions and that a 200-amino acid N-terminal region of DRH-1 could form a structure very rich in α-helices. We investigated expressions and purifications of a codon-optimized DRH-1 with four different N-terminal tags, identifying poly-histidine (His)-small ubiquitin-like modifier (SUMO) as a suitable tag for DRH-1 preparation. Full-length (isoform a) and a N-terminal truncated (isoform b) of DRH-1 were purified as the His-SUMO-tagged fusion proteins. Finally, the nucleic acid-dependent ATPase activities were investigated for the two His-SUMO-tagged DRH-1 isoforms and His-tagged DRH-3. The tagged DRH-3 exhibited dsRNA-dependent ATPase activity. However, detectable dsRNA dependency of ATPase activities was not found in either isoform of tagged DRH-1 and a tag-free DRH-1 (isoform a) treated with SUMO protease. These observations suggest that DRH-1 and its short isoform have no or poor nucleic acid-dependent ATPase activity, unlike DRH-3 and mammalian DRHs.
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36
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Lewis A, Berkyurek AC, Greiner A, Sawh AN, Vashisht A, Merrett S, Flamand MN, Wohlschlegel J, Sarov M, Miska EA, Duchaine TF. A Family of Argonaute-Interacting Proteins Gates Nuclear RNAi. Mol Cell 2020; 78:862-875.e8. [PMID: 32348780 PMCID: PMC7613089 DOI: 10.1016/j.molcel.2020.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 02/19/2020] [Accepted: 04/06/2020] [Indexed: 12/17/2022]
Abstract
Nuclear RNA interference (RNAi) pathways work together with histone modifications to regulate gene expression and enact an adaptive response to transposable RNA elements. In the germline, nuclear RNAi can lead to trans-generational epigenetic inheritance (TEI) of gene silencing. We identified and characterized a family of nuclear Argonaute-interacting proteins (ENRIs) that control the strength and target specificity of nuclear RNAi in C. elegans, ensuring faithful inheritance of epigenetic memories. ENRI-1/2 prevent misloading of the nuclear Argonaute NRDE-3 with small RNAs that normally effect maternal piRNAs, which prevents precocious nuclear translocation of NRDE-3 in the early embryo. Additionally, they are negative regulators of nuclear RNAi triggered from exogenous sources. Loss of ENRI-3, an unstable protein expressed mostly in the male germline, misdirects the RNAi response to transposable elements and impairs TEI. The ENRIs determine the potency and specificity of nuclear RNAi responses by gating small RNAs into specific nuclear Argonautes.
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Affiliation(s)
- Alexandra Lewis
- Department of Biochemistry & Goodman Cancer Research Centre, McGill University, Montréal, QC H3A 1A3, Canada
| | | | - Andre Greiner
- Molecular Cell Biology and Genetics, Max Planck Institute, 01307 Dresden, Germany
| | - Ahilya N Sawh
- Department of Biochemistry & Goodman Cancer Research Centre, McGill University, Montréal, QC H3A 1A3, Canada
| | - Ajay Vashisht
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Stephanie Merrett
- Molecular Cell Biology and Genetics, Max Planck Institute, 01307 Dresden, Germany
| | - Mathieu N Flamand
- Department of Biochemistry & Goodman Cancer Research Centre, McGill University, Montréal, QC H3A 1A3, Canada
| | - James Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Mihail Sarov
- Molecular Cell Biology and Genetics, Max Planck Institute, 01307 Dresden, Germany
| | - Eric A Miska
- Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
| | - Thomas F Duchaine
- Department of Biochemistry & Goodman Cancer Research Centre, McGill University, Montréal, QC H3A 1A3, Canada.
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37
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Cohen-Berkman M, Dudkevich R, Ben-Hamo S, Fishman A, Salzberg Y, Waldman Ben-Asher H, Lamm AT, Henis-Korenblit S. Endogenous siRNAs promote proteostasis and longevity in germline-less Caenorhabditis elegans. eLife 2020; 9:e50896. [PMID: 32213289 PMCID: PMC7136021 DOI: 10.7554/elife.50896] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 03/26/2020] [Indexed: 12/19/2022] Open
Abstract
How lifespan and the rate of aging are set is a key problem in biology. Small RNAs are conserved molecules that impact diverse biological processes through the control of gene expression. However, in contrast to miRNAs, the role of endo-siRNAs in aging remains unexplored. Here, by combining deep sequencing and genomic and genetic approaches in Caenorhabditis elegans, we reveal an unprecedented role for endo-siRNA molecules in the maintenance of proteostasis and lifespan extension in germline-less animals. Furthermore, we identify an endo-siRNA-regulated tyrosine phosphatase, which limits the longevity of germline-less animals by restricting the activity of the heat shock transcription factor HSF-1. Altogether, our findings point to endo-siRNAs as a link between germline removal and the HSF-1 proteostasis and longevity-promoting somatic pathway. This establishes a role for endo siRNAs in the aging process and identifies downstream genes and physiological processes that are regulated by the endo siRNAs to affect longevity.
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Affiliation(s)
- Moran Cohen-Berkman
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan UniversityRamat-GanIsrael
| | - Reut Dudkevich
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan UniversityRamat-GanIsrael
| | - Shani Ben-Hamo
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan UniversityRamat-GanIsrael
| | - Alla Fishman
- Faculty of Biology, Technion-Israel Institute of Technology, Technion CityHaifaIsrael
| | - Yehuda Salzberg
- Department of Neurobiology, Weizmann Institute of ScienceRehovotIsrael
| | | | - Ayelet T Lamm
- Faculty of Biology, Technion-Israel Institute of Technology, Technion CityHaifaIsrael
| | - Sivan Henis-Korenblit
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan UniversityRamat-GanIsrael
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38
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Small RNAs in the Transgenerational Inheritance of Epigenetic Information. Trends Genet 2020; 36:203-214. [DOI: 10.1016/j.tig.2019.12.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/19/2019] [Accepted: 12/06/2019] [Indexed: 01/21/2023]
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39
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Gutbrod MJ, Martienssen RA. Conserved chromosomal functions of RNA interference. Nat Rev Genet 2020; 21:311-331. [PMID: 32051563 DOI: 10.1038/s41576-019-0203-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2019] [Indexed: 12/21/2022]
Abstract
RNA interference (RNAi), a cellular process through which small RNAs target and regulate complementary RNA transcripts, has well-characterized roles in post-transcriptional gene regulation and transposon repression. Recent studies have revealed additional conserved roles for RNAi proteins, such as Argonaute and Dicer, in chromosome function. By guiding chromatin modification, RNAi components promote chromosome segregation during both mitosis and meiosis and regulate chromosomal and genomic dosage response. Small RNAs and the RNAi machinery also participate in the resolution of DNA damage. Interestingly, many of these lesser-studied functions seem to be more strongly conserved across eukaryotes than are well-characterized functions such as the processing of microRNAs. These findings have implications for the evolution of RNAi since the last eukaryotic common ancestor, and they provide a more complete view of the functions of RNAi.
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Affiliation(s)
- Michael J Gutbrod
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Robert A Martienssen
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA. .,Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
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40
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Karunanithi S, Oruganti V, de Wijn R, Drews F, Cheaib M, Nordström K, Simon M, Schulz MH. Feeding exogenous dsRNA interferes with endogenous sRNA accumulation in Paramecium. DNA Res 2020; 27:5825730. [PMID: 32339224 PMCID: PMC7315353 DOI: 10.1093/dnares/dsaa005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 04/21/2020] [Indexed: 11/29/2022] Open
Abstract
Supply of exogenous dsRNA (exo-dsRNA), either by injection or by feeding, is a fast and powerful alternative to classical knockout studies. The biotechnical potential of feeding techniques is evident from the numerous studies focusing on oral administration of dsRNA to control pests and viral infection in crops/animal farming. We aimed to dissect the direct and indirect effects of exo-dsRNA feeding on the endogenous short interfering RNA (endo-siRNA) populations of the free-living ciliate Paramecium. We introduced dsRNA fragments against Dicer1 (DCR1), involved in RNA interference (RNAi) against exo- and few endo-siRNAs, and an RNAi unrelated gene, ND169. Any feeding, even the control dsRNA, diminishes genome wide the accumulation of endo-siRNAs and mRNAs. This cannot be explained by direct off-target effects and suggests mechanistic overlaps of the exo- and endo-RNAi mechanisms. Nevertheless, we observe a stronger down-regulation of mRNAs in DCR1 feeding compared with ND169 knockdown. This is likely due to the direct involvement of DCR1 in endo-siRNA accumulation. We further observed a cis-regulatory effect on mRNAs that overlap with phased endo-siRNAs. This interference of exo-dsRNA with endo-siRNAs warrants further investigations into secondary effects in target species/consumers, risk assessment of dsRNA feeding applications, and environmental pollution with dsRNA.
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Affiliation(s)
- Sivarajan Karunanithi
- Cluster of Excellence for Multimodal Computing and Interaction, and Department for Computational Biology & Applied Algorithms, Max Planck Institute for Informatics, Saarland Informatics Campus, Saarbrücken, Germany.,Graduate School of Computer Science, Saarland Informatics Campus, Saarland University, Saarbrücken, Germany.,Institute for Cardiovascular Regeneration, Goethe University Hospital, Frankfurt am Main, Germany
| | - Vidya Oruganti
- Cluster of Excellence for Multimodal Computing and Interaction, and Department for Computational Biology & Applied Algorithms, Max Planck Institute for Informatics, Saarland Informatics Campus, Saarbrücken, Germany
| | - Raphael de Wijn
- Molecular Cell Dynamics, Centre for Human and Molecular Biology, Saarland University, Saarbrücken, Germany
| | - Franziska Drews
- Molecular Cell Biology and Microbiology, Wuppertal University, Wuppertal, Germany
| | - Miriam Cheaib
- Molecular Cell Dynamics, Centre for Human and Molecular Biology, Saarland University, Saarbrücken, Germany
| | - Karl Nordström
- Genetics/Epigenetics, Centre for Human and Molecular Biology, Saarland University, Saarbrücken, Germany
| | - Martin Simon
- Molecular Cell Dynamics, Centre for Human and Molecular Biology, Saarland University, Saarbrücken, Germany.,Molecular Cell Biology and Microbiology, Wuppertal University, Wuppertal, Germany
| | - Marcel H Schulz
- Cluster of Excellence for Multimodal Computing and Interaction, and Department for Computational Biology & Applied Algorithms, Max Planck Institute for Informatics, Saarland Informatics Campus, Saarbrücken, Germany.,Institute for Cardiovascular Regeneration, Goethe University Hospital, Frankfurt am Main, Germany
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41
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The Caenorhabditis elegans RIG-I Homolog DRH-1 Mediates the Intracellular Pathogen Response upon Viral Infection. J Virol 2020; 94:JVI.01173-19. [PMID: 31619561 DOI: 10.1128/jvi.01173-19] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 10/04/2019] [Indexed: 02/07/2023] Open
Abstract
Mammalian retinoic acid-inducible gene I (RIG-I)-like receptors detect viral double-stranded RNA (dsRNA) and 5'-triphosphorylated RNA to activate the transcription of interferon genes and promote antiviral defense. The Caenorhabditis elegans RIG-I-like receptor DRH-1 promotes defense through antiviral RNA interference (RNAi), but less is known about its role in regulating transcription. Here, we describe a role for DRH-1 in directing a transcriptional response in C. elegans called the intracellular pathogen response (IPR), which is associated with increased pathogen resistance. The IPR includes a set of genes induced by diverse stimuli, including intracellular infection and proteotoxic stress. Previous work suggested that the proteotoxic stress caused by intracellular infections might be the common trigger of the IPR, but here, we demonstrate that different stimuli act through distinct pathways. Specifically, we demonstrate that DRH-1/RIG-I is required for inducing the IPR in response to Orsay virus infection but not in response to other triggers like microsporidian infection or proteotoxic stress. Furthermore, DRH-1 appears to be acting independently of its known role in RNAi. Interestingly, expression of the replication-competent Orsay virus RNA1 segment alone is sufficient to induce most of the IPR genes in a manner dependent on RNA-dependent RNA polymerase activity and on DRH-1. Altogether, these results suggest that DRH-1 is a pattern recognition receptor that detects viral replication products to activate the IPR stress/immune program in C. elegans IMPORTANCE C. elegans lacks homologs of most mammalian pattern recognition receptors, and how nematodes detect pathogens is poorly understood. We show that the C. elegans RIG-I homolog DRH-1 mediates the induction of the intracellular pathogen response (IPR), a novel transcriptional defense program, in response to infection by the natural C. elegans viral pathogen Orsay virus. DRH-1 appears to act as a pattern recognition receptor to induce the IPR transcriptional defense program by sensing the products of viral RNA-dependent RNA polymerase activity. Interestingly, this signaling role of DRH-1 is separable from its previously known role in antiviral RNAi. In addition, we show that there are multiple host pathways for inducing the IPR, shedding light on the regulation of this novel transcriptional immune response.
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42
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Abstract
Caenorhabditis elegans has long been a laboratory model organism with no known natural pathogens. In the past ten years, however, natural viruses have been isolated from wild-caught C. elegans (Orsay virus) and its relative Caenorhabditis briggsae (Santeuil virus, Le Blanc virus, and Melnik virus). All are RNA positive-sense viruses related to Nodaviridae; they infect intestinal cells and are horizontally transmitted. The Orsay virus capsid structure has been determined and the virus can be reconstituted by transgenesis of the host. Recent use of the Orsay virus has enabled researchers to identify evolutionarily conserved proviral and antiviral genes that function in nematodes and mammals. These pathways include endocytosis through SID-3 and WASP; a uridylyltransferase that destabilizes viral RNAs by uridylation of their 3′ end; ubiquitin protein modifications and turnover; and the RNA interference pathway, which recognizes and degrades viral RNA.
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Affiliation(s)
- Marie-Anne Félix
- Institute of Biology of the École Normale Supérieure, CNRS UMR8197, INSERM U1024, 75230 Paris CEDEX 05, France
| | - David Wang
- Departments of Molecular Microbiology and Pathology & Immunology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110, USA
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43
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Lev I, Toker IA, Mor Y, Nitzan A, Weintraub G, Antonova O, Bhonkar O, Ben Shushan I, Seroussi U, Claycomb JM, Anava S, Gingold H, Zaidel-Bar R, Rechavi O. Germ Granules Govern Small RNA Inheritance. Curr Biol 2019; 29:2880-2891.e4. [PMID: 31378614 PMCID: PMC6739422 DOI: 10.1016/j.cub.2019.07.054] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/01/2019] [Accepted: 07/17/2019] [Indexed: 02/04/2023]
Abstract
In C. elegans nematodes, components of liquid-like germ granules were shown to be required for transgenerational small RNA inheritance. Surprisingly, we show here that mutants with defective germ granules can nevertheless inherit potent small RNA-based silencing responses, but some of the mutants lose this ability after many generations of homozygosity. Animals mutated in pptr-1, which is required for stabilization of P granules in the early embryo, display extraordinarily strong heritable RNAi responses, lasting for tens of generations. Intriguingly, the RNAi capacity of descendants derived from mutants defective in the core germ granule proteins MEG-3 and MEG-4 is determined by the genotype of the ancestors and changes transgenerationally. Further, whether the meg-3/4 mutant alleles were present in the paternal or maternal lineages leads to different transgenerational consequences. Small RNA inheritance, rather than maternal contribution of the germ granules themselves, mediates the transgenerational defects in RNAi of meg-3/4 mutants and their progeny. Accordingly, germ granule defects lead to heritable genome-wide mis-expression of endogenous small RNAs. Upon disruption of germ granules, hrde-1 mutants can inherit RNAi, although HRDE-1 was previously thought to be absolutely required for RNAi inheritance. We propose that germ granules sort and shape the RNA pool, and that small RNA inheritance maintains this activity for multiple generations.
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Affiliation(s)
- Itamar Lev
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Itai Antoine Toker
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Yael Mor
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Anat Nitzan
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Guy Weintraub
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Olga Antonova
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ornit Bhonkar
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Itay Ben Shushan
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Uri Seroussi
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Sarit Anava
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hila Gingold
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ronen Zaidel-Bar
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
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44
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Oncogenic Biogenesis of pri-miR-17∼92 Reveals Hierarchy and Competition among Polycistronic MicroRNAs. Mol Cell 2019; 75:340-356.e10. [PMID: 31253575 DOI: 10.1016/j.molcel.2019.05.033] [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: 02/20/2019] [Revised: 03/26/2019] [Accepted: 05/23/2019] [Indexed: 01/07/2023]
Abstract
The microRNAs encoded by the miR-17∼92 polycistron are commonly overexpressed in cancer and orchestrate a wide range of oncogenic functions. Here, we identify a mechanism for miR-17∼92 oncogenic function through the disruption of endogenous microRNA (miRNA) processing. We show that, upon oncogenic overexpression of the miR-17∼92 primary transcript (pri-miR-17∼92), the microprocessor complex remains associated with partially processed intermediates that aberrantly accumulate. These intermediates reflect a series of hierarchical and conserved steps in the early processing of the pri-miR-17∼92 transcript. Encumbrance of the microprocessor by miR-17∼92 intermediates leads to the broad but selective downregulation of co-expressed polycistronic miRNAs, including miRNAs derived from tumor-suppressive miR-34b/c and from the Dlk1-Dio3 polycistrons. We propose that the identified steps of polycistronic miR-17∼92 biogenesis contribute to the oncogenic re-wiring of gene regulation networks. Our results reveal previously unappreciated functional paradigms for polycistronic miRNAs in cancer.
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45
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Chromatin Compaction by Small RNAs and the Nuclear RNAi Machinery in C. elegans. Sci Rep 2019; 9:9030. [PMID: 31227740 PMCID: PMC6588724 DOI: 10.1038/s41598-019-45052-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 05/28/2019] [Indexed: 11/25/2022] Open
Abstract
DNA is organized and compacted into higher-order structures in order to fit within nuclei and to facilitate gene regulation. Mechanisms by which higher order chromatin structures are established and maintained are poorly understood. In C. elegans, nuclear-localized small RNAs engage the nuclear RNAi machinery to regulate gene expression and direct the post-translational modification of histone proteins. Here we confirm a recent report suggesting that nuclear small RNAs initiate or maintain chromatin compaction states in C. elegans germ cells. Additionally, we show that experimentally provided small RNAs are sufficient to direct chromatin compaction and that this compaction requires the small RNA-binding Argonaute NRDE-3, the pre-mRNA associated factor NRDE-2, and the HP1-like protein HPL-2. Our results show that small RNAs, acting via the nuclear RNAi machinery and an HP1-like protein, are capable of driving chromatin compaction in C. elegans.
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46
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Posner R, Toker IA, Antonova O, Star E, Anava S, Azmon E, Hendricks M, Bracha S, Gingold H, Rechavi O. Neuronal Small RNAs Control Behavior Transgenerationally. Cell 2019; 177:1814-1826.e15. [PMID: 31178120 PMCID: PMC6579485 DOI: 10.1016/j.cell.2019.04.029] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/18/2019] [Accepted: 04/13/2019] [Indexed: 12/21/2022]
Abstract
It is unknown whether the activity of the nervous system can be inherited. In Caenorhabditis elegans nematodes, parental responses can transmit heritable small RNAs that regulate gene expression transgenerationally. In this study, we show that a neuronal process can impact the next generations. Neurons-specific synthesis of RDE-4-dependent small RNAs regulates germline amplified endogenous small interfering RNAs (siRNAs) and germline gene expression for multiple generations. Further, the production of small RNAs in neurons controls the chemotaxis behavior of the progeny for at least three generations via the germline Argonaute HRDE-1. Among the targets of these small RNAs, we identified the conserved gene saeg-2, which is transgenerationally downregulated in the germline. Silencing of saeg-2 following neuronal small RNA biogenesis is required for chemotaxis under stress. Thus, we propose a small-RNA-based mechanism for communication of neuronal processes transgenerationally. C. elegans neuronal small RNAs are characterized by RNA sequencing RDE-4-dependent neuronal endogenous small RNAs communicate with the germline Germline HRDE-1 mediates transgenerational regulation by neuronal small RNAs Neuronal small RNAs regulate germline genes to control behavior transgenerationally
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Affiliation(s)
- Rachel Posner
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Itai Antoine Toker
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Olga Antonova
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Ekaterina Star
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sarit Anava
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Eran Azmon
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Michael Hendricks
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
| | - Shahar Bracha
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Hila Gingold
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel.
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47
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Almeida MV, de Jesus Domingues AM, Ketting RF. Maternal and zygotic gene regulatory effects of endogenous RNAi pathways. PLoS Genet 2019; 15:e1007784. [PMID: 30759082 PMCID: PMC6391025 DOI: 10.1371/journal.pgen.1007784] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 02/26/2019] [Accepted: 01/23/2019] [Indexed: 11/30/2022] Open
Abstract
Endogenous small RNAs (sRNAs) and Argonaute proteins are ubiquitous regulators of gene expression in germline and somatic tissues. sRNA-Argonaute complexes are often expressed in gametes and are consequently inherited by the next generation upon fertilization. In Caenorhabditis elegans, 26G-RNAs are primary endogenous sRNAs that trigger the expression of downstream secondary sRNAs. Two subpopulations of 26G-RNAs exist, each of which displaying strongly compartmentalized expression: one is expressed in the spermatogenic gonad and associates with the Argonautes ALG-3/4; plus another expressed in oocytes and in embryos, which associates with the Argonaute ERGO-1. The determinants and dynamics of gene silencing elicited by 26G-RNAs are largely unknown. Here, we provide diverse new insights into these endogenous sRNA pathways of C. elegans. Using genetics and deep sequencing, we dissect a maternal effect of the ERGO-1 branch of the 26G-RNA pathway. We find that maternal primary sRNAs can trigger the production of zygotic secondary sRNAs that are able to silence targets, even in the absence of zygotic primary triggers. Thus, the interaction of maternal and zygotic sRNA populations, assures target gene silencing throughout animal development. Furthermore, we explore other facets of 26G-RNA biology related to the ALG-3/4 branch. We find that sRNA abundance, sRNA pattern of origin and the 3’ UTR length of target transcripts are predictors of the regulatory outcome by the Argonautes ALG-3/4. Lastly, we provide evidence suggesting that ALG-3 and ALG-4 regulate their own mRNAs in a negative feedback loop. Altogether, we provide several new regulatory insights on the dynamics, target regulation and self-regulation of the endogenous RNAi pathways of C. elegans. Small RNAs (sRNAs) and their partner Argonaute proteins regulate the expression of target RNAs. When sperm and egg meet upon fertilization, a diverse set of proteins and RNA, including sRNA-Argonaute complexes, is passed on to the developing progeny. Thus, these two players are important to initiate specific gene expression programs in the next generation. The nematode Caenorhabditis elegans expresses several classes of sRNAs. 26G-RNAs are a particular class of sRNAs that are divided into two subpopulations: one expressed in the spermatogenic gonad and another expressed in oocytes and in embryos. In this work, we describe the dynamics whereby oogenic 26G-RNAs setup gene silencing in the next generation. In addition, we show several ways that spermatogenic 26G-RNAs and their partner Argonautes, ALG-3 and ALG-4, use to regulate their targets. Finally, we show that ALG-3 and ALG-4 are fine-tuning their own expression, a rare role of Argonaute proteins. Overall, we provide new insights into how sRNAs and Argonautes are regulating gene expression.
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Affiliation(s)
- Miguel Vasconcelos Almeida
- Biology of Non-coding RNA Group, Institute of Molecular Biology, Ackermannweg 4, Mainz, Germany
- International PhD Programme on Gene Regulation, Epigenetics & Genome Stability, Mainz, Germany
| | | | - René F. Ketting
- Biology of Non-coding RNA Group, Institute of Molecular Biology, Ackermannweg 4, Mainz, Germany
- * E-mail:
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48
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Ishidate T, Ozturk AR, Durning DJ, Sharma R, Shen EZ, Chen H, Seth M, Shirayama M, Mello CC. ZNFX-1 Functions within Perinuclear Nuage to Balance Epigenetic Signals. Mol Cell 2019; 70:639-649.e6. [PMID: 29775580 DOI: 10.1016/j.molcel.2018.04.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/15/2018] [Accepted: 04/09/2018] [Indexed: 12/29/2022]
Abstract
Animal cells have a remarkable capacity to adopt durable and heritable gene expression programs or epigenetic states that define the physical properties and diversity of somatic cell types. The maintenance of epigenetic programs depends on poorly understood pathways that prevent gain or loss of inherited signals. In the germline, epigenetic factors are enriched in liquid-like perinuclear condensates called nuage. Here, we identify the deeply conserved helicase-domain protein, ZNFX-1, as an epigenetic regulator and component of nuage that interacts with Argonaute systems to balance epigenetic inheritance. Our findings suggest that ZNFX-1 promotes the 3' recruitment of machinery that propagates the small RNA epigenetic signal and thus counteracts a tendency for Argonaute targeting to shift 5' along the mRNA. These functional insights support the idea that recently identified subdomains of nuage, including ZNFX-1 granules or "Z-granules," may define spatial and temporal zones of molecular activity during epigenetic regulation.
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Affiliation(s)
- Takao Ishidate
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Howard Hughes Medical Institute, Worcester, MA 01605, USA
| | - Ahmet R Ozturk
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Daniel J Durning
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rita Sharma
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - En-Zhi Shen
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Hao Chen
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Meetu Seth
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Masaki Shirayama
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Howard Hughes Medical Institute, Worcester, MA 01605, USA
| | - Craig C Mello
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Howard Hughes Medical Institute, Worcester, MA 01605, USA.
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49
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Remmelzwaal S, Boxem M. Protein interactome mapping in Caenorhabditis elegans. CURRENT OPINION IN SYSTEMS BIOLOGY 2019; 13:1-9. [PMID: 32984658 PMCID: PMC7493430 DOI: 10.1016/j.coisb.2018.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The systematic identification of all protein-protein interactions that take place in an organism (the 'interactome') is an important goal in modern biology. The nematode Caenorhabditis elegans was one of the first multicellular models for which a proteome-wide interactome mapping project was initiated. Most Caenorhabditis elegans interactome mapping efforts have utilized the yeast two-hybrid system, yielding an extensive binary interactome, while recent developments in mass spectrometry-based approaches hold great potential for further improving our understanding of protein interactome networks in a multicellular context. For example, methods like co-fractionation, proximity labeling, and tissue-specific protein purification not only identify protein-protein interactions, but have the potential to provide crucial insight into when and where interactions take place. Here we review current standards and recent improvements in protein interaction mapping in C. elegans.
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Affiliation(s)
- Sanne Remmelzwaal
- Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Mike Boxem
- Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
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50
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Almeida MV, Andrade-Navarro MA, Ketting RF. Function and Evolution of Nematode RNAi Pathways. Noncoding RNA 2019; 5:E8. [PMID: 30650636 PMCID: PMC6468775 DOI: 10.3390/ncrna5010008] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 12/11/2022] Open
Abstract
Selfish genetic elements, like transposable elements or viruses, are a threat to genomic stability. A variety of processes, including small RNA-based RNA interference (RNAi)-like pathways, has evolved to counteract these elements. Amongst these, endogenous small interfering RNA and Piwi-interacting RNA (piRNA) pathways were implicated in silencing selfish genetic elements in a variety of organisms. Nematodes have several incredibly specialized, rapidly evolving endogenous RNAi-like pathways serving such purposes. Here, we review recent research regarding the RNAi-like pathways of Caenorhabditis elegans as well as those of other nematodes, to provide an evolutionary perspective. We argue that multiple nematode RNAi-like pathways share piRNA-like properties and together form a broad nematode toolkit that allows for silencing of foreign genetic elements.
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Affiliation(s)
| | - Miguel A Andrade-Navarro
- Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.
- Faculty of Biology, Johannes Gutenberg Universität, 55122 Mainz, Germany.
| | - René F Ketting
- Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.
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