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Spada M, Pugliesi C, Fambrini M, Pecchia S. Challenges and Opportunities Arising from Host- Botrytis cinerea Interactions to Outline Novel and Sustainable Control Strategies: The Key Role of RNA Interference. Int J Mol Sci 2024; 25:6798. [PMID: 38928507 PMCID: PMC11203536 DOI: 10.3390/ijms25126798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/18/2024] [Accepted: 06/18/2024] [Indexed: 06/28/2024] Open
Abstract
The necrotrophic plant pathogenic fungus Botrytis cinerea (Pers., 1794), the causative agent of gray mold disease, causes significant losses in agricultural production. Control of this fungal pathogen is quite difficult due to its wide host range and environmental persistence. Currently, the management of the disease is still mainly based on chemicals, which can have harmful effects not only on the environment and on human health but also because they favor the development of strains resistant to fungicides. The flexibility and plasticity of B. cinerea in challenging plant defense mechanisms and its ability to evolve strategies to escape chemicals require the development of new control strategies for successful disease management. In this review, some aspects of the host-pathogen interactions from which novel and sustainable control strategies could be developed (e.g., signaling pathways, molecules involved in plant immune mechanisms, hormones, post-transcriptional gene silencing) were analyzed. New biotechnological tools based on the use of RNA interference (RNAi) are emerging in the crop protection scenario as versatile, sustainable, effective, and environmentally friendly alternatives to the use of chemicals. RNAi-based fungicides are expected to be approved soon, although they will face several challenges before reaching the market.
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Affiliation(s)
- Maria Spada
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Claudio Pugliesi
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Marco Fambrini
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Susanna Pecchia
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
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2
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Frézal L, Saglio M, Zhang G, Noble L, Richaud A, Félix MA. Genome-wide association and environmental suppression of the mortal germline phenotype of wild C. elegans. EMBO Rep 2023; 24:e58116. [PMID: 37983674 DOI: 10.15252/embr.202358116] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/19/2023] [Accepted: 10/27/2023] [Indexed: 11/22/2023] Open
Abstract
The animal germline lineage needs to be maintained along generations. However, some Caenorhabditis elegans wild isolates display a mortal germline phenotype, leading to sterility after several generations at 25°C. Using a genome-wide association approach, we detect a significant peak on chromosome III around 5 Mb, confirmed by introgressions. Thus, a seemingly deleterious genotype is maintained at intermediate frequency in the species. Environmental rescue is a likely explanation, and indeed associated bacteria and microsporidia suppress the phenotype of wild isolates as well as mutants in small RNA inheritance (nrde-2) and histone modifications (set-2). Escherichia coli strains of the K-12 lineage suppress the phenotype compared to B strains. By shifting a wild strain from E. coli K-12 to E. coli B, we find that memory of the suppressing condition is maintained over several generations. Thus, the mortal germline phenotype of wild C. elegans is in part revealed by laboratory conditions and may represent variation in epigenetic inheritance and environmental interactions. This study also points to the importance of non-genetic memory in the face of environmental variation.
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Affiliation(s)
- Lise Frézal
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, Inserm, Paris, France
| | - Marie Saglio
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, Inserm, Paris, France
| | - Gaotian Zhang
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, Inserm, Paris, France
| | - Luke Noble
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, Inserm, Paris, France
| | - Aurélien Richaud
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, Inserm, Paris, France
| | - Marie-Anne Félix
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, Inserm, Paris, France
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3
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Phillips CM, Updike DL. Germ granules and gene regulation in the Caenorhabditis elegans germline. Genetics 2022; 220:6541922. [PMID: 35239965 PMCID: PMC8893257 DOI: 10.1093/genetics/iyab195] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/10/2021] [Indexed: 01/27/2023] Open
Abstract
The transparency of Caenorhabditis elegans provides a unique window to observe and study the function of germ granules. Germ granules are specialized ribonucleoprotein (RNP) assemblies specific to the germline cytoplasm, and they are largely conserved across Metazoa. Within the germline cytoplasm, they are positioned to regulate mRNA abundance, translation, small RNA production, and cytoplasmic inheritance to help specify and maintain germline identity across generations. Here we provide an overview of germ granules and focus on the significance of more recent observations that describe how they further demix into sub-granules, each with unique compositions and functions.
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Affiliation(s)
- Carolyn M Phillips
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA,Corresponding author: (C.M.P.); (D.L.U.)
| | - Dustin L Updike
- The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA,Corresponding author: (C.M.P.); (D.L.U.)
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4
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Germoglio M, Adamo A, Incerti G, Cartenì F, Gigliotti S, Storlazzi A, Mazzoleni S. Self-DNA Exposure Induces Developmental Defects and Germline DNA Damage Response in Caenorhabditis elegans. BIOLOGY 2022; 11:biology11020262. [PMID: 35205128 PMCID: PMC8869574 DOI: 10.3390/biology11020262] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 02/06/2023]
Abstract
Simple Summary All organisms, from bacteria to mammals, activate responses protecting themselves from dangers represented by outsider invaders and damages. Inappropriately localised self-DNA is one of the molecular clues detected as a danger and triggering defence reactions that may lead to chronic activation of inflammatory conditions. In this study, we investigate if dietary delivered self-DNA is detrimental in a simple metazoan model organism, the nematode Caenorhabditis elegans. Adverse effects were observed in the progenies of worms exposed to self-DNA integrated into their bacterial diet. The presence of self-DNA in the food significantly decreased egg deposition, induced high embryo death, and negatively affected larval development. The findings, on the one side, raise interesting questions on the basic molecular mechanisms involved in response to extracellular self-DNA. On the other side, the observed phenomenon suggests possible applications for the biocontrol of parasitic nematodes by appropriate delivery of their self-DNA in their growing environment. Abstract All organisms, from bacteria to mammals, sense and respond to foreign nucleic acids to fight infections in order to survive and preserve genome integrity across generations. The innate immune system is an evolutionarily conserved defence strategy. Complex organisms have developed various cellular processes to respond to and recognise not only infections, i.e., pathogen-associated molecular patterns (PAMPs), but also to sense injury and tissue dysfunctions, i.e., damage-associated molecular patterns (DAMPs). Mis-localized self-DNA can be sensed as DAMP by specific DNA-sensing pathways, and self-DNA chronic exposure can be detrimental to the organisms. Here, we investigate the effects of dietary delivered self-DNA in the nematode Caenorhabditis elegans. The hermaphrodite worms were fed on Escherichia coli genomic libraries: a C. elegans library (self) and a legume (Medicago truncatula) library (non-self). We show that the self-library diet affects embryogenesis, larval development and gametogenesis. DNA damage and activation of p53/CEP-1-dependent apoptosis occur in gonadal germ cells. Studies of self-DNA exposure in this model organism were not pursued up to now. The genetic tractability of C. elegans will help to identify the basic molecular pathways involved in such mechanisms. The specificity of the adverse effects associated with a self-DNA enriched diet suggests applications in biological pest control approaches.
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Affiliation(s)
- Marcello Germoglio
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Adele Adamo
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Guido Incerti
- Department of Agri-Food, Animal and Environmental Sciences (DI4A), University of Udine, 33100 Udine, Italy;
| | - Fabrizio Cartenì
- Department of Agricultural Sciences, Università degli Studi di Napoli Federico II, 80055 Portici, Italy;
| | - Silvia Gigliotti
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Aurora Storlazzi
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
- Correspondence: (A.S.); (S.M.)
| | - Stefano Mazzoleni
- Department of Agricultural Sciences, Università degli Studi di Napoli Federico II, 80055 Portici, Italy;
- Correspondence: (A.S.); (S.M.)
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5
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Pradhan RK, Ramakrishna W. Transposons: Unexpected players in cancer. Gene 2022; 808:145975. [PMID: 34592349 DOI: 10.1016/j.gene.2021.145975] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/19/2021] [Accepted: 09/24/2021] [Indexed: 12/21/2022]
Abstract
Transposons are repetitive DNA sequences encompassing about half of the human genome. They play a vital role in genome stability maintenance and contribute to genomic diversity and evolution. Their activity is regulated by various mechanisms considering the deleterious effects of these mobile elements. Various genetic risk factors and environmental stress conditions affect the regulatory pathways causing alteration of transposon expression. Our knowledge of the biological role of transposons is limited especially in various types of cancers. Retrotransposons of different types (LTR-retrotransposons, LINEs and SINEs) regulate a plethora of genes that have a role in cell reprogramming, tumor suppression, cell cycle, apoptosis, cell adhesion and migration, and DNA repair. The regulatory mechanisms of transposons, their deregulation and different mechanisms underlying transposon-mediated carcinogenesis in humans focusing on the three most prevalent types, lung, breast and colorectal cancers, were reviewed. The modes of regulation employed include alternative splicing, deletion, insertion, duplication in genes and promoters resulting in upregulation, downregulation or silencing of genes.
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6
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Tsouris A, Schacherer J, Ishchuk OP. RNA Interference (RNAi ) as a Tool for High-Resolution Phenotypic Screening of the Pathogenic Yeast Candida glabrata. Methods Mol Biol 2022; 2477:313-330. [PMID: 35524125 DOI: 10.1007/978-1-0716-2257-5_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
After its discovery RNA interference (RNAi) has become a powerful tool to study gene functions in different organisms. RNAi has been applied at genome-wide scale and can be nowadays performed using high-throughput automated systems (robotics). The simplest RNAi process requires the expression of two genes (Dicer and Argonaute) to function. To initiate the silencing, constructs generating either double-strand RNA or antisense RNA are required. Recently, RNAi was reconstituted by expressing Saccharomyces castellii genes in the human pathogenic yeast Candida glabrata and was used to identify new genes related to the virulence of this pathogen.In this chapter, we describe a method to make the C. glabrata pathogenic yeast competent for RNAi and to use RNA silencing as a tool for low- or high-resolution phenotypic screening in this species.
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Affiliation(s)
- Andreas Tsouris
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - Joseph Schacherer
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
- Institut Universitaire de France (IUF), Paris, France
| | - Olena P Ishchuk
- Department of Biology and Biological Engineering, Systems and Synthetic Biology, Chalmers University of Technology, Gothenburg, Sweden.
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7
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Montgomery BE, Vijayasarathy T, Marks TN, Cialek CA, Reed KJ, Montgomery TA. Dual roles for piRNAs in promoting and preventing gene silencing in C. elegans. Cell Rep 2021; 37:110101. [PMID: 34879267 PMCID: PMC8730336 DOI: 10.1016/j.celrep.2021.110101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/25/2021] [Accepted: 11/15/2021] [Indexed: 12/30/2022] Open
Abstract
Piwi-interacting RNAs (piRNAs) regulate many biological processes through mechanisms that are not fully understood. In Caenorhabditis elegans, piRNAs intersect the endogenous RNA interference (RNAi) pathway, involving a distinct class of small RNAs called 22G-RNAs, to regulate gene expression in the germline. In the absence of piRNAs, 22G-RNA production from many genes is reduced, pointing to a role for piRNAs in facilitating endogenous RNAi. Here, however, we show that many genes gain, rather than lose, 22G-RNAs in the absence of piRNAs, which is in some instances coincident with RNA silencing. Aberrant 22G-RNA production is somewhat stochastic but once established can occur within a population for at least 50 generations. Thus, piRNAs both promote and suppress 22G-RNA production and gene silencing. rRNAs and histones are hypersusceptible to aberrant silencing, but we do not find evidence that their misexpression is the primary cause of the transgenerational sterility observed in piRNA-defective mutants. Montgomery et al. show that piRNAs both promote and suppress siRNA production and RNA silencing in C. elegans. Gain or loss of siRNAs occurs somewhat stochastically in piRNA-defective mutants but once established, it occurs across numerous generations.
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Affiliation(s)
- Brooke E Montgomery
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Tarah Vijayasarathy
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Taylor N Marks
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Charlotte A Cialek
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA; Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Kailee J Reed
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA; Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
| | - Taiowa A Montgomery
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA; Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA.
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8
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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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9
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Hsu TY, Zhang B, L'Etoile ND, Juang BT. C. elegans orthologs MUT-7/CeWRN-1 of Werner syndrome protein regulate neuronal plasticity. eLife 2021; 10:62449. [PMID: 33646120 PMCID: PMC7946423 DOI: 10.7554/elife.62449] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/26/2021] [Indexed: 12/28/2022] Open
Abstract
Caenorhabditis elegans expresses human Werner syndrome protein (WRN) orthologs as two distinct proteins: MUT-7, with a 3′−5′ exonuclease domain, and CeWRN-1, with helicase domains. How these domains cooperate remains unclear. Here, we demonstrate the different contributions of MUT-7 and CeWRN-1 to 22G small interfering RNA (siRNA) synthesis and the plasticity of neuronal signaling. MUT-7 acts specifically in the cytoplasm to promote siRNA biogenesis and in the nucleus to associate with CeWRN-1. The import of siRNA by the nuclear Argonaute NRDE-3 promotes the loading of the heterochromatin-binding protein HP1 homolog HPL-2 onto specific loci. This heterochromatin complex represses the gene expression of the guanylyl cyclase ODR-1 to direct olfactory plasticity in C. elegans. Our findings suggest that the exonuclease and helicase domains of human WRN may act in concert to promote RNA-dependent loading into a heterochromatin complex, and the failure of this entire process reduces plasticity in postmitotic neurons.
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Affiliation(s)
- Tsung-Yuan Hsu
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, United States
| | - Bo Zhang
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, United States
| | - Noelle D L'Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, United States
| | - Bi-Tzen Juang
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
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10
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Padeken J, Methot S, Zeller P, Delaney CE, Kalck V, Gasser SM. Argonaute NRDE-3 and MBT domain protein LIN-61 redundantly recruit an H3K9me3 HMT to prevent embryonic lethality and transposon expression. Genes Dev 2021; 35:82-101. [PMID: 33303642 PMCID: PMC7778263 DOI: 10.1101/gad.344234.120] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/05/2020] [Indexed: 12/30/2022]
Abstract
The establishment and maintenance of chromatin domains shape the epigenetic memory of a cell, with the methylation of histone H3 lysine 9 (H3K9me) defining transcriptionally silent heterochromatin. We show here that the C. elegans SET-25 (SUV39/G9a) histone methyltransferase (HMT), which catalyzes H3K9me1, me2 and me3, can establish repressed chromatin domains de novo, unlike the SETDB1 homolog MET-2. Thus, SET-25 is needed to silence novel insertions of RNA or DNA transposons, and repress tissue-specific genes de novo during development. We identify two partially redundant pathways that recruit SET-25 to its targets. One pathway requires LIN-61 (L3MBTL2), which uses its four MBT domains to bind the H3K9me2 deposited by MET-2. The second pathway functions independently of MET-2 and involves the somatic Argonaute NRDE-3 and small RNAs. This pathway targets primarily highly conserved RNA and DNA transposons. These redundant SET-25 targeting pathways (MET-2-LIN-61-SET-25 and NRDE-3-SET-25) ensure repression of intact transposons and de novo insertions, while MET-2 can act alone to repress simple and satellite repeats. Removal of both pathways in the met-2;nrde-3 double mutant leads to the loss of somatic H3K9me2 and me3 and the synergistic derepression of transposons in embryos, strongly elevating embryonic lethality.
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Affiliation(s)
- Jan Padeken
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Stephen Methot
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Peter Zeller
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
| | - Colin E Delaney
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Veronique Kalck
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
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11
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Kurhanewicz NA, Dinwiddie D, Bush ZD, Libuda DE. Elevated Temperatures Cause Transposon-Associated DNA Damage in C. elegans Spermatocytes. Curr Biol 2020; 30:5007-5017.e4. [DOI: 10.1016/j.cub.2020.09.050] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 11/28/2022]
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12
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Manage KI, Rogers AK, Wallis DC, Uebel CJ, Anderson DC, Nguyen DAH, Arca K, Brown KC, Cordeiro Rodrigues RJ, de Albuquerque BF, Ketting RF, Montgomery TA, Phillips CM. A tudor domain protein, SIMR-1, promotes siRNA production at piRNA-targeted mRNAs in C. elegans. eLife 2020; 9:56731. [PMID: 32338603 PMCID: PMC7255803 DOI: 10.7554/elife.56731] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 04/24/2020] [Indexed: 02/06/2023] Open
Abstract
piRNAs play a critical role in the regulation of transposons and other germline genes. In Caenorhabditis elegans, regulation of piRNA target genes is mediated by the mutator complex, which synthesizes high levels of siRNAs through the activity of an RNA-dependent RNA polymerase. However, the steps between mRNA recognition by the piRNA pathway and siRNA amplification by the mutator complex are unknown. Here, we identify the Tudor domain protein, SIMR-1, as acting downstream of piRNA production and upstream of mutator complex-dependent siRNA biogenesis. Interestingly, SIMR-1 also localizes to distinct subcellular foci adjacent to P granules and Mutator foci, two phase-separated condensates that are the sites of piRNA-dependent mRNA recognition and mutator complex-dependent siRNA amplification, respectively. Thus, our data suggests a role for multiple perinuclear condensates in organizing the piRNA pathway and promoting mRNA regulation by the mutator complex. In the biological world, a process known as RNA interference helps cells to switch genes on and off and to defend themselves against harmful genetic material. This mechanism works by deactivating RNA sequences, the molecular templates cells can use to create proteins. Overall, RNA interference relies on the cell creating small RNA molecules that can target and inhibit the harmful RNA sequences that need to be silenced. More precisely, in round worms such as Caenorhabditis elegans, RNA interference happens in two steps. First, primary small RNAs identify the target sequences, which are then combatted by newly synthetised, secondary small RNAs. A number of proteins are also involved in both steps of the process. RNA interference is particularly important to preserve fertility, guarding sex cells against ‘rogue’ segments of genetic information that could be passed on to the next generation. In future sex cells, the proteins involved in RNA interference cluster together, forming a structure called a germ granule. Yet, little is known about the roles and identity of these proteins. To fill this knowledge gap, Manage et al. focused on the second stage of the RNA interference pathway in the germ granules of C. elegans, examining the molecules that physically interact with a key protein. This work revealed a new protein called SIMR-1. Looking into the role of SIMR-1 showed that the protein is required to amplify secondary small RNAs, but not to identify target sequences. However, it only promotes the creation of secondary small RNAs if a specific subtype of primary small RNAs have recognized the target RNAs for silencing. Further experiments also showed that within the germ granule, SIMR-1 is present in a separate substructure different from any compartment previously identified. This suggests that each substep of the RNA interference process takes place at a different location in the granule. In both C. elegans and humans, disruptions in the RNA interference pathway can lead to conditions such as cancer or infertility. Dissecting the roles of the proteins involved in this process in roundworms may help to better grasp how this process unfolds in mammals, and how it could be corrected in the case of disease.
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Affiliation(s)
- Kevin I Manage
- Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Alicia K Rogers
- Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Dylan C Wallis
- Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Celja J Uebel
- Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Dorian C Anderson
- Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Dieu An H Nguyen
- Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Katerina Arca
- Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Kristen C Brown
- Department of Biology, Colorado State University, Fort Collins, United States.,Cell and Molecular Biology Program, Colorado State University, Fort Collins, United States
| | - Ricardo J Cordeiro Rodrigues
- Biology of Non-coding RNA Group, Institute of Molecular Biology, Mainz, Germany.,International PhD Programme on Gene Regulation, Epigenetics, and Genome Stability, Mainz, Germany
| | | | - René F Ketting
- Biology of Non-coding RNA Group, Institute of Molecular Biology, Mainz, Germany
| | - Taiowa A Montgomery
- Department of Biology, Colorado State University, Fort Collins, United States
| | - Carolyn Marie Phillips
- Department of Biological Sciences, University of Southern California, Los Angeles, United States
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13
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Reed KJ, Svendsen JM, Brown KC, Montgomery BE, Marks TN, Vijayasarathy T, Parker DM, Nishimura EO, Updike DL, Montgomery TA. Widespread roles for piRNAs and WAGO-class siRNAs in shaping the germline transcriptome of Caenorhabditis elegans. Nucleic Acids Res 2020; 48:1811-1827. [PMID: 31872227 PMCID: PMC7038979 DOI: 10.1093/nar/gkz1178] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 12/31/2022] Open
Abstract
Piwi-interacting RNAs (piRNAs) and small interfering RNAs (siRNAs) are distinct classes of small RNAs required for proper germline development. To identify the roles of piRNAs and siRNAs in regulating gene expression in Caenorhabditis elegans, we subjected small RNAs and mRNAs from the gonads of piRNA and siRNA defective mutants to high-throughput sequencing. We show that piRNAs and an abundant class of siRNAs known as WAGO-class 22G-RNAs are required for proper expression of spermatogenic and oogenic genes. WAGO-class 22G-RNAs are also broadly required for transposon silencing, whereas piRNAs are largely dispensable. piRNAs, however, have a critical role in controlling histone gene expression. In the absence of piRNAs, histone mRNAs are misrouted into the nuclear RNAi pathway involving the Argonaute HRDE-1, concurrent with a reduction in the expression of many histone mRNAs. We also show that high-level gene expression in the germline is correlated with high level 22G-RNA production. However, most highly expressed genes produce 22G-RNAs through a distinct pathway that presumably involves the Argonaute CSR-1. In contrast, genes targeted by the WAGO branch of the 22G-RNA pathway are typically poorly expressed and respond unpredictably to loss of 22G-RNAs. Our results point to broad roles for piRNAs and siRNAs in controlling gene expression in the C. elegans germline.
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Affiliation(s)
- Kailee J Reed
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA.,Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
| | - Joshua M Svendsen
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA.,Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
| | - Kristen C Brown
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA.,Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
| | - Brooke E Montgomery
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Taylor N Marks
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Tarah Vijayasarathy
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Dylan M Parker
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Erin Osborne Nishimura
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Dustin L Updike
- Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
| | - Taiowa A Montgomery
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
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