1
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Waddell BM, Wu CW. A role for the C. elegans Argonaute protein CSR-1 in small nuclear RNA 3' processing. PLoS Genet 2024; 20:e1011284. [PMID: 38743783 PMCID: PMC11125478 DOI: 10.1371/journal.pgen.1011284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 05/24/2024] [Accepted: 05/02/2024] [Indexed: 05/16/2024] Open
Abstract
The Integrator is a multi-subunit protein complex that catalyzes the maturation of snRNA transcripts via 3' cleavage, a step required for snRNA incorporation with snRNP for spliceosome biogenesis. Here we developed a GFP based in vivo snRNA misprocessing reporter as a readout of Integrator function and performed a genome-wide RNAi screen for Integrator regulators. We found that loss of the Argonaute encoding csr-1 gene resulted in widespread 3' misprocessing of snRNA transcripts that is accompanied by a significant increase in alternative splicing. Loss of the csr-1 gene down-regulates the germline expression of Integrator subunits 4 and 6 and is accompanied by a reduced protein translation efficiency of multiple Integrator catalytic and non-catalytic subunits. Through isoform and motif mutant analysis, we determined that CSR-1's effect on snRNA processing is dependent on its catalytic slicer activity but does not involve the CSR-1a isoform. Moreover, mRNA-sequencing revealed high similarity in the transcriptome profile between csr-1 and Integrator subunit knockdown via RNAi. Together, our findings reveal CSR-1 as a new regulator of the Integrator complex and implicate a novel role of this Argonaute protein in snRNA 3' processing.
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Affiliation(s)
- Brandon M. Waddell
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Cheng-Wei Wu
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Biochemistry, Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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2
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Chen S, Phillips CM. HRDE-2 drives small RNA specificity for the nuclear Argonaute protein HRDE-1. Nat Commun 2024; 15:957. [PMID: 38302462 PMCID: PMC10834429 DOI: 10.1038/s41467-024-45245-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 01/18/2024] [Indexed: 02/03/2024] Open
Abstract
RNA interference (RNAi) is a conserved gene silencing process that exists in diverse organisms to protect genome integrity and regulate gene expression. In C. elegans, the majority of RNAi pathway proteins localize to perinuclear, phase-separated germ granules, which are comprised of sub-domains referred to as P granules, Mutator foci, Z granules, and SIMR foci. However, the protein components and function of the newly discovered SIMR foci are unknown. Here we demonstrate that HRDE-2 localizes to SIMR foci and interacts with the germline nuclear Argonaute HRDE-1 in its small RNA unbound state. In the absence of HRDE-2, HRDE-1 exclusively loads CSR-class 22G-RNAs rather than WAGO-class 22G-RNAs, resulting in inappropriate H3K9me3 deposition on CSR-target genes. Thus, our study demonstrates that the recruitment of unloaded HRDE-1 to germ granules, mediated by HRDE-2, is critical to ensure that the correct small RNAs are used to guide nuclear RNA silencing in the C. elegans germline.
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Affiliation(s)
- Shihui Chen
- 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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3
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Liu L, Wang X, Zhao W, Li Q, Li J, Chen H, Shan G. Systematic characterization of small RNAs associated with C. elegans Argonautes. SCIENCE CHINA. LIFE SCIENCES 2023:10.1007/s11427-022-2304-8. [PMID: 37154856 DOI: 10.1007/s11427-022-2304-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 12/28/2022] [Indexed: 05/10/2023]
Abstract
Argonaute proteins generally play regulatory roles by forming complexes with the corresponding small RNAs (sRNAs). An expanded Argonaute family with 20 potentially functional members has been identified in Caenorhabditis elegans. Canonical sRNAs in C. elegans are miRNAs, small interfering RNAs including 22G-RNAs and 26G-RNAs, and 21U-RNAs, which are C. elegans piRNAs. Previous studies have only covered some of these Argonautes for their sRNA partners, and thus, a systematic study is needed to reveal the comprehensive regulatory networks formed by C. elegans Argonautes and their associated sRNAs. We obtained in situ knockin (KI) strains of all C. elegans Argonautes with fusion tags by CRISPR/Cas9 technology. RNA immunoprecipitation against these endogenously expressed Argonautes and high-throughput sequencing acquired the sRNA profiles of individual Argonautes. The sRNA partners for each Argonaute were then analyzed. We found that there were 10 Argonautes enriched miRNAs, 17 Argonautes bound to 22G-RNAs, 8 Argonautes bound to 26G-RNAs, and 1 Argonaute PRG-1 bound to piRNAs. Uridylated 22G-RNAs were bound by four Argonautes HRDE-1, WAGO-4, CSR-1, and PPW-2. We found that all four Argonautes played a role in transgenerational epigenetic inheritance. Regulatory roles of the corresponding Argonaute-sRNA complex in managing levels of long transcripts and interspecies regulation were also demonstrated. In this study, we portrayed the sRNAs bound to each functional Argonaute in C. elegans. Bioinformatics analyses together with experimental investigations provided perceptions in the overall view of the regulatory network formed by C. elegans Argonautes and sRNAs. The sRNA profiles bound to individual Argonautes reported here will be valuable resources for further studies.
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Affiliation(s)
- Lei Liu
- Department of Laboratory Medicine, The First Affiliated Hospital of USTC, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, 230027, China
| | - Xiaolin Wang
- Department of Laboratory Medicine, The First Affiliated Hospital of USTC, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, 230027, China.
| | - Wenfang Zhao
- Department of Laboratory Medicine, The First Affiliated Hospital of USTC, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, 230027, China
| | - Qiqi Li
- Department of Laboratory Medicine, The First Affiliated Hospital of USTC, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, 230027, China
| | - Jingxin Li
- Department of Laboratory Medicine, The First Affiliated Hospital of USTC, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, 230027, China
| | - He Chen
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Anhui University, Hefei, 230601, China
| | - Ge Shan
- Department of Laboratory Medicine, The First Affiliated Hospital of USTC, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei, 230027, China.
- Department of Pulmonary and Critical Care Medicine, Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, 310016, China.
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4
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Seroussi U, Lugowski A, Wadi L, Lao RX, Willis AR, Zhao W, Sundby AE, Charlesworth AG, Reinke AW, Claycomb JM. A comprehensive survey of C. elegans argonaute proteins reveals organism-wide gene regulatory networks and functions. eLife 2023; 12:e83853. [PMID: 36790166 PMCID: PMC10101689 DOI: 10.7554/elife.83853] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 02/14/2023] [Indexed: 02/16/2023] Open
Abstract
Argonaute (AGO) proteins associate with small RNAs to direct their effector function on complementary transcripts. The nematode Caenorhabditis elegans contains an expanded family of 19 functional AGO proteins, many of which have not been fully characterized. In this work, we systematically analyzed every C. elegans AGO using CRISPR-Cas9 genome editing to introduce GFP::3xFLAG tags. We have characterized the expression patterns of each AGO throughout development, identified small RNA binding complements, and determined the effects of ago loss on small RNA populations and developmental phenotypes. Our analysis indicates stratification of subsets of AGOs into distinct regulatory modules, and integration of our data led us to uncover novel stress-induced fertility and pathogen response phenotypes due to ago loss.
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Affiliation(s)
- Uri Seroussi
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Andrew Lugowski
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Lina Wadi
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Robert X Lao
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | | | - Winnie Zhao
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Adam E Sundby
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | | | - Aaron W Reinke
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Julie M Claycomb
- Department of Molecular Genetics, University of TorontoTorontoCanada
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5
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Renaud MS, Seroussi U, Claycomb JM. Analysis of C. elegans Germline Small RNA Pathways. Methods Mol Biol 2023; 2677:37-59. [PMID: 37464234 DOI: 10.1007/978-1-0716-3259-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Sequence-specific gene regulation by small RNA (sRNA) pathways is essential for the development and function of organisms in all domains of life. These regulatory complexes, containing an Argonaute protein (AGO) guided by a bound sRNA, have the potential to regulate thousands of individual target transcripts at both the co- and post-transcriptional level. Determining the repertoire of transcripts that an AGO is capable of regulating in a particular context is essential to understanding the function of these regulatory modules. Immunoprecipitation (IP) of AGOs and subsequent RNA sequencing of their bound sRNAs allows for the inference of their target transcripts by mapping the sequences of the co-precipitated sRNAs back to their complementary target transcripts. This approach can be complemented by sequencing sRNAs from ago mutants as sRNA transcripts are degraded in the absence of their AGO binding partner. Here, we describe a framework for analyzing AGO/sRNA pathways in the germline, from using CRISPR-Cas9 to tag or mutate AGOs, through protocols for the extraction, sequencing, and analysis of sRNAs from AGO IPs and ago mutants.
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Affiliation(s)
- Mathias S Renaud
- Department of Molecular Genetics, University of Toronto, Toronto, ON, USA
| | - Uri Seroussi
- Department of Molecular Genetics, University of Toronto, Toronto, ON, USA
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON, USA.
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6
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Gajic Z, Kaur D, Ni J, Zhu Z, Zhebrun A, Gajic M, Kim M, Hong J, Priyadarshini M, Frøkjær-Jensen C, Gu S. Target-dependent suppression of siRNA production modulates the levels of endogenous siRNAs in the Caenorhabditis elegans germline. Development 2022; 149:dev200692. [PMID: 35876680 PMCID: PMC9481970 DOI: 10.1242/dev.200692] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/14/2022] [Indexed: 08/24/2023]
Abstract
Despite the prominent role of endo-siRNAs in transposon silencing, their expression is not limited to these 'nonself' DNA elements. Transcripts of protein-coding genes ('self' DNA) in some cases also produce endo-siRNAs in yeast, plants and animals. How cells distinguish these two populations of siRNAs to prevent unwanted silencing of active genes in animals is not well understood. To address this question, we inserted various self-gene or gfp fragments into an LTR retrotransposon that produces abundant siRNAs and examined the propensity of these gene fragments to produce ectopic siRNAs in the Caenorhabditis elegans germline. We found that fragments of germline genes are generally protected from production of ectopic siRNAs. This phenomenon, which we termed 'target-directed suppression of siRNA production' (or siRNA suppression), is dependent on the germline expression of target mRNA and requires germline P-granule components. We found that siRNA suppression can also occur in naturally produced endo-siRNAs. We suggest that siRNA suppression plays an important role in regulating siRNA expression and preventing self-genes from aberrant epigenetic silencing. This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Zoran Gajic
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Diljeet Kaur
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Julie Ni
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Zhaorong Zhu
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Anna Zhebrun
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Maria Gajic
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Matthew Kim
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Julia Hong
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Monika Priyadarshini
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955–6900, Kingdom of Saudi Arabia
| | - Christian Frøkjær-Jensen
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955–6900, Kingdom of Saudi Arabia
| | - Sam Gu
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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7
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Torri A, Jaeger J, Pradeu T, Saleh MC. The origin of RNA interference: Adaptive or neutral evolution? PLoS Biol 2022; 20:e3001715. [PMID: 35767561 PMCID: PMC9275709 DOI: 10.1371/journal.pbio.3001715] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/12/2022] [Indexed: 11/30/2022] Open
Abstract
The origin of RNA interference (RNAi) is usually explained by a defense-based hypothesis, in which RNAi evolved as a defense against transposable elements (TEs) and RNA viruses and was already present in the last eukaryotic common ancestor (LECA). However, since RNA antisense regulation and double-stranded RNAs (dsRNAs) are ancient and widespread phenomena, the origin of defensive RNAi should have occurred in parallel with its regulative functions to avoid imbalances in gene regulation. Thus, we propose a neutral evolutionary hypothesis for the origin of RNAi in which qualitative system drift from a prokaryotic antisense RNA gene regulation mechanism leads to the formation of RNAi through constructive neutral evolution (CNE). We argue that RNAi was already present in the ancestor of LECA before the need for a new defense system arose and that its presence helped to shape eukaryotic genomic architecture and stability. Where does RNA interference come from? This Essay describes a new step-by-step evolutionary model of how RNA interference might have originated in early eukaryotes through neutral events from the molecular machinery present in prokaryotes.
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Affiliation(s)
- Alessandro Torri
- Virus & RNA interference Unit, Department of Virology, Institut Pasteur, CNRS UMR 3569, Université Paris Cité, Paris, France
- * E-mail: (AT); (M-CS)
| | | | - Thomas Pradeu
- ImmunoConcEpT, CNRS UMR 5164, University of Bordeaux, Bordeaux, France
- Institut d’histoire et de philosophie des sciences et des techniques, CNRS UMR 8590, Pantheon-Sorbonne University, Paris, France
| | - Maria-Carla Saleh
- Virus & RNA interference Unit, Department of Virology, Institut Pasteur, CNRS UMR 3569, Université Paris Cité, Paris, France
- * E-mail: (AT); (M-CS)
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8
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Wang HQ, Wang T, Gao F, Ren WZ. Application of CRISPR/Cas Technology in Spermatogenesis Research and Male Infertility Treatment. Genes (Basel) 2022; 13:genes13061000. [PMID: 35741761 PMCID: PMC9223233 DOI: 10.3390/genes13061000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/25/2022] [Accepted: 05/28/2022] [Indexed: 12/04/2022] Open
Abstract
As the basis of animal reproductive activity, normal spermatogenesis directly determines the efficiency of livestock production. An in-depth understanding of spermatogenesis will greatly facilitate animal breeding efforts and male infertility treatment. With the continuous development and application of gene editing technologies, they have become valuable tools to study the mechanism of spermatogenesis. Gene editing technologies have provided us with a better understanding of the functions and potential mechanisms of action of factors that regulate spermatogenesis. This review summarizes the applications of gene editing technologies, especially CRISPR/Cas9, in deepening our understanding of the function of spermatogenesis-related genes and disease treatment. The problems of gene editing technologies in the field of spermatogenesis research are also discussed.
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9
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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: 3] [Impact Index Per Article: 1.5] [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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10
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Zagoskin MV, Wang J, Neff AT, Veronezi GMB, Davis RE. Small RNA pathways in the nematode Ascaris in the absence of piRNAs. Nat Commun 2022; 13:837. [PMID: 35149688 PMCID: PMC8837657 DOI: 10.1038/s41467-022-28482-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 01/13/2022] [Indexed: 02/07/2023] Open
Abstract
Small RNA pathways play key and diverse regulatory roles in C. elegans, but our understanding of their conservation and contributions in other nematodes is limited. We analyzed small RNA pathways in the divergent parasitic nematode Ascaris. Ascaris has ten Argonautes with five worm-specific Argonautes (WAGOs) that associate with secondary 5’-triphosphate 22-24G-RNAs. These small RNAs target repetitive sequences or mature mRNAs and are similar to the C. elegans mutator, nuclear, and CSR-1 small RNA pathways. Even in the absence of a piRNA pathway, Ascaris CSR-1 may still function to “license” as well as fine-tune or repress gene expression. Ascaris ALG-4 and its associated 26G-RNAs target and likely repress specific mRNAs during testis meiosis. Ascaris WAGO small RNAs demonstrate target plasticity changing their targets between repeats and mRNAs during development. We provide a unique and comprehensive view of mRNA and small RNA expression throughout spermatogenesis. Overall, our study illustrates the conservation, divergence, dynamics, and flexibility of small RNA pathways in nematodes. The parasitic nematode Ascaris lacks piRNAs. Here the authors compare Argonaute proteins and small RNAs from C. elegans and Ascaris, expanding our understanding of the conservation, divergence, and flexibility of Argonautes and small RNA pathways in nematodes.
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Affiliation(s)
- Maxim V Zagoskin
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA.,RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO, USA.,Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Jianbin Wang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA. .,RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO, USA. .,Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA. .,UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, USA.
| | - Ashley T Neff
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Giovana M B Veronezi
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Richard E Davis
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA. .,RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO, USA.
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11
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Cornes E, Bourdon L, Singh M, Mueller F, Quarato P, Wernersson E, Bienko M, Li B, Cecere G. piRNAs initiate transcriptional silencing of spermatogenic genes during C. elegans germline development. Dev Cell 2022; 57:180-196.e7. [PMID: 34921763 PMCID: PMC8796119 DOI: 10.1016/j.devcel.2021.11.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/02/2021] [Accepted: 11/26/2021] [Indexed: 12/22/2022]
Abstract
Eukaryotic genomes harbor invading transposable elements that are silenced by PIWI-interacting RNAs (piRNAs) to maintain genome integrity in animal germ cells. However, whether piRNAs also regulate endogenous gene expression programs remains unclear. Here, we show that C. elegans piRNAs trigger the transcriptional silencing of hundreds of spermatogenic genes during spermatogenesis, promoting sperm differentiation and function. This silencing signal requires piRNA-dependent small RNA biogenesis and loading into downstream nuclear effectors, which correlates with the dynamic reorganization of two distinct perinuclear biomolecular condensates present in germ cells. In addition, the silencing capacity of piRNAs is temporally counteracted by the Argonaute CSR-1, which targets and licenses spermatogenic gene transcription. The spatial and temporal overlap between these opposing small RNA pathways contributes to setting up the timing of the spermatogenic differentiation program. Thus, our work identifies a prominent role for piRNAs as direct regulators of endogenous transcriptional programs during germline development and gamete differentiation.
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Affiliation(s)
- Eric Cornes
- Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, Institut Pasteur, UMR 3738, CNRS, Paris 75015, France
| | - Loan Bourdon
- Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, Institut Pasteur, UMR 3738, CNRS, Paris 75015, France
| | - Meetali Singh
- Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, Institut Pasteur, UMR 3738, CNRS, Paris 75015, France
| | - Florian Mueller
- Imaging and Modeling Unit, Institut Pasteur, UMR 3691 CNRS, C3BI USR 3756 IP CNRS, Paris, France
| | - Piergiuseppe Quarato
- Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, Institut Pasteur, UMR 3738, CNRS, Paris 75015, France
| | - Erik Wernersson
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17165, Sweden; Science for Life Laboratory, Tomtebodavägen 23A, Stockholm 17165, Sweden
| | - Magda Bienko
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17165, Sweden; Science for Life Laboratory, Tomtebodavägen 23A, Stockholm 17165, Sweden
| | - Blaise Li
- Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, Institut Pasteur, UMR 3738, CNRS, Paris 75015, France; Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, USR 3756, CNRS, Paris 75015, France
| | - Germano Cecere
- Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, Institut Pasteur, UMR 3738, CNRS, Paris 75015, France.
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12
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Charlesworth AG, Nitschko V, Renaud MS, Claycomb JM. PIWI puts spermatogenesis in its place. Dev Cell 2022; 57:149-151. [DOI: 10.1016/j.devcel.2022.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Seroussi U, Li C, Sundby AE, Lee TL, Claycomb JM, Saltzman AL. Mechanisms of epigenetic regulation by C. elegans nuclear RNA interference pathways. Semin Cell Dev Biol 2021; 127:142-154. [PMID: 34876343 DOI: 10.1016/j.semcdb.2021.11.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/17/2021] [Accepted: 11/17/2021] [Indexed: 01/06/2023]
Abstract
RNA interference (RNAi) is a highly conserved gene regulatory phenomenon whereby Argonaute/small RNA (AGO/sRNA) complexes target transcripts by antisense complementarity to modulate gene expression. While initially appreciated as a cytoplasmic process, RNAi can also occur in the nucleus where AGO/sRNA complexes are recruited to nascent transcripts. Nuclear AGO/sRNA complexes recruit co-factors that regulate transcription by inhibiting RNA Polymerase II, modifying histones, compacting chromatin and, in some organisms, methylating DNA. C. elegans has a longstanding history in unveiling the mechanisms of RNAi and has become an outstanding model to delineate the mechanisms underlying nuclear RNAi. In this review we highlight recent discoveries in the field of nuclear RNAi in C. elegans and the roles of nuclear RNAi in the regulation of gene expression, chromatin organization, genome stability, and transgenerational epigenetic inheritance.
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Affiliation(s)
- Uri Seroussi
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Chengyin Li
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Adam E Sundby
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Tammy L Lee
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
| | - Arneet L Saltzman
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.
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14
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Cecere G. Small RNAs in epigenetic inheritance: from mechanisms to trait transmission. FEBS Lett 2021; 595:2953-2977. [PMID: 34671979 PMCID: PMC9298081 DOI: 10.1002/1873-3468.14210] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/08/2021] [Accepted: 10/18/2021] [Indexed: 01/02/2023]
Abstract
Inherited information is transmitted to progeny primarily by the genome through the gametes. However, in recent years, epigenetic inheritance has been demonstrated in several organisms, including animals. Although it is clear that certain post‐translational histone modifications, DNA methylation, and noncoding RNAs regulate epigenetic inheritance, the molecular mechanisms responsible for epigenetic inheritance are incompletely understood. This review focuses on the role of small RNAs in transmitting epigenetic information across generations in animals. Examples of documented cases of transgenerational epigenetic inheritance are discussed, from the silencing of transgenes to the inheritance of complex traits, such as fertility, stress responses, infections, and behavior. Experimental evidence supporting the idea that small RNAs are epigenetic molecules capable of transmitting traits across generations is highlighted, focusing on the mechanisms by which small RNAs achieve such a function. Just as the role of small RNAs in epigenetic processes is redefining the concept of inheritance, so too our understanding of the molecular pathways and mechanisms that govern epigenetic inheritance in animals is radically changing.
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Affiliation(s)
- Germano Cecere
- Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, Institut Pasteur, UMR3738, CNRS, Paris, France
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15
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Li Y, Snyder M, Maine EM. Meiotic H3K9me2 distribution is influenced by the ALG-3 and ALG-4 pathway and by poly(U) polymerase activity. MICROPUBLICATION BIOLOGY 2021; 2021:10.17912/micropub.biology.000455. [PMID: 34549171 PMCID: PMC8449255 DOI: 10.17912/micropub.biology.000455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 11/08/2022]
Abstract
Histone modifications influence gene expression and chromosome dynamics by altering chromatin structure and recruitment of nonhistone proteins. Dimethylation of histone H3 on lysine 9 (H3K9me2) is a conserved modification often found within heterochromatin. During first meiotic prophase when homologous chromosomes undergo pairing and synapsis, immunolabeling of C. elegans male germ cells detects a relatively high H3K9me2 level on the single X chromosome and a relatively low H3K9me2 level on synapsed autosomes. This H3K9me2 distribution is influenced by several components of the small RNA machinery, including: EGO-1 RNA-directed RNA polymerase (RdRP); DRH-3 helicase; EKL-1, a Tudor domain protein; CSR-1 Argonaute; and RRF-3 RdRP. EGO-1, DRH-3, and EKL-1 function together to generate/stabilize 22G RNAs in the germ line. A subset of these 22G RNAs function together with CSR-1 to ensure correct gene expression. RRF-3 RdRP functions in biogenesis of 26G RNAs that feed into two germline regulatory mechanisms mediated by ERGO-1 Argonaute and the redundant ALG-3 and ALG-4 Argonaute proteins. Here, we report that meiotic H3K9me2 distribution is influenced by ALG-3 and ALG-4, as well as by two other factors required for 26G RNA synthesis, ERI-1 and ERI-5. Moreover, meiotic H3K9me2 distribution is influenced by activity of the poly(U) polymerases, PUP-1 (aka CDE-1, CID-1) and PUP-2.
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Affiliation(s)
- Yini Li
- Department of Biology, Syracuse University, Syracuse, NY
| | - Matthew Snyder
- Department of Biology, Syracuse University, Syracuse, NY
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