101
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Oldroyd BP, Yagound B. Parent-of-origin effects, allele-specific expression, genomic imprinting and paternal manipulation in social insects. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200425. [PMID: 33866807 DOI: 10.1098/rstb.2020.0425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Haplo-diploidy and the relatedness asymmetries it generates mean that social insects are prime candidates for the evolution of genomic imprinting. In single-mating social insect species, some genes may be selected to evolve genomic mechanisms that enhance reproduction by workers when they are inherited from a female. This situation reverses in multiple mating species, where genes inherited from fathers can be under selection to enhance the reproductive success of daughters. Reciprocal crosses between subspecies of honeybees have shown strong parent-of-origin effects on worker reproductive phenotypes, and this could be evidence of such genomic imprinting affecting genes related to worker reproduction. It is also possible that social insect fathers directly affect gene expression in their daughters, for example, by placing small interfering RNA molecules in semen. Gene expression studies have repeatedly found evidence of parent-specific gene expression in social insects, but it is unclear at this time whether this arises from genomic imprinting, paternal manipulation, an artefact of cyto-nuclear interactions, or all of these. This article is part of the theme issue 'How does epigenetics influence the course of evolution?'
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Affiliation(s)
- Benjamin P Oldroyd
- Wissenschaftskolleg zu Berlin, Wallotstrasse 19, 14193 Berlin, Germany.,BEE Lab, School of Life and Environmental Sciences A12, University of Sydney, New South Wales 2006, Australia
| | - Boris Yagound
- BEE Lab, School of Life and Environmental Sciences A12, University of Sydney, New South Wales 2006, Australia
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102
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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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103
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Nono M, Kishimoto S, Sato-Carlton A, Carlton PM, Nishida E, Uno M. Intestine-to-Germline Transmission of Epigenetic Information Intergenerationally Ensures Systemic Stress Resistance in C. elegans. Cell Rep 2021; 30:3207-3217.e4. [PMID: 32160530 DOI: 10.1016/j.celrep.2020.02.050] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 10/31/2019] [Accepted: 02/10/2020] [Indexed: 01/29/2023] Open
Abstract
Changes in epigenetic states affect organismal homeostasis, including stress resistance. However, the mechanisms coordinating epigenetic states and systemic stress resistance remain largely unknown. Here, we identify the intestine-to-germline communication of epigenetic states, which intergenerationally enhances stress resistance in C. elegans. The alterations in epigenetic states by deficiency of the histone H3K4me3 modifier ASH-2 in the intestine or germline increase organismal stress resistance, which is abrogated by knockdown of the H3K4 demethylase RBR-2. Remarkably, the increase in stress resistance induced by ASH-2 deficiency in the intestine is abrogated by RBR-2 knockdown in the germline, suggesting the intestine-to-germline transmission of epigenetic information. This communication from intestine to germline in the parental generation increases stress resistance in the next generation. Moreover, the intertissue communication is mediated partly by transcriptional regulation of F08F1.3. These results reveal that intertissue communication of epigenetic information provides mechanisms for intergenerational regulation of systemic stress resistance.
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Affiliation(s)
- Masanori Nono
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan; RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
| | - Saya Kishimoto
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan; RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
| | - Aya Sato-Carlton
- Laboratory of Chromosome Function and Inheritance, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Peter Mark Carlton
- Laboratory of Chromosome Function and Inheritance, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan; Laboratory of Chromosome Function and Inheritance, Radiation Biology Center, Kyoto University, Kyoto 606-8501, Japan
| | - Eisuke Nishida
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan; RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan.
| | - Masaharu Uno
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan; RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan.
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104
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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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105
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Collens AB, Katz LA. Opinion: Genetic Conflict With Mobile Elements Drives Eukaryotic Genome Evolution, and Perhaps Also Eukaryogenesis. J Hered 2021; 112:140-144. [PMID: 33538295 PMCID: PMC7953837 DOI: 10.1093/jhered/esaa060] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 12/17/2020] [Indexed: 12/13/2022] Open
Abstract
Through analyses of diverse microeukaryotes, we have previously argued that eukaryotic genomes are dynamic systems that rely on epigenetic mechanisms to distinguish germline (i.e., DNA to be inherited) from soma (i.e., DNA that undergoes polyploidization, genome rearrangement, etc.), even in the context of a single nucleus. Here, we extend these arguments by including two well-documented observations: (1) eukaryotic genomes interact frequently with mobile genetic elements (MGEs) like viruses and transposable elements (TEs), creating genetic conflict, and (2) epigenetic mechanisms regulate MGEs. Synthesis of these ideas leads to the hypothesis that genetic conflict with MGEs contributed to the evolution of a dynamic eukaryotic genome in the last eukaryotic common ancestor (LECA), and may have contributed to eukaryogenesis (i.e., may have been a driver in the evolution of FECA, the first eukaryotic common ancestor). Sex (i.e., meiosis) may have evolved within the context of the development of germline-soma distinctions in LECA, as this process resets the germline genome by regulating/eliminating somatic (i.e., polyploid, rearranged) genetic material. Our synthesis of these ideas expands on hypotheses of the origin of eukaryotes by integrating the roles of MGEs and epigenetics.
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Affiliation(s)
- Adena B Collens
- Department of Biological Sciences, Smith College, Northampton, MA
| | - Laura A Katz
- Department of Biological Sciences, Smith College, Northampton, MA
- Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA
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106
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Huang X, Wong G. An old weapon with a new function: PIWI-interacting RNAs in neurodegenerative diseases. Transl Neurodegener 2021; 10:9. [PMID: 33685517 PMCID: PMC7938595 DOI: 10.1186/s40035-021-00233-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/16/2021] [Indexed: 12/16/2022] Open
Abstract
PIWI-interacting RNAs (piRNAs) are small non-coding transcripts that are highly conserved across species and regulate gene expression through pre- and post-transcriptional processes. piRNAs were originally discovered in germline cells and protect against transposable element expression to promote and maintain genome stability. In the recent decade, emerging roles of piRNAs have been revealed, including the roles in sterility, tumorigenesis, metabolic homeostasis, neurodevelopment, and neurodegenerative diseases. In this review, we summarize piRNA biogenesis in C. elegans, Drosophila, and mice, and further elaborate upon how piRNAs mitigate the harmful effects of transposons. Lastly, the most recent findings on piRNA participation in neurological diseases are highlighted. We speculate on the mechanisms of piRNA action in the development and progression of neurodegenerative diseases. Understanding the roles of piRNAs in neurological diseases may facilitate their applications in diagnostic and therapeutic practice.
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Affiliation(s)
- Xiaobing Huang
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Macau, 999078, S.A.R., China
| | - Garry Wong
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Macau, 999078, S.A.R., China.
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107
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Quarato P, Singh M, Cornes E, Li B, Bourdon L, Mueller F, Didier C, Cecere G. Germline inherited small RNAs facilitate the clearance of untranslated maternal mRNAs in C. elegans embryos. Nat Commun 2021; 12:1441. [PMID: 33664268 PMCID: PMC7933186 DOI: 10.1038/s41467-021-21691-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 02/05/2021] [Indexed: 01/16/2023] Open
Abstract
Inheritance and clearance of maternal mRNAs are two of the most critical events required for animal early embryonic development. However, the mechanisms regulating this process are still largely unknown. Here, we show that together with maternal mRNAs, C. elegans embryos inherit a complementary pool of small non-coding RNAs that facilitate the cleavage and removal of hundreds of maternal mRNAs. These antisense small RNAs are loaded into the maternal catalytically-active Argonaute CSR-1 and cleave complementary mRNAs no longer engaged in translation in somatic blastomeres. Induced depletion of CSR-1 specifically during embryonic development leads to embryonic lethality in a slicer-dependent manner and impairs the degradation of CSR-1 embryonic mRNA targets. Given the conservation of Argonaute catalytic activity, we propose that a similar mechanism operates to clear maternal mRNAs during the maternal-to-zygotic transition across species.
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Affiliation(s)
- Piergiuseppe Quarato
- Institut Pasteur, Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, UMR3738, CNRS, 75724, Paris, France
- Sorbonne Université, Collège Doctoral, F-75005, Paris, France
| | - Meetali Singh
- Institut Pasteur, Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, UMR3738, CNRS, 75724, Paris, France
| | - Eric Cornes
- Institut Pasteur, Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, UMR3738, CNRS, 75724, Paris, France
| | - Blaise Li
- Institut Pasteur, Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, UMR3738, CNRS, 75724, Paris, France
- Hub de Bioinformatique et Biostatistique - Département Biologie Computationnelle, Institut Pasteur, 75724, Paris, France
| | - Loan Bourdon
- Institut Pasteur, Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, UMR3738, CNRS, 75724, Paris, France
| | - Florian Mueller
- Institut Pasteur, Imaging and Modeling Unit, UMR 3691 CNRS, C3BI USR 3756 IP CNRS, 75724, Paris, France
| | - Celine Didier
- Institut Pasteur, Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, UMR3738, CNRS, 75724, Paris, France
| | - Germano Cecere
- Institut Pasteur, Mechanisms of Epigenetic Inheritance, Department of Developmental and Stem Cell Biology, UMR3738, CNRS, 75724, Paris, France.
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108
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Spichal M, Heestand B, Billmyre KK, Frenk S, Mello CC, Ahmed S. Germ granule dysfunction is a hallmark and mirror of Piwi mutant sterility. Nat Commun 2021; 12:1420. [PMID: 33658512 PMCID: PMC7930041 DOI: 10.1038/s41467-021-21635-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 01/29/2021] [Indexed: 01/31/2023] Open
Abstract
In several species, Piwi/piRNA genome silencing defects cause immediate sterility that correlates with transposon expression and transposon-induced genomic instability. In C. elegans, mutations in the Piwi-related gene (prg-1) and other piRNA deficient mutants cause a transgenerational decline in fertility over a period of several generations. Here we show that the sterility of late generation piRNA mutants correlates poorly with increases in DNA damage signaling. Instead, sterile individuals consistently exhibit altered perinuclear germ granules. We show that disruption of germ granules does not activate transposon expression but induces multiple phenotypes found in sterile prg-1 pathway mutants. Furthermore, loss of the germ granule component pgl-1 enhances prg-1 mutant infertility. Environmental restoration of germ granule function for sterile pgl-1 mutants restores their fertility. We propose that Piwi mutant sterility is a reproductive arrest phenotype that is characterized by perturbed germ granule structure and is phenocopied by germ granule dysfunction, independent of genomic instability.
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Affiliation(s)
- Maya Spichal
- grid.410711.20000 0001 1034 1720Department of Genetics, University of North Carolina, Chapel Hill, NC USA ,grid.410711.20000 0001 1034 1720Department of Biology, University of North Carolina, Chapel Hill, NC USA ,grid.168645.80000 0001 0742 0364RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA USA
| | - Bree Heestand
- grid.410711.20000 0001 1034 1720Department of Genetics, University of North Carolina, Chapel Hill, NC USA ,grid.410711.20000 0001 1034 1720Department of Biology, University of North Carolina, Chapel Hill, NC USA
| | - Katherine Kretovich Billmyre
- grid.410711.20000 0001 1034 1720Department of Genetics, University of North Carolina, Chapel Hill, NC USA ,grid.410711.20000 0001 1034 1720Department of Biology, University of North Carolina, Chapel Hill, NC USA ,grid.250820.d0000 0000 9420 1591Present Address: Stowers Institute for Medical Research, Kansas City, MO USA
| | - Stephen Frenk
- grid.410711.20000 0001 1034 1720Department of Genetics, University of North Carolina, Chapel Hill, NC USA ,grid.410711.20000 0001 1034 1720Department of Biology, University of North Carolina, Chapel Hill, NC USA ,Present Address: Achilles Therapeutics Limited, London, UK
| | - Craig C. Mello
- grid.168645.80000 0001 0742 0364RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA USA ,grid.413575.10000 0001 2167 1581Howard Hughes Medical Institute, Worcester, MA USA
| | - Shawn Ahmed
- grid.410711.20000 0001 1034 1720Department of Genetics, University of North Carolina, Chapel Hill, NC USA ,grid.410711.20000 0001 1034 1720Department of Biology, University of North Carolina, Chapel Hill, NC USA ,grid.410711.20000 0001 1034 1720Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC USA
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109
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Berkyurek AC, Furlan G, Lampersberger L, Beltran T, Weick E, Nischwitz E, Cunha Navarro I, Braukmann F, Akay A, Price J, Butter F, Sarkies P, Miska EA. The RNA polymerase II subunit RPB-9 recruits the integrator complex to terminate Caenorhabditis elegans piRNA transcription. EMBO J 2021; 40:e105565. [PMID: 33533030 PMCID: PMC7917558 DOI: 10.15252/embj.2020105565] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 12/14/2020] [Accepted: 12/19/2020] [Indexed: 01/03/2023] Open
Abstract
PIWI-interacting RNAs (piRNAs) are genome-encoded small RNAs that regulate germ cell development and maintain germline integrity in many animals. Mature piRNAs engage Piwi Argonaute proteins to silence complementary transcripts, including transposable elements and endogenous genes. piRNA biogenesis mechanisms are diverse and remain poorly understood. Here, we identify the RNA polymerase II (RNA Pol II) core subunit RPB-9 as required for piRNA-mediated silencing in the nematode Caenorhabditis elegans. We show that rpb-9 initiates heritable piRNA-mediated gene silencing at two DNA transposon families and at a subset of somatic genes in the germline. We provide genetic and biochemical evidence that RPB-9 is required for piRNA biogenesis by recruiting the Integrator complex at piRNA genes, hence promoting transcriptional termination. We conclude that, as a part of its rapid evolution, the piRNA pathway has co-opted an ancient machinery for high-fidelity transcription.
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Affiliation(s)
- Ahmet C Berkyurek
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Giulia Furlan
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Lisa Lampersberger
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Toni Beltran
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
| | - Eva‐Maria Weick
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Present address:
Structural Biology ProgramSloan Kettering InstituteMemorial Sloan Kettering Cancer CenterNew YorkNYUSA
| | - Emily Nischwitz
- Quantitative ProteomicsInstitute of Molecular BiologyMainzGermany
| | - Isabela Cunha Navarro
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Fabian Braukmann
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Alper Akay
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
- Present address:
School of Biological SciencesUniversity of East AngliaNorwich, NorfolkUK
| | - Jonathan Price
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
| | - Falk Butter
- Quantitative ProteomicsInstitute of Molecular BiologyMainzGermany
| | - Peter Sarkies
- MRC London Institute of Medical SciencesLondonUK
- Institute of Clinical SciencesImperial College LondonLondonUK
| | - Eric A Miska
- Wellcome Trust/Cancer Research UK Gurdon InstituteUniversity of CambridgeCambridgeUK
- Department of GeneticsUniversity of CambridgeCambridgeUK
- Wellcome Sanger InstituteWellcome Trust Genome CampusCambridgeUK
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110
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How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans? Biochem Soc Trans 2021; 48:1019-1034. [PMID: 32539084 DOI: 10.1042/bst20190944] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 12/20/2022]
Abstract
Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.
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111
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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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112
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Choi CP, Tay RJ, Starostik MR, Feng S, Moresco JJ, Montgomery BE, Xu E, Hammonds MA, Schatz MC, Montgomery TA, Yates JR, Jacobsen SE, Kim JK. SNPC-1.3 is a sex-specific transcription factor that drives male piRNA expression in C. elegans. eLife 2021; 10:e60681. [PMID: 33587037 PMCID: PMC7884074 DOI: 10.7554/elife.60681] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 02/02/2021] [Indexed: 12/29/2022] Open
Abstract
Piwi-interacting RNAs (piRNAs) play essential roles in silencing repetitive elements to promote fertility in metazoans. Studies in worms, flies, and mammals reveal that piRNAs are expressed in a sex-specific manner. However, the mechanisms underlying this sex-specific regulation are unknown. Here we identify SNPC-1.3, a male germline-enriched variant of a conserved subunit of the small nuclear RNA-activating protein complex, as a male-specific piRNA transcription factor in Caenorhabditis elegans. SNPC-1.3 colocalizes with the core piRNA transcription factor, SNPC-4, in nuclear foci of the male germline. Binding of SNPC-1.3 at male piRNA loci drives spermatogenic piRNA transcription and requires SNPC-4. Loss of snpc-1.3 leads to depletion of male piRNAs and defects in male-dependent fertility. Furthermore, TRA-1, a master regulator of sex determination, binds to the snpc-1.3 promoter and represses its expression during oogenesis. Loss of TRA-1 targeting causes ectopic expression of snpc-1.3 and male piRNAs during oogenesis. Thus, sexually dimorphic regulation of snpc-1.3 expression coordinates male and female piRNA expression during germline development.
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Affiliation(s)
- Charlotte P Choi
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Rebecca J Tay
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | | | - Suhua Feng
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los AngelesLos AngelesUnited States
| | - James J Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical CenterDallasUnited States
| | | | - Emily Xu
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Maya A Hammonds
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Michael C Schatz
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
- Department of Computer Science, Johns Hopkins UniversityBaltimoreUnited States
| | | | - John R Yates
- Department of Molecular Medicine, The Scripps Research InstituteLa JollaUnited States
| | - Steven E Jacobsen
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
- Howard Hughes Medical Institute, University of California, Los AngelesLos AngelesUnited States
| | - John K Kim
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
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113
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Carpenter BS, Lee TW, Plott CF, Rodriguez JD, Brockett JS, Myrick DA, Katz DJ. Caenorhabditis elegans establishes germline versus soma by balancing inherited histone methylation. Development 2021; 148:dev.196600. [PMID: 33462111 DOI: 10.1242/dev.196600] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/04/2021] [Indexed: 12/12/2022]
Abstract
Formation of a zygote is coupled with extensive epigenetic reprogramming to enable appropriate inheritance of histone methylation and prevent developmental delays. In Caenorhabditis elegans, this reprogramming is mediated by the H3K4me2 demethylase SPR-5 and the H3K9 methyltransferase, MET-2. In contrast, the H3K36 methyltransferase MES-4 maintains H3K36me2/3 at germline genes between generations to facilitate re-establishment of the germline. To determine whether the MES-4 germline inheritance pathway antagonizes spr-5; met-2 reprogramming, we examined the interaction between these two pathways. We found that the developmental delay of spr-5; met-2 mutant progeny is associated with ectopic H3K36me3 and the ectopic expression of MES-4-targeted germline genes in somatic tissues. Furthermore, the developmental delay is dependent upon MES-4 and the H3K4 methyltransferase, SET-2. We propose that MES-4 prevents crucial germline genes from being repressed by antagonizing maternal spr-5; met-2 reprogramming. Thus, the balance of inherited histone modifications is necessary to distinguish germline versus soma and prevent developmental delay.This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Brandon S Carpenter
- Department of Cell Biology, Emory University School of Medicine, Atlanta GA 30322, USA
| | - Teresa W Lee
- Department of Cell Biology, Emory University School of Medicine, Atlanta GA 30322, USA
| | - Caroline F Plott
- Johns Hopkins University School of Medicine, Baltimore MD 21205, USA
| | - Juan D Rodriguez
- Department of Cell Biology, Emory University School of Medicine, Atlanta GA 30322, USA
| | - Jovan S Brockett
- Department of Biology, Oglethorpe University, Atlanta GA 30319, USA
| | - Dexter A Myrick
- Department of Cell Biology, Emory University School of Medicine, Atlanta GA 30322, USA
| | - David J Katz
- Department of Cell Biology, Emory University School of Medicine, Atlanta GA 30322, USA
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114
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Lister-Shimauchi EH, Dinh M, Maddox P, Ahmed S. Gametes deficient for Pot1 telomere binding proteins alter levels of telomeric foci for multiple generations. Commun Biol 2021; 4:158. [PMID: 33542458 PMCID: PMC7862594 DOI: 10.1038/s42003-020-01624-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 12/15/2020] [Indexed: 11/20/2022] Open
Abstract
Deficiency for telomerase results in transgenerational shortening of telomeres. However, telomeres have no known role in transgenerational epigenetic inheritance. C. elegans Protection Of Telomeres 1 (Pot1) proteins form foci at the telomeres of germ cells that disappear at fertilization and gradually accumulate during development. We find that gametes from mutants deficient for Pot1 proteins alter levels of telomeric foci for multiple generations. Gametes from pot-2 mutants give rise to progeny with abundant POT-1::mCherry and mNeonGreen::POT-2 foci throughout development, which persists for six generations. In contrast, gametes from pot-1 mutants or pot-1; pot-2 double mutants induce diminished Pot1 foci for several generations. Deficiency for MET-2, SET-25, or SET-32 methyltransferases, which promote heterochromatin formation, results in gametes that induce diminished Pot1 foci for several generations. We propose that C. elegans POT-1 may interact with H3K9 methyltransferases during pot-2 mutant gametogenesis to induce a persistent form of transgenerational epigenetic inheritance that causes constitutively high levels of heterochromatic Pot1 foci.
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Affiliation(s)
- Evan H Lister-Shimauchi
- Department of Genetics, University of North Carolina, Chapel Hill, NC, 27599, USA.
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA.
| | - Michael Dinh
- Department of Genetics, University of North Carolina, Chapel Hill, NC, 27599, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Paul Maddox
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Shawn Ahmed
- Department of Genetics, University of North Carolina, Chapel Hill, NC, 27599, USA.
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA.
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA.
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, 27599, USA.
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115
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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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116
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Sundby AE, Molnar RI, Claycomb JM. Connecting the Dots: Linking Caenorhabditis elegans Small RNA Pathways and Germ Granules. Trends Cell Biol 2021; 31:387-401. [PMID: 33526340 DOI: 10.1016/j.tcb.2020.12.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 12/15/2022]
Abstract
Germ granules are non-membrane bound, phase-separated organelles, composed of RNAs and proteins. Germ granules are present only within the germ cells of animals, including model systems such as Caenorhabditis elegans, Drosophila, mice, and zebrafish, where they play critical roles in specifying the germ lineage, the inheritance of epigenetic information, and post-transcriptional gene regulation. Across species, conserved germ granule proteins reflect these essential functions. A significant proportion of proteins that localize to germ granules are components of RNA metabolism and small RNA (sRNA) gene regulatory pathways. Here we synthesize our current knowledge of the roles that germ granules and their components play in sRNA pathway functions, transgenerational inheritance, and fertility in the C. elegans germline.
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Affiliation(s)
- Adam E Sundby
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ruxandra I Molnar
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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117
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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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118
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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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119
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Abstract
Recognizing and remembering dangerous pathogens is of the utmost importance for an animal's survival. Nematodes use a digested bacterial small RNA molecule as a cue of pathogenicity. Inheritance of this RNA even protects the progeny from infection.
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120
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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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121
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Ewe CK, Alok G, Rothman JH. Stressful development: integrating endoderm development, stress, and longevity. Dev Biol 2020; 471:34-48. [PMID: 33307045 DOI: 10.1016/j.ydbio.2020.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 10/22/2022]
Abstract
In addition to performing digestion and nutrient absorption, the intestine serves as one of the first barriers to the external environment, crucial for protecting the host from environmental toxins, pathogenic invaders, and other stress inducers. The gene regulatory network (GRN) governing embryonic development of the endoderm and subsequent differentiation and maintenance of the intestine has been well-documented in C. elegans. A key regulatory input that initiates activation of the embryonic GRN for endoderm and mesoderm in this animal is the maternally provided SKN-1 transcription factor, an ortholog of the vertebrate Nrf1 and 2, which, like C. elegans SKN-1, perform conserved regulatory roles in mediating a variety of stress responses across metazoan phylogeny. Other key regulatory factors in early gut development also participate in stress response as well as in innate immunity and aging and longevity. In this review, we discuss the intersection between genetic nodes that mediate endoderm/intestine differentiation and regulation of stress and homeostasis. We also consider how direct signaling from the intestine to the germline, in some cases involving SKN-1, facilitates heritable epigenetic changes, allowing transmission of adaptive stress responses across multiple generations. These connections between regulation of endoderm/intestine development and stress response mechanisms suggest that varying selective pressure exerted on the stress response pathways may influence the architecture of the endoderm GRN, thereby leading to genetic and epigenetic variation in early embryonic GRN regulatory events.
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Affiliation(s)
- Chee Kiang Ewe
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA.
| | - Geneva Alok
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA.
| | - Joel H Rothman
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA.
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122
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Environmentally Induced Epigenetic Transgenerational Inheritance and the Weismann Barrier: The Dawn of Neo-Lamarckian Theory. J Dev Biol 2020; 8:jdb8040028. [PMID: 33291540 PMCID: PMC7768451 DOI: 10.3390/jdb8040028] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/13/2020] [Accepted: 11/20/2020] [Indexed: 12/11/2022] Open
Abstract
For the past 120 years, the Weismann barrier and associated germ plasm theory of heredity have been a doctrine that has impacted evolutionary biology and our concepts of inheritance through the germline. Although August Weismann in his 1872 book was correct that the sperm and egg were the only cells to transmit molecular information to the subsequent generation, the concept that somatic cells do not impact the germline (i.e., the Weismann barrier) is incorrect. However, the doctrine or dogma of the Weismann barrier still influences many scientific fields and topics. The discovery of epigenetics, and more recently environmentally induced epigenetic transgenerational inheritance of phenotypic variation and pathology, have had significant impacts on evolution theory and medicine today. Environmental epigenetics and the concept of epigenetic transgenerational inheritance refute aspects of the Weismann barrier and require a re-evaluation of both inheritance theory and evolution theory.
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123
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Wan G, Yan J, Fei Y, Pagano DJ, Kennedy S. A Conserved NRDE-2/MTR-4 Complex Mediates Nuclear RNAi in Caenorhabditis elegans. Genetics 2020; 216:1071-1085. [PMID: 33055090 PMCID: PMC7768265 DOI: 10.1534/genetics.120.303631] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 10/05/2020] [Indexed: 12/21/2022] Open
Abstract
Small regulatory RNAs, such as small interfering RNAs (siRNAs) and PIWI-interacting RNAs, regulate splicing, transcription, and genome integrity in many eukaryotes. In Caenorhabditis elegans, siRNAs bind nuclear Argonautes (AGOs), which interact with homologous premessenger RNAs to recruit downstream silencing effectors, such as NRDE-2, to direct cotranscriptional gene silencing [or nuclear RNA interference (RNAi)]. To further our understanding of the mechanism of nuclear RNAi, we conducted immunoprecipitation-mass spectrometry on C. elegans NRDE-2 The major NRDE-2 interacting protein identified was the RNA helicase MTR-4 Co-immunoprecipitation analyses confirmed a physical association between NRDE-2 and MTR-4 MTR-4 colocalizes with NRDE-2 within the nuclei of most/all C. elegans somatic and germline cells. MTR-4 is required for nuclear RNAi, and interestingly, MTR-4 is recruited to premessenger RNAs undergoing nuclear RNAi via a process requiring nuclear siRNAs, the nuclear AGO HRDE-1, and NRDE-2, indicating that MTR-4 is a component of the C. elegans nuclear RNAi machinery. Finally, we confirm previous reports showing that human (Hs)NRDE2 and HsMTR4 also physically interact. Our data show that the NRDE-2/MTR-4 interactions are evolutionarily conserved, and that, in C. elegans, the NRDE-2/MTR-4 complex contributes to siRNA-directed cotranscriptional gene silencing.
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Affiliation(s)
- Gang Wan
- Ministry Of Education Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China 510275
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, Massachusetts 02115
| | - Jenny Yan
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, Massachusetts 02115
| | - Yuhan Fei
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, Massachusetts 02115
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Agriculture, Nanjing Agricultural University, Nanjing, China 210095
| | - Daniel J Pagano
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, Massachusetts 02115
| | - Scott Kennedy
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, Massachusetts 02115
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124
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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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125
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Bergthorsson U, Sheeba CJ, Konrad A, Belicard T, Beltran T, Katju V, Sarkies P. Long-term experimental evolution reveals purifying selection on piRNA-mediated control of transposable element expression. BMC Biol 2020; 18:162. [PMID: 33158445 PMCID: PMC7646084 DOI: 10.1186/s12915-020-00897-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 10/13/2020] [Indexed: 11/29/2022] Open
Abstract
Background Transposable elements (TEs) are an almost universal constituent of eukaryotic genomes. In animals, Piwi-interacting small RNAs (piRNAs) and repressive chromatin often play crucial roles in preventing TE transcription and thus restricting TE activity. Nevertheless, TE content varies widely across eukaryotes and the dynamics of TE activity and TE silencing across evolutionary time is poorly understood. Results Here, we used experimentally evolved populations of C. elegans to study the dynamics of TE expression over 409 generations. The experimental populations were evolved at population sizes of 1, 10 and 100 individuals to manipulate the efficiency of natural selection versus genetic drift. We demonstrate increased TE expression relative to the ancestral population, with the largest increases occurring in the smallest populations. We show that the transcriptional activation of TEs within active regions of the genome is associated with failure of piRNA-mediated silencing, whilst desilenced TEs in repressed chromatin domains retain small RNAs. Additionally, we find that the sequence context of the surrounding region influences the propensity of TEs to lose silencing through failure of small RNA-mediated silencing. Conclusions Our results show that natural selection in C. elegans is responsible for maintaining low levels of TE expression, and provide new insights into the epigenomic features responsible.
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Affiliation(s)
- Ulfar Bergthorsson
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77845, USA
| | - Caroline J Sheeba
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Anke Konrad
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77845, USA.,Present Address: Intituto Gulbenkian de Ciencia, Rua da Quinta Grande, 6, 2780-156, Oeiras, Portugal
| | - Tony Belicard
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Toni Beltran
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Du Cane Road, London, W12 0NN, UK.,Present Address: Centre for Genomic Regulation, PRBB Building, 08003, Barcelona, Spain
| | - Vaishali Katju
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77845, USA.
| | - Peter Sarkies
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK. .,Institute of Clinical Sciences, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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126
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DasGupta A, Lee TL, Li C, Saltzman AL. Emerging Roles for Chromo Domain Proteins in Genome Organization and Cell Fate in C. elegans. Front Cell Dev Biol 2020; 8:590195. [PMID: 33195254 PMCID: PMC7649781 DOI: 10.3389/fcell.2020.590195] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/08/2020] [Indexed: 11/28/2022] Open
Abstract
In most eukaryotes, the genome is packaged with histones and other proteins to form chromatin. One of the major mechanisms for chromatin regulation is through post-translational modification of histone proteins. Recognition of these modifications by effector proteins, often dubbed histone “readers,” provides a link between the chromatin landscape and gene regulation. The diversity of histone reader proteins for each modification provides an added layer of regulatory complexity. In this review, we will focus on the roles of chromatin organization modifier (chromo) domain containing proteins in the model nematode, Caenorhabditis elegans. An amenability to genetic and cell biological approaches, well-studied development and a short life cycle make C. elegans a powerful system to investigate the diversity of chromo domain protein functions in metazoans. We will highlight recent insights into the roles of chromo domain proteins in the regulation of heterochromatin and the spatial conformation of the genome as well as their functions in cell fate, fertility, small RNA pathways and transgenerational epigenetic inheritance. The spectrum of different chromatin readers may represent a layer of regulation that integrates chromatin landscape, genome organization and gene expression.
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Affiliation(s)
- Abhimanyu DasGupta
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Tammy L Lee
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Chengyin Li
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Arneet L Saltzman
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
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127
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Morgan CP, Shetty AC, Chan JC, Berger DS, Ament SA, Epperson CN, Bale TL. Repeated sampling facilitates within- and between-subject modeling of the human sperm transcriptome to identify dynamic and stress-responsive sncRNAs. Sci Rep 2020; 10:17498. [PMID: 33060642 PMCID: PMC7562703 DOI: 10.1038/s41598-020-73867-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/25/2020] [Indexed: 12/17/2022] Open
Abstract
Epidemiological studies from the last century have drawn strong associations between paternal life experiences and offspring health and disease outcomes. Recent studies have demonstrated sperm small non-coding RNA (sncRNA) populations vary in response to diverse paternal insults. However, for studies in retrospective or prospective human cohorts to identify changes in paternal germ cell epigenetics in association with offspring disease risk, a framework must first be built with insight into the expected biological variation inherent in human populations. In other words, how will we know what to look for if we don't first know what is stable and what is dynamic, and what is consistent within and between men over time? From sperm samples from a 'normative' cohort of healthy human subjects collected repeatedly from each subject over 6 months, 17 healthy male participants met inclusion criteria and completed donations and psychological evaluations of perceived stress monthly. sncRNAs (including miRNA, piRNA, and tRNA) isolated from mature sperm from these samples were subjected to Illumina small RNA sequencing, aligned to subtype-specific reference transcriptomes, and quantified. The repeated measures design allowed us to define both within- and between-subject variation in the expression of 254 miRNA, 194 tRNA, and 937 piRNA in sperm over time. We developed screening criteria to identify a subset of potential environmentally responsive 'dynamic' sperm sncRNA. Implementing complex modeling of the relationships between individual dynamic sncRNA and perceived stress states in these data, we identified 5 miRNA (including let-7f-5p and miR-181a-5p) and 4 tRNA that are responsive to the dynamics of prior stress experience and fit our established mouse model. In the current study, we aligned repeated sampling of human sperm sncRNA expression data with concurrent measures of perceived stress as a novel framework that can now be applied across a range of studies focused on diverse environmental factors able to influence germ cell programming and potentially impact offspring development.
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Affiliation(s)
- Christopher P Morgan
- Department of Pharmacology and Center for Epigenetic Research in Child Health and Brain Development, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Amol C Shetty
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jennifer C Chan
- Department of Biomedical Sciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Dara S Berger
- Division of Reproductive Endocrinology and Infertility, Perelman School of Medicine, Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Seth A Ament
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - C Neill Epperson
- Department of Psychiatry, University of Colorado School of Medicine, CU-Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Tracy L Bale
- Department of Pharmacology and Center for Epigenetic Research in Child Health and Brain Development, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Departments of Pharmacology and Psychiatry, Center for Epigenetic Research in Child Health and Brain Development, HSF3, Room 9-171, University of Maryland School of Medicine, 670 W. Baltimore St., Baltimore, MD, 21201, USA.
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128
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Wu C, Sirard MA. Parental Effects on Epigenetic Programming in Gametes and Embryos of Dairy Cows. Front Genet 2020; 11:557846. [PMID: 33173533 PMCID: PMC7591718 DOI: 10.3389/fgene.2020.557846] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
The bovine represents an important agriculture species and dairy breeds have experienced intense genetic selection over the last decades. The selection of breeders focused initially on milk production, but now includes feed efficiency, health, and fertility, although these traits show lower heritability. The non-genetic paternal and maternal effects on the next generation represent a new research topic that is part of epigenetics. The evidence for embryo programming from both parents is increasing. Both oocytes and spermatozoa carry methylation marks, histones modifications, small RNAs, and chromatin state variations. These epigenetic modifications may remain active in the early zygote and influence the embryonic period and beyond. In this paper, we review parental non-genetic effects retained in gametes on early embryo development of dairy cows, with emphasis on parental age (around puberty), the metabolism of the mother at the time of conception and in vitro culture (IVC) conditions. In our recent findings, transcriptomic signatures and DNA methylation patterns of blastocysts and gametes originating from various parental and IVC conditions revealed surprisingly similar results. Embryos from all these experiments displayed a metabolic signature that could be described as an "economy" mode where protein synthesis is reduced, mitochondria are considered less functional. In the absence of any significant phenotype, these results indicated a possible similar adaptation of the embryo to younger parental age, post-partum metabolic status and IVC conditions mediated by epigenetic factors.
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Affiliation(s)
| | - Marc-André Sirard
- Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle (CRDSI), Département des Sciences Animales, Faculté des Sciences de l’Agriculture et de l’Alimentation, Université Laval, Québec City, QC, Canada
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129
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Uebel CJ, Agbede D, Wallis DC, Phillips CM. Mutator Foci Are Regulated by Developmental Stage, RNA, and the Germline Cell Cycle in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2020; 10:3719-3728. [PMID: 32763952 PMCID: PMC7534428 DOI: 10.1534/g3.120.401514] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/03/2020] [Indexed: 02/02/2023]
Abstract
RNA interference is a crucial gene regulatory mechanism in Caenorhabditis elegans Phase-separated perinuclear germline compartments called Mutator foci are a key element of RNAi, ensuring robust gene silencing and transgenerational epigenetic inheritance. Despite their importance, Mutator foci regulation is not well understood, and observations of Mutator foci have been largely limited to adult hermaphrodite germlines. Here we reveal that punctate Mutator foci arise in the progenitor germ cells of early embryos and persist throughout all larval stages. They are additionally present throughout the male germline and in the cytoplasm of post-meiotic spermatids, suggestive of a role in paternal epigenetic inheritance. In the adult germline, transcriptional inhibition results in a pachytene-specific loss of Mutator foci, indicating that Mutator foci are partially reliant on RNA for their stability. Finally, we demonstrate that Mutator foci intensity is modulated by the stage of the germline cell cycle and specifically, that Mutator foci are brightest and most robust in the mitotic cells, transition zone, and late pachytene of adult germlines. Thus, our data defines several new factors that modulate Mutator foci morphology which may ultimately have implications for efficacy of RNAi in certain cell stages or environments.
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Affiliation(s)
- Celja J Uebel
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | - Dana Agbede
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | - Dylan C Wallis
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | - Carolyn M Phillips
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
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130
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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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131
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Dodson AE, Kennedy S. Phase Separation in Germ Cells and Development. Dev Cell 2020; 55:4-17. [PMID: 33007213 DOI: 10.1016/j.devcel.2020.09.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/28/2020] [Accepted: 09/05/2020] [Indexed: 12/20/2022]
Abstract
The animal germline is an immortal cell lineage that gives rise to eggs and/or sperm each generation. Fusion of an egg and sperm, or fertilization, sets off a cascade of developmental events capable of producing an array of different cell types and body plans. How germ cells develop, function, and eventually give rise to entirely new organisms is an important question in biology. A growing body of evidence suggests that phase separation events likely play a significant and multifaceted role in germ cells and development. Here, we discuss the organization, dynamics, and potential functions of phase-separated compartments in germ cells and examine the various ways in which phase separation might contribute to the development of multicellular organisms.
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Affiliation(s)
- Anne E Dodson
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, MA 02115, USA.
| | - Scott Kennedy
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, MA 02115, USA
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132
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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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133
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Johnson LM, Smith OJ, Hahn DA, Baer CF. Short-term heritable variation overwhelms 200 generations of mutational variance for metabolic traits in Caenorhabditis elegans. Evolution 2020; 74:2451-2464. [PMID: 32989734 DOI: 10.1111/evo.14104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/05/2020] [Accepted: 09/21/2020] [Indexed: 10/23/2022]
Abstract
Metabolic disorders have a large heritable component, and have increased markedly in human populations over the past few generations. Genome-wide association studies of metabolic traits typically find a substantial unexplained fraction of total heritability, suggesting an important role of spontaneous mutation. An alternative explanation is that epigenetic effects contribute significantly to the heritable variation. Here, we report a study designed to quantify the cumulative effects of spontaneous mutation on adenosine metabolism in the nematode Caenorhabditis elegans, including both the activity and concentration of two metabolic enzymes and the standing pools of their associated metabolites. The only prior studies on the effects of mutation on metabolic enzyme activity, in Drosophila melanogaster, found that total enzyme activity presents a mutational target similar to that of morphological and life-history traits. However, those studies were not designed to account for short-term heritable effects. We find that the short-term heritable variance for most traits is of similar magnitude as the variance among MA lines. This result suggests that the potential heritable effects of epigenetic variation in metabolic disease warrant additional scrutiny.
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Affiliation(s)
- Lindsay M Johnson
- Department of Biology, University of Florida, Gainesville, Florida, 32611.,Ology Bioservices, Inc., Alachua, Florida, 32615
| | - Olivia J Smith
- Department of Biology, University of Florida, Gainesville, Florida, 32611
| | - Daniel A Hahn
- Department of Entomology and Nematology, University of Florida, Gainesville, Florida, 32611.,University of Florida Genetics Institute, Gainesville, Florida, 32611
| | - Charles F Baer
- Department of Biology, University of Florida, Gainesville, Florida, 32611.,University of Florida Genetics Institute, Gainesville, Florida, 32611
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134
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Svendsen JM, Reed KJ, Vijayasarathy T, Montgomery BE, Tucci RM, Brown KC, Marks TN, Nguyen DAH, Phillips CM, Montgomery TA. henn-1/HEN1 Promotes Germline Immortality in Caenorhabditis elegans. Cell Rep 2020; 29:3187-3199.e4. [PMID: 31801082 PMCID: PMC6922003 DOI: 10.1016/j.celrep.2019.10.114] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 09/28/2019] [Accepted: 10/28/2019] [Indexed: 12/21/2022] Open
Abstract
The germline contains an immortal cell lineage that ensures the faithful transmission of genetic and, in some instances, epigenetic information from one generation to the next. Here, we show that in Caenorhabditis elegans, the small RNA 3′-2′-O-methyltransferase henn-1/HEN1 is required for sustained fertility across generations. In the absence of henn-1, animals become progressively less fertile, becoming sterile after ~30 generations at 25°C. Sterility in henn-1 mutants is accompanied by severe defects in germline proliferation and maintenance. The requirement for henn-1 in transgenerational fertility is likely due to its role in methylating and, thereby, stabilizing Piwi-interacting RNAs (piRNAs). However, despite being essential for piRNA stability in embryos, henn-1 is not required for piRNA stability in adults. Thus, we propose that methylation is important for the role of piRNAs in establishing proper gene silencing during early stages of development but is dispensable for their role in the proliferated germline. Svendsen et al. identify a requirement for the small RNA methyltransferase HENN-1 in germline immortality. HENN-1 is required for piRNA stability during embryogenesis but is dispensable in the adult germline, pointing to a role for piRNAs in establishing a gene regulatory network in embryos that protects the germline throughout development.
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Affiliation(s)
- 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
| | - 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
| | - Tarah Vijayasarathy
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Brooke E Montgomery
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Rachel M Tucci
- Department of Biology, 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
| | - Taylor N Marks
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Dieu An H Nguyen
- 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
| | - Taiowa A Montgomery
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA.
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135
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Kim IV, Riedelbauch S, Kuhn CD. The piRNA pathway in planarian flatworms: new model, new insights. Biol Chem 2020; 401:1123-1141. [DOI: 10.1515/hsz-2019-0445] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/12/2020] [Indexed: 12/22/2022]
Abstract
AbstractPIWI-interacting RNAs (piRNAs) are small regulatory RNAs that associate with members of the PIWI clade of the Argonaute superfamily of proteins. piRNAs are predominantly found in animal gonads. There they silence transposable elements (TEs), regulate gene expression and participate in DNA methylation, thus orchestrating proper germline development. Furthermore, PIWI proteins are also indispensable for the maintenance and differentiation capabilities of pluripotent stem cells in free-living invertebrate species with regenerative potential. Thus, PIWI proteins and piRNAs seem to constitute an essential molecular feature of somatic pluripotent stem cells and the germline. In keeping with this hypothesis, both PIWI proteins and piRNAs are enriched in neoblasts, the adult stem cells of planarian flatworms, and their presence is a prerequisite for the proper regeneration and perpetual tissue homeostasis of these animals. The piRNA pathway is required to maintain the unique biology of planarians because, in analogy to the animal germline, planarian piRNAs silence TEs and ensure stable genome inheritance. Moreover, planarian piRNAs also contribute to the degradation of numerous protein-coding transcripts, a function that may be critical for neoblast differentiation. This review gives an overview of the planarian piRNA pathway and of its crucial function in neoblast biology.
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Affiliation(s)
- Iana V. Kim
- Gene regulation by Non-coding RNA, Elite Network of Bavaria and University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
| | - Sebastian Riedelbauch
- Gene regulation by Non-coding RNA, Elite Network of Bavaria and University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
| | - Claus-D. Kuhn
- Gene regulation by Non-coding RNA, Elite Network of Bavaria and University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
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136
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Navarro-Martín L, Martyniuk CJ, Mennigen JA. Comparative epigenetics in animal physiology: An emerging frontier. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2020; 36:100745. [PMID: 33126028 DOI: 10.1016/j.cbd.2020.100745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/08/2020] [Accepted: 09/13/2020] [Indexed: 12/19/2022]
Abstract
The unprecedented access to annotated genomes now facilitates the investigation of the molecular basis of epigenetic phenomena in phenotypically diverse animals. In this critical review, we describe the roles of molecular epigenetic mechanisms in regulating mitotically and meiotically stable spatiotemporal gene expression, phenomena that provide the molecular foundation for the intra-, inter-, and trans-generational emergence of physiological phenotypes. By focusing principally on emerging comparative epigenetic roles of DNA-level and transcriptome-level epigenetic mark dynamics in the emergence of phenotypes, we highlight the relationship between evolutionary conservation and innovation of specific epigenetic pathways, and their interplay as a priority for future study. This comparative approach is expected to significantly advance our understanding of epigenetic phenomena, as animals show a diverse array of strategies to epigenetically modify physiological responses. Additionally, we review recent technological advances in the field of molecular epigenetics (single-cell epigenomics and transcriptomics and editing of epigenetic marks) in order to (1) investigate environmental and endogenous factor dependent epigenetic mark dynamics in an integrative manner; (2) functionally test the contribution of specific epigenetic marks for animal phenotypes via genome and transcript-editing tools. Finally, we describe advantages and limitations of emerging animal models, which under the Krogh principle, may be particularly useful in the advancement of comparative epigenomics and its potential translational applications in animal science, ecotoxicology, ecophysiology, climate change science and wild-life conservation, as well as organismal health.
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Affiliation(s)
- Laia Navarro-Martín
- Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Barcelona, Catalunya 08034, Spain.
| | - Christopher J Martyniuk
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
| | - Jan A Mennigen
- Department of Biology, University of Ottawa, Ottawa, ON K1N6N5, Canada
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137
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Pereira AG, Gracida X, Kagias K, Zhang Y. C. elegans aversive olfactory learning generates diverse intergenerational effects. J Neurogenet 2020; 34:378-388. [PMID: 32940103 DOI: 10.1080/01677063.2020.1819265] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Parental experience can modulate the behavior of their progeny. While the molecular mechanisms underlying parental effects or inheritance of behavioral traits have been studied under several environmental conditions, it remains largely unexplored how the nature of parental experience affects the information transferred to the next generation. To address this question, we used C. elegans, a nematode that feeds on bacteria in its habitat. Some of these bacteria are pathogenic and the worm learns to avoid them after a brief exposure. We found, unexpectedly, that a short parental experience increased the preference for the pathogen in the progeny. Furthermore, increasing the duration of parental exposure switched the response of the progeny from attraction to avoidance. To characterize the underlying molecular mechanisms, we found that the RNA-dependent RNA Polymerase (RdRP) RRF-3, required for the biogenesis of 26 G endo-siRNAs, regulated both types of intergenerational effects. Together, we show that different parental experiences with the same environmental stimulus generate different effects on the behavior of the progeny through small RNA-mediated regulation of gene expression.
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Affiliation(s)
- Ana Goncalves Pereira
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Xicotencatl Gracida
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Konstantinos Kagias
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
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138
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Harnessing the power of genetics: fast forward genetics in Caenorhabditis elegans. Mol Genet Genomics 2020; 296:1-20. [PMID: 32888055 DOI: 10.1007/s00438-020-01721-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 08/27/2020] [Indexed: 12/23/2022]
Abstract
Forward genetics is a powerful tool to unravel molecular mechanisms of diverse biological processes. The success of genetic screens primarily relies on the ease of genetic manipulation of an organism and the availability of a plethora of genetic tools. The roundworm Caenorhabditis elegans has been one of the favorite models for genetic studies due to its hermaphroditic lifestyle, ease of maintenance, and availability of various genetic manipulation tools. The strength of C. elegans genetics is highlighted by the leading role of this organism in the discovery of several conserved biological processes. In this review, the principles and strategies for forward genetics in C. elegans are discussed. Further, the recent advancements that have drastically accelerated the otherwise time-consuming process of mutation identification, making forward genetic screens a method of choice for understanding biological functions, are discussed. The emphasis of the review has been on providing practical and conceptual pointers for designing genetic screens that will identify mutations, specifically disrupting the biological processes of interest.
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139
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Houri-Zeevi L, Korem Kohanim Y, Antonova O, Rechavi O. Three Rules Explain Transgenerational Small RNA Inheritance in C. elegans. Cell 2020; 182:1186-1197.e12. [PMID: 32841602 PMCID: PMC7479518 DOI: 10.1016/j.cell.2020.07.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/21/2020] [Accepted: 07/17/2020] [Indexed: 02/06/2023]
Abstract
Experiences trigger transgenerational small RNA-based responses in C. elegans nematodes. Dedicated machinery ensures that heritable effects are reset, but how the responses segregate in the population is unknown. We show that isogenic individuals differ dramatically in the persistence of transgenerational responses. By examining lineages of more than 20,000 worms, three principles emerge: (1) The silencing each mother initiates is distributed evenly among her descendants; heritable RNAi dissipates but is uniform in every generation. (2) Differences between lineages arise because the mothers that initiate heritable responses stochastically assume different "inheritance states" that determine the progeny's fate. (3) The likelihood that an RNAi response would continue to be inherited increases the more generations it lasts. The inheritance states are determined by HSF-1, which regulates silencing factors and, accordingly, small RNA levels. We found that, based on the parents' inheritance state, the descendants' developmental rate in response to stress can be predicted.
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Affiliation(s)
- Leah Houri-Zeevi
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Yael Korem Kohanim
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Olga Antonova
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
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140
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Beltran T, Shahrezaei V, Katju V, Sarkies P. Epimutations driven by small RNAs arise frequently but most have limited duration in Caenorhabditis elegans. Nat Ecol Evol 2020; 4:1539-1548. [PMID: 32868918 DOI: 10.1038/s41559-020-01293-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/21/2020] [Indexed: 01/25/2023]
Abstract
Epigenetic regulation involves changes in gene expression independent of DNA sequence variation that are inherited through cell division. In addition to a fundamental role in cell differentiation, some epigenetic changes can also be transmitted transgenerationally through meiosis. Epigenetic alterations (epimutations) could thus contribute to heritable variation within populations and be subject to evolutionary processes such as natural selection and drift. However, the rate at which epimutations arise and their typical persistence are unknown, making it difficult to evaluate their potential for evolutionary adaptation. Here, we perform a genome-wide study of epimutations in a metazoan organism. We use experimental evolution to characterize the rate, spectrum and stability of epimutations driven by small silencing RNAs in the model nematode Caenorhabditis elegans. We show that epimutations arise spontaneously at a rate approximately 25 times greater than DNA sequence changes and typically have short half-lives of two to three generations. Nevertheless, some epimutations last at least ten generations. Epimutations mediated by small RNAs may thus contribute to evolutionary processes over a short timescale but are unlikely to bring about long-term divergence in the absence of selection.
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Affiliation(s)
- Toni Beltran
- MRC London Institute of Medical Sciences, London, UK.,Institute of Clinical Sciences, Imperial College London, London, UK
| | - Vahid Shahrezaei
- Department of Mathematics, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Vaishali Katju
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
| | - Peter Sarkies
- MRC London Institute of Medical Sciences, London, UK. .,Institute of Clinical Sciences, Imperial College London, London, UK.
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141
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Suen KM, Braukmann F, Butler R, Bensaddek D, Akay A, Lin CC, Milonaitytė D, Doshi N, Sapetschnig A, Lamond A, Ladbury JE, Miska EA. DEPS-1 is required for piRNA-dependent silencing and PIWI condensate organisation in Caenorhabditis elegans. Nat Commun 2020; 11:4242. [PMID: 32843637 PMCID: PMC7447803 DOI: 10.1038/s41467-020-18089-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 07/18/2020] [Indexed: 12/13/2022] Open
Abstract
Membraneless organelles are sites for RNA biology including small non-coding RNA (ncRNA) mediated gene silencing. How small ncRNAs utilise phase separated environments for their function is unclear. We investigated how the PIWI-interacting RNA (piRNA) pathway engages with the membraneless organelle P granule in Caenorhabditis elegans. Proteomic analysis of the PIWI protein PRG-1 reveals an interaction with the constitutive P granule protein DEPS-1. DEPS-1 is not required for piRNA biogenesis but piRNA-dependent silencing: deps-1 mutants fail to produce the secondary endo-siRNAs required for the silencing of piRNA targets. We identify a motif on DEPS-1 which mediates a direct interaction with PRG-1. DEPS-1 and PRG-1 form intertwining clusters to build elongated condensates in vivo which are dependent on the Piwi-interacting motif of DEPS-1. Additionally, we identify EDG-1 as an interactor of DEPS-1 and PRG-1. Our study reveals how specific protein-protein interactions drive the spatial organisation and piRNA-dependent silencing within membraneless organelles.
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Affiliation(s)
- Kin Man Suen
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Fabian Braukmann
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Richard Butler
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Dalila Bensaddek
- Laboratory for Quantitative Proteomics, Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
- Bioscience Core labs, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Alper Akay
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Chi-Chuan Lin
- School of Molecular and Cellular Biology, University of Leeds, LC Miall Building, Leeds, LS2 9JT, UK
| | - Dovilė Milonaitytė
- School of Molecular and Cellular Biology, University of Leeds, LC Miall Building, Leeds, LS2 9JT, UK
| | - Neel Doshi
- University of Cambridge, School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, CB2 0SP, UK
| | | | - Angus Lamond
- Laboratory for Quantitative Proteomics, Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - John Edward Ladbury
- School of Molecular and Cellular Biology, University of Leeds, LC Miall Building, Leeds, LS2 9JT, UK
| | - Eric Alexander Miska
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB10 1SA, UK.
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142
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Willis AR, Sukhdeo R, Reinke AW. Remembering your enemies: mechanisms of within-generation and multigenerational immune priming in Caenorhabditis elegans. FEBS J 2020; 288:1759-1770. [PMID: 32767821 DOI: 10.1111/febs.15509] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/17/2020] [Accepted: 07/30/2020] [Indexed: 12/12/2022]
Abstract
Pathogens are abundant and drive evolution of host immunity. Whilst immune memory is classically associated with adaptive immunity, studies in diverse species now show that priming of innate immune defences can also protect against secondary infection. Remarkably, priming may also be passed on to progeny to enhance pathogen resistance and promote survival in future generations. Phenotypic changes that occur independent of DNA sequence underlie both 'within-generation' priming and 'multigenerational' priming. However, the molecular mechanisms responsible for these phenomena are still poorly understood. Caenorhabditis elegans is a simple and genetically tractable model organism that has enabled key advances in immunity and environmental epigenetics. Using both natural and human pathogens, researchers have uncovered numerous examples of innate immune priming in this animal. Viral infection models have provided key evidence for a conserved antiviral RNA silencing mechanism that is inherited in progeny. Bacterial infection models have explored mechanisms of within-generation and multigenerational priming that span chromatin modification and transcriptional changes, small RNA pathways, maternal provisioning and pathogen avoidance strategies. Together, these studies are providing novel insight into the immune reactivity of the genome and have important consequences for our understanding of health and evolution. In this review, we present the current evidence for learned protection against pathogens in C. elegans, discuss the significance and limitations of these findings and highlight important avenues of future investigation.
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Affiliation(s)
| | - Ronesh Sukhdeo
- Department of Molecular Genetics, University of Toronto, ON, Canada
| | - Aaron W Reinke
- Department of Molecular Genetics, University of Toronto, ON, Canada
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143
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Schwartz-Orbach L, Zhang C, Sidoli S, Amin R, Kaur D, Zhebrun A, Ni J, Gu SG. Caenorhabditis elegans nuclear RNAi factor SET-32 deposits the transgenerational histone modification, H3K23me3. eLife 2020; 9:e54309. [PMID: 32804637 PMCID: PMC7431132 DOI: 10.7554/elife.54309] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 08/04/2020] [Indexed: 12/29/2022] Open
Abstract
Nuclear RNAi provides a highly tractable system to study RNA-mediated chromatin changes and epigenetic inheritance. Recent studies have indicated that the regulation and function of nuclear RNAi-mediated heterochromatin are highly complex. Our knowledge of histone modifications and the corresponding histonemodifying enzymes involved in the system remains limited. In this study, we show that the heterochromatin mark, H3K23me3, is induced by nuclear RNAi at both exogenous and endogenous targets in C. elegans. In addition, dsRNA-induced H3K23me3 can persist for multiple generations after the dsRNA exposure has stopped. We demonstrate that the histone methyltransferase SET-32, methylates H3K23 in vitro. Both set-32 and the germline nuclear RNAi Argonaute, hrde-1, are required for nuclear RNAi-induced H3K23me3 in vivo. Our data poise H3K23me3 as an additional chromatin modification in the nuclear RNAi pathway and provides the field with a new target for uncovering the role of heterochromatin in transgenerational epigenetic silencing.
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Affiliation(s)
- Lianna Schwartz-Orbach
- Department of Molecular Biology and Biochemistry, Rutgers the State University of New JerseyPiscatawayUnited States
| | - Chenzhen Zhang
- Department of Molecular Biology and Biochemistry, Rutgers the State University of New JerseyPiscatawayUnited States
| | - Simone Sidoli
- Department of Biochemistry, Albert Einstein College of Medicine, BronxNew YorkUnited States
| | - Richa Amin
- Department of Molecular Biology and Biochemistry, Rutgers the State University of New JerseyPiscatawayUnited States
| | - Diljeet Kaur
- Department of Molecular Biology and Biochemistry, Rutgers the State University of New JerseyPiscatawayUnited States
| | - Anna Zhebrun
- Department of Molecular Biology and Biochemistry, Rutgers the State University of New JerseyPiscatawayUnited States
| | - Julie Ni
- Department of Molecular Biology and Biochemistry, Rutgers the State University of New JerseyPiscatawayUnited States
| | - Sam G Gu
- Department of Molecular Biology and Biochemistry, Rutgers the State University of New JerseyPiscatawayUnited States
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144
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Environmental Impact on Male (In)Fertility via Epigenetic Route. J Clin Med 2020; 9:jcm9082520. [PMID: 32764255 PMCID: PMC7463911 DOI: 10.3390/jcm9082520] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/21/2020] [Accepted: 07/31/2020] [Indexed: 12/14/2022] Open
Abstract
In the last 40 years, male reproductive health-which is very sensitive to both environmental exposure and metabolic status-has deteriorated and the poor sperm quality observed has been suggested to affect offspring development and its health in adult life. In this scenario, evidence now suggests that epigenetics shapes endocrine functions, linking genetics and environment. During fertilization, spermatozoa share with the oocyte their epigenome, along with their haploid genome, in order to orchestrate embryo development. The epigenetic signature of spermatozoa is the result of a dynamic modulation of the epigenetic marks occurring, firstly, in the testis-during germ cell progression-then, along the epididymis, where spermatozoa still receive molecules, conveyed by epididymosomes. Paternal lifestyle, including nutrition and exposure to hazardous substances, alters the phenotype of the next generations, through the remodeling of a sperm epigenetic blueprint that dynamically reacts to a wide range of environmental and lifestyle stressors. With that in mind, this review will summarize and discuss insights into germline epigenetic plasticity caused by environmental stimuli and diet and how spermatozoa may be carriers of induced epimutations across generations through a mechanism known as paternal transgenerational epigenetic inheritance.
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145
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Zeng C, Weng C, Wang X, Yan YH, Li WJ, Xu D, Hong M, Liao S, Dong MQ, Feng X, Xu C, Guang S. Functional Proteomics Identifies a PICS Complex Required for piRNA Maturation and Chromosome Segregation. Cell Rep 2020; 27:3561-3572.e3. [PMID: 31216475 DOI: 10.1016/j.celrep.2019.05.076] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 04/08/2019] [Accepted: 05/20/2019] [Indexed: 01/19/2023] Open
Abstract
piRNAs play significant roles in suppressing transposons and nonself nucleic acids, maintaining genome integrity, and defending against viral infections. In C. elegans, piRNA precursors are transcribed in the nucleus and are subjected to a number of processing and maturation steps. The biogenesis of piRNAs is not fully understood. We use functional proteomics in C. elegans and identify a piRNA biogenesis and chromosome segregation (PICS) complex. The PICS complex contains TOFU-6, PID-1, PICS-1, TOST-1, and ERH-2, which exhibit dynamic localization among different subcellular compartments. In the germlines, the PICS complex contains TOFU-6/PICS-1/ERH-2/PID-1, is largely concentrated at the perinuclear granule zone, and engages in piRNA processing. During embryogenesis, the TOFU-6/PICS-1/ERH-2/TOST-1 complex accumulates in the nucleus and plays essential roles in chromosome segregation. The functions of these factors in mediating chromosome segregation are independent of piRNA production. We speculate that differential compositions of PICS factors may help cells coordinate distinct cellular processes.
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Affiliation(s)
- Chenming Zeng
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Chenchun Weng
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Xiaoyang Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Yong-Hong Yan
- National Institute of Biological Sciences, Beijing 102206, China
| | - Wen-Jun Li
- National Institute of Biological Sciences, Beijing 102206, China
| | - Demin Xu
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Minjie Hong
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Shanhui Liao
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing 102206, China
| | - Xuezhu Feng
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China.
| | - Chao Xu
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China.
| | - Shouhong Guang
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China; CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Hefei, Anhui 230027, P.R. China.
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146
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Rogers AK, Phillips CM. RNAi pathways repress reprogramming of C. elegans germ cells during heat stress. Nucleic Acids Res 2020; 48:4256-4273. [PMID: 32187370 PMCID: PMC7192617 DOI: 10.1093/nar/gkaa174] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 03/02/2020] [Accepted: 03/10/2020] [Indexed: 01/08/2023] Open
Abstract
Repression of cellular reprogramming in germ cells is critical to maintaining cell fate and fertility. When germ cells mis-express somatic genes they can be directly converted into other cell types, resulting in loss of totipotency and reproductive potential. Identifying the molecular mechanisms that coordinate these cell fate decisions is an active area of investigation. Here we show that RNAi pathways play a key role in maintaining germline gene expression and totipotency after heat stress. By examining transcriptional changes that occur in mut-16 mutants, lacking a key protein in the RNAi pathway, at elevated temperature we found that genes normally expressed in the soma are mis-expressed in germ cells. Furthermore, these genes displayed increased chromatin accessibility in the germlines of mut-16 mutants at elevated temperature. These findings indicate that the RNAi pathway plays a key role in preventing aberrant expression of somatic genes in the germline during heat stress. This regulation occurs in part through the maintenance of germline chromatin, likely acting through the nuclear RNAi pathway. Identification of new pathways governing germ cell reprogramming is critical to understanding how cells maintain proper gene expression and may provide key insights into how cell identity is lost in some germ cell tumors.
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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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147
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Chen Q, Meng X, Liao Q, Chen M. Versatile interactions and bioinformatics analysis of noncoding RNAs. Brief Bioinform 2020; 20:1781-1794. [PMID: 29939215 DOI: 10.1093/bib/bby050] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/02/2018] [Indexed: 02/07/2023] Open
Abstract
Advances in RNA sequencing technologies and computational methodologies have provided a huge impetus to noncoding RNA (ncRNA) study. Once regarded as inconsequential results of transcriptional promiscuity, ncRNAs were later found to exert great roles in various aspects of biological functions. They are emerging as key players in gene regulatory networks by interacting with other biomolecules (DNA, RNA or protein). Here, we provide an overview of ncRNA repertoire and highlight recent discoveries of their versatile interactions. To better investigate the ncRNA-mediated regulation, it is necessary to make full use of innovative sequencing techniques and computational tools. We further describe a comprehensive workflow for in silico ncRNA analysis, providing up-to-date platforms, databases and tools dedicated to ncRNA identification and functional annotation.
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Affiliation(s)
- Qi Chen
- Department of Bioinformatics, The State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, P. R. China
| | - Xianwen Meng
- Department of Bioinformatics, The State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, P. R. China
| | - Qi Liao
- Department of Bioinformatics, The State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, P. R. China
| | - Ming Chen
- Department of Preventative Medicine, Zhejiang Provincial Key Laboratory of Pathological and Physiological Technology, Medical School of Ningbo University, Ningbo, Zhejiang, P. R. China
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148
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Jones ARC, Mallon EB. Evidence of capacitation in the parasitoid wasp, Nasonia vitripennis, and its potential role in sex allocation. Ecol Evol 2020; 10:7212-7220. [PMID: 32760522 PMCID: PMC7391552 DOI: 10.1002/ece3.6422] [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: 03/02/2020] [Revised: 04/29/2020] [Accepted: 05/03/2020] [Indexed: 12/02/2022] Open
Abstract
The allocation of resources to the production of one sex or another has been observed in a large variety of animals. Its theoretical basis allows accurate predictions of offspring sex ratios in many species, but the mechanisms by which sex allocation is controlled are poorly understood. Using previously published data, we investigated whether alternative splicing, combined with differential gene expression, was involved with sex allocation in the parasitoid wasp, Nasonia vitripennis. We found that sex allocation is not controlled by alternative splicing but changes in gene and transcript-specific expression, which were identified to be involved with oviposition, were shown to be similar to those involved in sperm motility and capacitation. Genes involved in cholesterol efflux, a key component of capacitation, along with calcium transport, neurotransmission, trypsin, and MAPKinase activity were regulated in ovipositing wasps. The results show evidence for regulation of sperm motility and of capacitation in an insect which, in the context of the physiology of the N. vitripennis spermatheca, could be important for sex allocation.
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Affiliation(s)
- Alun R. C. Jones
- Department of Genetics and Genome BiologyUniversity of LeicesterLeicesterUK
| | - Eamonn B. Mallon
- Department of Genetics and Genome BiologyUniversity of LeicesterLeicesterUK
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149
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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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150
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Natural cryptic variation in epigenetic modulation of an embryonic gene regulatory network. Proc Natl Acad Sci U S A 2020; 117:13637-13646. [PMID: 32482879 DOI: 10.1073/pnas.1920343117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Gene regulatory networks (GRNs) that direct animal embryogenesis must respond to varying environmental and physiological conditions to ensure robust construction of organ systems. While GRNs are evolutionarily modified by natural genomic variation, the roles of epigenetic processes in shaping plasticity of GRN architecture are not well understood. The endoderm GRN in Caenorhabditis elegans is initiated by the maternally supplied SKN-1/Nrf2 bZIP transcription factor; however, the requirement for SKN-1 in endoderm specification varies widely among distinct C. elegans wild isotypes, owing to rapid developmental system drift driven by accumulation of cryptic genetic variants. We report here that heritable epigenetic factors that are stimulated by transient developmental diapause also underlie cryptic variation in the requirement for SKN-1 in endoderm development. This epigenetic memory is inherited from the maternal germline, apparently through a nuclear, rather than cytoplasmic, signal, resulting in a parent-of-origin effect (POE), in which the phenotype of the progeny resembles that of the maternal founder. The occurrence and persistence of POE varies between different parental pairs, perduring for at least 10 generations in one pair. This long-perduring POE requires piwi-interacting RNA (piRNA) function and the germline nuclear RNA interference (RNAi) pathway, as well as MET-2 and SET-32, which direct histone H3K9 trimethylation and drive heritable epigenetic modification. Such nongenetic cryptic variation may provide a resource of additional phenotypic diversity through which adaptation may facilitate evolutionary changes and shape developmental regulatory systems.
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