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Harris I, Immler S, Chapman T, Maklakov AA. Selection on the epigenome: small RNA inheritance in animal evolution. Trends Genet 2025:S0168-9525(25)00082-4. [PMID: 40379494 DOI: 10.1016/j.tig.2025.04.007] [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: 02/27/2025] [Revised: 04/15/2025] [Accepted: 04/16/2025] [Indexed: 05/19/2025]
Abstract
The inheritance of small RNAs (sRNAs) is taxonomically widespread. Changing environments alter the production and presence of sRNAs in the germline, and this can in theory either increase offspring phenotypic variance as an evolutionary bet-hedging strategy or elicit predictive and adaptive phenotypic responses that increase offspring fitness. Nevertheless, the putative role of sRNA inheritance systems in adaptive evolution is still debated and it is currently unclear how selection acts on sRNAs. We outline two adaptive sRNA inheritance strategies - specialist and generalist - and discuss non-adaptive alternatives and the evolutionary implications of different strategies. Our review suggests that the role of natural selection in sRNA inheritance has been significantly overlooked, potentially leading to misinterpretations of the causal agents and the evolutionary implications of sRNA inheritance.
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Affiliation(s)
- Isaac Harris
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Simone Immler
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Tracey Chapman
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Alexei A Maklakov
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
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2
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Fitz-James M, Sparrow P, Paton C, Sarkies P. Polycomb-mediated transgenerational epigenetic inheritance of Drosophila eye colour is independent of small RNAs. Open Biol 2025; 15:240298. [PMID: 40068813 PMCID: PMC11896699 DOI: 10.1098/rsob.240298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2024] [Revised: 01/20/2025] [Accepted: 02/01/2025] [Indexed: 03/15/2025] Open
Abstract
Transgenerational epigenetic inheritance (TEI) describes the process whereby distinct epigenetic states are transmitted between generations, resulting in heritable gene expression and phenotypic differences that are independent of DNA sequence variation. Chromatin modifications have been demonstrated to be important in TEI; however, the extent to which they require other signals to establish and maintain epigenetic states is still unclear. Here we investigate whether small non-coding RNAs contribute to different epigenetic states of the Fab2L transgene in Drosophila triggered by transient long-range chromosomal contacts, which requires Polycomb complex activity to deposit the H3K27me3 modification for long-term TEI. By analysing mutants deficient in small non-coding RNAs, high-throughput sequencing data, long-range chromosomal contacts and gene expression, we demonstrate that small non-coding RNAs do not contribute directly to initiation or maintenance of silencing. However, we uncover an indirect role for microRNA expression in transgene silencing through effects on the Polycomb group gene Pleiohomeotic. Additionally, we show that a commonly used marker gene, Stubble (Sb), affects Pleiohomeotic expression, which may be important in interpreting experiments assaying Polycomb function in Drosophila development. By ruling out a plausible candidate for TEI at the Fab2L transgene, our work highlights the variability in different modes of TEI across species.
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3
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Fitz-James MH, Sabarís G, Sarkies P, Bantignies F, Cavalli G. Interchromosomal contacts between regulatory regions trigger stable transgenerational epigenetic inheritance in Drosophila. Mol Cell 2025; 85:677-691.e6. [PMID: 39667935 DOI: 10.1016/j.molcel.2024.11.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 08/19/2024] [Accepted: 11/15/2024] [Indexed: 12/14/2024]
Abstract
Non-genetic information can be inherited across generations in a process known as transgenerational epigenetic inheritance (TEI). In Drosophila, hemizygosity of the Fab-7 regulatory element triggers inheritance of the histone mark H3K27me3 at a homologous locus on another chromosome, resulting in heritable epigenetic differences in eye color. Here, by mutating transcription factor binding sites within the Fab-7 element, we demonstrate the importance of the proteins pleiohomeotic and GAGA factor in the establishment and maintenance of TEI. We show that these proteins function by recruiting the polycomb repressive complex 2 and by mediating interchromosomal chromatin contacts between Fab-7 and its homologous locus, respectively. Using an in vivo synthetic biology system to induce them, we then show that chromatin contacts alone can establish TEI, providing a mechanism by which hemizygosity of one locus can establish epigenetic memory at another distant locus in trans through chromatin contacts.
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Affiliation(s)
- Maximilian H Fitz-James
- Institute of Human Genetics, CNRS and University of Montpellier, 141 Rue de la Cardonille, 34094 Montpellier, France; Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Gonzalo Sabarís
- Institute of Human Genetics, CNRS and University of Montpellier, 141 Rue de la Cardonille, 34094 Montpellier, France
| | - Peter Sarkies
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Frédéric Bantignies
- Institute of Human Genetics, CNRS and University of Montpellier, 141 Rue de la Cardonille, 34094 Montpellier, France
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS and University of Montpellier, 141 Rue de la Cardonille, 34094 Montpellier, France.
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4
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Feng X, Guang S. Functions and applications of RNA interference and small regulatory RNAs. Acta Biochim Biophys Sin (Shanghai) 2024; 57:119-130. [PMID: 39578714 PMCID: PMC11802346 DOI: 10.3724/abbs.2024196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2024] [Accepted: 09/03/2024] [Indexed: 11/24/2024] Open
Abstract
Small regulatory RNAs play a variety of crucial roles in eukaryotes, influencing gene regulation, developmental timing, antiviral defense, and genome integrity via a process termed RNA interference (RNAi). This process involves Argonaute/small RNA (AGO/sRNA) complexes that target transcripts via sequence complementarity and modulate gene expression and epigenetic modifications. RNAi is a highly conserved gene regulatory phenomenon that recognizes self- and non-self nucleic acids, thereby defending against invasive sequences. Since its discovery, RNAi has been widely applied in functional genomic studies and a range of practical applications. In this review, we focus on the current understanding of the biological roles of the RNAi pathway in transposon silencing, fertility, developmental regulation, immunity, stress responses, and acquired transgenerational inheritance. Additionally, we provide an overview of the applications of RNAi technology in biomedical research, agriculture, and therapeutics.
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Affiliation(s)
- Xuezhu Feng
- School of Basic Medical SciencesAnhui Medical UniversityHefei230032China
| | - Shouhong Guang
- Department of Obstetrics and Gynecologythe First Affiliated Hospital of USTCThe USTC RNA InstituteMinistry of Education Key Laboratory for Membraneless Organelles & Cellular DynamicsHefei National Research Center for Physical Sciences at the MicroscaleCenter for Advanced Interdisciplinary Science and Biomedicine of IHMSchool of Life SciencesDivision of Life Sciences and MedicineBiomedical Sciences and Health Laboratory of Anhui ProvinceUniversity of Science and Technology of ChinaHefei230027China
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5
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Alexanian AR. Epigenetic inheritance of acquired traits via stem cells dedifferentiation/differentiation or transdifferentiation cycles. Cells Dev 2024; 179:203928. [PMID: 38768658 DOI: 10.1016/j.cdev.2024.203928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/20/2024] [Accepted: 05/17/2024] [Indexed: 05/22/2024]
Abstract
Inheritance of acquired characteristics is the once widely accepted idea that multiple modifications acquired by an organism during its life, can be inherited by the offspring. This belief is at least as old as Hippocrates and became popular in early 19th century, leading Lamarck to suggest his theory of evolution. Charles Darwin, along with other thinkers of the time attempted to explain the mechanism of acquired traits' inheritance by proposing the theory of pangenesis. While later this and similar theories were rejected because of the lack of hard evidence, the studies aimed at revealing the mechanism by which somatic information can be passed to germ cells have continued up to the present. In this paper, we present a new theory and provide supporting literature to explain this phenomenon. We hypothesize existence of pluripotent adult stem cells that can serve as collectors and carriers of new epigenetic traits by entering different developmentally active organ/tissue compartments through blood circulation and acquiring new epigenetic marks though cycles of differentiation/dedifferentiation or transdifferentiation. During gametogenesis, these epigenetically modified cells are attracted by gonads, transdifferentiate into germ cells, and pass the acquired epigenetic modifications collected from the entire body's somatic cells to the offspring.
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Affiliation(s)
- Arshak R Alexanian
- Cell Reprogramming & Therapeutics LLC, Wauwatosa (Milwaukee County), WI 53226, USA.
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6
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Baran JK, Kosztyła P, Antoł W, Labocha MK, Sychta K, Drobniak SM, Prokop ZM. Reproductive system, temperature, and genetic background effects in experimentally evolving populations of Caenorhabditis elegans. PLoS One 2024; 19:e0300276. [PMID: 38557670 PMCID: PMC10984399 DOI: 10.1371/journal.pone.0300276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 02/25/2024] [Indexed: 04/04/2024] Open
Abstract
Experimental evolution (EE) is a powerful research framework for gaining insights into many biological questions, including the evolution of reproductive systems. We designed a long-term and highly replicated EE project using the nematode C. elegans, with the main aim of investigating the impact of reproductive system on adaptation and diversification under environmental challenge. From the laboratory-adapted strain N2, we derived isogenic lines and introgressed the fog-2(q71) mutation, which changes the reproductive system from nearly exclusive selfing to obligatory outcrossing, independently into 3 of them. This way, we obtained 3 pairs of isogenic ancestral populations differing in reproductive system; from these, we derived replicate EE populations and let them evolve in either novel (increased temperature) or control conditions for over 100 generations. Subsequently, fitness of both EE and ancestral populations was assayed under the increased temperature conditions. Importantly, each population was assayed in 2-4 independent blocks, allowing us to gain insight into the reproducibility of fitness scores. We expected to find upward fitness divergence, compared to ancestors, in populations which had evolved in this treatment, particularly in the outcrossing ones due to the benefits of genetic shuffling. However, our data did not support these predictions. The first major finding was very strong effect of replicate block on populations' fitness scores. This indicates that despite standardization procedures, some important environmental effects were varying among blocks, and possibly compounded by epigenetic inheritance. Our second key finding was that patterns of EE populations' divergence from ancestors differed among the ancestral isolines, suggesting that research conclusions derived for any particular genetic background should never be generalized without sampling a wider set of backgrounds. Overall, our results support the calls to pay more attention to biological variability when designing studies and interpreting their results, and to avoid over-generalizations of outcomes obtained for specific genetic and/or environmental conditions.
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Affiliation(s)
- Joanna K. Baran
- Faculty of Biology, Institute of Environmental Sciences, Jagiellonian University in Krakow, Krakow, Poland
| | - Paulina Kosztyła
- Faculty of Biology, Institute of Environmental Sciences, Jagiellonian University in Krakow, Krakow, Poland
| | - Weronika Antoł
- Faculty of Biology, Institute of Environmental Sciences, Jagiellonian University in Krakow, Krakow, Poland
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Krakow, Poland
| | - Marta K. Labocha
- Faculty of Biology, Institute of Environmental Sciences, Jagiellonian University in Krakow, Krakow, Poland
| | - Karolina Sychta
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Krakow, Poland
| | - Szymon M. Drobniak
- Faculty of Biology, Institute of Environmental Sciences, Jagiellonian University in Krakow, Krakow, Poland
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Zofia M. Prokop
- Faculty of Biology, Institute of Environmental Sciences, Jagiellonian University in Krakow, Krakow, Poland
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7
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Webster AK, Phillips PC. Heritable epigenetic variation facilitates long-term maintenance of epigenetic and genetic variation. G3 (BETHESDA, MD.) 2024; 14:jkad287. [PMID: 38113034 PMCID: PMC10849368 DOI: 10.1093/g3journal/jkad287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/03/2023] [Accepted: 11/22/2023] [Indexed: 12/21/2023]
Abstract
How genetic and phenotypic variation are maintained has long been one of the fundamental questions in population and quantitative genetics. A variety of factors have been implicated to explain the maintenance of genetic variation in some contexts (e.g. balancing selection), but the potential role of epigenetic regulation to influence population dynamics has been understudied. It is well recognized that epigenetic regulation, including histone methylation, small RNA expression, and DNA methylation, helps to define differences between cell types and facilitate phenotypic plasticity. In recent years, empirical studies have shown the potential for epigenetic regulation to also be heritable for at least a few generations without selection, raising the possibility that differences in epigenetic regulation can act alongside genetic variation to shape evolutionary trajectories. Heritable differences in epigenetic regulation that arise spontaneously are termed "epimutations." Epimutations differ from genetic mutations in 2 key ways-they occur at a higher rate and the loci at which they occur often revert back to their original state within a few generations. Here, we present an extension of the standard population genetic model with selection to incorporate epigenetic variation arising via epimutation. Our model assumes a diploid, sexually reproducing population with random mating. In addition to spontaneous genetic mutation, we included parameters for spontaneous epimutation and back-epimutation, allowing for 4 potential epialleles at a single locus (2 genetic alleles, each with 2 epigenetic states), each of which affect fitness. We then analyzed the conditions under which stable epialleles were maintained. Our results show that highly reversible epialleles can be maintained in long-term equilibrium under neutral conditions in a manner that depends on the epimutation and back-epimutation rates, which we term epimutation-back-epimutation equilibrium. On the other hand, epialleles that compensate for deleterious mutations cause deviations from the expectations of mutation-selection balance by a simple factor that depends on the epimutation and back-epimutation rates. We also numerically analyze several sets of fitness parameters for which large deviations from mutation-selection balance occur. Together, these results demonstrate that transient epigenetic regulation may be an important factor in the maintenance of both epigenetic and genetic variation in populations.
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Affiliation(s)
- Amy K Webster
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Patrick C Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
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8
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Ow MC, Hall SE. Inheritance of Stress Responses via Small Non-Coding RNAs in Invertebrates and Mammals. EPIGENOMES 2023; 8:1. [PMID: 38534792 DOI: 10.3390/epigenomes8010001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/06/2023] [Accepted: 12/12/2023] [Indexed: 03/28/2024] Open
Abstract
While reports on the generational inheritance of a parental response to stress have been widely reported in animals, the molecular mechanisms behind this phenomenon have only recently emerged. The booming interest in epigenetic inheritance has been facilitated in part by the discovery that small non-coding RNAs are one of its principal conduits. Discovered 30 years ago in the Caenorhabditis elegans nematode, these small molecules have since cemented their critical roles in regulating virtually all aspects of eukaryotic development. Here, we provide an overview on the current understanding of epigenetic inheritance in animals, including mice and C. elegans, as it pertains to stresses such as temperature, nutritional, and pathogenic encounters. We focus on C. elegans to address the mechanistic complexity of how small RNAs target their cohort mRNAs to effect gene expression and how they govern the propagation or termination of generational perdurance in epigenetic inheritance. Presently, while a great amount has been learned regarding the heritability of gene expression states, many more questions remain unanswered and warrant further investigation.
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Affiliation(s)
- Maria C Ow
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA
| | - Sarah E Hall
- Department of Biology and Program in Neuroscience, Syracuse University, Syracuse, NY 13210, USA
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9
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Tando Y, Matsui Y. Inheritance of environment-induced phenotypic changes through epigenetic mechanisms. ENVIRONMENTAL EPIGENETICS 2023; 9:dvad008. [PMID: 38094661 PMCID: PMC10719065 DOI: 10.1093/eep/dvad008] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/09/2023] [Accepted: 11/20/2023] [Indexed: 03/08/2024]
Abstract
Growing evidence suggests that epigenetic changes through various parental environmental factors alter the phenotypes of descendants in various organisms. Environmental factors, including exposure to chemicals, stress and abnormal nutrition, affect the epigenome in parental germ cells by different epigenetic mechanisms, such as DNA methylation, histone modification as well as small RNAs via metabolites. Some current remaining questions are the causal relationship between environment-induced epigenetic changes in germ cells and altered phenotypes of descendants, and the molecular basis of how the abnormal epigenetic changes escape reprogramming in germ cells. In this review, we introduce representative examples of intergenerational and transgenerational inheritance of phenotypic changes through parental environmental factors and the accompanied epigenetic and metabolic changes, with a focus on animal species. We also discuss the molecular mechanisms of epigenomic inheritance and their possible biological significance.
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Affiliation(s)
- Yukiko Tando
- Cell Resource Center for Biomedical Research, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi 980-8575, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
- Graduate School of Medicine, Tohoku University, Sendai, Miyagi 980-8575, Japan
| | - Yasuhisa Matsui
- Cell Resource Center for Biomedical Research, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi 980-8575, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
- Graduate School of Medicine, Tohoku University, Sendai, Miyagi 980-8575, Japan
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10
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Lenzi C, Piat A, Schlich P, Ducau J, Bregliano JC, Aguilaniu H, Laurençon A. Parental age effect on the longevity and healthspan in Drosophila melanogaster and Caenorhabditis elegans. Aging (Albany NY) 2023; 15:11720-11739. [PMID: 37917003 PMCID: PMC10683632 DOI: 10.18632/aging.205098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 09/18/2023] [Indexed: 11/03/2023]
Abstract
Several studies have investigated the effect of parental age on biological parameters such as reproduction, lifespan, and health; however, the results have been inconclusive, largely due to inter-species variation and/or modest effect sizes. Here, we examined the effect of parental age on the lifespan, reproductive capacity, and locomotor activity of genetic isogenic lines of the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster. We found that the progeny of successive generations of old parents had significantly shorter lifespans than the progeny of young parents in both species. Moreover, we investigated the fertility, fecundity, and locomotor activity of C. elegans. Interestingly, both the shorter lifespan and deteriorated healthspan of the progeny were significantly improved by switching to only one generation of younger parents. Collectively, these data demonstrate that the detrimental effect of older parental age on the longevity of the progeny can be reversed, suggesting the existence of a beneficial non-genetic mechanism.
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Affiliation(s)
| | | | - Pascal Schlich
- INRA, Centre des Sciences du Goût et de l’Alimentation (CSGA), Dijon, France
| | - Judith Ducau
- IBDM, Parc Scientifique de Luminy, Marseille, France
| | | | | | - Anne Laurençon
- Institut de Genomique Fonctionnelle de Lyon, UMR5242, Universite Claude Bernard-Lyon 1, Ecole Normale Superieure de Lyon, Lyon, France
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11
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Liberman N, Rothi MH, Gerashchenko MV, Zorbas C, Boulias K, MacWhinnie FG, Ying AK, Flood Taylor A, Al Haddad J, Shibuya H, Roach L, Dong A, Dellacona S, Lafontaine DLJ, Gladyshev VN, Greer EL. 18S rRNA methyltransferases DIMT1 and BUD23 drive intergenerational hormesis. Mol Cell 2023; 83:3268-3282.e7. [PMID: 37689068 PMCID: PMC11990152 DOI: 10.1016/j.molcel.2023.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 07/25/2023] [Accepted: 08/10/2023] [Indexed: 09/11/2023]
Abstract
Heritable non-genetic information can regulate a variety of complex phenotypes. However, what specific non-genetic cues are transmitted from parents to their descendants are poorly understood. Here, we perform metabolic methyl-labeling experiments to track the heritable transmission of methylation from ancestors to their descendants in the nematode Caenorhabditis elegans (C. elegans). We find heritable methylation in DNA, RNA, proteins, and lipids. We find that parental starvation elicits reduced fertility, increased heat stress resistance, and extended longevity in fed, naïve progeny. This intergenerational hormesis is accompanied by a heritable increase in N6'-dimethyl adenosine (m6,2A) on the 18S ribosomal RNA at adenosines 1735 and 1736. We identified DIMT-1/DIMT1 as the m6,2A and BUD-23/BUD23 as the m7G methyltransferases in C. elegans that are both required for intergenerational hormesis, while other rRNA methyltransferases are dispensable. This study labels and tracks heritable non-genetic material across generations and demonstrates the importance of rRNA methylation for regulating epigenetic inheritance.
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Affiliation(s)
- Noa Liberman
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - M Hafiz Rothi
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Maxim V Gerashchenko
- Division of Genetics, Department of Medicine, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Christiane Zorbas
- RNA Molecular Biology, Fonds de la Recherche Scientifique (F.R.S./FNRS), Université libre de Bruxelles (ULB), Biopark Campus, 6041 Gosselies, Belgium
| | - Konstantinos Boulias
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Fiona G MacWhinnie
- Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Albert Kejun Ying
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Anya Flood Taylor
- Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Joseph Al Haddad
- Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Hiroki Shibuya
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Lara Roach
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Anna Dong
- Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Scarlett Dellacona
- Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Denis L J Lafontaine
- RNA Molecular Biology, Fonds de la Recherche Scientifique (F.R.S./FNRS), Université libre de Bruxelles (ULB), Biopark Campus, 6041 Gosselies, Belgium
| | - Vadim N Gladyshev
- Division of Genetics, Department of Medicine, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Eric Lieberman Greer
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston, MA, USA; Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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12
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Seroussi U, Lugowski A, Wadi L, Lao RX, Willis AR, Zhao W, Sundby AE, Charlesworth AG, Reinke AW, Claycomb JM. A comprehensive survey of C. elegans argonaute proteins reveals organism-wide gene regulatory networks and functions. eLife 2023; 12:e83853. [PMID: 36790166 PMCID: PMC10101689 DOI: 10.7554/elife.83853] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 02/14/2023] [Indexed: 02/16/2023] Open
Abstract
Argonaute (AGO) proteins associate with small RNAs to direct their effector function on complementary transcripts. The nematode Caenorhabditis elegans contains an expanded family of 19 functional AGO proteins, many of which have not been fully characterized. In this work, we systematically analyzed every C. elegans AGO using CRISPR-Cas9 genome editing to introduce GFP::3xFLAG tags. We have characterized the expression patterns of each AGO throughout development, identified small RNA binding complements, and determined the effects of ago loss on small RNA populations and developmental phenotypes. Our analysis indicates stratification of subsets of AGOs into distinct regulatory modules, and integration of our data led us to uncover novel stress-induced fertility and pathogen response phenotypes due to ago loss.
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Affiliation(s)
- Uri Seroussi
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Andrew Lugowski
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Lina Wadi
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Robert X Lao
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | | | - Winnie Zhao
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Adam E Sundby
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | | | - Aaron W Reinke
- Department of Molecular Genetics, University of TorontoTorontoCanada
| | - Julie M Claycomb
- Department of Molecular Genetics, University of TorontoTorontoCanada
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13
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Zhao Y, Chen J, Wang R, Pu X, Wang D. A review of transgenerational and multigenerational toxicology in the in vivo model animal Caenorhabditis elegans. J Appl Toxicol 2023; 43:122-145. [PMID: 35754092 DOI: 10.1002/jat.4360] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/09/2022] [Accepted: 06/24/2022] [Indexed: 11/09/2022]
Abstract
A large number of pollutants existing in the environment can last for a long time, and their potential toxic effects can transfer from parents to their offspring. Thus, it is necessary to investigate the toxicity of environmental pollutants across multigenerations and the underlying mechanisms in organisms. Due to its short life cycle and sensitivity to environmental exposures, Caenorhabditis elegans is an important animal model for toxicity assessment of environmental pollutants across multigenerations. In this review, we introduced the transgenerational and multigenerational toxicity caused by various environmental pollutants in C. elegans. Moreover, we discussed the underlying mechanisms for the observed transgenerational and multigenerational toxicity of environmental contaminants in C. elegans.
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Affiliation(s)
- Yunli Zhao
- Medical School, Southeast University, Nanjing, China.,School of Public Health, Bengbu Medical College, Bengbu, China
| | - Jingya Chen
- School of Public Health, Bengbu Medical College, Bengbu, China
| | - Rui Wang
- School of Public Health, Bengbu Medical College, Bengbu, China
| | - Xiaoxiao Pu
- School of Public Health, Bengbu Medical College, Bengbu, China
| | - Dayong Wang
- Medical School, Southeast University, Nanjing, China
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14
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Toker IA, Lev I, Mor Y, Gurevich Y, Fisher D, Houri-Zeevi L, Antonova O, Doron H, Anava S, Gingold H, Hadany L, Shaham S, Rechavi O. Transgenerational inheritance of sexual attractiveness via small RNAs enhances evolvability in C. elegans. Dev Cell 2022; 57:298-309.e9. [PMID: 35134343 PMCID: PMC8826646 DOI: 10.1016/j.devcel.2022.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 09/12/2021] [Accepted: 01/05/2022] [Indexed: 11/16/2022]
Abstract
It is unknown whether transient transgenerational epigenetic responses to environmental challenges affect the process of evolution, which typically unfolds over many generations. Here, we show that in C. elegans, inherited small RNAs control genetic variation by regulating the crucial decision of whether to self-fertilize or outcross. We found that under stressful temperatures, younger hermaphrodites secrete a male-attracting pheromone. Attractiveness transmits transgenerationally to unstressed progeny via heritable small RNAs and the Argonaute Heritable RNAi Deficient-1 (HRDE-1). We identified an endogenous small interfering RNA pathway, enriched in endo-siRNAs that target sperm genes, that transgenerationally regulates sexual attraction, male prevalence, and outcrossing rates. Multigenerational mating competition experiments and mathematical simulations revealed that over generations, animals that inherit attractiveness mate more and their alleles spread in the population. We propose that the sperm serves as a "stress-sensor" that, via small RNA inheritance, promotes outcrossing in challenging environments when increasing genetic variation is advantageous.
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Affiliation(s)
- Itai Antoine Toker
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
| | - Itamar Lev
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
| | - Yael Mor
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
| | - Yael Gurevich
- School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Doron Fisher
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Leah Houri-Zeevi
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Olga Antonova
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Hila Doron
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Sarit Anava
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Hila Gingold
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Lilach Hadany
- School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, New York, NY, USA
| | - Oded Rechavi
- Department of Neurobiology, Faculty of Life Sciences & Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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15
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Abstract
Increasing evidence indicates that non-DNA sequence-based epigenetic information can be inherited across several generations in organisms ranging from yeast to plants to humans. This raises the possibility of heritable 'epimutations' contributing to heritable phenotypic variation and thus to evolution. Recent work has shed light on both the signals that underpin these epimutations, including DNA methylation, histone modifications and non-coding RNAs, and the mechanisms by which they are transmitted across generations at the molecular level. These mechanisms can vary greatly among species and have a more limited effect in mammals than in plants and other animal species. Nevertheless, common principles are emerging, with transmission occurring either via direct replicative mechanisms or indirect reconstruction of the signal in subsequent generations. As these processes become clearer we continue to improve our understanding of the distinctive features and relative contribution of DNA sequence and epigenetic variation to heritable differences in phenotype.
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16
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Burton NO, Greer EL. Multigenerational epigenetic inheritance: Transmitting information across generations. Semin Cell Dev Biol 2021; 127:121-132. [PMID: 34426067 DOI: 10.1016/j.semcdb.2021.08.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 01/07/2023]
Abstract
Inherited epigenetic information has been observed to regulate a variety of complex organismal phenotypes across diverse taxa of life. This continually expanding body of literature suggests that epigenetic inheritance plays a significant, and potentially fundamental, role in inheritance. Despite the important role these types of effects play in biology, the molecular mediators of this non-genetic transmission of information are just now beginning to be deciphered. Here we provide an intellectual framework for interpreting these findings and how they can interact with each other. We also define the different types of mechanisms that have been found to mediate epigenetic inheritance and to regulate whether epigenetic information persists for one or many generations. The field of epigenetic inheritance is entering an exciting phase, in which we are beginning to understand the mechanisms by which non-genetic information is transmitted to, and deciphered by, subsequent generations to maintain essential environmental information without permanently altering the genetic code. A more complete understanding of how and when epigenetic inheritance occurs will advance our understanding of numerous different aspects of biology ranging from how organisms cope with changing environments to human pathologies influenced by a parent's environment.
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Affiliation(s)
- Nicholas O Burton
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK; Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK; Center for Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA.
| | - Eric L Greer
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Harvard Medical School Initiative for RNA Medicine, Boston, MA 02115, USA.
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17
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Perez MF, Shamalnasab M, Mata-Cabana A, Della Valle S, Olmedo M, Francesconi M, Lehner B. Neuronal perception of the social environment generates an inherited memory that controls the development and generation time of C. elegans. Curr Biol 2021; 31:4256-4268.e7. [PMID: 34358445 DOI: 10.1016/j.cub.2021.07.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/29/2021] [Accepted: 07/13/2021] [Indexed: 12/31/2022]
Abstract
An old and controversial question in biology is whether information perceived by the nervous system of an animal can "cross the Weismann barrier" to alter the phenotypes and fitness of their progeny. Here, we show that such intergenerational transmission of sensory information occurs in the model organism, C. elegans, with a major effect on fitness. Specifically, that perception of social pheromones by chemosensory neurons controls the post-embryonic timing of the development of one tissue, the germline, relative to others in the progeny of an animal. Neuronal perception of the social environment thus intergenerationally controls the generation time of this animal.
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Affiliation(s)
- Marcos Francisco Perez
- Systems Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Mehrnaz Shamalnasab
- Université de Lyon, ENS de Lyon, Université de Claude Bernard, CNRS UMR 5239, INSERM U1210, Laboratory of Biology and Modelling of the Cell, 46 Allée d'Italie, Site Jacques Monod, 69007 Lyon, France
| | - Alejandro Mata-Cabana
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Simona Della Valle
- Systems Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - María Olmedo
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Mirko Francesconi
- Université de Lyon, ENS de Lyon, Université de Claude Bernard, CNRS UMR 5239, INSERM U1210, Laboratory of Biology and Modelling of the Cell, 46 Allée d'Italie, Site Jacques Monod, 69007 Lyon, France.
| | - Ben Lehner
- Systems Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluis Companys 23, Barcelona 08010, Spain.
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18
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Silva WTAF, Otto SP, Immler S. Evolution of plasticity in production and transgenerational inheritance of small RNAs under dynamic environmental conditions. PLoS Genet 2021; 17:e1009581. [PMID: 34038409 PMCID: PMC8186813 DOI: 10.1371/journal.pgen.1009581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 06/08/2021] [Accepted: 05/05/2021] [Indexed: 01/07/2023] Open
Abstract
In a changing environment, small RNAs (sRNAs) play an important role in the post-transcriptional regulation of gene expression and can vary in abundance depending on the conditions experienced by an individual (phenotypic plasticity) and its parents (non-genetic inheritance). Many sRNAs are unusual in that they can be produced in two ways, either using genomic DNA as the template (primary sRNAs) or existing sRNAs as the template (secondary sRNAs). Thus, organisms can evolve rapid plastic responses to their current environment by adjusting the amplification rate of sRNA templates. sRNA levels can also be transmitted transgenerationally by the direct transfer of either sRNAs or the proteins involved in amplification. Theory is needed to describe the selective forces acting on sRNA levels, accounting for the dual nature of sRNAs as regulatory elements and templates for amplification and for the potential to transmit sRNAs and their amplification agents to offspring. Here, we develop a model to study the dynamics of sRNA production and inheritance in a fluctuating environment. We tested the selective advantage of mutants capable of sRNA-mediated phenotypic plasticity within resident populations with fixed levels of sRNA transcription. Even when the resident was allowed to evolve an optimal constant rate of sRNA production, plastic amplification rates capable of responding to environmental conditions were favored. Mechanisms allowing sRNA transcripts or amplification agents to be inherited were favored primarily when parents and offspring face similar environments and when selection acts before the optimal level of sRNA can be reached within the organism. Our study provides a clear set of testable predictions for the evolution of sRNA-related mechanisms of phenotypic plasticity and transgenerational inheritance.
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Affiliation(s)
| | - Sarah P. Otto
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Simone Immler
- Department of Evolutionary Biology, Uppsala University, Uppsala, Sweden
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
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19
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Frolows N, Ashe A. Small RNAs and chromatin in the multigenerational epigenetic landscape of Caenorhabditis elegans. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200112. [PMID: 33866817 DOI: 10.1098/rstb.2020.0112] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
For decades, it was thought that the only heritable information transmitted from one individual to another was that encoded in the DNA sequence. However, it has become increasingly clear that this is not the case and that the transmission of molecules from within the cytoplasm of the gamete also plays a significant role in heritability. The roundworm, Caenorhabditis elegans, has emerged as one of the leading model organisms in which to study the mechanisms of transgenerational epigenetic inheritance (TEI). Collaborative efforts over the past few years have revealed that RNA molecules play a critical role in transmitting transgenerational responses, but precisely how they do so is as yet uncertain. In addition, the role of histone modifications in epigenetic inheritance is increasingly apparent, and RNA and histones interact in a way that we do not yet fully understand. Furthermore, both exogenous and endogenous RNA molecules, as well as other environmental triggers, are able to induce heritable epigenetic changes that affect transcription across the genome. In most cases, these epigenetic changes last only for a handful of generations, but occasionally can be maintained much longer: perhaps indefinitely. In this review, we discuss the current understanding of the role of RNA and histones in TEI, as well as making clear the gaps in our knowledge. We also speculate on the evolutionary implications of epigenetic inheritance, particularly in the context of a short-lived, clonally propagating species. This article is part of the theme issue 'How does epigenetics influence the course of evolution?'
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Affiliation(s)
- Natalya Frolows
- School of Life and Environmental Sciences, University of Sydney, New South Wales, 2006, Australia.,CSIRO Health and Biosecurity, Sydney, New South Wales, 2113, Australia
| | - Alyson Ashe
- School of Life and Environmental Sciences, University of Sydney, New South Wales, 2006, Australia
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20
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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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21
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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: 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: 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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22
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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: 3.0] [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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23
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Abstract
With a nervous system that has only a few hundred neurons, Caenorhabditis elegans was initially not regarded as a model for studies on learning. However, the collective effort of the C. elegans field in the past several decades has shown that the worm displays plasticity in its behavioral response to a wide range of sensory cues in the environment. As a bacteria-feeding worm, C. elegans is highly adaptive to the bacteria enriched in its habitat, especially those that are pathogenic and pose a threat to survival. It uses several common forms of behavioral plasticity that last for different amounts of time, including imprinting and adult-stage associative learning, to modulate its interactions with pathogenic bacteria. Probing the molecular, cellular and circuit mechanisms underlying these forms of experience-dependent plasticity has identified signaling pathways and regulatory insights that are conserved in more complex animals.
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Affiliation(s)
- He Liu
- 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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24
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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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25
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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: 23] [Impact Index Per Article: 4.6] [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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26
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Huang J, Wu Z, Zhang X. Short-Term Mild Temperature-Stress-Induced Alterations in the C. elegans Phosphoproteome. Int J Mol Sci 2020; 21:ijms21176409. [PMID: 32899194 PMCID: PMC7504583 DOI: 10.3390/ijms21176409] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/28/2020] [Accepted: 08/31/2020] [Indexed: 12/22/2022] Open
Abstract
Exposure to mild early-life stresses can slow down aging, and protein phosphorylation might be an essential regulator in this process. However, the mechanisms of phosphorylation-based signaling networks during mild early-life stress remain elusive. Herein, we systematically analyzed the phosphoproteomes of Caenorhabditis elegans, which were treated with three mild temperatures (15 °C, 20 °C, and 25 °C) in two different short-term groups (10 min and 60 min). By utilizing an iTRAQ-based quantitative phosphoproteomic approach, 18,187 phosphosites from 3330 phosphoproteins were detected in this study. Volcano plots illustrated that the phosphorylation abundance of 374 proteins and 347 proteins, were significantly changed at 15 °C and 25 °C, respectively. Gene ontology, KEGG pathway and protein-protein interaction network analyses revealed that these phosphoproteins were primarily associated with metabolism, translation, development, and lifespan determination. A motif analysis of kinase substrates suggested that MAPK, CK, and CAMK were most likely involved in the adaption processes. Moreover, 16 and 14 aging-regulated proteins were found to undergo phosphorylation modifications under the mild stresses of 15 °C and 25 °C, respectively, indicating that these proteins might be important for maintaining long-term health. Further lifespan experiments confirmed that the candidate phosphoproteins, e.g., EGL-27 and XNP-1 modulated longevity at 15 °C, 20 °C, and 25 °C, and they showed increased tolerance to thermal and oxidative stresses. In conclusion, our findings offered data that supports understanding of the phosphorylation mechanisms involved in mild early-life stresses in C. elegans. Data are available via ProteomeXchange with identifier PXD021081.
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Affiliation(s)
- Jichang Huang
- Correspondence: (J.H.); (X.Z.); Tel.: +86-021-3124-6575 (X.Z.)
| | | | - Xumin Zhang
- Correspondence: (J.H.); (X.Z.); Tel.: +86-021-3124-6575 (X.Z.)
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27
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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: 18] [Impact Index Per Article: 3.6] [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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28
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Lind MI, Zwoinska MK, Andersson J, Carlsson H, Krieg T, Larva T, Maklakov AA. Environmental variation mediates the evolution of anticipatory parental effects. Evol Lett 2020; 4:371-381. [PMID: 32774885 PMCID: PMC7403678 DOI: 10.1002/evl3.177] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 05/11/2020] [Indexed: 12/02/2022] Open
Abstract
Theory maintains that when future environment is predictable, parents should adjust the phenotype of their offspring to match the anticipated environment. The plausibility of positive anticipatory parental effects is hotly debated and the experimental evidence for the evolution of such effects is currently lacking. We experimentally investigated the evolution of anticipatory maternal effects in a range of environments that differ drastically in how predictable they are. Populations of the nematode Caenorhabditis remanei, adapted to 20°C, were exposed to a novel temperature (25°C) for 30 generations with either positive or zero correlation between parent and offspring environment. We found that populations evolving in novel environments that were predictable across generations evolved a positive anticipatory maternal effect, because they required maternal exposure to 25°C to achieve maximum reproduction in that temperature. In contrast, populations evolving under zero environmental correlation had lost this anticipatory maternal effect. Similar but weaker patterns were found if instead rate‐sensitive population growth was used as a fitness measure. These findings demonstrate that anticipatory parental effects evolve in response to environmental change so that ill‐fitting parental effects can be rapidly lost. Evolution of positive anticipatory parental effects can aid population viability in rapidly changing but predictable environments.
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Affiliation(s)
- Martin I Lind
- Animal Ecology, Department of Ecology and Genetics Uppsala University Uppsala 752 36 Sweden.,Centre for Biodiversity Dynamics, Department of Biology Norwegian University of Science and Technology (NTNU) Trondheim NO-7491 Norway
| | - Martyna K Zwoinska
- Animal Ecology, Department of Ecology and Genetics Uppsala University Uppsala 752 36 Sweden
| | - Johan Andersson
- Animal Ecology, Department of Ecology and Genetics Uppsala University Uppsala 752 36 Sweden
| | - Hanne Carlsson
- Animal Ecology, Department of Ecology and Genetics Uppsala University Uppsala 752 36 Sweden.,School of Biological Sciences University of East Anglia Norwich NR4 7TJ United Kingdom
| | - Therese Krieg
- Animal Ecology, Department of Ecology and Genetics Uppsala University Uppsala 752 36 Sweden
| | - Tuuli Larva
- Animal Ecology, Department of Ecology and Genetics Uppsala University Uppsala 752 36 Sweden
| | - Alexei A Maklakov
- Animal Ecology, Department of Ecology and Genetics Uppsala University Uppsala 752 36 Sweden.,School of Biological Sciences University of East Anglia Norwich NR4 7TJ United Kingdom
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poly(UG)-tailed RNAs in genome protection and epigenetic inheritance. Nature 2020; 582:283-288. [PMID: 32499657 PMCID: PMC8396162 DOI: 10.1038/s41586-020-2323-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 04/16/2020] [Indexed: 12/17/2022]
Abstract
Mobile genetic elements threaten genome integrity in all organisms. MUT-2/RDE-3 is a ribonucleotidyltransferase required for transposon silencing and RNA interference (RNAi) in C. elegans1–4. When tethered to RNAs in heterologous expression systems, RDE-3 can add long stretches of alternating non-templated uridine (U) and guanosine (G) ribonucleotides to the 3’ termini of these RNAs (poly(UG) or pUG tails)5. Here we show that, in its natural context in C. elegans, RDE-3 adds pUG tails to targets of RNAi, as well as to transposon RNAs. pUG tails with more than 16 perfectly alternating 3’ U and G nucleotides convert RNA fragments into agents of gene silencing. pUG tails promote gene silencing by recruiting RNA-dependent RNA polymerases (RdRPs), which use pUG-tailed RNAs (pUG RNAs) as templates to synthesize small interfering RNAs (siRNAs). Our results show that cycles of pUG RNA–templated siRNA synthesis and siRNA-directed mRNA pUGylation underlie dsRNA-directed transgenerational epigenetic inheritance in the C. elegans germline. We speculate that this pUG RNA/siRNA silencing loop allows parents to inoculate progeny against the expression of unwanted or parasitic genetic elements
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30
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Pispa J, Matilainen O, Holmberg CI. Tissue-specific effects of temperature on proteasome function. Cell Stress Chaperones 2020; 25:563-572. [PMID: 32306217 PMCID: PMC7192876 DOI: 10.1007/s12192-020-01107-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/13/2020] [Accepted: 03/24/2020] [Indexed: 12/23/2022] Open
Abstract
Variation in ambient growth temperature can cause changes in normal animal physiology and cellular functions such as control of protein homeostasis. A key mechanism for maintaining proteostasis is the selective degradation of polyubiquitinated proteins, mediated by the ubiquitin-proteasome system (UPS). It is still largely unsolved how temperature changes affect the UPS at the organismal level. Caenorhabditis elegans nematodes are normally bred at 20 °C, but for some experimental conditions, 25 °C is often used. We studied the effect of 25 °C on C. elegans UPS by measuring proteasome activity and polyubiquitinated proteins both in vitro in whole animal lysates and in vivo in tissue-specific transgenic reporter strains. Our results show that an ambient temperature shift from 20 to 25 °C increases the UPS activity in the intestine, but not in the body wall muscle tissue, where a concomitant accumulation of polyubiquitinated proteins occurs. These changes in the UPS activity and levels of polyubiquitinated proteins were not detectable in whole animal lysates. The exposure of transgenic animals to 25 °C also induced ER stress reporter fluorescence, but not the fluorescence of a heat shock responsive reporter, albeit detection of a mild induction in hsp-16.2 mRNA levels. In conclusion, C. elegans exhibits tissue-specific responses of the UPS as an organismal strategy to cope with a rise in ambient temperature.
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Affiliation(s)
- Johanna Pispa
- Medicum, Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Olli Matilainen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Carina I. Holmberg
- Medicum, Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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31
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Small RNAs in the Transgenerational Inheritance of Epigenetic Information. Trends Genet 2020; 36:203-214. [DOI: 10.1016/j.tig.2019.12.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/19/2019] [Accepted: 12/06/2019] [Indexed: 01/21/2023]
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32
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Liberman N, Wang SY, Greer EL. Transgenerational epigenetic inheritance: from phenomena to molecular mechanisms. Curr Opin Neurobiol 2019; 59:189-206. [PMID: 31634674 DOI: 10.1016/j.conb.2019.09.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Accepted: 09/11/2019] [Indexed: 02/07/2023]
Abstract
Inherited information not encoded in the DNA sequence can regulate a variety of complex phenotypes. However, how this epigenetic information escapes the typical epigenetic erasure that occurs upon fertilization and how it regulates behavior is still unclear. Here we review recent examples of brain related transgenerational epigenetic inheritance and delineate potential molecular mechanisms that could regulate how non-genetic information could be transmitted.
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Affiliation(s)
- Noa Liberman
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston MA 02115, USA
| | - Simon Yuan Wang
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston MA 02115, USA
| | - Eric Lieberman Greer
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston MA 02115, USA.
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33
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Casier K, Boivin A, Carré C, Teysset L. Environmentally-Induced Transgenerational Epigenetic Inheritance: Implication of PIWI Interacting RNAs. Cells 2019; 8:cells8091108. [PMID: 31546882 PMCID: PMC6770481 DOI: 10.3390/cells8091108] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 12/11/2022] Open
Abstract
Environmentally-induced transgenerational epigenetic inheritance is an emerging field. The understanding of associated epigenetic mechanisms is currently in progress with open questions still remaining. In this review, we present an overview of the knowledge of environmentally-induced transgenerational inheritance and associated epigenetic mechanisms, mainly in animals. The second part focuses on the role of PIWI-interacting RNAs (piRNAs), a class of small RNAs involved in the maintenance of the germline genome, in epigenetic memory to put into perspective cases of environmentally-induced transgenerational inheritance involving piRNA production. Finally, the last part addresses how genomes are facing production of new piRNAs, and from a broader perspective, how this process might have consequences on evolution and on sporadic disease development.
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Affiliation(s)
- Karine Casier
- Transgenerational Epigenetics & small RNA Biology, Sorbonne Université, CNRS, Laboratoire Biologie du Développement, Institut de Biologie Paris-Seine, UMR7622, 75005 Paris, France.
| | - Antoine Boivin
- Transgenerational Epigenetics & small RNA Biology, Sorbonne Université, CNRS, Laboratoire Biologie du Développement, Institut de Biologie Paris-Seine, UMR7622, 75005 Paris, France.
| | - Clément Carré
- Transgenerational Epigenetics & small RNA Biology, Sorbonne Université, CNRS, Laboratoire Biologie du Développement, Institut de Biologie Paris-Seine, UMR7622, 75005 Paris, France.
| | - Laure Teysset
- Transgenerational Epigenetics & small RNA Biology, Sorbonne Université, CNRS, Laboratoire Biologie du Développement, Institut de Biologie Paris-Seine, UMR7622, 75005 Paris, France.
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34
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Zhou L, He B, Deng J, Pang S, Tang H. Histone acetylation promotes long-lasting defense responses and longevity following early life heat stress. PLoS Genet 2019; 15:e1008122. [PMID: 31034475 PMCID: PMC6508741 DOI: 10.1371/journal.pgen.1008122] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 05/09/2019] [Accepted: 04/03/2019] [Indexed: 02/02/2023] Open
Abstract
Early exposure to some mild stresses can slow down the aging process and extend lifespan, raising the question of how early life stress might impact the somatic health of aged animals. Here, we reveal that early life heat experience triggers the establishment of epigenetic memory in soma, which promotes long-lasting stress responses and longevity in C. elegans. Unlike lethal heat shock, mild heat activates a unique transcriptional program mimicking pathogen defense responses, characterized by the enhanced expression of innate immune and detoxification genes. Surprisingly, the expression of defense response genes persists long after heat exposure, conferring enhanced stress resistance even in aged animals. Further studies identify the histone acetyltransferase CBP-1 and the chromatin remodeling SWI/SNF complex as epigenetic modulators of the long-lasting defense responses. Histone acetylation is elevated by heat stress and maintained into agedness thereafter. Accordingly, histone acetylation levels were increased on the promoters of defense genes. Moreover, disruption of epigenetic memory abrogates the longevity response to early hormetic heat stress, indicating that long-lasting defense responses are crucial for the survival of aged animals. Together, our findings provide mechanistic insights into how temperature stress experienced in early life provides animals with lifetime health benefits. Organism aging is a deleterious process characterized by the progressive decline of cellular and tissue functions in the late life stage. However, the rate of aging is often determined by an organism’s historic experiences that occur in early life. For example, some mild stresses experienced in early life can extend animal lifespan, implying that early stresses might impact the health of aged animals, the mechanisms of which remain largely unknown. Here, by using the model organism C. elegans, we reveal a mechanism of how early life heat stress impacts the health of aged animals and promotes longevity. We find that early exposure to mild heat activates basal innate immune and detoxification responses, which are surprisingly maintained long after temperature drop, even into agedness, and therefore contribute to lifespan extension. Remarkably, the long-lasting defense responses require epigenetic memory established by histone acetyltransferase CBP-1 and chromatin remodeling complex SWI/SNF. As a previous study has reported high temperature-induced transgenerational epigenetic effects in germline that involve histone methylation, our findings suggest that temperature may trigger distinct epigenetic changes in soma and germline, conferring adaptations in both the parental generation and their offspring.
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Affiliation(s)
- Lei Zhou
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Bin He
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Jianhui Deng
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Shanshan Pang
- School of Life Sciences, Chongqing University, Chongqing, China
- * E-mail: (SP); (HT)
| | - Haiqing Tang
- School of Life Sciences, Chongqing University, Chongqing, China
- * E-mail: (SP); (HT)
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35
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Lev I, Bril R, Liu Y, Ceré LI, Rechavi O. Inter-generational consequences for growing Caenorhabditis elegans in liquid. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180125. [PMID: 30966881 PMCID: PMC6460074 DOI: 10.1098/rstb.2018.0125] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2018] [Indexed: 12/12/2022] Open
Abstract
In recent years, studies in Caenorhabditis elegans nematodes have shown that different stresses can generate multigenerational changes. Here, we show that worms that grow in liquid media, and also their plate-grown progeny, are different from worms whose ancestors were grown on plates. It has been suggested that C. elegans might encounter liquid environments in nature, although actual observations in the wild are few and far between. By contrast, in the laboratory, growing worms in liquid is commonplace, and often used as an alternative to growing worms on agar plates, to control the composition of the worms' diet, to starve (and synchronize) worms or to grow large populations for biochemical assays. We found that plate-grown descendants of M9 liquid medium-grown worms were longer than control worms, and the heritable effects were already apparent very early in development. We tested for the involvement of different known epigenetic inheritance mechanisms, but could not find a single mutant in which these inter-generational effects are cancelled. While we found that growing in liquid always leads to inter-generational changes in the worms' size, trans-generational effects were found to be variable, and in some cases, the effects were gone after one to two generations. These results demonstrate that standard cultivation conditions in early life can dramatically change the worms' physiology in adulthood, and can also affect the next generations. This article is part of the theme issue 'Developing differences: early-life effects and evolutionary medicine'.
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Affiliation(s)
- Itamar Lev
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Roberta Bril
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yunan Liu
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Lucila Inés Ceré
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
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36
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Histone Methylation and Memory of Environmental Stress. Cells 2019; 8:cells8040339. [PMID: 30974922 PMCID: PMC6523599 DOI: 10.3390/cells8040339] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 04/05/2019] [Accepted: 04/07/2019] [Indexed: 02/07/2023] Open
Abstract
Cellular adaptation to environmental stress relies on a wide range of tightly controlled regulatory mechanisms, including transcription. Changes in chromatin structure and organization accompany the transcriptional response to stress, and in some cases, can impart memory of stress exposure to subsequent generations through mechanisms of epigenetic inheritance. In the budding yeast Saccharomyces cerevisiae, histone post-translational modifications, and in particular histone methylation, have been shown to confer transcriptional memory of exposure to environmental stress conditions through mitotic divisions. Recent evidence from Caenorhabditis elegans also implicates histone methylation in transgenerational inheritance of stress responses, suggesting a more widely conserved role in epigenetic memory.
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37
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Almeida MV, de Jesus Domingues AM, Ketting RF. Maternal and zygotic gene regulatory effects of endogenous RNAi pathways. PLoS Genet 2019; 15:e1007784. [PMID: 30759082 PMCID: PMC6391025 DOI: 10.1371/journal.pgen.1007784] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 02/26/2019] [Accepted: 01/23/2019] [Indexed: 11/30/2022] Open
Abstract
Endogenous small RNAs (sRNAs) and Argonaute proteins are ubiquitous regulators of gene expression in germline and somatic tissues. sRNA-Argonaute complexes are often expressed in gametes and are consequently inherited by the next generation upon fertilization. In Caenorhabditis elegans, 26G-RNAs are primary endogenous sRNAs that trigger the expression of downstream secondary sRNAs. Two subpopulations of 26G-RNAs exist, each of which displaying strongly compartmentalized expression: one is expressed in the spermatogenic gonad and associates with the Argonautes ALG-3/4; plus another expressed in oocytes and in embryos, which associates with the Argonaute ERGO-1. The determinants and dynamics of gene silencing elicited by 26G-RNAs are largely unknown. Here, we provide diverse new insights into these endogenous sRNA pathways of C. elegans. Using genetics and deep sequencing, we dissect a maternal effect of the ERGO-1 branch of the 26G-RNA pathway. We find that maternal primary sRNAs can trigger the production of zygotic secondary sRNAs that are able to silence targets, even in the absence of zygotic primary triggers. Thus, the interaction of maternal and zygotic sRNA populations, assures target gene silencing throughout animal development. Furthermore, we explore other facets of 26G-RNA biology related to the ALG-3/4 branch. We find that sRNA abundance, sRNA pattern of origin and the 3’ UTR length of target transcripts are predictors of the regulatory outcome by the Argonautes ALG-3/4. Lastly, we provide evidence suggesting that ALG-3 and ALG-4 regulate their own mRNAs in a negative feedback loop. Altogether, we provide several new regulatory insights on the dynamics, target regulation and self-regulation of the endogenous RNAi pathways of C. elegans. Small RNAs (sRNAs) and their partner Argonaute proteins regulate the expression of target RNAs. When sperm and egg meet upon fertilization, a diverse set of proteins and RNA, including sRNA-Argonaute complexes, is passed on to the developing progeny. Thus, these two players are important to initiate specific gene expression programs in the next generation. The nematode Caenorhabditis elegans expresses several classes of sRNAs. 26G-RNAs are a particular class of sRNAs that are divided into two subpopulations: one expressed in the spermatogenic gonad and another expressed in oocytes and in embryos. In this work, we describe the dynamics whereby oogenic 26G-RNAs setup gene silencing in the next generation. In addition, we show several ways that spermatogenic 26G-RNAs and their partner Argonautes, ALG-3 and ALG-4, use to regulate their targets. Finally, we show that ALG-3 and ALG-4 are fine-tuning their own expression, a rare role of Argonaute proteins. Overall, we provide new insights into how sRNAs and Argonautes are regulating gene expression.
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Affiliation(s)
- Miguel Vasconcelos Almeida
- Biology of Non-coding RNA Group, Institute of Molecular Biology, Ackermannweg 4, Mainz, Germany
- International PhD Programme on Gene Regulation, Epigenetics & Genome Stability, Mainz, Germany
| | | | - René F. Ketting
- Biology of Non-coding RNA Group, Institute of Molecular Biology, Ackermannweg 4, Mainz, Germany
- * E-mail:
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38
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Bezler A, Braukmann F, West SM, Duplan A, Conconi R, Schütz F, Gönczy P, Piano F, Gunsalus K, Miska EA, Keller L. Tissue- and sex-specific small RNAomes reveal sex differences in response to the environment. PLoS Genet 2019; 15:e1007905. [PMID: 30735500 PMCID: PMC6383947 DOI: 10.1371/journal.pgen.1007905] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 02/21/2019] [Accepted: 12/17/2018] [Indexed: 11/19/2022] Open
Abstract
RNA interference (RNAi) related pathways are essential for germline development and fertility in metazoa and can contribute to inter- and trans-generational inheritance. In the nematode Caenorhabditis elegans, environmental double-stranded RNA provided by feeding can lead to heritable changes in phenotype and gene expression. Notably, transmission efficiency differs between the male and female germline, yet the underlying mechanisms remain elusive. Here we use high-throughput sequencing of dissected gonads to quantify sex-specific endogenous piRNAs, miRNAs and siRNAs in the C. elegans germline and the somatic gonad. We identify genes with exceptionally high levels of secondary 22G RNAs that are associated with low mRNA expression, a signature compatible with silencing. We further demonstrate that contrary to the hermaphrodite germline, the male germline, but not male soma, is resistant to environmental RNAi triggers provided by feeding, in line with previous work. This sex-difference in silencing efficacy is associated with lower levels of gonadal RNAi amplification products. Moreover, this tissue- and sex-specific RNAi resistance is regulated by the germline, since mutant males with a feminized germline are RNAi sensitive. This study provides important sex- and tissue-specific expression data of miRNA, piRNA and siRNA as well as mechanistic insights into sex-differences of gene regulation in response to environmental cues.
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Affiliation(s)
- Alexandra Bezler
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Fabian Braukmann
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Cambridge, United Kingdom
| | - Sean M. West
- Center for Genomics & Systems Biology, New York University, New York, New York, United States of America
| | - Arthur Duplan
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Raffaella Conconi
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Frédéric Schütz
- Bioinformatics Core Facility; SIB Swiss Institute of Bioinformatics and Centre for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Pierre Gönczy
- Swiss Institute for Experimental Cancer Research (ISREC), Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Fabio Piano
- Center for Genomics & Systems Biology, New York University, New York, New York, United States of America
- Center for Genomics & Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Kristin Gunsalus
- Center for Genomics & Systems Biology, New York University, New York, New York, United States of America
- Center for Genomics & Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Eric A. Miska
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Cambridge, United Kingdom
| | - Laurent Keller
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
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39
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Almeida MV, Andrade-Navarro MA, Ketting RF. Function and Evolution of Nematode RNAi Pathways. Noncoding RNA 2019; 5:E8. [PMID: 30650636 PMCID: PMC6468775 DOI: 10.3390/ncrna5010008] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 12/11/2022] Open
Abstract
Selfish genetic elements, like transposable elements or viruses, are a threat to genomic stability. A variety of processes, including small RNA-based RNA interference (RNAi)-like pathways, has evolved to counteract these elements. Amongst these, endogenous small interfering RNA and Piwi-interacting RNA (piRNA) pathways were implicated in silencing selfish genetic elements in a variety of organisms. Nematodes have several incredibly specialized, rapidly evolving endogenous RNAi-like pathways serving such purposes. Here, we review recent research regarding the RNAi-like pathways of Caenorhabditis elegans as well as those of other nematodes, to provide an evolutionary perspective. We argue that multiple nematode RNAi-like pathways share piRNA-like properties and together form a broad nematode toolkit that allows for silencing of foreign genetic elements.
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Affiliation(s)
| | - Miguel A Andrade-Navarro
- Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.
- Faculty of Biology, Johannes Gutenberg Universität, 55122 Mainz, Germany.
| | - René F Ketting
- Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.
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40
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Perez MF, Lehner B. Intergenerational and transgenerational epigenetic inheritance in animals. Nat Cell Biol 2019; 21:143-151. [PMID: 30602724 DOI: 10.1038/s41556-018-0242-9] [Citation(s) in RCA: 325] [Impact Index Per Article: 54.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/29/2018] [Indexed: 12/12/2022]
Abstract
Animals transmit not only DNA but also other molecules, such as RNA, proteins and metabolites, to their progeny via gametes. It is currently unclear to what extent these molecules convey information between generations and whether this information changes according to their physiological state and environment. Here, we review recent work on the molecular mechanisms by which 'epigenetic' information is transmitted between generations over different timescales, and the importance of this information for development and physiology.
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Affiliation(s)
- Marcos Francisco Perez
- Systems Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Ben Lehner
- Systems Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain. .,Universitat Pompeu Fabra (UPF), Barcelona, Spain. .,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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41
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Chow YL, Sato F. Transgenerational lipid-reducing activity of benzylisoquinoline alkaloids in Caenorhabditis elegans. Genes Cells 2018; 24:70-81. [DOI: 10.1111/gtc.12657] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 10/25/2018] [Accepted: 11/04/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Yit-Lai Chow
- Division of Integrated Life Science, Graduate School of Biostudies; Kyoto University; Kyoto Japan
| | - Fumihiko Sato
- Division of Integrated Life Science, Graduate School of Biostudies; Kyoto University; Kyoto Japan
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42
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Belicard T, Jareosettasin P, Sarkies P. The piRNA pathway responds to environmental signals to establish intergenerational adaptation to stress. BMC Biol 2018; 16:103. [PMID: 30227863 PMCID: PMC6145337 DOI: 10.1186/s12915-018-0571-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/30/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND piRNAs have a constitutive role in genome defence by silencing transposable elements in the germline. In the nematode Caenorhabditis elegans, piRNAs also induce epigenetic silencing of transgenes, which can be maintained for many generations in the absence of the piRNA pathway. The role of multi-generational epigenetic inheritance in adaptation to the environment is unknown. RESULTS Here, we show that piRNA biogenesis is downregulated in response to a small increase in temperature. Some effects on gene expression persist into subsequent generations and are associated with a negative fitness cost. We show that simultaneous infection with pathogenic bacteria suppresses downregulation of the piRNA pathway in response to increased temperature. This effect is associated with increased fitness of progeny of infected animals in subsequent generations. CONCLUSIONS Our results show that the piRNA pathway integrates inputs from the environment to establish intergenerational responses to environmental conditions, with important consequences for the fitness of the subsequent generation.
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Affiliation(s)
- Tony Belicard
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Pree Jareosettasin
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Peter Sarkies
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK. .,Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK.
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43
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Webster AK, Jordan JM, Hibshman JD, Chitrakar R, Baugh LR. Transgenerational Effects of Extended Dauer Diapause on Starvation Survival and Gene Expression Plasticity in Caenorhabditis elegans. Genetics 2018; 210:263-274. [PMID: 30049782 PMCID: PMC6116965 DOI: 10.1534/genetics.118.301250] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 07/24/2018] [Indexed: 12/29/2022] Open
Abstract
Phenotypic plasticity is facilitated by epigenetic regulation, and remnants of such regulation may persist after plasticity-inducing cues are gone. However, the relationship between plasticity and transgenerational epigenetic memory is not understood. Dauer diapause in Caenorhabditis elegans provides an opportunity to determine how a plastic response to the early-life environment affects traits later in life and in subsequent generations. We report that, after extended diapause, postdauer worms initially exhibit reduced reproductive success and greater interindividual variation. In contrast, F3 progeny of postdauers display increased starvation resistance and lifespan, revealing potentially adaptive transgenerational effects. Transgenerational effects are dependent on the duration of diapause, indicating an effect of extended starvation. In agreement, RNA-seq demonstrates a transgenerational effect on nutrient-responsive genes. Further, postdauer F3 progeny exhibit reduced gene expression plasticity, suggesting a trade-off between plasticity and epigenetic memory. This work reveals complex effects of nutrient stress over different time scales in an animal that evolved to thrive in feast and famine.
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Affiliation(s)
- Amy K Webster
- Department of Biology, Duke University, Durham, North Carolina 27708
- University Program in Genetics and Genomics, Duke University, Durham, North Carolina 27708
| | - James M Jordan
- Department of Biology, Duke University, Durham, North Carolina 27708
| | - Jonathan D Hibshman
- Department of Biology, Duke University, Durham, North Carolina 27708
- University Program in Genetics and Genomics, Duke University, Durham, North Carolina 27708
| | - Rojin Chitrakar
- Department of Biology, Duke University, Durham, North Carolina 27708
| | - L Ryan Baugh
- Department of Biology, Duke University, Durham, North Carolina 27708
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Evolution without standing genetic variation: change in transgenerational plastic response under persistent predation pressure. Heredity (Edinb) 2018; 121:266-281. [PMID: 29959428 DOI: 10.1038/s41437-018-0108-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 05/22/2018] [Accepted: 06/03/2018] [Indexed: 11/08/2022] Open
Abstract
Transgenerational phenotypic plasticity is a fast non-genetic response to environmental modifications that can buffer the effects of environmental stresses on populations. However, little is known about the evolution of plasticity in the absence of standing genetic variation although several non-genetic inheritance mechanisms have now been identified. Here we monitored the pea aphid transgenerational phenotypic response to ladybird predators (production of winged offspring) during 27 generations of experimental evolution in the absence of initial genetic variation (clonal multiplication starting from a single individual). We found that the frequency of winged aphids first increased rapidly in response to predators and then remained stable over 25 generations, implying a stable phenotypic reconstruction at each generation. We also found that the high frequency of winged aphids persisted for one generation after removing predators. Winged aphid frequency then entered a refractory phase during which it dropped below the level of control lines for at least two generations before returning to it. Interestingly, the persistence of the winged phenotype decreased and the refractory phase lasted longer with the increasing number of generations of exposure to predators. Finally, we found that aphids continuously exposed to predators for 22 generations evolved a significantly weaker plastic response than aphids never exposed to predators, which, in turn, increased their fitness in presence of predators. Our findings therefore showcased an example of experimental evolution of plasticity in the absence of initial genetic variation and highlight the importance of integrating several components of non-genetic inheritance to detect evolutionary responses to environmental changes.
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Minkina O, Hunter CP. Intergenerational Transmission of Gene Regulatory Information in Caenorhabditis elegans. Trends Genet 2017; 34:54-64. [PMID: 29103876 DOI: 10.1016/j.tig.2017.09.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 01/12/2023]
Abstract
Epigenetic mechanisms can stably maintain gene expression states even after the initiating conditions have changed. Often epigenetic information is transmitted only to daughter cells, but evidence is emerging, in both vertebrate and invertebrate systems, for transgenerational epigenetic inheritance (TEI), the transmission of epigenetic gene regulatory information across generations. Each new description of TEI helps uncover the properties, molecular mechanisms and biological roles for TEI. The nematode Caenorhabditis elegans has been particularly instrumental in the effort to understand TEI, as multiple environmental and genetic triggers can initiate an epigenetic signal that can alter the expression of both transgenes and endogenous loci. Here, we review recent studies of TEI in C. elegans.
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Affiliation(s)
- Olga Minkina
- Department of Biology, New York University, New York, New York 10003, USA
| | - Craig P Hunter
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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46
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Palominos MF, Verdugo L, Gabaldon C, Pollak B, Ortíz-Severín J, Varas MA, Chávez FP, Calixto A. Transgenerational Diapause as an Avoidance Strategy against Bacterial Pathogens in Caenorhabditis elegans. mBio 2017; 8:e01234-17. [PMID: 29018118 PMCID: PMC5635688 DOI: 10.1128/mbio.01234-17] [Citation(s) in RCA: 42] [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: 07/14/2017] [Accepted: 08/30/2017] [Indexed: 12/22/2022] Open
Abstract
The dynamic response of organisms exposed to environmental pathogens determines their survival or demise, and the outcome of this interaction depends on the host's susceptibility and pathogen-dependent virulence factors. The transmission of acquired information about the nature of a pathogen to progeny may ensure effective defensive strategies for the progeny's survival in adverse environments. Environmental RNA interference (RNAi) is a systemic and heritable mechanism and has recently been linked to antibacterial and antifungal defenses in both plants and animals. Here, we report that the second generation of Caenorhabditis elegans living on pathogenic bacteria can avoid bacterial infection by entering diapause in an RNAi pathway-dependent mechanism. Furthermore, we demonstrate that the information encoding this survival strategy is transgenerationally transmitted to the progeny via the maternal germ line.IMPORTANCE Bacteria vastly influence physiology and behavior, and yet, the specific mechanisms by which they cause behavioral changes in hosts are not known. We use C. elegans as a host and the bacteria they eat to understand how microbes trigger a behavioral change that helps animals to survive. We found that animals faced with an infection for two generations could enter a hibernationlike state, arresting development by forming dauer larvae. Dauers have closed mouths and effectively avoid infection. Animals accumulate information that is transgenerationally transmitted to the next generations to form dauers. This work gives insight on how bacteria communicate in noncanonical ways with their hosts, resulting in long-lasting effects providing survival strategies to the community.
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Affiliation(s)
- M Fernanda Palominos
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Lidia Verdugo
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Carolaing Gabaldon
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Bernardo Pollak
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Javiera Ortíz-Severín
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Macarena A Varas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Francisco P Chávez
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Andrea Calixto
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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Wang E, Hunter CP. SID-1 Functions in Multiple Roles To Support Parental RNAi in Caenorhabditis elegans. Genetics 2017; 207:547-557. [PMID: 28751423 PMCID: PMC5629322 DOI: 10.1534/genetics.117.300067] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 07/20/2017] [Indexed: 11/18/2022] Open
Abstract
Systemic RNA interference (RNAi) in Caenorhbaditis elegans requires sid-1, sid-3, and sid-5 Injected, expressed, or ingested double-stranded RNA (dsRNA) is transported between cells, enabling RNAi in most tissues, including the germline and progeny (parental RNAi). A recent report claims that parental RNAi also requires the yolk receptor rme-2 Here, we characterize the role of the sid genes and rme-2 in parental RNAi. We identify multiple independent paths for maternal dsRNA to reach embryos and initiate RNAi. We showed previously that maternal and embryonic sid-1 contribute independently to parental RNAi. Here we demonstrate a role for embryonic sid-5, but not sid-2 or sid-3 in parental RNAi. We also find that maternal rme-2 contributes to but is not required for parental RNAi. We determine that parental RNAi by feeding occurs nearly exclusively in adults. We also introduce 5-ethynyluridine to densely internally label dsRNA, avoiding complications associated with other labeling strategies such as inhibition of normal dsRNA trafficking and separation of label and RNA. Labeling shows that yolk and dsRNA do not colocalize following endocytosis, suggesting independent uptake, and, furthermore, dsRNA appears to rapidly progress through the RAB-7 endocytosis pathway independently of sid-1 activity. Our results support the premise that although sid-1 functions in multiple roles, it alone is central and absolutely required for inheritance of silencing RNAs.
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Affiliation(s)
- Eddie Wang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Craig P Hunter
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138
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Minkina O, Hunter CP. Stable Heritable Germline Silencing Directs Somatic Silencing at an Endogenous Locus. Mol Cell 2017; 65:659-670.e5. [PMID: 28212751 DOI: 10.1016/j.molcel.2017.01.034] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/27/2016] [Accepted: 01/09/2017] [Indexed: 12/19/2022]
Abstract
The importance of transgenerationally inherited epigenetic states to organismal fitness remains unknown as well-documented examples are often not amenable to mechanistic analysis or rely on artificial reporter loci. Here we describe an induced silenced state at an endogenous locus that persists, at 100% transmission without selection, for up to 13 generations. This unusually persistent silencing enables a detailed molecular genetic analysis of an inherited epigenetic state. We find that silencing is dependent on germline nuclear RNAi factors and post-transcriptional mechanisms. Consistent with these later observations, inheritance does not require the silenced locus, and we provide genetic evidence that small RNAs embody the inherited silencing signal. Notably, heritable germline silencing directs somatic epigenetic silencing. Somatic silencing does not require somatic nuclear RNAi but instead requires both maternal germline nuclear RNAi and chromatin-modifying activity. Coupling inherited germline silencing to somatic silencing may enable selection for physiologically important traits.
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Affiliation(s)
- Olga Minkina
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Craig P Hunter
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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Klosin A, Reis K, Hidalgo-Carcedo C, Casas E, Vavouri T, Lehner B. Impaired DNA replication derepresses chromatin and generates a transgenerationally inherited epigenetic memory. SCIENCE ADVANCES 2017; 3:e1701143. [PMID: 28835928 PMCID: PMC5559210 DOI: 10.1126/sciadv.1701143] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/21/2017] [Indexed: 06/07/2023]
Abstract
Impaired DNA replication is a hallmark of cancer and a cause of genomic instability. We report that, in addition to causing genetic change, impaired DNA replication during embryonic development can have major epigenetic consequences for a genome. In a genome-wide screen, we identified impaired DNA replication as a cause of increased expression from a repressed transgene in Caenorhabditis elegans. The acquired expression state behaved as an "epiallele," being inherited for multiple generations before fully resetting. Derepression was not restricted to the transgene but was caused by a global reduction in heterochromatin-associated histone modifications due to the impaired retention of modified histones on DNA during replication in the early embryo. Impaired DNA replication during development can therefore globally derepress chromatin, creating new intergenerationally inherited epigenetic expression states.
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Affiliation(s)
- Adam Klosin
- European Molecular Biology Laboratory–Centre for Genomic Regulation (EMBL-CRG) Systems Biology Unit, CRG, the Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Kadri Reis
- European Molecular Biology Laboratory–Centre for Genomic Regulation (EMBL-CRG) Systems Biology Unit, CRG, the Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Cristina Hidalgo-Carcedo
- European Molecular Biology Laboratory–Centre for Genomic Regulation (EMBL-CRG) Systems Biology Unit, CRG, the Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Eduard Casas
- Program of Predictive and Personalized Medicine of Cancer–Institute Germans Trias i Pujol, Can Ruti Campus, Ctra de Can Ruti, Camí de les Escoles s/n, Badalona, 08916 Barcelona, Spain
| | - Tanya Vavouri
- Program of Predictive and Personalized Medicine of Cancer–Institute Germans Trias i Pujol, Can Ruti Campus, Ctra de Can Ruti, Camí de les Escoles s/n, Badalona, 08916 Barcelona, Spain
- Josep Carreras Leukaemia Research Institute (IJC), Can Ruti Campus, Ctra de Can Ruti, Camí de les Escoles s/n, Badalona, 08916 Barcelona, Spain
| | - Ben Lehner
- European Molecular Biology Laboratory–Centre for Genomic Regulation (EMBL-CRG) Systems Biology Unit, CRG, the Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08003 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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50
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Klosin A, Casas E, Hidalgo-Carcedo C, Vavouri T, Lehner B. Transgenerational transmission of environmental information inC. elegans. Science 2017; 356:320-323. [DOI: 10.1126/science.aah6412] [Citation(s) in RCA: 254] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 12/21/2016] [Accepted: 03/24/2017] [Indexed: 01/03/2023]
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