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Baumgartner L, Ipsaro JJ, Hohmann U, Handler D, Schleiffer A, Duchek P, Brennecke J. Evolutionary adaptation of an HP1-protein chromodomain integrates chromatin and DNA sequence signals. eLife 2024; 13:RP93194. [PMID: 38995818 PMCID: PMC11245307 DOI: 10.7554/elife.93194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024] Open
Abstract
Members of the diverse heterochromatin protein 1 (HP1) family play crucial roles in heterochromatin formation and maintenance. Despite the similar affinities of their chromodomains for di- and tri-methylated histone H3 lysine 9 (H3K9me2/3), different HP1 proteins exhibit distinct chromatin-binding patterns, likely due to interactions with various specificity factors. Previously, we showed that the chromatin-binding pattern of the HP1 protein Rhino, a crucial factor of the Drosophila PIWI-interacting RNA (piRNA) pathway, is largely defined by a DNA sequence-specific C2H2 zinc finger protein named Kipferl (Baumgartner et al., 2022). Here, we elucidate the molecular basis of the interaction between Rhino and its guidance factor Kipferl. Through phylogenetic analyses, structure prediction, and in vivo genetics, we identify a single amino acid change within Rhino's chromodomain, G31D, that does not affect H3K9me2/3 binding but disrupts the interaction between Rhino and Kipferl. Flies carrying the rhinoG31D mutation phenocopy kipferl mutant flies, with Rhino redistributing from piRNA clusters to satellite repeats, causing pronounced changes in the ovarian piRNA profile of rhinoG31D flies. Thus, Rhino's chromodomain functions as a dual-specificity module, facilitating interactions with both a histone mark and a DNA-binding protein.
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Affiliation(s)
- Lisa Baumgartner
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Jonathan J Ipsaro
- Howard Hughes Medical Institute, W.M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States
| | - Ulrich Hohmann
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Dominik Handler
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Alexander Schleiffer
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Peter Duchek
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Julius Brennecke
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
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Srivastav SP, Feschotte C, Clark AG. Rapid evolution of piRNA clusters in the Drosophila melanogaster ovary. Genome Res 2024; 34:711-724. [PMID: 38749655 PMCID: PMC11216404 DOI: 10.1101/gr.278062.123] [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: 05/08/2023] [Accepted: 05/07/2024] [Indexed: 05/28/2024]
Abstract
The piRNA pathway is a highly conserved mechanism to repress transposable element (TE) activity in the animal germline via a specialized class of small RNAs called piwi-interacting RNAs (piRNAs). piRNAs are produced from discrete genomic regions called piRNA clusters (piCs). Although the molecular processes by which piCs function are relatively well understood in Drosophila melanogaster, much less is known about the origin and evolution of piCs in this or any other species. To investigate piC origin and evolution, we use a population genomic approach to compare piC activity and sequence composition across eight geographically distant strains of D. melanogaster with high-quality long-read genome assemblies. We perform annotations of ovary piCs and genome-wide TE content in each strain. Our analysis uncovers extensive variation in piC activity across strains and signatures of rapid birth and death of piCs. Most TEs inferred to be recently active show an enrichment of insertions into old and large piCs, consistent with the previously proposed "trap" model of piC evolution. In contrast, a small subset of active LTR families is enriched for the formation of new piCs, suggesting that these TEs have higher proclivity to form piCs. Thus, our findings uncover processes leading to the origin of piCs. We propose that piC evolution begins with the emergence of piRNAs from individual insertions of a few select TE families prone to seed new piCs that subsequently expand by accretion of insertions from most other TE families during evolution to form larger "trap" clusters. Our study shows that TEs themselves are the major force driving the rapid evolution of piCs.
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Affiliation(s)
- Satyam P Srivastav
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
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3
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Chen P, Pan KC, Park EH, Luo Y, Lee YCG, Aravin AA. Escalation of genome defense capacity enables control of an expanding meiotic driver. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.12.598716. [PMID: 38915551 PMCID: PMC11195268 DOI: 10.1101/2024.06.12.598716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
From RNA interference to chromatin silencing, diverse genome defense pathways silence selfish genetic elements to safeguard genome integrity1,2. Despite their diversity, different defense pathways share a modular organization, where numerous specificity factors identify diverse targets and common effectors silence them. In the PIWI-interacting RNA (piRNA) pathway, which controls selfish elements in the metazoan germline, diverse target RNAs are first identified by complementary base pairing with piRNAs and then silenced by PIWI-clade nucleases via enzymatic cleavage1,3. Such a binary architecture allows the defense systems to be readily adaptable, where new targets can be captured via the innovation of new specificity factors4,5. Thus, our current understanding of genome defense against lineage-specific selfish genes has been largely limited to the evolution of specificity factors, while it remains poorly understood whether other types of innovations are required. Here, we describe a new type of innovation, which escalates the defense capacity of the piRNA pathway to control a recently expanded selfish gene in Drosophila melanogaster. Through an in vivo RNAi screen for repressors of Stellate-a recently evolved and expanded selfish meiotic driver6-8-we discovered a novel defense factor, Trailblazer. Trailblazer is a transcription factor that promotes the expression of two PIWI-clade nucleases, Aub and AGO3, to match Stellate in abundance. Recent innovation in the DNA-binding domain of Trailblazer enabled it to drastically elevate Aub and AGO3 expression in the D. melanogaster lineage, thereby escalating the silencing capacity of the piRNA pathway to control expanded Stellate and safeguard fertility. As copy-number expansion is a recurrent feature of diverse selfish genes across the tree of life9-12, we envision that augmenting the defense capacity to quantitatively match selfish genes is likely a repeatedly employed defense strategy in evolution.
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Affiliation(s)
- Peiwei Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Katherine C. Pan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Eunice H. Park
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Yicheng Luo
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Yuh Chwen G. Lee
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California 92697, USA
| | - Alexei A. Aravin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Kotov AA, Adashev VE, Kombarov IA, Bazylev SS, Shatskikh AS, Olenina LV. Molecular Insights into Female Hybrid Sterility in Interspecific Crosses between Drosophila melanogaster and Drosophila simulans. Int J Mol Sci 2024; 25:5681. [PMID: 38891872 PMCID: PMC11172174 DOI: 10.3390/ijms25115681] [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: 04/19/2024] [Revised: 05/19/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024] Open
Abstract
Species of the genus Drosophila have served as favorite models in speciation studies; however, genetic factors of interspecific reproductive incompatibility are under-investigated. Here, we performed an analysis of hybrid female sterility by crossing Drosophila melanogaster females and Drosophila simulans males. Using transcriptomic data analysis and molecular, cellular, and genetic approaches, we analyzed differential gene expression, transposable element (TE) activity, piRNA biogenesis, and functional defects of oogenesis in hybrids. Premature germline stem cell loss was the most prominent defect of oogenesis in hybrid ovaries. Because of the differential expression of genes encoding piRNA pathway components, rhino and deadlock, the functional RDCmel complex in hybrid ovaries was not assembled. However, the activity of the RDCsim complex was maintained in hybrids independent of the genomic origin of piRNA clusters. Despite the identification of a cohort of overexpressed TEs in hybrid ovaries, we found no evidence that their activity can be considered the main cause of hybrid sterility. We revealed a complicated pattern of Vasa protein expression in the hybrid germline, including partial AT-chX piRNA targeting of the vasasim allele and a significant zygotic delay in vasamel expression. We arrived at the conclusion that the hybrid sterility phenotype was caused by intricate multi-locus differences between the species.
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Affiliation(s)
- Alexei A. Kotov
- Department of Molecular Mechanisms for Realization of Genetic Information, National Research Centre “Kurchatov Institute”, Moscow 123182, Russia; (A.A.K.); (V.E.A.); (S.S.B.)
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow 119334, Russia; (I.A.K.); (A.S.S.)
| | - Vladimir E. Adashev
- Department of Molecular Mechanisms for Realization of Genetic Information, National Research Centre “Kurchatov Institute”, Moscow 123182, Russia; (A.A.K.); (V.E.A.); (S.S.B.)
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow 119334, Russia; (I.A.K.); (A.S.S.)
| | - Ilia A. Kombarov
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow 119334, Russia; (I.A.K.); (A.S.S.)
| | - Sergei S. Bazylev
- Department of Molecular Mechanisms for Realization of Genetic Information, National Research Centre “Kurchatov Institute”, Moscow 123182, Russia; (A.A.K.); (V.E.A.); (S.S.B.)
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow 119334, Russia; (I.A.K.); (A.S.S.)
| | - Aleksei S. Shatskikh
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow 119334, Russia; (I.A.K.); (A.S.S.)
| | - Ludmila V. Olenina
- Department of Molecular Mechanisms for Realization of Genetic Information, National Research Centre “Kurchatov Institute”, Moscow 123182, Russia; (A.A.K.); (V.E.A.); (S.S.B.)
- Laboratory of Functional Genomics, Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow 119334, Russia; (I.A.K.); (A.S.S.)
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Ames A, Seman M, Larkin A, Raiymbek G, Chen Z, Levashkevich A, Kim B, Biteen JS, Ragunathan K. Epigenetic memory is governed by an effector recruitment specificity toggle in Heterochromatin Protein 1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.28.569027. [PMID: 38077059 PMCID: PMC10705379 DOI: 10.1101/2023.11.28.569027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
HP1 proteins are essential for establishing and maintaining transcriptionally silent heterochromatin. They dimerize, forming a binding interface to recruit diverse chromatin-associated factors. HP1 proteins are specialized and rapidly evolve, but the extent of variation required to achieve functional specialization is unknown. To investigate how changes in amino acid sequence impacts epigenetic inheritance, we performed a targeted mutagenesis screen of the S. pombe HP1 homolog, Swi6. Substitutions within an auxiliary surface adjacent to the HP1 dimerization interface produced Swi6 variants with divergent maintenance properties. Remarkably, substitutions at a single amino acid position led to the persistent gain or loss of epigenetic inheritance. These substitutions increased Swi6 chromatin occupancy in vivo and altered Swi6-protein interactions that reprogram H3K9me maintenance. We show that relatively minor changes in Swi6 amino acid composition can lead to profound changes in epigenetic inheritance which provides a redundant mechanism to evolve novel effector specificity. .
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6
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Ho S, Theurkauf W, Rice N. piRNA-Guided Transposon Silencing and Response to Stress in Drosophila Germline. Viruses 2024; 16:714. [PMID: 38793595 PMCID: PMC11125864 DOI: 10.3390/v16050714] [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: 03/28/2024] [Revised: 04/23/2024] [Accepted: 04/27/2024] [Indexed: 05/26/2024] Open
Abstract
Transposons are integral genome constituents that can be domesticated for host functions, but they also represent a significant threat to genome stability. Transposon silencing is especially critical in the germline, which is dedicated to transmitting inherited genetic material. The small Piwi-interacting RNAs (piRNAs) have a deeply conserved function in transposon silencing in the germline. piRNA biogenesis and function are particularly well understood in Drosophila melanogaster, but some fundamental mechanisms remain elusive and there is growing evidence that the pathway is regulated in response to genotoxic and environmental stress. Here, we review transposon regulation by piRNAs and the piRNA pathway regulation in response to stress, focusing on the Drosophila female germline.
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Affiliation(s)
- Samantha Ho
- Program in Molecular Medicine, University Campus, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA;
| | | | - Nicholas Rice
- Program in Molecular Medicine, University Campus, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA;
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7
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Balan T, Lerner LK, Holoch D, Duharcourt S. Small-RNA-guided histone modifications and somatic genome elimination in ciliates. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1848. [PMID: 38605483 DOI: 10.1002/wrna.1848] [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: 01/25/2024] [Revised: 03/22/2024] [Accepted: 03/22/2024] [Indexed: 04/13/2024]
Abstract
Transposable elements and other repeats are repressed by small-RNA-guided histone modifications in fungi, plants and animals. The specificity of silencing is achieved through base-pairing of small RNAs corresponding to the these genomic loci to nascent noncoding RNAs, which allows the recruitment of histone methyltransferases that methylate histone H3 on lysine 9. Self-reinforcing feedback loops enhance small RNA production and ensure robust and heritable repression. In the unicellular ciliate Paramecium tetraurelia, small-RNA-guided histone modifications lead to the elimination of transposable elements and their remnants, a definitive form of repression. In this organism, germline and somatic functions are separated within two types of nuclei with different genomes. At each sexual cycle, development of the somatic genome is accompanied by the reproducible removal of approximately a third of the germline genome. Instead of recruiting a H3K9 methyltransferase, small RNAs corresponding to eliminated sequences tether Polycomb Repressive Complex 2, which in ciliates has the unique property of catalyzing both lysine 9 and lysine 27 trimethylation of histone H3. These histone modifications that are crucial for the elimination of transposable elements are thought to guide the endonuclease complex, which triggers double-strand breaks at these specific genomic loci. The comparison between ciliates and other eukaryotes underscores the importance of investigating small-RNAs-directed chromatin silencing in a diverse range of organisms. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > RNAi: Mechanisms of Action.
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Affiliation(s)
- Thomas Balan
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | | | - Daniel Holoch
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
- Institut Curie, INSERM U934/CNRS UMR 3215, Paris Sciences et Lettres Research University, Sorbonne University, Paris, France
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8
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Panyushev N, Selitskiy M, Melnichenko V, Lebedev E, Okorokova L, Adonin L. Dynamic Evolution of Repetitive Elements and Chromatin States in Apis mellifera Subspecies. Genes (Basel) 2024; 15:89. [PMID: 38254978 PMCID: PMC10815273 DOI: 10.3390/genes15010089] [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: 12/15/2023] [Revised: 01/07/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
In this study, we elucidate the contribution of repetitive DNA sequences to the establishment of social structures in honeybees (Apis mellifera). Despite recent advancements in understanding the molecular mechanisms underlying the formation of honeybee castes, primarily associated with Notch signaling, the comprehensive identification of specific genomic cis-regulatory sequences remains elusive. Our objective is to characterize the repetitive landscape within the genomes of two honeybee subspecies, namely A. m. mellifera and A. m. ligustica. An observed recent burst of repeats in A. m. mellifera highlights a notable distinction between the two subspecies. After that, we transitioned to identifying differentially expressed DNA elements that may function as cis-regulatory elements. Nevertheless, the expression of these sequences showed minimal disparity in the transcriptome during caste differentiation, a pivotal process in honeybee eusocial organization. Despite this, chromatin segmentation, facilitated by ATAC-seq, ChIP-seq, and RNA-seq data, revealed a distinct chromatin state associated with repeats. Lastly, an analysis of sequence divergence among elements indicates successive changes in repeat states, correlating with their respective time of origin. Collectively, these findings propose a potential role of repeats in acquiring novel regulatory functions.
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Affiliation(s)
- Nick Panyushev
- Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, 625003 Tyumen, Russia; (N.P.); (M.S.)
- Bioinformatics Institute, 197342 St. Petersburg, Russia;
| | - Max Selitskiy
- Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, 625003 Tyumen, Russia; (N.P.); (M.S.)
| | - Vasilina Melnichenko
- International Scientific and Research Institute of Bioengineering, ITMO University, 197101 St. Petersburg, Russia;
| | - Egor Lebedev
- Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, 625003 Tyumen, Russia; (N.P.); (M.S.)
| | | | - Leonid Adonin
- Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, 625003 Tyumen, Russia; (N.P.); (M.S.)
- Institute of Biomedical Chemistry, Group of Mechanisms for Nanosystems Targeted Delivery, 119121 Moscow, Russia
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9
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Scarpa A, Kofler R. The impact of paramutations on the invasion dynamics of transposable elements. Genetics 2023; 225:iyad181. [PMID: 37819004 PMCID: PMC10697812 DOI: 10.1093/genetics/iyad181] [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: 07/14/2023] [Revised: 09/25/2023] [Accepted: 09/28/2023] [Indexed: 10/13/2023] Open
Abstract
According to the prevailing view, the trap model, the activity of invading transposable elements (TEs) is greatly reduced when a TE copy jumps into a piRNA cluster, which triggers the emergence of piRNAs that silence the TE. One crucial component in the host defence are paramutations. Mediated by maternally deposited piRNAs, paramutations convert TE insertions into piRNA producing loci, thereby transforming selfish TEs into agents of the host defence. Despite this significant effect, the impact of paramutations on the dynamics of TE invasions remains unknown. To address this issue, we performed extensive forward simulations of TE invasions with piRNA clusters and paramutations. We found that paramutations significantly affect TE dynamics, by accelerating the silencing of TE invasions, reducing the number of insertions accumulating during the invasions and mitigating the fitness cost of TEs. We also demonstrate that piRNA production induced by paramutations, an epigenetically inherited trait, may be positively selected. Finally, we show that paramutations may account for three important open problems with the trap model. Firstly, paramutated TE insertions may compensate for the insufficient number of insertions in piRNA clusters observed in previous studies. Secondly, paramutations may explain the discrepancy between the observed and the expected abundance of different TE families in Drosophila melanogaster. Thirdly, piRNA clusters may be crucial to trigger the host defence, but paramutations render the clusters dispensable once the defence has been established. This could account for the lack of TE activation when three major piRNA clusters were deleted in a previous study.
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Affiliation(s)
- Almorò Scarpa
- Institut für Populationsgenetik, Vetmeduni Vienna, Veterinärplatz 1, Wien 1210, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Veterinärplatz 1, Wien 1210, Austria
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10
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Wierzbicki F, Kofler R. The composition of piRNA clusters in Drosophila melanogaster deviates from expectations under the trap model. BMC Biol 2023; 21:224. [PMID: 37858221 PMCID: PMC10588112 DOI: 10.1186/s12915-023-01727-7] [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: 03/06/2023] [Accepted: 10/06/2023] [Indexed: 10/21/2023] Open
Abstract
BACKGROUND It is widely assumed that the invasion of a transposable element (TE) in mammals and invertebrates is stopped when a copy of the TE jumps into a piRNA cluster (i.e., the trap model). However, recent works, which for example showed that deletion of three major piRNA clusters has no effect on TE activity, cast doubt on the trap model. RESULTS Here, we test the trap model from a population genetics perspective. Our simulations show that the composition of regions that act as transposon traps (i.e., potentially piRNA clusters) ought to deviate from regions that have no effect on TE activity. We investigated TEs in five Drosophila melanogaster strains using three complementary approaches to test whether the composition of piRNA clusters matches these expectations. We found that the abundance of TE families inside and outside of piRNA clusters is highly correlated, although this is not expected under the trap model. Furthermore, the distribution of the number of TE insertions in piRNA clusters is also much broader than expected. CONCLUSIONS We found that the observed composition of piRNA clusters is not in agreement with expectations under the simple trap model. Dispersed piRNA producing TE insertions and temporal as well as spatial heterogeneity of piRNA clusters may account for these deviations.
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Affiliation(s)
- Filip Wierzbicki
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vienna, Austria
| | - Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria.
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Venkei ZG, Gainetdinov I, Bagci A, Starostik MR, Choi CP, Fingerhut JM, Chen P, Balsara C, Whitfield TW, Bell GW, Feng S, Jacobsen SE, Aravin AA, Kim JK, Zamore PD, Yamashita YM. A maternally programmed intergenerational mechanism enables male offspring to make piRNAs from Y-linked precursor RNAs in Drosophila. Nat Cell Biol 2023; 25:1495-1505. [PMID: 37723298 PMCID: PMC10567549 DOI: 10.1038/s41556-023-01227-4] [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: 09/26/2022] [Accepted: 08/09/2023] [Indexed: 09/20/2023]
Abstract
In animals, PIWI-interacting RNAs (piRNAs) direct PIWI proteins to silence complementary targets such as transposons. In Drosophila and other species with a maternally specified germline, piRNAs deposited in the egg initiate piRNA biogenesis in the progeny. However, Y chromosome loci cannot participate in such a chain of intergenerational inheritance. How then can the biogenesis of Y-linked piRNAs be initiated? Here, using Suppressor of Stellate (Su(Ste)), a Y-linked Drosophila melanogaster piRNA locus as a model, we show that Su(Ste) piRNAs are made in the early male germline via 5'-to-3' phased piRNA biogenesis initiated by maternally deposited 1360/Hoppel transposon piRNAs. Notably, deposition of Su(Ste) piRNAs from XXY mothers obviates the need for phased piRNA biogenesis in sons. Together, our study uncovers a developmentally programmed, intergenerational mechanism that allows fly mothers to protect their sons using a Y-linked piRNA locus.
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Affiliation(s)
- Zsolt G Venkei
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ildar Gainetdinov
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Ayca Bagci
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | | | - Charlotte P Choi
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Jaclyn M Fingerhut
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Howard Hughes Medical Institute, Whitehead Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Peiwei Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Chiraag Balsara
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Troy W Whitfield
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - George W Bell
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Suhua Feng
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA, USA
- Eli and Edyth Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, USA
| | - Steven E Jacobsen
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA, USA
- Eli and Edyth Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, USA
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Alexei A Aravin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - John K Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Phillip D Zamore
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, USA.
- Howard Hughes Medical Institute, University of Massachusetts Chan Medical School, Worcester, MA, USA.
| | - Yukiko M Yamashita
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Whitehead Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.
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12
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Lawlor MA, Ellison CE. Evolutionary dynamics between transposable elements and their host genomes: mechanisms of suppression and escape. Curr Opin Genet Dev 2023; 82:102092. [PMID: 37517354 PMCID: PMC10530431 DOI: 10.1016/j.gde.2023.102092] [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: 02/28/2023] [Revised: 06/27/2023] [Accepted: 07/02/2023] [Indexed: 08/01/2023]
Abstract
Transposable elements (TEs) are ubiquitous among eukaryotic species. Their evolutionary persistence is likely due to a combination of tolerogenic, evasive/antagonistic, and cooperative interactions with their host genomes. Here, we focus on metazoan species and review recent advances related to the harmful effects of TE insertions, including how epigenetic effects and TE-derived RNAs can damage host cells. We discuss new findings related to host pathways that silence TEs, such as the piRNA pathway and the APOBEC3 and Kruppel-associated box zinc finger gene families. Finally, we summarize novel strategies used by TEs to evade host silencing, including the Y chromosome as a permissive niche for TE mobilization and TE counterdefense strategies to block host silencing factors.
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Wells JN, Chang NC, McCormick J, Coleman C, Ramos N, Jin B, Feschotte C. Transposable elements drive the evolution of metazoan zinc finger genes. Genome Res 2023; 33:1325-1339. [PMID: 37714714 PMCID: PMC10547256 DOI: 10.1101/gr.277966.123] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 06/15/2023] [Indexed: 09/17/2023]
Abstract
Cys2-His2 zinc finger genes (ZNFs) form the largest family of transcription factors in metazoans. ZNF evolution is highly dynamic and characterized by the rapid expansion and contraction of numerous subfamilies across the animal phylogeny. The forces and mechanisms underlying rapid ZNF evolution remain poorly understood, but there is growing evidence that, in tetrapods, the targeting and repression of lineage-specific transposable elements (TEs) plays a critical role in the evolution of the Krüppel-associated box ZNF (KZNF) subfamily. Currently, it is unknown whether this function and coevolutionary relationship is unique to KZNFs or is a broader feature of metazoan ZNFs. Here, we present evidence that genomic conflict with TEs has been a central driver of the diversification of ZNFs in animals. Sampling from 3221 genome assemblies, we show that the copy number of retroelements correlates with that of ZNFs across at least 750 million years of metazoan evolution. Using computational predictions, we show that ZNFs preferentially bind TEs in diverse animal species. We further investigate the largest ZNF subfamily found in cyprinid fish, which is characterized by a conserved sequence we dubbed the fish N-terminal zinc finger-associated (FiNZ) domain. Zebrafish possess approximately 700 FiNZ-ZNFs, many of which are evolving adaptively under positive selection. Like mammalian KZNFs, most zebrafish FiNZ-ZNFs are expressed at the onset of zygotic genome activation, and blocking their translation using morpholinos during early embryogenesis results in derepression of transcriptionally active TEs. Together, these data suggest that ZNF diversification has been intimately connected to TE expansion throughout animal evolution.
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Affiliation(s)
- Jonathan N Wells
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA;
| | - Ni-Chen Chang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - John McCormick
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - Caitlyn Coleman
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida 33620, USA
| | - Nathalie Ramos
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
- Department of Genetics and Genomic Sciences, Center for Transformative Disease Modeling, Tisch Cancer Institute, Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Bozhou Jin
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA;
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Pozmanter C, Van Doren M. Germline sex determination: How males and females tame transposons in their own ways. Curr Biol 2023; 33:R442-R444. [PMID: 37279665 PMCID: PMC10436265 DOI: 10.1016/j.cub.2023.04.001] [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] [Indexed: 06/08/2023]
Abstract
The piRNA pathway represses transposon activity to protect the germline genome for future generations. A new study shows how germline sex determination influences the production of different piRNAs in male and female germ cells.
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Affiliation(s)
| | - Mark Van Doren
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
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Asif-Laidin A, Casier K, Ziriat Z, Boivin A, Viodé E, Delmarre V, Ronsseray S, Carré C, Teysset L. Modeling early germline immunization after horizontal transfer of transposable elements reveals internal piRNA cluster heterogeneity. BMC Biol 2023; 21:117. [PMID: 37226160 DOI: 10.1186/s12915-023-01616-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 05/05/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND A fraction of all genomes is composed of transposable elements (TEs) whose mobility needs to be carefully controlled. In gonads, TE activity is repressed by PIWI-interacting RNAs (piRNAs), a class of small RNAs synthesized by heterochromatic loci enriched in TE fragments, called piRNA clusters. Maintenance of active piRNA clusters across generations is secured by maternal piRNA inheritance providing the memory for TE repression. On rare occasions, genomes encounter horizontal transfer (HT) of new TEs with no piRNA targeting them, threatening the host genome integrity. Naïve genomes can eventually start to produce new piRNAs against these genomic invaders, but the timing of their emergence remains elusive. RESULTS Using a set of TE-derived transgenes inserted in different germline piRNA clusters and functional assays, we have modeled a TE HT in Drosophila melanogaster. We have found that the complete co-option of these transgenes by a germline piRNA cluster can occur within four generations associated with the production of new piRNAs all along the transgenes and the germline silencing of piRNA sensors. Synthesis of new transgenic TE piRNAs is linked to piRNA cluster transcription dependent on Moonshiner and heterochromatin mark deposition that propagates more efficiently on short sequences. Moreover, we found that sequences located within piRNA clusters can have different piRNA profiles and can influence transcript accumulation of nearby sequences. CONCLUSIONS Our study reveals that genetic and epigenetic properties, such as transcription, piRNA profiles, heterochromatin, and conversion efficiency along piRNA clusters, could be heterogeneous depending on the sequences that compose them. These findings suggest that the capacity of transcriptional signal erasure induced by the chromatin complex specific of the piRNA cluster can be incomplete through the piRNA cluster loci. Finally, these results have revealed an unexpected level of complexity that highlights a new magnitude of piRNA cluster plasticity fundamental for the maintenance of genome integrity.
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Affiliation(s)
- Amna Asif-Laidin
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Karine Casier
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
- Present Address: CNRS, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, UMR8226, Telomere Biology, Paris, F-75005, France
| | - Zoheir Ziriat
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Antoine Boivin
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Elise Viodé
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Valérie Delmarre
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Stéphane Ronsseray
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Clément Carré
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Laure Teysset
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France.
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16
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Chen P, Aravin AA. Genetic control of a sex-specific piRNA program. Curr Biol 2023; 33:1825-1835.e3. [PMID: 37059098 PMCID: PMC10431932 DOI: 10.1016/j.cub.2023.03.057] [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: 11/17/2022] [Revised: 02/15/2023] [Accepted: 03/17/2023] [Indexed: 04/16/2023]
Abstract
Sexually dimorphic traits in morphologies are widely studied,1,2,3,4 but those in essential molecular pathways remain largely unexplored. Previous work showed substantial sex differences in Drosophila gonadal piRNAs,5 which guide PIWI proteins to silence selfish genetic elements, thereby safeguarding fertility.6,7,8 However, the genetic control mechanisms of piRNA sexual dimorphism remain unknown. Here, we showed that most sex differences in the piRNA program originate from the germ line rather than the gonadal somatic cells. Building on this, we dissected the contribution of sex chromosomes and cellular sexual identity toward the sex-specific germline piRNA program. We found that the presence of the Y chromosome is sufficient to recapitulate some aspects of the male piRNA program in a female cellular environment. Meanwhile, sexual identity controls the sexually divergent piRNA production from X-linked and autosomal loci, revealing a crucial input from sex determination into piRNA biogenesis. Sexual identity regulates piRNA biogenesis through Sxl, and this effect is mediated, in part, through chromatin proteins Phf7 and Kipferl. Together, our work delineated the genetic control of a sex-specific piRNA program, where sex chromosomes and sexual identity collectively sculpt an essential molecular trait.
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Affiliation(s)
- Peiwei Chen
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, CA 91125, USA.
| | - Alexei A Aravin
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, CA 91125, USA.
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17
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Akkouche A, Brasset E. More than just an inert dense region. eLife 2022; 11:83076. [PMID: 36239700 PMCID: PMC9566848 DOI: 10.7554/elife.83076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A newly discovered protein helps define a subset of heterochromatin regions that can silence harmful mobile genetic elements in the genome of fruit flies.
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Affiliation(s)
- Abdou Akkouche
- iGReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, Clermont-Ferrand, France
| | - Emilie Brasset
- iGReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, Clermont-Ferrand, France
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