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McQuarrie DWJ, Alizada A, Nicholson BC, Soller M. Rapid evolution of promoters from germline-specifically expressed genes including transposon silencing factors. BMC Genomics 2024; 25:678. [PMID: 38977960 PMCID: PMC11229233 DOI: 10.1186/s12864-024-10584-9] [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: 04/10/2024] [Accepted: 07/01/2024] [Indexed: 07/10/2024] Open
Abstract
BACKGROUND The piRNA pathway in animal gonads functions as an 'RNA-based immune system', serving to silence transposable elements and prevent inheritance of novel invaders. In Drosophila, this pathway relies on three gonad-specific Argonaute proteins (Argonaute-3, Aubergine and Piwi) that associate with 23-28 nucleotide piRNAs, directing the silencing of transposon-derived transcripts. Transposons constitute a primary driver of genome evolution, yet the evolution of piRNA pathway factors has not received in-depth exploration. Specifically, channel nuclear pore proteins, which impact piRNA processing, exhibit regions of rapid evolution in their promoters. Consequently, the question arises whether such a mode of evolution is a general feature of transposon silencing pathways. RESULTS By employing genomic analysis of coding and promoter regions within genes that function in transposon silencing in Drosophila, we demonstrate that the promoters of germ cell-specific piRNA factors are undergoing rapid evolution. Our findings indicate that rapid promoter evolution is a common trait among piRNA factors engaged in germline silencing across insect species, potentially contributing to gene expression divergence in closely related taxa. Furthermore, we observe that the promoters of genes exclusively expressed in germ cells generally exhibit rapid evolution, with some divergence in gene expression. CONCLUSION Our results suggest that increased germline promoter evolution, in partnership with other factors, could contribute to transposon silencing and evolution of species through differential expression of genes driven by invading transposons.
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Affiliation(s)
- David W J McQuarrie
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Azad Alizada
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Benjamin Czech Nicholson
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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2
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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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3
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Münch L, Helmprobst F, Volff JN, Chalopin D, Schartl M, Kneitz S. Transposable Element Expression Profiles in Premalignant Pigment Cell Lesions and Melanoma of Xiphophorus. Genes (Basel) 2024; 15:620. [PMID: 38790249 PMCID: PMC11121471 DOI: 10.3390/genes15050620] [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: 05/03/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
Transposable elements (TEs) are characterized by their ability to change their genomic position. Through insertion or recombination leading to deletions and other chromosomal aberrations, they can cause genetic instability. The extent to which they thereby exert regulatory influence on cellular functions is unclear. To better characterize TEs in processes such as carcinogenesis, we used the well-established Xiphophorus melanoma model. By transcriptome sequencing, we show that an increasing total number in transposons correlates with progression of malignancy in melanoma samples from Xiphophorus interspecific hybrids. Further, by comparing the presence of TEs in the parental genomes of Xiphophorus maculatus and Xiphophorus hellerii, we could show that even in closely related species, genomic location and spectrum of TEs are considerably different.
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Affiliation(s)
- Luca Münch
- Neurology Asklepios Klinik Barmbek, Rübenkamp 220, 22307 Hamburg, Germany;
| | - Frederik Helmprobst
- Institute of Neuropathology, Philipps-University Marburg, 35037 Marburg, Germany;
| | | | | | - Manfred Schartl
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 786666, USA
- Developmental Biochemistry, University of Würzburg, 97974 Würzburg, Germany
| | - Susanne Kneitz
- Biochemistry and Cell Biology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany;
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4
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Cutter AD. Speciation and development. Evol Dev 2023; 25:289-327. [PMID: 37545126 DOI: 10.1111/ede.12454] [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: 03/07/2023] [Revised: 06/13/2023] [Accepted: 07/20/2023] [Indexed: 08/08/2023]
Abstract
Understanding general principles about the origin of species remains one of the foundational challenges in evolutionary biology. The genomic divergence between groups of individuals can spawn hybrid inviability and hybrid sterility, which presents a tantalizing developmental problem. Divergent developmental programs may yield either conserved or divergent phenotypes relative to ancestral traits, both of which can be responsible for reproductive isolation during the speciation process. The genetic mechanisms of developmental evolution involve cis- and trans-acting gene regulatory change, protein-protein interactions, genetic network structures, dosage, and epigenetic regulation, all of which also have roots in population genetic and molecular evolutionary processes. Toward the goal of demystifying Darwin's "mystery of mysteries," this review integrates microevolutionary concepts of genetic change with principles of organismal development, establishing explicit links between population genetic process and developmental mechanisms in the production of macroevolutionary pattern. This integration aims to establish a more unified view of speciation that binds process and mechanism.
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Affiliation(s)
- Asher D Cutter
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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5
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Bodelón A, Fablet M, Veber P, Vieira C, García Guerreiro MP. OUP accepted manuscript. Genome Biol Evol 2022; 14:6526395. [PMID: 35143649 PMCID: PMC8872975 DOI: 10.1093/gbe/evac024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2022] [Indexed: 11/21/2022] Open
Abstract
Interspecific hybridization is often seen as a genomic stress that may lead to new gene expression patterns and deregulation of transposable elements (TEs). The understanding of expression changes in hybrids compared with parental species is essential to disentangle their putative role in speciation processes. However, to date we ignore the detailed mechanisms involved in genomic deregulation in hybrids. We studied the ovarian transcriptome and epigenome of the Drosophila buzzatii and Drosophila koepferae species together with their F1 hybrid females. We found a trend toward underexpression of genes and TE families in hybrids. The epigenome in hybrids was highly similar to the parental epigenomes and showed intermediate histone enrichments between parental species in most cases. Differential gene expression in hybrids was often associated only with changes in H3K4me3 enrichments, whereas differential TE family expression in hybrids may be associated with changes in H3K4me3, H3K9me3, or H3K27me3 enrichments. We identified specific genes and TE families, which their differential expression in comparison with the parental species was explained by their differential chromatin mark combination enrichment. Finally, cis–trans compensatory regulation could also contribute in some way to the hybrid deregulation. This work provides the first study of histone content in Drosophila interspecific hybrids and their effect on gene and TE expression deregulation.
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Affiliation(s)
- Alejandra Bodelón
- Grup de Genòmica, Bioinformática i Biologia Evolutiva, Departament de Genètica i Microbiologia (Edifici C), Universitat Autònoma de Barcelona, Spain
| | - Marie Fablet
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
- Institut universitaire de France, France
| | - Philippe Veber
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Cristina Vieira
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Maria Pilar García Guerreiro
- Grup de Genòmica, Bioinformática i Biologia Evolutiva, Departament de Genètica i Microbiologia (Edifici C), Universitat Autònoma de Barcelona, Spain
- Corresponding author: E-mail:
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6
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Xie D, Ye P, Ma Y, Li Y, Liu X, Sarkies P, Zhao Z. Genetic exchange with an outcrossing sister species causes severe genome-wide dysregulation in a selfing Caenorhabditis nematode. Genome Res 2022; 32:2015-2027. [PMID: 36351773 PMCID: PMC9808620 DOI: 10.1101/gr.277205.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 11/04/2022] [Indexed: 11/11/2022]
Abstract
Different modes of reproduction evolve rapidly, with important consequences for genome composition. Selfing species often occupy a similar niche as their outcrossing sister species with which they are able to mate and produce viable hybrid progeny, raising the question of how they maintain genomic identity. Here, we investigate this issue by using the nematode Caenorhabditis briggsae, which reproduces as a hermaphrodite, and its outcrossing sister species Caenorhabditis nigoni We hypothesize that selfing species might develop some barriers to prevent gene intrusions through gene regulation. We therefore examined gene regulation in the hybrid F2 embryos resulting from reciprocal backcrosses between F1 hybrid progeny and C. nigoni or C. briggsae F2 hybrid embryos with ∼75% of their genome derived from C. briggsae (termed as bB2) were inviable, whereas those with ∼75% of their genome derived from C. nigoni (termed as nB2) were viable. Misregulation of transposable elements, coding genes, and small regulatory RNAs was more widespread in the bB2 compared with the nB2 hybrids, which is a plausible explanation for the differential phenotypes between the two hybrids. Our results show that regulation of the C. briggsae genome is strongly affected by genetic exchanges with its outcrossing sister species, C. nigoni, whereas regulation of the C. nigoni genome is more robust on genetic exchange with C. briggsae The results provide new insights into how selfing species might maintain their identity despite genetic exchanges with closely related outcrossing species.
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Affiliation(s)
- Dongying Xie
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Pohao Ye
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Yiming Ma
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Yongbin Li
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Xiao Liu
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Peter Sarkies
- Department of Biochemistry, University of Oxford, Oxford, OX1 4BH, United Kingdom
| | - Zhongying Zhao
- Department of Biology, Hong Kong Baptist University, Hong Kong, China;,State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong, China
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7
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8
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Banho CA, Oliveira DS, Haudry A, Fablet M, Vieira C, Carareto CMA. Transposable Element Expression and Regulation Profile in Gonads of Interspecific Hybrids of Drosophila arizonae and Drosophila mojavensis wrigleyi. Cells 2021; 10:cells10123574. [PMID: 34944084 PMCID: PMC8700503 DOI: 10.3390/cells10123574] [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: 11/09/2021] [Revised: 12/07/2021] [Accepted: 12/13/2021] [Indexed: 11/16/2022] Open
Abstract
Interspecific hybridization may lead to sterility and/or inviability through differential expression of genes and transposable elements (TEs). In Drosophila, studies have reported massive TE mobilization in hybrids from interspecific crosses of species presenting high divergence times. However, few studies have examined the consequences of TE mobilization upon hybridization in recently diverged species, such as Drosophila arizonae and D. mojavensis. We have sequenced transcriptomes of D. arizonae and the subspecies D. m. wrigleyi and their reciprocal hybrids, as well as piRNAs, to analyze the impact of genomic stress on TE regulation. Our results revealed that the differential expression in both gonadal tissues of parental species was similar. Globally, ovaries and testes showed few deregulated TEs compared with both parental lines. Analyses of small RNA data showed that in ovaries, the TE upregulation is likely due to divergence of copies inherited from parental genomes and lack of piRNAs mapping to them. Nevertheless, in testes, the divergent expression of genes associated with chromatin state and piRNA pathway potentially indicates that TE differential expression is related to the divergence of regulatory genes that play a role in modulating transcriptional and post-transcriptional mechanisms.
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Affiliation(s)
- Cecília Artico Banho
- Institute of Biosciences, Humanities and Exact Sciences, São Paulo State University (Unesp), São José do Rio Preto 15054-000, SP, Brazil; (C.A.B.); (D.S.O.)
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR 5558, F-69622 Villeurbanne, France; (A.H.); (M.F.)
| | - Daniel Siqueira Oliveira
- Institute of Biosciences, Humanities and Exact Sciences, São Paulo State University (Unesp), São José do Rio Preto 15054-000, SP, Brazil; (C.A.B.); (D.S.O.)
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR 5558, F-69622 Villeurbanne, France; (A.H.); (M.F.)
| | - Annabelle Haudry
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR 5558, F-69622 Villeurbanne, France; (A.H.); (M.F.)
| | - Marie Fablet
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR 5558, F-69622 Villeurbanne, France; (A.H.); (M.F.)
- Institut Universitaire de France (IUF), F-75231 Paris, France
| | - Cristina Vieira
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR 5558, F-69622 Villeurbanne, France; (A.H.); (M.F.)
- Correspondence: (C.V.); (C.M.A.C.)
| | - Claudia Marcia Aparecida Carareto
- Institute of Biosciences, Humanities and Exact Sciences, São Paulo State University (Unesp), São José do Rio Preto 15054-000, SP, Brazil; (C.A.B.); (D.S.O.)
- Correspondence: (C.V.); (C.M.A.C.)
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9
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Rosser N, Edelman NB, Queste LM, Nelson M, Seixas F, Dasmahapatra KK, Mallet J. Complex basis of hybrid female sterility and Haldane's rule in Heliconius butterflies: Z-linkage and epistasis. Mol Ecol 2021; 31:959-977. [PMID: 34779079 DOI: 10.1111/mec.16272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 09/14/2021] [Accepted: 09/27/2021] [Indexed: 12/19/2022]
Abstract
Hybrids between species are often sterile or inviable. Hybrid unfitness usually evolves first in the heterogametic sex-a pattern known as Haldane's rule. The genetics of Haldane's rule have been extensively studied in species where the male is the heterogametic (XX/XY) sex, but its basis in taxa where the female is heterogametic (ZW/ZZ), such as Lepidoptera and birds, is largely unknown. Here, we analyse a new case of female hybrid sterility between geographic subspecies of Heliconius pardalinus. The two subspecies mate freely in captivity, but female F1 hybrids in both directions of cross are sterile. Sterility is due to arrested development of oocytes after they become differentiated from nurse cells, but before yolk deposition. We backcrossed fertile male F1 hybrids to parental females and mapped quantitative trait loci (QTLs) for female sterility. We also identified genes differentially expressed in the ovary as a function of oocyte development. The Z chromosome has a major effect, similar to the 'large X effect' in Drosophila, with strong epistatic interactions between loci at either end of the Z chromosome, and between the Z chromosome and autosomal loci on chromosomes 8 and 20. By intersecting the list of genes within these QTLs with those differentially expressed in sterile and fertile hybrids, we identified three candidate genes with relevant phenotypes. This study is the first to characterize hybrid sterility using genome mapping in the Lepidoptera and shows that it is produced by multiple complex epistatic interactions often involving the sex chromosome, as predicted by the dominance theory of Haldane's rule.
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Affiliation(s)
- Neil Rosser
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.,Department of Biology, University of York, York, UK
| | - Nathaniel B Edelman
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.,Yale Institute for Biospheric Studies, Yale University, New Haven, Connecticut, USA.,Yale School for the Environment, Yale University, New Haven, Connecticut, USA
| | | | | | - Fernando Seixas
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | | | - James Mallet
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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10
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Nallasivan MP, Haussmann IU, Civetta A, Soller M. Channel nuclear pore protein 54 directs sexual differentiation and neuronal wiring of female reproductive behaviors in Drosophila. BMC Biol 2021; 19:226. [PMID: 34666772 PMCID: PMC8527774 DOI: 10.1186/s12915-021-01154-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 09/15/2021] [Indexed: 11/23/2022] Open
Abstract
Background Female reproductive behaviors and physiology change profoundly after mating. The control of pregnancy-associated changes in physiology and behaviors are largely hard-wired into the brain to guarantee reproductive success, yet the gene expression programs that direct neuronal differentiation and circuit wiring at the end of the sex determination pathway in response to mating are largely unknown. In Drosophila, the post-mating response induced by male-derived sex-peptide in females is a well-established model to elucidate how complex innate behaviors are hard-wired into the brain. Here, we use a genetic approach to further characterize the molecular and cellular architecture of the sex-peptide response in Drosophila females. Results Screening for mutations that affect the sensitivity to sex-peptide, we identified the channel nuclear pore protein Nup54 gene as an essential component for mediating the sex-peptide response, with viable mutant alleles leading to the inability of laying eggs and reducing receptivity upon sex-peptide exposure. Nup54 directs correct wiring of eight adult brain neurons that express pickpocket and are required for egg-laying, while additional channel Nups also mediate sexual differentiation. Consistent with links of Nups to speciation, the Nup54 promoter is a hot spot for rapid evolution and promoter variants alter nucleo-cytoplasmic shuttling. Conclusions These results implicate nuclear pore functionality to neuronal wiring underlying the sex-peptide response and sexual differentiation as a response to sexual conflict arising from male-derived sex-peptide to direct the female post-mating response. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01154-6.
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Affiliation(s)
- Mohanakarthik P Nallasivan
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Irmgard U Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Department of Life Science, School of Health Sciences, Birmingham City University, Birmingham, B15 3TN, UK
| | - Alberto Civetta
- Department of Biology, University of Winnipeg, Winnipeg, MB, R3B 2E9, Canada
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. .,Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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11
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Serrato-Capuchina A, D’Agostino ERR, Peede D, Roy B, Isbell K, Wang J, Matute DR. P-elements strengthen reproductive isolation within the Drosophila simulans species complex. Evolution 2021; 75:2425-2440. [PMID: 34463356 PMCID: PMC8772388 DOI: 10.1111/evo.14319] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 04/29/2021] [Accepted: 05/06/2021] [Indexed: 11/28/2022]
Abstract
Determining mechanisms that underlie reproductive isolation (RI) is key to understanding how species boundaries are maintained in nature. Transposable elements (TEs) are ubiquitous across eukaryotic genomes. However, the role of TEs in modulating the strength of RI between species is poorly understood. Several species of Drosophila have been found to harbor P-elements (PEs), yet only D. simulans is known to be currently polymorphic for their presence in wild populations. PEs can cause RI between PE-containing (P) and PE-lacking (M) lineages of the same species. However, it is unclear whether they also contribute to the magnitude of RI between species. Here, we use the simulans species complex to assess whether differences in PE status between D. simulans and its sister species, which do not harbor PEs, contribute to multiple barriers to gene flow between species. We show that crosses involving a P D. simulans father and an M mother from a sister species exhibit lower F1 female fecundity than crosses involving an M D. simulans father and an M sister-species mother. We also find that another TE, I-element, might play a minor role in determining the frequency of dysgenesis between species. Our results suggest that the presence of PEs in a species can strengthen isolation from its sister species, providing evidence that TEs can play a role in RI.
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Affiliation(s)
- Antonio Serrato-Capuchina
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Emmanuel R. R. D’Agostino
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - David Peede
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Baylee Roy
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Kristin Isbell
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Jeremy Wang
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Daniel R. Matute
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
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12
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Lukacs A, Thomae AW, Krueger P, Schauer T, Venkatasubramani AV, Kochanova NY, Aftab W, Choudhury R, Forne I, Imhof A. The Integrity of the HMR complex is necessary for centromeric binding and reproductive isolation in Drosophila. PLoS Genet 2021; 17:e1009744. [PMID: 34424906 PMCID: PMC8412352 DOI: 10.1371/journal.pgen.1009744] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/02/2021] [Accepted: 07/27/2021] [Indexed: 12/26/2022] Open
Abstract
Postzygotic isolation by genomic conflict is a major cause for the formation of species. Despite its importance, the molecular mechanisms that result in the lethality of interspecies hybrids are still largely unclear. The genus Drosophila, which contains over 1600 different species, is one of the best characterized model systems to study these questions. We showed in the past that the expression levels of the two hybrid incompatibility factors Hmr and Lhr diverged in the two closely related Drosophila species, D. melanogaster and D. simulans, resulting in an increased level of both proteins in interspecies hybrids. The overexpression of the two proteins also leads to mitotic defects, a misregulation in the expression of transposable elements and decreased fertility in pure species. In this work, we describe a distinct six subunit protein complex containing HMR and LHR and analyse the effect of Hmr mutations on complex integrity and function. Our experiments suggest that HMR needs to bring together components of centromeric and pericentromeric chromatin to fulfil its physiological function and to cause hybrid male lethality. A major cause of biological speciation is the sterility and/or lethality of hybrids. This hybrid lethality is thought to be the consequence of two incompatible genomes of the two different species. We used the fruit fly Drosophila melanogaster as a model system to isolate a defined protein complex, which mediates this hybrid lethality. Our data suggest that this complex containing six subunits has evolved in one Drosophila species (Drosophila melanogaster) to bring together components of centromeric and pericentromeric chromatin. We show that the integrity of the complex is necessary for its genomic binding patterns and its ability to maintain fertility in female Drosophila melanogaster flies. Hybrid males between Drosophila melanogaster and the very closely related species Drosophila simulans die because they contain elevated levels of this complex. These high levels result in mitotic defects and a misregulation in the expression of transposable elements in those hybrids. Our results show that mutations that interfere with the complex’s function in Drosophila melanogaster also fail to induce lethality in hybrids suggesting that its evolutionary acquired functions in one species induce lethality in interspecies hybrids.
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Affiliation(s)
- Andrea Lukacs
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Andreas W. Thomae
- Biomedical Center, Core Facility Bioimaging, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Peter Krueger
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Tamas Schauer
- Biomedical Center, Bioinformatics Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Anuroop V. Venkatasubramani
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Natalia Y. Kochanova
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Wasim Aftab
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Rupam Choudhury
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Ignasi Forne
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Axel Imhof
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- * E-mail:
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13
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Drouin M, Hénault M, Hallin J, Landry CR. Testing the Genomic Shock Hypothesis Using Transposable Element Expression in Yeast Hybrids. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:729264. [PMID: 37744137 PMCID: PMC10512236 DOI: 10.3389/ffunb.2021.729264] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 07/26/2021] [Indexed: 09/26/2023]
Abstract
Transposable element (TE) insertions are a source of structural variation and can cause genetic instability and gene expression changes. A host can limit the spread of TEs with various repression mechanisms. Many examples of plant and animal interspecific hybrids show disrupted TE repression leading to TE propagation. Recent studies in yeast did not find any increase in transposition rate in hybrids. However, this does not rule out the possibility that the transcriptional or translational activity of TEs increases following hybridization because of a disruption of the host TE control mechanisms. Thus, whether total expression of a TE family is higher in hybrids than in their parental species remains to be examined. We leveraged publically available RNA-seq and ribosomal profiling data on yeast artificial hybrids of the Saccharomyces genus and performed differential expression analysis of their LTR retrotransposons (Ty elements). Our analyses of total mRNA levels show that Ty elements are generally not differentially expressed in hybrids, even when the hybrids are exposed to a low temperature stress condition. Overall, only 2/26 Ty families show significantly higher expression in the S. cerevisiae × S. uvarum hybrids while there are 3/26 showing significantly lower expression in the S. cerevisiae x S. paradoxus hybrids. Our analysis of ribosome profiling data of S. cerevisiae × S. paradoxus hybrids shows similar translation efficiency of Ty in both parents and hybrids, except for Ty1_cer showing higher translation efficiency. Overall, our results do not support the hypothesis that hybridization could act as a systematic trigger of TE expression in yeast and suggest that the impact of hybridization on TE activity is strain and TE specific.
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Affiliation(s)
- Marika Drouin
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- PROTEO - Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
| | - Mathieu Hénault
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- PROTEO - Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
| | - Johan Hallin
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- PROTEO - Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Département de Biologie, Université Laval, Québec, QC, Canada
| | - Christian R. Landry
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- PROTEO - Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Département de Biologie, Université Laval, Québec, QC, Canada
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14
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Fabry MH, Falconio FA, Joud F, Lythgoe EK, Czech B, Hannon GJ. Maternally inherited piRNAs direct transient heterochromatin formation at active transposons during early Drosophila embryogenesis. eLife 2021; 10:e68573. [PMID: 34236313 PMCID: PMC8352587 DOI: 10.7554/elife.68573] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 07/07/2021] [Indexed: 12/12/2022] Open
Abstract
The PIWI-interacting RNA (piRNA) pathway controls transposon expression in animal germ cells, thereby ensuring genome stability over generations. In Drosophila, piRNAs are intergenerationally inherited through the maternal lineage, and this has demonstrated importance in the specification of piRNA source loci and in silencing of I- and P-elements in the germ cells of daughters. Maternally inherited Piwi protein enters somatic nuclei in early embryos prior to zygotic genome activation and persists therein for roughly half of the time required to complete embryonic development. To investigate the role of the piRNA pathway in the embryonic soma, we created a conditionally unstable Piwi protein. This enabled maternally deposited Piwi to be cleared from newly laid embryos within 30 min and well ahead of the activation of zygotic transcription. Examination of RNA and protein profiles over time, and correlation with patterns of H3K9me3 deposition, suggests a role for maternally deposited Piwi in attenuating zygotic transposon expression in somatic cells of the developing embryo. In particular, robust deposition of piRNAs targeting roo, an element whose expression is mainly restricted to embryonic development, results in the deposition of transient heterochromatic marks at active roo insertions. We hypothesize that roo, an extremely successful mobile element, may have adopted a lifestyle of expression in the embryonic soma to evade silencing in germ cells.
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Affiliation(s)
- Martin H Fabry
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Federica A Falconio
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Fadwa Joud
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Emily K Lythgoe
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Benjamin Czech
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
| | - Gregory J Hannon
- CRUK Cambridge Institute, University of Cambridge, Li Ka Shing CentreCambridgeUnited Kingdom
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15
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Banho CA, Mérel V, Oliveira TYK, Carareto CMA, Vieira C. Comparative transcriptomics between Drosophila mojavensis and D. arizonae reveals transgressive gene expression and underexpression of spermatogenesis-related genes in hybrid testes. Sci Rep 2021; 11:9844. [PMID: 33972659 PMCID: PMC8110761 DOI: 10.1038/s41598-021-89366-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/19/2021] [Indexed: 01/02/2023] Open
Abstract
Interspecific hybridization is a stressful condition that can lead to sterility and/or inviability through improper gene regulation in Drosophila species with a high divergence time. However, the extent of these abnormalities in hybrids of recently diverging species is not well known. Some studies have shown that in Drosophila, the mechanisms of postzygotic isolation may evolve more rapidly in males than in females and that the degree of viability and sterility is associated with the genetic distance between species. Here, we used transcriptomic comparisons between two Drosophila mojavensis subspecies and D. arizonae (repleta group, Drosophila) and identified greater differential gene expression in testes than in ovaries. We tested the hypothesis that the severity of the interspecies hybrid phenotype is associated with the degree of gene misregulation. We showed limited gene misregulation in fertile females and an increase in the amount of misregulation in males with more severe sterile phenotypes (motile vs. amotile sperm). In addition, for these hybrids, we identified candidate genes that were mostly associated with spermatogenesis dysfunction.
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Affiliation(s)
- Cecilia A Banho
- Department of Biology, UNESP - São Paulo State University, São José do Rio Preto, São Paulo State (SP), Brazil.,Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Claude Bernard Lyon 1, University of Lyon, 69622, Villeurbanne, France
| | - Vincent Mérel
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Claude Bernard Lyon 1, University of Lyon, 69622, Villeurbanne, France
| | - Thiago Y K Oliveira
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY, USA
| | - Claudia M A Carareto
- Department of Biology, UNESP - São Paulo State University, São José do Rio Preto, São Paulo State (SP), Brazil
| | - Cristina Vieira
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Claude Bernard Lyon 1, University of Lyon, 69622, Villeurbanne, France.
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16
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The challenges of predicting transposable element activity in hybrids. Curr Genet 2021; 67:567-572. [PMID: 33738571 DOI: 10.1007/s00294-021-01169-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 02/07/2023]
Abstract
Transposable elements (TEs) are ubiquitous mobile genetic elements that hold both disruptive and adaptive potential for species. It has long been postulated that their activity may be triggered by hybridization, a hypothesis that received mixed support from studies in various species. While host defense mechanisms against TEs are being elucidated, the increasing volume of genomic data and bioinformatic tools specialized in TE detection enable in-depth characterization of TEs at the levels of species and populations. Here, I borrow elements from the genome ecology theory to illustrate how knowledge of the diversity of TEs and host defense mechanisms may help predict the activity of TEs in the face of hybridization, and how current limitations make this task especially challenging.
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17
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Parhad SS, Yu T, Zhang G, Rice NP, Weng Z, Theurkauf WE. Adaptive Evolution Targets a piRNA Precursor Transcription Network. Cell Rep 2021; 30:2672-2685.e5. [PMID: 32101744 PMCID: PMC7061269 DOI: 10.1016/j.celrep.2020.01.109] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 10/23/2019] [Accepted: 01/30/2020] [Indexed: 12/18/2022] Open
Abstract
In Drosophila, transposon-silencing piRNAs are derived from heterochromatic clusters and a subset of euchromatic transposon insertions, which are bound by the Rhino-Deadlock-Cutoff complex. The HP1 homolog Rhino binds to Deadlock, which recruits TRF2 to promote non-canonical transcription from both genomic strands. Cuff function is less well understood, but this Rai1 homolog shows hallmarks of adaptive evolution, which can remodel functional interactions within host defense systems. Supporting this hypothesis, Drosophila simulans Cutoff is a dominant-negative allele when expressed in Drosophila melanogaster, in which it traps Deadlock, TRF2, and the conserved transcriptional co-repressor CtBP in stable complexes. Cutoff functions with Rhino and Deadlock to drive non-canonical transcription. In contrast, CtBP suppresses canonical transcription of transposons and promoters flanking the major germline clusters, and canonical transcription interferes with downstream non-canonical transcription and piRNA production. Adaptive evolution thus targets interactions among Cutoff, TRF2, and CtBP that balance canonical and non-canonical piRNA precursor transcription.
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Affiliation(s)
- Swapnil S Parhad
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Tianxiong Yu
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA; School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Gen Zhang
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Nicholas P Rice
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - William E Theurkauf
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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18
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Smukowski Heil C, Patterson K, Hickey ASM, Alcantara E, Dunham MJ. Transposable Element Mobilization in Interspecific Yeast Hybrids. Genome Biol Evol 2021; 13:6141023. [PMID: 33595639 PMCID: PMC7952228 DOI: 10.1093/gbe/evab033] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2021] [Indexed: 12/13/2022] Open
Abstract
Barbara McClintock first hypothesized that interspecific hybridization could provide a “genomic shock” that leads to the mobilization of transposable elements (TEs). This hypothesis is based on the idea that regulation of TE movement is potentially disrupted in hybrids. However, the handful of studies testing this hypothesis have yielded mixed results. Here, we set out to identify if hybridization can increase transposition rate and facilitate colonization of TEs in Saccharomyces cerevisiae × Saccharomyces uvarum interspecific yeast hybrids. Saccharomyces cerevisiae have a small number of active long terminal repeat retrotransposons (Ty elements), whereas their distant relative S. uvarum have lost the Ty elements active in S. cerevisiae. Although the regulation system of Ty elements is known in S. cerevisiae, it is unclear how Ty elements are regulated in other Saccharomyces species, and what mechanisms contributed to the loss of most classes of Ty elements in S. uvarum. Therefore, we first assessed whether TEs could insert in the S. uvarum sub-genome of a S. cerevisiae × S. uvarum hybrid. We induced transposition to occur in these hybrids and developed a sequencing technique to show that Ty elements insert readily and nonrandomly in the S. uvarum genome. We then used an in vivo reporter construct to directly measure transposition rate in hybrids, demonstrating that hybridization itself does not alter rate of mobilization. However, we surprisingly show that species-specific mitochondrial inheritance can change transposition rate by an order of magnitude. Overall, our results provide evidence that hybridization can potentially facilitate the introduction of TEs across species boundaries and alter transposition via mitochondrial transmission, but that this does not lead to unrestrained proliferation of TEs suggested by the genomic shock theory.
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Affiliation(s)
- Caiti Smukowski Heil
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Kira Patterson
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | | | - Erica Alcantara
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
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19
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Ellison CE, Kagda MS, Cao W. Telomeric TART elements target the piRNA machinery in Drosophila. PLoS Biol 2020; 18:e3000689. [PMID: 33347429 PMCID: PMC7785250 DOI: 10.1371/journal.pbio.3000689] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 01/05/2021] [Accepted: 12/10/2020] [Indexed: 11/23/2022] Open
Abstract
Coevolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by reestablishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. The TART-A TE functions as an important component of Drosophila telomeres but has also reportedly inserted into the Drosophila melanogaster nuclear export factor gene nxf2. We find that, rather than inserting into nxf2, TART-A has actually captured a portion of nxf2 sequence. We show that TART-A produces abundant Piwi-interacting small RNAs (piRNAs), some of which are antisense to the nxf2 transcript, and that the TART-like region of nxf2 is evolving rapidly. Furthermore, in D. melanogaster, TART-A is present at higher copy numbers, and nxf2 shows reduced expression, compared to the closely related species Drosophila simulans. We propose that capturing nxf2 sequence allowed TART-A to target the nxf2 gene for piRNA-mediated repression and that these 2 elements are engaged in antagonistic coevolution despite the fact that TART-A is serving a critical role for its host genome. Co-evolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by re-establishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. This study shows that a specialized Drosophila retrotransposon that functions as a telomere has captured a portion of a host piRNA gene which may allow it to evade silencing.
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Affiliation(s)
- Christopher E. Ellison
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
| | - Meenakshi S. Kagda
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Weihuan Cao
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
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20
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Gamez S, Srivastav S, Akbari OS, Lau NC. Diverse Defenses: A Perspective Comparing Dipteran Piwi-piRNA Pathways. Cells 2020; 9:E2180. [PMID: 32992598 PMCID: PMC7601171 DOI: 10.3390/cells9102180] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 02/07/2023] Open
Abstract
Animals face the dual threat of virus infections hijacking cellular function and transposons proliferating in germline genomes. For insects, the deeply conserved RNA interference (RNAi) pathways and other chromatin regulators provide an important line of defense against both viruses and transposons. For example, this innate immune system displays adaptiveness to new invasions by generating cognate small RNAs for targeting gene silencing measures against the viral and genomic intruders. However, within the Dipteran clade of insects, Drosophilid fruit flies and Culicids mosquitoes have evolved several unique mechanistic aspects of their RNAi defenses to combat invading transposons and viruses, with the Piwi-piRNA arm of the RNAi pathways showing the greatest degree of novel evolution. Whereas central features of Piwi-piRNA pathways are conserved between Drosophilids and Culicids, multiple lineage-specific innovations have arisen that may reflect distinct genome composition differences and specific ecological and physiological features dividing these two branches of Dipterans. This perspective review focuses on the most recent findings illuminating the Piwi/piRNA pathway distinctions between fruit flies and mosquitoes, and raises open questions that need to be addressed in order to ameliorate human diseases caused by pathogenic viruses that mosquitoes transmit as vectors.
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Affiliation(s)
- Stephanie Gamez
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, CA 92093, USA; (S.G.); (O.S.A.)
| | - Satyam Srivastav
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-2703, USA;
| | - Omar S. Akbari
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, CA 92093, USA; (S.G.); (O.S.A.)
| | - Nelson C. Lau
- Department of Biochemistry and Genome Science Institute, Boston University School of Medicine, Boston, MA 02118, USA
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21
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Abstract
New species arise as the genomes of populations diverge. The developmental 'alarm clock' of speciation sounds off when sufficient divergence in genetic control of development leads hybrid individuals to infertility or inviability, the world awoken to the dawn of new species with intrinsic post-zygotic reproductive isolation. Some developmental stages will be more prone to hybrid dysfunction due to how molecular evolution interacts with the ontogenetic timing of gene expression. Considering the ontogeny of hybrid incompatibilities provides a profitable connection between 'evo-devo' and speciation genetics to better link macroevolutionary pattern, microevolutionary process, and molecular mechanisms. Here, we explore speciation alongside development, emphasizing their mutual dependence on genetic network features, fitness landscapes, and developmental system drift. We assess models for how ontogenetic timing of reproductive isolation can be predictable. Experiments and theory within this synthetic perspective can help identify new rules of speciation as well as rules in the molecular evolution of development.
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Affiliation(s)
- Asher D Cutter
- Department of Ecology & Evolutionary Biology, University of TorontoTorontoCanada
| | - Joanna D Bundus
- Department of Integrative Biology, University of Wisconsin – MadisonMadisonUnited States
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22
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Dalziel AC, Tirbhowan S, Drapeau HF, Power C, Jonah LS, Gbotsyo YA, Dion‐Côté A. Using asexual vertebrates to study genome evolution and animal physiology: Banded ( Fundulus diaphanus) x Common Killifish ( F. heteroclitus) hybrid lineages as a model system. Evol Appl 2020; 13:1214-1239. [PMID: 32684956 PMCID: PMC7359844 DOI: 10.1111/eva.12975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/12/2020] [Accepted: 03/16/2020] [Indexed: 12/27/2022] Open
Abstract
Wild, asexual, vertebrate hybrids have many characteristics that make them good model systems for studying how genomes evolve and epigenetic modifications influence animal physiology. In particular, the formation of asexual hybrid lineages is a form of reproductive incompatibility, but we know little about the genetic and genomic mechanisms by which this mode of reproductive isolation proceeds in animals. Asexual lineages also provide researchers with the ability to produce genetically identical individuals, enabling the study of autonomous epigenetic modifications without the confounds of genetic variation. Here, we briefly review the cellular and molecular mechanisms leading to asexual reproduction in vertebrates and the known genetic and epigenetic consequences of the loss of sex. We then specifically discuss what is known about asexual lineages of Fundulus diaphanus x F. heteroclitus to highlight gaps in our knowledge of the biology of these clones. Our preliminary studies of F. diaphanus and F. heteroclitus karyotypes from Porter's Lake (Nova Scotia, Canada) agree with data from other populations, suggesting a conserved interspecific chromosomal arrangement. In addition, genetic analyses suggest that: (a) the same major clonal lineage (Clone A) of F. diaphanus x F. heteroclitus has remained dominant over the past decade, (b) some minor clones have also persisted, (c) new clones may have recently formed, and iv) wild clones still mainly descend from F. diaphanus ♀ x F. heteroclitus ♂ crosses (96% in 2017-2018). These data suggest that clone formation may be a relatively rare, but continuous process, and there are persistent environmental or genetic factors causing a bias in cross direction. We end by describing our current research on the genomic causes and consequences of a transition to asexuality and the potential physiological consequences of epigenetic variation.
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Affiliation(s)
| | - Svetlana Tirbhowan
- Department of BiologySaint Mary's UniversityHalifaxNSCanada
- Département de biologieUniversité de MonctonMonctonNBCanada
| | | | - Claude Power
- Département de biologieUniversité de MonctonMonctonNBCanada
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23
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Wang L, Barbash DA, Kelleher ES. Adaptive evolution among cytoplasmic piRNA proteins leads to decreased genomic auto-immunity. PLoS Genet 2020; 16:e1008861. [PMID: 32525870 PMCID: PMC7310878 DOI: 10.1371/journal.pgen.1008861] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 06/23/2020] [Accepted: 05/14/2020] [Indexed: 02/05/2023] Open
Abstract
In metazoan germlines, the piRNA pathway acts as a genomic immune system, employing small RNA-mediated silencing to defend host DNA from the harmful effects of transposable elements (TEs). Expression of genomic TEs is proposed to initiate self regulation by increasing the production of repressive piRNAs, thereby “adapting” piRNA-mediated control to the most active TE families. Surprisingly, however, piRNA pathway proteins, which execute piRNA biogenesis and enforce silencing of targeted sequences, evolve rapidly and adaptively in animals. If TE silencing is ensured through piRNA biogenesis, what necessitates changes in piRNA pathway proteins? Here we used interspecific complementation to test for functional differences between Drosophila melanogaster and D. simulans alleles of three adaptively evolving piRNA pathway proteins: Armitage, Aubergine and Spindle-E. In contrast to piRNA-mediated transcriptional regulators examined in previous studies, these three proteins have cytoplasmic functions in piRNA maturation and post-transcriptional silencing. Across all three proteins we observed interspecific divergence in the regulation of only a handful of TE families, which were more robustly silenced by the heterospecific piRNA pathway protein. This unexpected result suggests that unlike transcriptional regulators, positive selection has not acted on cytoplasmic piRNA effector proteins to enhance their function in TE repression. Rather, TEs may evolve to “escape” silencing by host proteins. We further discovered that D. simulans alleles of aub and armi exhibit enhanced off-target effects on host transcripts in a D. melanogaster background, as well as modest reductions in the efficiency of piRNA biogenesis, suggesting that promiscuous binding of D. simulans Aub and Armi proteins to host transcripts reduces their participation in piRNA production. Avoidance of genomic auto-immunity may therefore be a critical target of selection. Our observations suggest that piRNA effector proteins are subject to an evolutionary trade-off between defending the host genome from the harmful effect of TEs while also minimizing collateral damage to host genes. Transposable elements are mobile fragments of selfish DNA that burden host genomes with deleterious mutations and incite genome instability. Host cells employ a specialized small-RNA mediated silencing pathway, the piRNA pathway, to act as a genomic immune system suppressing the mobilization of TEs. Changes in genomic TE content are met with rapid changes in the piRNA pool, thereby maintaining host control over transposition. However, piRNA pathway proteins—which enact piRNA biogenesis and silence target TEs—also evolve adaptively. To isolate forces that underlie this adaptive evolution, we examined functional divergence between two Drosophila species for three adaptively evolving piRNA pathway proteins. To our surprise, we found very few differences in TE regulation, suggesting that evolution has not generally acted to enhance control of TE parasites. Rather, we discovered interspecific differences in the regulation of host mRNAs for two proteins, which suggested that proteins evolve to avoid off-target silencing of host transcripts. We propose that the avoidance of such “genomic autoimmunity” is an important and underappreciated force driving the adaptive evolution of piRNA proteins.
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Affiliation(s)
- Luyang Wang
- Dept. Biology & Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Daniel A. Barbash
- Dept. Molecular Biology & Genetics, Cornell University, Ithaca, New York, United States of America
| | - Erin S. Kelleher
- Dept. Biology & Biochemistry, University of Houston, Houston, Texas, United States of America
- * E-mail:
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Serrato-Capuchina A, Wang J, Earley E, Peede D, Isbell K, Matute DR. Paternally Inherited P-Element Copy Number Affects the Magnitude of Hybrid Dysgenesis in Drosophila simulans and D. melanogaster. Genome Biol Evol 2020; 12:808-826. [PMID: 32339225 PMCID: PMC7313671 DOI: 10.1093/gbe/evaa084] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2020] [Indexed: 12/16/2022] Open
Abstract
Transposable elements (TEs) are repetitive regions of DNA that are able to self-replicate and reinsert themselves throughout host genomes. Since the discovery of TEs, a prevalent question has been whether increasing TE copy number has an effect on the fitness of their hosts. P-elements (PEs) in Drosophila are a well-studied TE that has strong phenotypic effects. When a female without PEs (M) is crossed to a male with them (P), the resulting females are often sterile, a phenomenon called hybrid dysgenesis (HD). Here, we used short- and long-read sequencing to infer the number of PEs in the genomes of dozens of isofemale lines from two Drosophila species and measured whether the magnitude of HD was correlated with the number of PEs in the paternal genome. Consistent with previous reports, we find evidence for a positive correlation between the paternal PE copy number and the magnitude of HD in progeny from ♀M × ♂ P crosses for both species. Other crosses are not affected by the number of PE copies. We also find that the correlation between the strength of HD and PE copy number differs between species, which suggests that there are genetic differences that might make some genomes more resilient to the potentially deleterious effects of TEs. Our results suggest that PE copy number interacts with other factors in the genome and the environment to cause HD and that the importance of these interactions is species specific.
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Affiliation(s)
| | - Jeremy Wang
- Genetics Department, University of North Carolina, Chapel Hill
| | - Eric Earley
- Genomics in Public Health and Medicine RTI International, Research Triangle Park, North Carolina
| | - David Peede
- Biology Department, University of North Carolina, Chapel Hill
| | - Kristin Isbell
- Biology Department, University of North Carolina, Chapel Hill
| | - Daniel R Matute
- Biology Department, University of North Carolina, Chapel Hill
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25
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Kochanova NY, Schauer T, Mathias GP, Lukacs A, Schmidt A, Flatley A, Schepers A, Thomae AW, Imhof A. A multi-layered structure of the interphase chromocenter revealed by proximity-based biotinylation. Nucleic Acids Res 2020; 48:4161-4178. [PMID: 32182352 PMCID: PMC7192626 DOI: 10.1093/nar/gkaa145] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/18/2020] [Accepted: 02/25/2020] [Indexed: 12/26/2022] Open
Abstract
During interphase centromeres often coalesce into a small number of chromocenters, which can be visualized as distinct, DAPI dense nuclear domains. Intact chromocenters play a major role in maintaining genome stability as they stabilize the transcriptionally silent state of repetitive DNA while ensuring centromere function. Despite its biological importance, relatively little is known about the molecular composition of the chromocenter or the processes that mediate chromocenter formation and maintenance. To provide a deeper molecular insight into the composition of the chromocenter and to demonstrate the usefulness of proximity-based biotinylation as a tool to investigate those questions, we performed super resolution microscopy and proximity-based biotinylation experiments of three distinct proteins associated with the chromocenter in Drosophila. Our work revealed an intricate internal architecture of the chromocenter suggesting a complex multilayered structure of this intranuclear domain.
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Affiliation(s)
- Natalia Y Kochanova
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Tamas Schauer
- Biomedical Center, Bioinformatics Core Facility, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Grusha Primal Mathias
- Biomedical Center, Core Facility Bioimaging, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Andrea Lukacs
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Andreas Schmidt
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Andrew Flatley
- Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility and Research Group Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Aloys Schepers
- Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility and Research Group Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Andreas W Thomae
- Biomedical Center, Core Facility Bioimaging, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Axel Imhof
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
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26
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Feng JX, Riddle NC. Epigenetics and genome stability. Mamm Genome 2020; 31:181-195. [PMID: 32296924 DOI: 10.1007/s00335-020-09836-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 04/07/2020] [Indexed: 12/19/2022]
Abstract
Maintaining genome stability is essential to an organism's health and survival. Breakdown of the mechanisms protecting the genome and the resulting genome instability are an important aspect of the aging process and have been linked to diseases such as cancer. Thus, a large network of interconnected pathways is responsible for ensuring genome integrity in the face of the continuous challenges that induce DNA damage. While these pathways are diverse, epigenetic mechanisms play a central role in many of them. DNA modifications, histone variants and modifications, chromatin structure, and non-coding RNAs all carry out a variety of functions to ensure that genome stability is maintained. Epigenetic mechanisms ensure the functions of centromeres and telomeres that are essential for genome stability. Epigenetic mechanisms also protect the genome from the invasion by transposable elements and contribute to various DNA repair pathways. In this review, we highlight the integral role of epigenetic mechanisms in the maintenance of genome stability and draw attention to issues in need of further study.
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Affiliation(s)
- Justina X Feng
- Department of Biology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nicole C Riddle
- Department of Biology, The University of Alabama at Birmingham, Birmingham, AL, USA.
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Abstract
Transposons are major genome constituents that can mobilize and trigger mutations, DNA breaks and chromosome rearrangements. Transposon silencing is particularly important in the germline, which is dedicated to transmission of the inherited genome. Piwi-interacting RNAs (piRNAs) guide a host defence system that transcriptionally and post-transcriptionally silences transposons during germline development. While germline control of transposons by the piRNA pathway is conserved, many piRNA pathway genes are evolving rapidly under positive selection, and the piRNA biogenesis machinery shows remarkable phylogenetic diversity. Conservation of core function combined with rapid gene evolution is characteristic of a host–pathogen arms race, suggesting that transposons and the piRNA pathway are engaged in an evolutionary tug of war that is driving divergence of the biogenesis machinery. Recent studies suggest that this process may produce biochemical incompatibilities that contribute to reproductive isolation and species divergence.
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Affiliation(s)
- Swapnil S Parhad
- Program in Molecular Medicine, University of Massachusetts Medical School , 373 Plantation Street, Worcester, MA 01605 , USA
| | - William E Theurkauf
- Program in Molecular Medicine, University of Massachusetts Medical School , 373 Plantation Street, Worcester, MA 01605 , USA
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Drosophila Interspecific Hybridization Causes A Deregulation of the piRNA Pathway Genes. Genes (Basel) 2020; 11:genes11020215. [PMID: 32092860 PMCID: PMC7073935 DOI: 10.3390/genes11020215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/11/2020] [Accepted: 02/14/2020] [Indexed: 12/17/2022] Open
Abstract
Almost all eukaryotes have transposable elements (TEs) against which they have developed defense mechanisms. In the Drosophila germline, the main transposable element (TE) regulation pathway is mediated by specific Piwi-interacting small RNAs (piRNAs). Nonetheless, for unknown reasons, TEs sometimes escape cellular control during interspecific hybridization processes. Because the piRNA pathway genes are involved in piRNA biogenesis and TE control, we sequenced and characterized nine key genes from this pathway in Drosophila buzzatii and Drosophila koepferae species and studied their expression pattern in ovaries of both species and their F1 hybrids. We found that gene structure is, in general, maintained between both species and that two genes—armitage and aubergine—are under positive selection. Three genes—krimper, methyltransferase 2, and zucchini—displayed higher expression values in hybrids than both parental species, while others had RNA levels similar to the parental species with the highest expression. This suggests that the overexpression of some piRNA pathway genes can be a primary response to hybrid stress. Therefore, these results reinforce the hypothesis that TE deregulation may be due to the protein incompatibility caused by the rapid evolution of these genes, leading to a TE silencing failure, rather than to an underexpression of piRNA pathway genes.
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Hemmer LW, Dias GB, Smith B, Van Vaerenberghe K, Howard A, Bergman CM, Blumenstiel JP. Hybrid dysgenesis in Drosophila virilis results in clusters of mitotic recombination and loss-of-heterozygosity but leaves meiotic recombination unaltered. Mob DNA 2020; 11:10. [PMID: 32082426 PMCID: PMC7023781 DOI: 10.1186/s13100-020-0205-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/28/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Transposable elements (TEs) are endogenous mutagens and their harmful effects are especially evident in syndromes of hybrid dysgenesis. In Drosophila virilis, hybrid dysgenesis is a syndrome of incomplete gonadal atrophy that occurs when males with multiple active TE families fertilize females that lack active copies of the same families. This has been demonstrated to cause the transposition of paternally inherited TE families, with gonadal atrophy driven by the death of germline stem cells. Because there are abundant, active TEs in the male inducer genome, that are not present in the female reactive genome, the D. virilis syndrome serves as an excellent model for understanding the effects of hybridization between individuals with asymmetric TE profiles. RESULTS Using the D. virilis syndrome of hybrid dysgenesis as a model, we sought to determine how the landscape of germline recombination is affected by parental TE asymmetry. Using a genotyping-by-sequencing approach, we generated a high-resolution genetic map of D. virilis and show that recombination rate and TE density are negatively correlated in this species. We then contrast recombination events in the germline of dysgenic versus non-dysgenic F1 females to show that the landscape of meiotic recombination is hardly perturbed during hybrid dysgenesis. In contrast, hybrid dysgenesis in the female germline increases transmission of chromosomes with mitotic recombination. Using a de novo PacBio assembly of the D. virilis inducer genome we show that clusters of mitotic recombination events in dysgenic females are associated with genomic regions with transposons implicated in hybrid dysgenesis. CONCLUSIONS Overall, we conclude that increased mitotic recombination is likely the result of early TE activation in dysgenic progeny, but a stable landscape of meiotic recombination indicates that either transposition is ameliorated in the adult female germline or that regulation of meiotic recombination is robust to ongoing transposition. These results indicate that the effects of parental TE asymmetry on recombination are likely sensitive to the timing of transposition.
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Affiliation(s)
- Lucas W. Hemmer
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045 USA
- Present Address: Department of Biology, University of Rochester, Rochester, NY 14627 USA
| | - Guilherme B. Dias
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602 USA
| | - Brittny Smith
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045 USA
| | - Kelley Van Vaerenberghe
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045 USA
| | - Ashley Howard
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045 USA
| | - Casey M. Bergman
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602 USA
| | - Justin P. Blumenstiel
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045 USA
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30
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Kotov AA, Adashev VE, Godneeva BK, Ninova M, Shatskikh AS, Bazylev SS, Aravin AA, Olenina LV. piRNA silencing contributes to interspecies hybrid sterility and reproductive isolation in Drosophila melanogaster. Nucleic Acids Res 2019; 47:4255-4271. [PMID: 30788506 PMCID: PMC6486647 DOI: 10.1093/nar/gkz130] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/12/2019] [Accepted: 02/16/2019] [Indexed: 12/05/2022] Open
Abstract
The piRNA pathway is an adaptive mechanism that maintains genome stability by repression of selfish genomic elements. In the male germline of Drosophila melanogaster repression of Stellate genes by piRNAs generated from Supressor of Stellate (Su(Ste)) locus is required for male fertility, but both Su(Ste) piRNAs and their targets are absent in other Drosophila species. We found that D. melanogaster genome contains multiple X-linked non-coding genomic repeats that have sequence similarity to the protein-coding host gene vasa. In the male germline, these vasa-related AT-chX repeats produce abundant piRNAs that are antisense to vasa; however, vasa mRNA escapes silencing due to imperfect complementarity to AT-chX piRNAs. Unexpectedly, we discovered AT-chX piRNAs target vasa of Drosophila mauritiana in the testes of interspecies hybrids. In the majority of hybrid flies, the testes were strongly reduced in size and germline content. A minority of hybrids maintained wild-type array of premeiotic germ cells in the testes, but in them harmful Stellate genes were derepressed due to the absence of Su(Ste) piRNAs, and meiotic failures were observed. Thus, the piRNA pathway contributes to reproductive isolation between D. melanogaster and closely related species, causing hybrid male sterility via misregulation of two different host protein factors.
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Affiliation(s)
- Alexei A Kotov
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Vladimir E Adashev
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Baira K Godneeva
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Maria Ninova
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Aleksei S Shatskikh
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Sergei S Bazylev
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
| | - Alexei A Aravin
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia.,California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 E. California Blvd., Pasadena, CA 91125, USA
| | - Ludmila V Olenina
- Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov Sq. 2, Moscow, 123182 Russia
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31
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Cutter AD. Reproductive transitions in plants and animals: selfing syndrome, sexual selection and speciation. THE NEW PHYTOLOGIST 2019; 224:1080-1094. [PMID: 31336389 DOI: 10.1111/nph.16075] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/17/2019] [Indexed: 05/23/2023]
Abstract
The evolution of predominant self-fertilisation frequently coincides with the evolution of a collection of phenotypes that comprise the 'selfing syndrome', in both plants and animals. Genomic features also display a selfing syndrome. Selfing syndrome traits often involve changes to male and female reproductive characters that were subject to sexual selection and sexual conflict in the obligatorily outcrossing ancestor, including the gametic phase for both plants and animals. Rapid evolution of reproductive traits, due to both relaxed selection and directional selection under the new status of predominant selfing, lays the genetic groundwork for reproductive isolation. Consequently, shifts in sexual selection pressures coupled to transitions to selfing provide a powerful paradigm for investigating the speciation process. Plant and animal studies, however, emphasise distinct selective forces influencing reproductive-mode transitions: genetic transmission advantage to selfing or reproductive assurance outweighing the costs of inbreeding depression vs the costs of males and meiosis. Here, I synthesise links between sexual selection, evolution of selfing and speciation, with particular focus on identifying commonalities and differences between plant and animal systems and pointing to areas warranting further synergy.
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Affiliation(s)
- Asher D Cutter
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
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32
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Helleu Q, Levine MT. Recurrent Amplification of the Heterochromatin Protein 1 (HP1) Gene Family across Diptera. Mol Biol Evol 2019; 35:2375-2389. [PMID: 29924345 PMCID: PMC6188558 DOI: 10.1093/molbev/msy128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The heterochromatic genome compartment mediates strictly conserved cellular processes such as chromosome segregation, telomere integrity, and genome stability. Paradoxically, heterochromatic DNA sequence is wildly unconserved. Recent reports that many hybrid incompatibility genes encode heterochromatin proteins, together with the observation that interspecies hybrids suffer aberrant heterochromatin-dependent processes, suggest that heterochromatic DNA packaging requires species-specific innovations. Testing this model of coevolution between fast-evolving heterochromatic DNA and its packaging proteins begins with defining the latter. Here we describe many such candidates encoded by the Heterochromatin Protein 1 (HP1) gene family across Diptera, an insect Order that encompasses dramatic episodes of heterochromatic sequence turnover. Using BLAST, synteny analysis, and phylogenetic tree building across 64 Diptera genomes, we discovered a staggering 121 HP1 duplication events. In contrast, we observed virtually no gene duplication in gene families that share a common “chromodomain” with HP1s, including Polycomb and Su(var)3-9. The remarkably high number of Dipteran HP1 paralogs arises from distant clades undergoing convergent HP1 family amplifications. These independently derived, young HP1s span diverse ages, domain structures, and rates of molecular evolution, including episodes of positive selection. Moreover, independently derived HP1s exhibit convergent expression evolution. While ancient HP1 parent genes are transcribed ubiquitously, young HP1 paralogs are transcribed primarily in male germline tissue, a pattern typical of young genes. Pervasive gene youth, rapid evolution, and germline specialization implicate heterochromatin-encoded selfish elements driving recurrent HP1 gene family expansions. The 121 young genes offer valuable experimental traction for elucidating the germline processes shaped by Diptera’s many dramatic episodes of heterochromatin turnover.
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Affiliation(s)
- Quentin Helleu
- Department of Biology, Epigenetics Institute, University of Pennsylvania, Philadelphia, PA
| | - Mia T Levine
- Department of Biology, Epigenetics Institute, University of Pennsylvania, Philadelphia, PA
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33
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Dennenmoser S, Sedlazeck FJ, Schatz MC, Altmüller J, Zytnicki M, Nolte AW. Genome‐wide patterns of transposon proliferation in an evolutionary young hybrid fish. Mol Ecol 2019; 28:1491-1505. [DOI: 10.1111/mec.14969] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 10/15/2018] [Accepted: 10/23/2018] [Indexed: 01/19/2023]
Affiliation(s)
- Stefan Dennenmoser
- Institute for Biology and Environmental Sciences Carl von Ossietzky University Oldenburg Oldenburg Germany
| | | | - Michael C. Schatz
- Cold Spring Harbor Laboratory Cold Spring Harbor New York
- Departments of Computer Science and Biology Johns Hopkins University Baltimore Maryland
| | - Janine Altmüller
- Cologne Center for Genomics, and Institute of Human Genetics University of Cologne Cologne Germany
| | | | - Arne W. Nolte
- Institute for Biology and Environmental Sciences Carl von Ossietzky University Oldenburg Oldenburg Germany
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34
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Fontdevila A. Hybrid Genome Evolution by Transposition: An Update. J Hered 2019; 110:124-136. [PMID: 30107415 DOI: 10.1093/jhered/esy040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/06/2018] [Indexed: 02/02/2023] Open
Abstract
Contrary to the view that hybrids are lineages devoid of evolutionary value, a number of case studies that have been lately reported show how hybrids are at the origin of many species. Some well-documented cases demonstrate that bursts of transposition often follow hybridization, generating new genetic variability. Studies in hybrid transposition strongly suggest that epigenetic changes and divergence in piRNA pathways drive deregulation in TE landscapes. Here, I have focused on mechanisms acting in Drosophila hybrids between two cactophilic species. The results reported here show that while hybrid instability by transposition is a genome-wide event, deregulation by TE overexpression in hybrid ovaries is not a general rule. When piRNA pools of ovaries are studied, results show that TEs with parental differences higher than 2-fold in their piRNA amounts are not more commonly deregulated in hybrids than TEs with similar levels, partially discrediting the generality of the maternal cytotype hypothesis. Some promising results on the piRNA pathway global failure hypothesis, which states that accumulated divergence of piRNA effector proteins is responsible for hybrid TE deregulation, have also been obtained. Altogether, these results suggest that TE deregulation might be driven by several interacting mechanisms. A natural scenario is proposed in which genome instability by transposition leads to hybrid genome reorganization. Small hybrid populations, subjected to natural selection helped by genetic drift, evolve new adaptations adapted to novel environments. The final step is either introgression or even a new hybrid species.
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Affiliation(s)
- Antonio Fontdevila
- Grup de Genòmica, Bioinformàtica i Biologia Evolutiva, Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Bellaterra, Spain
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35
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Guio L, González J. New Insights on the Evolution of Genome Content: Population Dynamics of Transposable Elements in Flies and Humans. Methods Mol Biol 2019; 1910:505-530. [PMID: 31278675 DOI: 10.1007/978-1-4939-9074-0_16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Understanding the abundance, diversity, and distribution of TEs in genomes is crucial to understand genome structure, function, and evolution. Advances in whole-genome sequencing techniques, as well as in bioinformatics tools, have increased our ability to detect and analyze the transposable element content in genomes. In addition to reference genomes, we now have access to population datasets in which multiple individuals within a species are sequenced. In this chapter, we highlight the recent advances in the study of TE population dynamics focusing on fruit flies and humans, which represent two extremes in terms of TE abundance, diversity, and activity. We review the most recent methodological approaches applied to the study of TE dynamics as well as the new knowledge on host factors involved in the regulation of TE activity. In addition to transposition rates, we also focus on TE deletion rates and on the selective forces that affect the dynamics of TEs in genomes.
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Affiliation(s)
- Lain Guio
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Josefa González
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain.
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36
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Czech B, Munafò M, Ciabrelli F, Eastwood EL, Fabry MH, Kneuss E, Hannon GJ. piRNA-Guided Genome Defense: From Biogenesis to Silencing. Annu Rev Genet 2018; 52:131-157. [PMID: 30476449 PMCID: PMC10784713 DOI: 10.1146/annurev-genet-120417-031441] [Citation(s) in RCA: 303] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
PIWI-interacting RNAs (piRNAs) and their associated PIWI clade Argonaute proteins constitute the core of the piRNA pathway. In gonadal cells, this conserved pathway is crucial for genome defense, and its main function is to silence transposable elements. This is achieved through posttranscriptional and transcriptional gene silencing. Precursors that give rise to piRNAs require specialized transcription and transport machineries because piRNA biogenesis is a cytoplasmic process. The ping-pong cycle, a posttranscriptional silencing mechanism, combines the cleavage-dependent silencing of transposon RNAs with piRNA production. PIWI proteins also function in the nucleus, where they scan for nascent target transcripts with sequence complementarity, instructing transcriptional silencing and deposition of repressive chromatin marks at transposon loci. Although studies have revealed numerous factors that participate in each branch of the piRNA pathway, the precise molecular roles of these factors often remain unclear. In this review, we summarize our current understanding of the mechanisms involved in piRNA biogenesis and function.
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Affiliation(s)
- Benjamin Czech
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Marzia Munafò
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Filippo Ciabrelli
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Evelyn L Eastwood
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Martin H Fabry
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Emma Kneuss
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Gregory J Hannon
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
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Yoshida K, Ishikawa A, Toyoda A, Shigenobu S, Fujiyama A, Kitano J. Functional divergence of a heterochromatin‐binding protein during stickleback speciation. Mol Ecol 2018; 28:1563-1578. [DOI: 10.1111/mec.14841] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/03/2018] [Accepted: 08/10/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Kohta Yoshida
- Division of Ecological Genetics National Institute of Genetics Mishima Shizuoka Japan
| | - Asano Ishikawa
- Division of Ecological Genetics National Institute of Genetics Mishima Shizuoka Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory National Institute of Genetics Mishima Shizuoka Japan
| | - Shuji Shigenobu
- NIBB Core Research Facilities National Institute for Basic Biology Okazaki Aichi Japan
| | - Asao Fujiyama
- Comparative Genomics Laboratory National Institute of Genetics Mishima Shizuoka Japan
| | - Jun Kitano
- Division of Ecological Genetics National Institute of Genetics Mishima Shizuoka Japan
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Bundus JD, Wang D, Cutter AD. Genetic basis to hybrid inviability is more complex than hybrid male sterility in Caenorhabditis nematodes. Heredity (Edinb) 2018; 121:169-182. [PMID: 29626207 PMCID: PMC6039526 DOI: 10.1038/s41437-018-0069-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/22/2018] [Accepted: 02/11/2018] [Indexed: 12/31/2022] Open
Abstract
Hybrid male sterility often evolves before female sterility or inviability of hybrids, implying that the accumulation of divergence between separated lineages should lead hybrid male sterility to have a more polygenic basis. However, experimental evidence is mixed. Here, we use the nematodes Caenorhabditis remanei and C. latens to characterize the underlying genetic basis of asymmetric hybrid male sterility and hybrid inviability. We demonstrate that hybrid male sterility is consistent with a simple genetic basis, involving a single X-autosome incompatibility. We also show that hybrid inviability involves more genomic compartments, involving diverse nuclear-nuclear incompatibilities, a mito-nuclear incompatibility, and maternal effects. These findings demonstrate that male sensitivity to genetic perturbation may be genetically simple compared to hybrid inviability in Caenorhabditis and motivates tests of generality for the genetic architecture of hybrid incompatibility across the breadth of phylogeny.
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Affiliation(s)
- Joanna D Bundus
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Donglin Wang
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada.
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Genetic Analyses of Elys Mutations in Drosophila Show Maternal-Effect Lethality and Interactions with Nucleoporin Genes. G3-GENES GENOMES GENETICS 2018; 8:2421-2431. [PMID: 29773558 PMCID: PMC6027884 DOI: 10.1534/g3.118.200361] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
ELYS determines the subcellular localizations of Nucleoporins (Nups) during interphase and mitosis. We made loss-of-function mutations of Elys in Drosophila melanogaster and found that ELYS is dispensable for zygotic viability and male fertility but the maternal supply is necessary for embryonic development. Subsequent to fertilization, mitotic progression of the embryos produced by the mutant females is severely disrupted at the first cleavage division, accompanied by irregular behavior of mitotic centrosomes. The Nup160 introgression from D. simulans shows close resemblance to that of the Elys mutations, suggesting a common role for those proteins in the first cleavage division. Our genetic experiments indicated critical interactions between ELYS and three Nup107-160 subcomplex components; hemizygotes of either Nup37, Nup96 or Nup160 were lethal in the genetic background of the Elys mutation. Not only Nup96 and Nup160 but also Nup37 of D. simulans behave as recessive hybrid incompatibility genes with D. melanogaster An evolutionary analysis indicated positive natural selection in the ELYS-like domain of ELYS. Here we propose that genetic incompatibility between Elys and Nups may lead to reproductive isolation between D. melanogaster and D. simulans, although direct evidence is necessary.
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40
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Funikov SY, Kulikova DA, Krasnov GS, Rezvykh AP, Chuvakova LN, Shostak NG, Zelentsova ES, Blumenstiel JP, Evgen’ev MB. Spontaneous gain of susceptibility suggests a novel mechanism of resistance to hybrid dysgenesis in Drosophila virilis. PLoS Genet 2018; 14:e1007400. [PMID: 29813067 PMCID: PMC5993320 DOI: 10.1371/journal.pgen.1007400] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 06/08/2018] [Accepted: 05/08/2018] [Indexed: 11/18/2022] Open
Abstract
Syndromes of hybrid dysgenesis (HD) have been critical for our understanding of the transgenerational maintenance of genome stability by piRNA. HD in D. virilis represents a special case of HD since it includes simultaneous mobilization of a set of TEs that belong to different classes. The standard explanation for HD is that eggs of the responder strains lack an abundant pool of piRNAs corresponding to the asymmetric TE families transmitted solely by sperm. However, there are several strains of D. virilis that lack asymmetric TEs, but exhibit a "neutral" cytotype that confers resistance to HD. To characterize the mechanism of resistance to HD, we performed a comparative analysis of the landscape of ovarian small RNAs in strains that vary in their resistance to HD mediated sterility. We demonstrate that resistance to HD cannot be solely explained by a maternal piRNA pool that matches the assemblage of TEs that likely cause HD. In support of this, we have witnessed a cytotype shift from neutral (N) to susceptible (M) in a strain devoid of all major TEs implicated in HD. This shift occurred in the absence of significant change in TE copy number and expression of piRNAs homologous to asymmetric TEs. Instead, this shift is associated with a change in the chromatin profile of repeat sequences unlikely to be causative of paternal induction. Overall, our data suggest that resistance to TE-mediated sterility during HD may be achieved by mechanisms that are distinct from the canonical syndromes of HD.
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Affiliation(s)
- Sergei Y. Funikov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Dina A. Kulikova
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - George S. Krasnov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Alexander P. Rezvykh
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Lubov N. Chuvakova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Natalia G. Shostak
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Elena S. Zelentsova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Justin P. Blumenstiel
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, United States of America
| | - Michael B. Evgen’ev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
- * E-mail:
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Serrato-Capuchina A, Matute DR. The Role of Transposable Elements in Speciation. Genes (Basel) 2018; 9:E254. [PMID: 29762547 PMCID: PMC5977194 DOI: 10.3390/genes9050254] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 01/20/2023] Open
Abstract
Understanding the phenotypic and molecular mechanisms that contribute to genetic diversity between and within species is fundamental in studying the evolution of species. In particular, identifying the interspecific differences that lead to the reduction or even cessation of gene flow between nascent species is one of the main goals of speciation genetic research. Transposable elements (TEs) are DNA sequences with the ability to move within genomes. TEs are ubiquitous throughout eukaryotic genomes and have been shown to alter regulatory networks, gene expression, and to rearrange genomes as a result of their transposition. However, no systematic effort has evaluated the role of TEs in speciation. We compiled the evidence for TEs as potential causes of reproductive isolation across a diversity of taxa. We find that TEs are often associated with hybrid defects that might preclude the fusion between species, but that the involvement of TEs in other barriers to gene flow different from postzygotic isolation is still relatively unknown. Finally, we list a series of guides and research avenues to disentangle the effects of TEs on the origin of new species.
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Affiliation(s)
- Antonio Serrato-Capuchina
- Biology Department, Genome Sciences Building, University of North Carolina, Chapel Hill, NC 27514, USA.
| | - Daniel R Matute
- Biology Department, Genome Sciences Building, University of North Carolina, Chapel Hill, NC 27514, USA.
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42
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Romero-Soriano V, Modolo L, Lopez-Maestre H, Mugat B, Pessia E, Chambeyron S, Vieira C, Garcia Guerreiro MP. Transposable Element Misregulation Is Linked to the Divergence between Parental piRNA Pathways in Drosophila Hybrids. Genome Biol Evol 2018; 9:1450-1470. [PMID: 28854624 PMCID: PMC5499732 DOI: 10.1093/gbe/evx091] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2017] [Indexed: 12/30/2022] Open
Abstract
Interspecific hybridization is a genomic stress condition that leads to the activation of transposable elements (TEs) in both animals and plants. In hybrids between Drosophila buzzatii and Drosophila koepferae, mobilization of at least 28 TEs has been described. However, the molecular mechanisms underlying this TE release remain poorly understood. To give insight on the causes of this TE activation, we performed a TE transcriptomic analysis in ovaries (notorious for playing a major role in TE silencing) of parental species and their F1 and backcrossed (BC) hybrids. We find that 15.2% and 10.6% of the expressed TEs are deregulated in F1 and BC1 ovaries, respectively, with a bias toward overexpression in both cases. Although differences between parental piRNA (Piwi-interacting RNA) populations explain only partially these results, we demonstrate that piRNA pathway proteins have divergent sequences and are differentially expressed between parental species. Thus, a functional divergence of the piRNA pathway between parental species, together with some differences between their piRNA pools, might be at the origin of hybrid instabilities and ultimately cause TE misregulation in ovaries. These analyses were complemented with the study of F1 testes, where TEs tend to be less expressed than in D. buzzatii. This can be explained by an increase in piRNA production, which probably acts as a defence mechanism against TE instability in the male germline. Hence, we describe a differential impact of interspecific hybridization in testes and ovaries, which reveals that TE expression and regulation are sex-biased.
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Affiliation(s)
- Valèria Romero-Soriano
- Grup de Genòmica, Bioinformàtica i Biologia Evolutiva, Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Spain
| | - Laurent Modolo
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Hélène Lopez-Maestre
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Bruno Mugat
- Institut de Génétique Humaine, UMR9002, CNRS-Université de Montpellier, France
| | - Eugénie Pessia
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Séverine Chambeyron
- Institut de Génétique Humaine, UMR9002, CNRS-Université de Montpellier, France
| | - Cristina Vieira
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Maria Pilar Garcia Guerreiro
- Grup de Genòmica, Bioinformàtica i Biologia Evolutiva, Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Spain
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43
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Moving Speciation Genetics Forward: Modern Techniques Build on Foundational Studies in Drosophila. Genetics 2018; 207:825-842. [PMID: 29097397 DOI: 10.1534/genetics.116.187120] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 06/23/2017] [Indexed: 12/12/2022] Open
Abstract
The question of how new species evolve has been examined at every level, from macroevolutionary patterns of diversification to molecular population genetic analyses of specific genomic regions between species pairs. Drosophila has been at the center of many of these research efforts. Though our understanding of the speciation process has grown considerably over the past few decades, very few genes have been identified that contribute to barriers to reproduction. The development of advanced molecular genetic and genomic methods provides promising avenues for the rapid discovery of more genes that contribute to speciation, particularly those involving prezygotic isolation. The continued expansion of tools and resources, especially for species other than Drosophila melanogaster, will be most effective when coupled with comparative approaches that reveal the genetic basis of reproductive isolation across a range of divergence times. Future research programs in Drosophila have high potential to answer long-standing questions in speciation. These include identifying the selective forces that contribute to divergence between populations and the genetic basis of traits that cause reproductive isolation. The latter can be expanded upon to understand how the genetic basis of reproductive isolation changes over time and whether certain pathways and genes are more commonly involved.
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44
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Germline Genome Protection on an Evolutionary Treadmill. Dev Cell 2017; 43:1-3. [PMID: 29017026 DOI: 10.1016/j.devcel.2017.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Preservation of genome integrity is a conserved, essential function, yet genome defense machinery evolves rapidly. In this issue of Developmental Cell, Parhad et al. (2017) harness an evolution-guided approach to define the genetic determinants of genome defense and to reveal the molecular and cellular mechanisms shaped by adaptive evolution.
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45
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Parhad SS, Tu S, Weng Z, Theurkauf WE. Adaptive Evolution Leads to Cross-Species Incompatibility in the piRNA Transposon Silencing Machinery. Dev Cell 2017; 43:60-70.e5. [PMID: 28919205 DOI: 10.1016/j.devcel.2017.08.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/11/2017] [Accepted: 08/15/2017] [Indexed: 12/25/2022]
Abstract
Reproductive isolation defines species divergence and is linked to adaptive evolution of hybrid incompatibility genes. Hybrids between Drosophila melanogaster and Drosophila simulans are sterile, and phenocopy mutations in the PIWI interacting RNA (piRNA) pathway, which silences transposons and shows pervasive adaptive evolution, and Drosophila rhino and deadlock encode rapidly evolving components of a complex that binds to piRNA clusters. We show that Rhino and Deadlock interact and co-localize in simulans and melanogaster, but simulans Rhino does not bind melanogaster Deadlock, due to substitutions in the rapidly evolving Shadow domain. Significantly, a chimera expressing the simulans Shadow domain in a melanogaster Rhino backbone fails to support piRNA production, disrupts binding to piRNA clusters, and leads to ectopic localization to bulk heterochromatin. Fusing melanogaster Deadlock to simulans Rhino, by contrast, restores localization to clusters. Deadlock binding thus directs Rhino to piRNA clusters, and Rhino-Deadlock co-evolution has produced cross-species incompatibilities, which may contribute to reproductive isolation.
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Affiliation(s)
- Swapnil S Parhad
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Shikui Tu
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA.
| | - William E Theurkauf
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
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46
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Dion-Côté AM, Barbash DA. Beyond speciation genes: an overview of genome stability in evolution and speciation. Curr Opin Genet Dev 2017; 47:17-23. [PMID: 28830007 DOI: 10.1016/j.gde.2017.07.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/17/2017] [Accepted: 07/28/2017] [Indexed: 01/03/2023]
Abstract
Genome stability ensures individual fitness and reliable transmission of genetic information. Hybridization between diverging lineages can trigger genome instability, highlighting its potential role in post-zygotic reproductive isolation. We argue that genome instability is not merely one of several types of hybrid incompatibility, but rather that genome stability is one of the very first and most fundamental traits that can break down when two diverged genomes are combined. Future work will reveal how frequent and predictable genome instability is in hybrids, how it affects hybrid fitness, and whether it is a direct cause or consequence of speciation.
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Affiliation(s)
- Anne-Marie Dion-Côté
- Department of Molecular Biology and Genetics, Cornell University, 526 Campus Road, Ithaca, NY 14853, United States
| | - Daniel A Barbash
- Department of Molecular Biology and Genetics, Cornell University, 526 Campus Road, Ithaca, NY 14853, United States.
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47
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Lee YCG, Karpen GH. Pervasive epigenetic effects of Drosophila euchromatic transposable elements impact their evolution. eLife 2017; 6. [PMID: 28695823 PMCID: PMC5505702 DOI: 10.7554/elife.25762] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 06/09/2017] [Indexed: 12/21/2022] Open
Abstract
Transposable elements (TEs) are widespread genomic parasites, and their evolution has remained a critical question in evolutionary genomics. Here, we study the relatively unexplored epigenetic impacts of TEs and provide the first genome-wide quantification of such effects in D. melanogaster and D. simulans. Surprisingly, the spread of repressive epigenetic marks (histone H3K9me2) to nearby DNA occurs at >50% of euchromatic TEs, and can extend up to 20 kb. This results in differential epigenetic states of genic alleles and, in turn, selection against TEs. Interestingly, the lower TE content in D. simulans compared to D. melanogaster correlates with stronger epigenetic effects of TEs and higher levels of host genetic factors known to promote epigenetic silencing. Our study demonstrates that the epigenetic effects of euchromatic TEs, and host genetic factors modulating such effects, play a critical role in the evolution of TEs both within and between species. DOI:http://dx.doi.org/10.7554/eLife.25762.001 The DNA inside an organism encodes all the instructions needed for the organism to develop and work properly. Organisms carefully organize and maintain their DNA (collectively known as the genome) so that the genetic information remains intact and the cell can understand the instructions. However, there are some pieces of DNA that are capable of moving around the genome. For example, pieces known as transposable elements can make new copies of themselves and jump into new locations in the genome. Most transposons do not appear to have any important roles, and in fact they are usually harmful to organisms. Despite this, transposons are present in the genomes of almost all species. The number of transposons in a genome varies greatly between individuals and species, but it is not clear why this is the case. Organisms have evolved ways to limit the damage caused by transposons. For example, many cells package regions of DNA containing transposons into a tightly packed structure known as heterochromatin. However, this type of DNA packaging sometimes spreads to neighboring sections of DNA. This is a problem because cells are not usually able to read the information contained within heterochromatin. This means that transposons can prevent some instructions from being produced when they should be. Lee and Karpen used fruit flies to investigate to what extent transposons harm organisms by changing the way DNA is packaged, and whether this influences how transposons evolve. The experiments show that that more than half of the transposons in fruit flies cause neighboring sections of DNA to be packaged into heterochromatin. This can negatively impact up to 20% of genes in the genome. As a result, transposons that have harmful effects on DNA packaging are more likely to be lost from the fly population during evolution than transposons that do not have harmful effects. Fruit fly species containing transposons that tend to package more neighboring sections of DNA into heterochromatin generally have fewer transposons than genomes containing less harmful transposons. The findings of Lee and Karpen provide new insight as to why the numbers of transposons vary among organisms. The next challenge is to find out whether transposons that alter how DNA is packaged are also common in primates and other animals. DOI:http://dx.doi.org/10.7554/eLife.25762.002
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Affiliation(s)
- Yuh Chwen G Lee
- Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States.,Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, United States
| | - Gary H Karpen
- Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States.,Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, United States
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48
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Silencing of Transposable Elements by piRNAs in Drosophila: An Evolutionary Perspective. GENOMICS PROTEOMICS & BIOINFORMATICS 2017; 15:164-176. [PMID: 28602845 PMCID: PMC5487533 DOI: 10.1016/j.gpb.2017.01.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 01/02/2017] [Accepted: 01/12/2017] [Indexed: 11/28/2022]
Abstract
Transposable elements (TEs) are DNA sequences that can move within the genome. TEs have greatly shaped the genomes, transcriptomes, and proteomes of the host organisms through a variety of mechanisms. However, TEs generally disrupt genes and destabilize the host genomes, which substantially reduce fitness of the host organisms. Understanding the genomic distribution and evolutionary dynamics of TEs will greatly deepen our understanding of the TE-mediated biological processes. Most TE insertions are highly polymorphic in Drosophila melanogaster, providing us a good system to investigate the evolution of TEs at the population level. Decades of theoretical and experimental studies have well established “transposition-selection” population genetics model, which assumes that the equilibrium between TE replication and purifying selection determines the copy number of TEs in the genome. In the last decade, P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) were demonstrated to be master repressors of TE activities in Drosophila. The discovery of piRNAs revolutionized our understanding of TE repression, because it reveals that the host organisms have evolved an adaptive mechanism to defend against TE invasion. Tremendous progress has been made to understand the molecular mechanisms by which piRNAs repress active TEs, although many details in this process remain to be further explored. The interaction between piRNAs and TEs well explains the molecular mechanisms underlying hybrid dysgenesis for the I-R and P-M systems in Drosophila, which have puzzled evolutionary biologists for decades. The piRNA repression pathway provides us an unparalleled system to study the co-evolutionary process between parasites and host organisms.
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49
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Gerland TA, Sun B, Smialowski P, Lukacs A, Thomae AW, Imhof A. The Drosophila speciation factor HMR localizes to genomic insulator sites. PLoS One 2017; 12:e0171798. [PMID: 28207793 PMCID: PMC5312933 DOI: 10.1371/journal.pone.0171798] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 01/26/2017] [Indexed: 12/22/2022] Open
Abstract
Hybrid incompatibility between Drosophila melanogaster and D. simulans is caused by a lethal interaction of the proteins encoded by the Hmr and Lhr genes. In D. melanogaster the loss of HMR results in mitotic defects, an increase in transcription of transposable elements and a deregulation of heterochromatic genes. To better understand the molecular mechanisms that mediate HMR’s function, we measured genome-wide localization of HMR in D. melanogaster tissue culture cells by chromatin immunoprecipitation. Interestingly, we find HMR localizing to genomic insulator sites that can be classified into two groups. One group belongs to gypsy insulators and another one borders HP1a bound regions at active genes. The transcription of the latter group genes is strongly affected in larvae and ovaries of Hmr mutant flies. Our data suggest a novel link between HMR and insulator proteins, a finding that implicates a potential role for genome organization in the formation of species.
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Affiliation(s)
- Thomas Andreas Gerland
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Bo Sun
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Pawel Smialowski
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Biomedical Center, Core Facility Computational Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Andrea Lukacs
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Andreas Walter Thomae
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Biomedical Center, Core Facility Bioimaging, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Axel Imhof
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Munich, Germany
- * E-mail:
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Identification of misexpressed genetic elements in hybrids between Drosophila-related species. Sci Rep 2017; 7:40618. [PMID: 28091568 PMCID: PMC5238404 DOI: 10.1038/srep40618] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 12/09/2016] [Indexed: 12/30/2022] Open
Abstract
Crosses between close species can lead to genomic disorders, often considered to be the cause of hybrid incompatibility, one of the initial steps in the speciation process. How these incompatibilities are established and what are their causes remain unclear. To understand the initiation of hybrid incompatibility, we performed reciprocal crosses between two species of Drosophila (D. mojavensis and D. arizonae) that diverged less than 1 Mya. We performed a genome-wide transcriptomic analysis on ovaries from parental lines and on hybrids from reciprocal crosses. Using an innovative procedure of co-assembling transcriptomes, we show that parental lines differ in the expression of their genes and transposable elements. Reciprocal hybrids presented specific gene categories and few transposable element families misexpressed relative to the parental lines. Because TEs are mainly silenced by piwi-interacting RNAs (piRNAs), we hypothesize that in hybrids the deregulation of specific TE families is due to the absence of such small RNAs. Small RNA sequencing confirmed our hypothesis and we therefore propose that TEs can indeed be major players of genome differentiation and be implicated in the first steps of genomic incompatibilities through small RNA regulation.
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