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Tralamazza SM, Gluck-Thaler E, Feurtey A, Croll D. Copy number variation introduced by a massive mobile element facilitates global thermal adaptation in a fungal wheat pathogen. Nat Commun 2024; 15:5728. [PMID: 38977688 PMCID: PMC11231334 DOI: 10.1038/s41467-024-49913-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 06/25/2024] [Indexed: 07/10/2024] Open
Abstract
Copy number variation (CNV) can drive rapid evolution in changing environments. In microbial pathogens, such adaptation is a key factor underpinning epidemics and colonization of new niches. However, the genomic determinants of such adaptation remain poorly understood. Here, we systematically investigate CNVs in a large genome sequencing dataset spanning a worldwide collection of 1104 genomes from the major wheat pathogen Zymoseptoria tritici. We found overall strong purifying selection acting on most CNVs. Genomic defense mechanisms likely accelerated gene loss over episodes of continental colonization. Local adaptation along climatic gradients was likely facilitated by CNVs affecting secondary metabolite production and gene loss in general. One of the strongest loci for climatic adaptation is a highly conserved gene of the NAD-dependent Sirtuin family. The Sirtuin CNV locus localizes to an ~68-kb Starship mobile element unique to the species carrying genes highly expressed during plant infection. The element has likely lost the ability to transpose, demonstrating how the ongoing domestication of cargo-carrying selfish elements can contribute to selectable variation within populations. Our work highlights how standing variation in gene copy numbers at the global scale can be a major factor driving climatic and metabolic adaptation in microbial species.
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Affiliation(s)
- Sabina Moser Tralamazza
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
| | - Emile Gluck-Thaler
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
| | - Alice Feurtey
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
- Plant Pathology, D-USYS, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland.
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Ohtani H, Liu M, Liang G, Jang HJ, Jones PA. Efficient activation of hundreds of LTR12C elements reveals cis-regulatory function determined by distinct epigenetic mechanisms. Nucleic Acids Res 2024:gkae498. [PMID: 38874474 DOI: 10.1093/nar/gkae498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 05/23/2024] [Accepted: 06/05/2024] [Indexed: 06/15/2024] Open
Abstract
Long terminal repeats (LTRs), which often contain promoter and enhancer sequences of intact endogenous retroviruses (ERVs), are known to be co-opted as cis-regulatory elements for fine-tuning host-coding gene expression. Since LTRs are mainly silenced by the deposition of repressive epigenetic marks, substantial activation of LTRs has been found in human cells after treatment with epigenetic inhibitors. Although the LTR12C family makes up the majority of ERVs activated by epigenetic inhibitors, how these epigenetically and transcriptionally activated LTR12C elements can regulate the host-coding gene expression remains unclear due to genome-wide alteration of transcriptional changes after epigenetic inhibitor treatments. Here, we specifically transactivated >600 LTR12C elements by using single guide RNA-based dCas9-SunTag-VP64, a site-specific targeting CRISPR activation (CRISPRa) system, with minimal off-target events. Interestingly, most of the transactivated LTR12C elements acquired the H3K27ac-marked enhancer feature, while only 20% were co-marked with promoter-associated H3K4me3 modifications. The enrichment of the H3K4me3 signal was intricately associated with downstream regions of LTR12C, such as internal regions of intact ERV9 or other types of retrotransposons. Here, we leverage an optimized CRISPRa system to identify two distinct epigenetic signatures that define LTR12C transcriptional activation, which modulate the expression of proximal protein-coding genes.
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Affiliation(s)
- Hitoshi Ohtani
- Department of Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA
- Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Minmin Liu
- Department of Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Gangning Liang
- Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - H Josh Jang
- Department of Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Peter A Jones
- Department of Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA
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3
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Zhang GJ, Jia KL, Wang J, Gao WJ, Li SF. Genome-wide analysis of transposable elements and satellite DNA in Humulus scandens, a dioecious plant with XX/XY 1Y 2 chromosomes. FRONTIERS IN PLANT SCIENCE 2023; 14:1230250. [PMID: 37908838 PMCID: PMC10614002 DOI: 10.3389/fpls.2023.1230250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 10/04/2023] [Indexed: 11/02/2023]
Abstract
Transposable elements (TEs) and satellite DNAs, two major categories of repetitive sequences, are expected to accumulate in non-recombining genome regions, including sex-linked regions, and contribute to sex chromosome evolution. The dioecious plant, Humulus scandens, can be used for studying the evolution of the XX/XY1Y2 sex chromosomes. In this study, we thoroughly examined the repetitive components of male and female H. scandens using next-generation sequencing data followed by bioinformatics analysis and florescence in situ hybridization (FISH). The H. scandens genome has a high overall repetitive sequence composition, 68.30% in the female and 66.78% in the male genome, with abundant long terminal repeat (LTR) retrotransposons (RTs), including more Ty3/Gypsy than Ty1/Copia elements, particularly two Ty3/Gypsy lineages, Tekay and Retand. Most LTR-RT lineages were found dispersed across the chromosomes, though CRM and Athila elements were predominately found within the centromeres and the pericentromeric regions. The Athila elements also showed clearly higher FISH signal intensities in the Y1 and Y2 chromosomes than in the X or autosomes. Three novel satellite DNAs were specifically distributed in the centromeric and/or telomeric regions, with markedly different distributions on the X, Y1, and Y2 chromosomes. Combined with FISH using satellite DNAs to stain chromosomes during meiotic diakinesis, we determined the synapsis pattern and distinguish pseudoautosomal regions (PARs). The results indicate that the XY1Y2 sex chromosomes of H. scandens might have originated from a centric fission event. This study improves our understanding of the repetitive sequence organization of H. scandens genome and provides a basis for further analysis of their chromosome evolution process.
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Affiliation(s)
- Guo-Jun Zhang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Ke-Li Jia
- College of Life Sciences, Henan Normal University, Xinxiang, China
- SanQuan Medical College, Xinxiang Medical University, Xinxiang, China
| | - Jin Wang
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Wu-Jun Gao
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Shu-Fen Li
- College of Life Sciences, Henan Normal University, Xinxiang, China
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4
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Scheuren M, Möhner J, Zischler H. R-loop landscape in mature human sperm: Regulatory and evolutionary implications. Front Genet 2023; 14:1069871. [PMID: 37139234 PMCID: PMC10149866 DOI: 10.3389/fgene.2023.1069871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 04/03/2023] [Indexed: 05/05/2023] Open
Abstract
R-loops are three-stranded nucleic acid structures consisting of an RNA:DNA hybrid and a displaced DNA strand. While R-loops pose a potential threat to genome integrity, they constitute 5% of the human genome. The role of R-loops in transcriptional regulation, DNA replication, and chromatin signature is becoming increasingly clear. R-loops are associated with various histone modifications, suggesting that they may modulate chromatin accessibility. To potentially harness transcription-coupled repair mechanisms in the germline, nearly the entire genome is expressed during the early stages of male gametogenesis in mammals, providing ample opportunity for the formation of a transcriptome-dependent R-loop landscape in male germ cells. In this study, our data demonstrated the presence of R-loops in fully mature human and bonobo sperm heads and their partial correspondence to transcribed regions and chromatin structure, which is massively reorganized from mainly histone to mainly protamine-packed chromatin in mature sperm. The sperm R-loop landscape resembles characteristic patterns of somatic cells. Surprisingly, we detected R-loops in both residual histone and protamine-packed chromatin and localize them to still-active retroposons, ALUs and SINE-VNTR-ALUs (SVAs), the latter has recently arisen in hominoid primates. We detected both evolutionarily conserved and species-specific localizations. Comparing our DNA-RNA immunoprecipitation (DRIP) data with published DNA methylation and histone chromatin immunoprecipitation (ChIP) data, we hypothesize that R-loops epigenetically reduce methylation of SVAs. Strikingly, we observe a strong influence of R-loops on the transcriptomes of zygotes from early developmental stages before zygotic genome activation. Overall, these findings suggest that chromatin accessibility influenced by R-loops may represent a system of inherited gene regulation.
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Ruggieri AA, Livraghi L, Lewis JJ, Evans E, Cicconardi F, Hebberecht L, Ortiz-Ruiz Y, Montgomery SH, Ghezzi A, Rodriguez-Martinez JA, Jiggins CD, McMillan WO, Counterman BA, Papa R, Van Belleghem SM. A butterfly pan-genome reveals that a large amount of structural variation underlies the evolution of chromatin accessibility. Genome Res 2022; 32:1862-1875. [PMID: 36109150 PMCID: PMC9712634 DOI: 10.1101/gr.276839.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 09/13/2022] [Indexed: 01/16/2023]
Abstract
Despite insertions and deletions being the most common structural variants (SVs) found across genomes, not much is known about how much these SVs vary within populations and between closely related species, nor their significance in evolution. To address these questions, we characterized the evolution of indel SVs using genome assemblies of three closely related Heliconius butterfly species. Over the relatively short evolutionary timescales investigated, up to 18.0% of the genome was composed of indels between two haplotypes of an individual Heliconius charithonia butterfly and up to 62.7% included lineage-specific SVs between the genomes of the most distant species (11 Mya). Lineage-specific sequences were mostly characterized as transposable elements (TEs) inserted at random throughout the genome and their overall distribution was similarly affected by linked selection as single nucleotide substitutions. Using chromatin accessibility profiles (i.e., ATAC-seq) of head tissue in caterpillars to identify sequences with potential cis-regulatory function, we found that out of the 31,066 identified differences in chromatin accessibility between species, 30.4% were within lineage-specific SVs and 9.4% were characterized as TE insertions. These TE insertions were localized closer to gene transcription start sites than expected at random and were enriched for sites with significant resemblance to several transcription factor binding sites with known function in neuron development in Drosophila We also identified 24 TE insertions with head-specific chromatin accessibility. Our results show high rates of structural genome evolution that were previously overlooked in comparative genomic studies and suggest a high potential for structural variation to serve as raw material for adaptive evolution.
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Affiliation(s)
- Angelo A Ruggieri
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan PR 00931, Puerto Rico
| | - Luca Livraghi
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
- Smithsonian Tropical Research Institute, Apartado 0843-03092 Panamá, Panama
| | - James J Lewis
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Elizabeth Evans
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan PR 00931, Puerto Rico
| | - Francesco Cicconardi
- School of Biological Sciences, Bristol University, Bristol BS8 1QU, United Kingdom
| | - Laura Hebberecht
- School of Biological Sciences, Bristol University, Bristol BS8 1QU, United Kingdom
| | - Yadira Ortiz-Ruiz
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan PR 00931, Puerto Rico
- Molecular Sciences and Research Center, University of Puerto Rico, San Juan 00926, Puerto Rico
| | - Stephen H Montgomery
- School of Biological Sciences, Bristol University, Bristol BS8 1QU, United Kingdom
| | - Alfredo Ghezzi
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan PR 00931, Puerto Rico
| | | | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
| | - W Owen McMillan
- Smithsonian Tropical Research Institute, Apartado 0843-03092 Panamá, Panama
| | - Brian A Counterman
- Department of Biological Sciences, Auburn University, Auburn, Alabama 36849, USA
| | - Riccardo Papa
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan PR 00931, Puerto Rico
- Molecular Sciences and Research Center, University of Puerto Rico, San Juan 00926, Puerto Rico
| | - Steven M Van Belleghem
- Department of Biology, University of Puerto Rico-Rio Piedras, San Juan PR 00931, Puerto Rico
- Ecology, Evolution and Conservation Biology, Biology Department, KU Leuven, 3000 Leuven, Belgium
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6
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Iwasaki YW, Sriswasdi S, Kinugasa Y, Adachi J, Horikoshi Y, Shibuya A, Iwasaki W, Tashiro S, Tomonaga T, Siomi H. Piwi-piRNA complexes induce stepwise changes in nuclear architecture at target loci. EMBO J 2021; 40:e108345. [PMID: 34337769 PMCID: PMC8441340 DOI: 10.15252/embj.2021108345] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/04/2021] [Accepted: 07/09/2021] [Indexed: 12/25/2022] Open
Abstract
PIWI‐interacting RNAs (piRNAs) are germline‐specific small RNAs that form effector complexes with PIWI proteins (Piwi–piRNA complexes) and play critical roles for preserving genomic integrity by repressing transposable elements (TEs). Drosophila Piwi transcriptionally silences specific targets through heterochromatin formation and increases histone H3K9 methylation (H3K9me3) and histone H1 deposition at these loci, with nuclear RNA export factor variant Nxf2 serving as a co‐factor. Using ChEP and DamID‐seq, we now uncover a Piwi/Nxf2‐dependent target association with nuclear lamins. Hi‐C analysis of Piwi or Nxf2‐depleted cells reveals decreased intra‐TAD and increased inter‐TAD interactions in regions harboring Piwi–piRNA target TEs. Using a forced tethering system, we analyze the functional effects of Piwi–piRNA/Nxf2‐mediated recruitment of piRNA target regions to the nuclear periphery. Removal of active histone marks is followed by transcriptional silencing, chromatin conformational changes, and H3K9me3 and H1 association. Our data show that the Piwi–piRNA pathway can induce stepwise changes in nuclear architecture and chromatin state at target loci for transcriptional silencing.
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Affiliation(s)
- Yuka W Iwasaki
- Department of Molecular Biology, Keio University School of Medicine, Tokyo, Japan.,Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Saitama, Japan
| | - Sira Sriswasdi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.,Computational Molecular Biology Group, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Yasuha Kinugasa
- Department of Cellular Biology, Research Institute for Radiation Biology Medicine, Hiroshima University, Hiroshima, Japan
| | - Jun Adachi
- Laboratory of Proteome Research, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - Yasunori Horikoshi
- Department of Cellular Biology, Research Institute for Radiation Biology Medicine, Hiroshima University, Hiroshima, Japan
| | - Aoi Shibuya
- Department of Molecular Biology, Keio University School of Medicine, Tokyo, Japan
| | - Wataru Iwasaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Satoshi Tashiro
- Department of Cellular Biology, Research Institute for Radiation Biology Medicine, Hiroshima University, Hiroshima, Japan
| | - Takeshi Tomonaga
- Laboratory of Proteome Research, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - Haruhiko Siomi
- Department of Molecular Biology, Keio University School of Medicine, Tokyo, Japan
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