1
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Wiegand T, Hoffmann FT, Walker MWG, Tang S, Richard E, Le HC, Meers C, Sternberg SH. TnpB homologues exapted from transposons are RNA-guided transcription factors. Nature 2024:10.1038/s41586-024-07598-4. [PMID: 38926585 DOI: 10.1038/s41586-024-07598-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 05/23/2024] [Indexed: 06/28/2024]
Abstract
Transposon-encoded tnpB and iscB genes encode RNA-guided DNA nucleases that promote their own selfish spread through targeted DNA cleavage and homologous recombination1-4. These widespread gene families were repeatedly domesticated over evolutionary timescales, leading to the emergence of diverse CRISPR-associated nucleases including Cas9 and Cas12 (refs. 5,6). We set out to test the hypothesis that TnpB nucleases may have also been repurposed for novel, unexpected functions other than CRISPR-Cas adaptive immunity. Here, using phylogenetics, structural predictions, comparative genomics and functional assays, we uncover multiple independent genesis events of programmable transcription factors, which we name TnpB-like nuclease-dead repressors (TldRs). These proteins use naturally occurring guide RNAs to specifically target conserved promoter regions of the genome, leading to potent gene repression in a mechanism akin to CRISPR interference technologies invented by humans7. Focusing on a TldR clade found broadly in Enterobacteriaceae, we discover that bacteriophages exploit the combined action of TldR and an adjacently encoded phage gene to alter the expression and composition of the host flagellar assembly, a transformation with the potential to impact motility8, phage susceptibility9, and host immunity10. Collectively, this work showcases the diverse molecular innovations that were enabled through repeated exaptation of transposon-encoded genes, and reveals the evolutionary trajectory of diverse RNA-guided transcription factors.
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Affiliation(s)
- Tanner Wiegand
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Florian T Hoffmann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Matt W G Walker
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Stephen Tang
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Egill Richard
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Hoang C Le
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Chance Meers
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Samuel H Sternberg
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
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2
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Srivastav SP, Feschotte C, Clark AG. Rapid evolution of piRNA clusters in the Drosophila melanogaster ovary. Genome Res 2024; 34:711-724. [PMID: 38749655 DOI: 10.1101/gr.278062.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 05/07/2024] [Indexed: 05/28/2024]
Abstract
The piRNA pathway is a highly conserved mechanism to repress transposable element (TE) activity in the animal germline via a specialized class of small RNAs called piwi-interacting RNAs (piRNAs). piRNAs are produced from discrete genomic regions called piRNA clusters (piCs). Although the molecular processes by which piCs function are relatively well understood in Drosophila melanogaster, much less is known about the origin and evolution of piCs in this or any other species. To investigate piC origin and evolution, we use a population genomic approach to compare piC activity and sequence composition across eight geographically distant strains of D. melanogaster with high-quality long-read genome assemblies. We perform annotations of ovary piCs and genome-wide TE content in each strain. Our analysis uncovers extensive variation in piC activity across strains and signatures of rapid birth and death of piCs. Most TEs inferred to be recently active show an enrichment of insertions into old and large piCs, consistent with the previously proposed "trap" model of piC evolution. In contrast, a small subset of active LTR families is enriched for the formation of new piCs, suggesting that these TEs have higher proclivity to form piCs. Thus, our findings uncover processes leading to the origin of piCs. We propose that piC evolution begins with the emergence of piRNAs from individual insertions of a few select TE families prone to seed new piCs that subsequently expand by accretion of insertions from most other TE families during evolution to form larger "trap" clusters. Our study shows that TEs themselves are the major force driving the rapid evolution of piCs.
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Affiliation(s)
- Satyam P Srivastav
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
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3
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Gluck-Thaler E, Vogan A. Systematic identification of cargo-mobilizing genetic elements reveals new dimensions of eukaryotic diversity. Nucleic Acids Res 2024; 52:5496-5513. [PMID: 38686785 PMCID: PMC11162782 DOI: 10.1093/nar/gkae327] [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: 10/24/2023] [Revised: 03/12/2024] [Accepted: 04/15/2024] [Indexed: 05/02/2024] Open
Abstract
Cargo-mobilizing mobile elements (CMEs) are genetic entities that faithfully transpose diverse protein coding sequences. Although common in bacteria, we know little about eukaryotic CMEs because no appropriate tools exist for their annotation. For example, Starships are giant fungal CMEs whose functions are largely unknown because they require time-intensive manual curation. To address this knowledge gap, we developed starfish, a computational workflow for high-throughput eukaryotic CME annotation. We applied starfish to 2 899 genomes of 1 649 fungal species and found that starfish recovers known Starships with 95% combined precision and recall while expanding the number of annotated elements ten-fold. Extant Starship diversity is partitioned into 11 families that differ in their enrichment patterns across fungal classes. Starship cargo changes rapidly such that elements from the same family differ substantially in their functional repertoires, which are predicted to contribute to diverse biological processes such as metabolism. Many elements have convergently evolved to insert into 5S rDNA and AT-rich sequence while others integrate into random locations, revealing both specialist and generalist strategies for persistence. Our work establishes a framework for advancing mobile element biology and provides the means to investigate an emerging dimension of eukaryotic genetic diversity, that of genomes within genomes.
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Affiliation(s)
- Emile Gluck-Thaler
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Neuchâtel 2000, Switzerland
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Wisconsin Institute for Discovery, Madison, WI 53706, USA
| | - Aaron A Vogan
- Systematic Biology, Department of Organismal Biology, Uppsala University, Uppsala, 752 36, Sweden
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4
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Baril T, Galbraith J, Hayward A. Earl Grey: A Fully Automated User-Friendly Transposable Element Annotation and Analysis Pipeline. Mol Biol Evol 2024; 41:msae068. [PMID: 38577785 PMCID: PMC11003543 DOI: 10.1093/molbev/msae068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 02/20/2024] [Accepted: 03/22/2024] [Indexed: 04/06/2024] Open
Abstract
Transposable elements (TEs) are major components of eukaryotic genomes and are implicated in a range of evolutionary processes. Yet, TE annotation and characterization remain challenging, particularly for nonspecialists, since existing pipelines are typically complicated to install, run, and extract data from. Current methods of automated TE annotation are also subject to issues that reduce overall quality, particularly (i) fragmented and overlapping TE annotations, leading to erroneous estimates of TE count and coverage, and (ii) repeat models represented by short sections of total TE length, with poor capture of 5' and 3' ends. To address these issues, we present Earl Grey, a fully automated TE annotation pipeline designed for user-friendly curation and annotation of TEs in eukaryotic genome assemblies. Using nine simulated genomes and an annotation of Drosophila melanogaster, we show that Earl Grey outperforms current widely used TE annotation methodologies in ameliorating the issues mentioned above while scoring highly in benchmarking for TE annotation and classification and being robust across genomic contexts. Earl Grey provides a comprehensive and fully automated TE annotation toolkit that provides researchers with paper-ready summary figures and outputs in standard formats compatible with other bioinformatics tools. Earl Grey has a modular format, with great scope for the inclusion of additional modules focused on further quality control and tailored analyses in future releases.
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Affiliation(s)
- Tobias Baril
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - James Galbraith
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Alex Hayward
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
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5
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Almeida MV, Blumer M, Yuan CU, Sierra P, Price JL, Quah FX, Friman A, Dallaire A, Vernaz G, Putman ALK, Smith AM, Joyce DA, Butter F, Haase AD, Durbin R, Santos ME, Miska EA. Dynamic co-evolution of transposable elements and the piRNA pathway in African cichlid fishes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.01.587621. [PMID: 38617250 PMCID: PMC11014572 DOI: 10.1101/2024.04.01.587621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
East African cichlid fishes have diversified in an explosive fashion, but the (epi)genetic basis of the phenotypic diversity of these fishes remains largely unknown. Although transposable elements (TEs) have been associated with phenotypic variation in cichlids, little is known about their transcriptional activity and epigenetic silencing. Here, we describe dynamic patterns of TE expression in African cichlid gonads and during early development. Orthology inference revealed an expansion of piwil1 genes in Lake Malawi cichlids, likely driven by PiggyBac TEs. The expanded piwil1 copies have signatures of positive selection and retain amino acid residues essential for catalytic activity. Furthermore, the gonads of African cichlids express a Piwi-interacting RNA (piRNA) pathway that target TEs. We define the genomic sites of piRNA production in African cichlids and find divergence in closely related species, in line with fast evolution of piRNA-producing loci. Our findings suggest dynamic co-evolution of TEs and host silencing pathways in the African cichlid radiations. We propose that this co-evolution has contributed to cichlid genomic diversity.
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Affiliation(s)
- Miguel Vasconcelos Almeida
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Moritz Blumer
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- These authors contributed equally
| | - Chengwei Ulrika Yuan
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- These authors contributed equally
| | - Pío Sierra
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Jonathan L. Price
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Fu Xiang Quah
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Aleksandr Friman
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
- Biophysics Graduate Program, Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - Alexandra Dallaire
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Comparative Fungal Biology, Royal Botanic Gardens Kew, Jodrell Laboratory, Richmond TW9 3DS, UK
| | - Grégoire Vernaz
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- Present address: Zoological Institute, Department of Environmental Sciences, University of Basel, Vesalgasse 1, Basel, 4051, Switzerland
| | - Audrey L. K. Putman
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Alan M. Smith
- School of Natural Sciences, University of Hull, Hull, HU6 7RX, UK
| | - Domino A. Joyce
- School of Natural Sciences, University of Hull, Hull, HU6 7RX, UK
| | - Falk Butter
- Institute of Molecular Biology (IMB), Quantitative Proteomics, Ackermannweg 4, Mainz, 55128, Germany
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institute, Südufer, Greifswald, 17493, Germany
| | - Astrid D. Haase
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Richard Durbin
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- Wellcome Sanger Institute, Tree of Life, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
| | - M. Emília Santos
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Eric A. Miska
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
- Wellcome/CRUK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Wellcome Sanger Institute, Tree of Life, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
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6
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Uneme Y, Maeda R, Nakayama G, Narita H, Takeda N, Hiramatsu R, Nishihara H, Nakato R, Kanai Y, Araki K, Siomi MC, Yamanaka S. Morc1 reestablishes H3K9me3 heterochromatin on piRNA-targeted transposons in gonocytes. Proc Natl Acad Sci U S A 2024; 121:e2317095121. [PMID: 38502704 PMCID: PMC10990106 DOI: 10.1073/pnas.2317095121] [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: 10/02/2023] [Accepted: 01/23/2024] [Indexed: 03/21/2024] Open
Abstract
To maintain fertility, male mice re-repress transposable elements (TEs) that were de-silenced in the early gonocytes before their differentiation into spermatogonia. However, the mechanism of TE silencing re-establishment remains unknown. Here, we found that the DNA-binding protein Morc1, in cooperation with the methyltransferase SetDB1, deposits the repressive histone mark H3K9me3 on a large fraction of activated TEs, leading to heterochromatin. Morc1 also triggers DNA methylation, but TEs targeted by Morc1-driven DNA methylation only slightly overlapped with those repressed by Morc1/SetDB1-dependent heterochromatin formation, suggesting that Morc1 silences TEs in two different manners. In contrast, TEs regulated by Morc1 and Miwi2, the nuclear PIWI-family protein, almost overlapped. Miwi2 binds to PIWI-interacting RNAs (piRNAs) that base-pair with TE mRNAs via sequence complementarity, while Morc1 DNA binding is not sequence specific, suggesting that Miwi2 selects its targets, and then, Morc1 acts to repress them with cofactors. A high-ordered mechanism of TE repression in gonocytes has been identified.
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Affiliation(s)
- Yuta Uneme
- Department of Biophysics and Biochemistry, Faculty of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Ryu Maeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Gen Nakayama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Haruka Narita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Naoki Takeda
- Division of Developmental Genetics, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto860-0811, Japan
| | - Ryuji Hiramatsu
- Department of Veterinary Anatomy, The University of Tokyo, Tokyo113-8657, Japan
| | - Hidenori Nishihara
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, Nara631-8505, Japan
| | - Ryuichiro Nakato
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo113-0032, Japan
| | - Yoshiakira Kanai
- Department of Veterinary Anatomy, The University of Tokyo, Tokyo113-8657, Japan
| | - Kimi Araki
- Division of Developmental Genetics, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto860-0811, Japan
- Faculty of Life Sciences, Center for Metabolic Regulation of Healthy Aging, Kumamoto University, Honjo, Kumamoto860-8556, Japan
| | - Mikiko C. Siomi
- Department of Biophysics and Biochemistry, Faculty of Science, The University of Tokyo, Tokyo113-0032, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
| | - Soichiro Yamanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo113-0032, Japan
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7
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Chang NC, Wells JN, Wang AY, Schofield P, Huang YC, Truong VH, Simoes-Costa M, Feschotte C. Gag proteins encoded by endogenous retroviruses are required for zebrafish development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.25.586437. [PMID: 38585793 PMCID: PMC10996621 DOI: 10.1101/2024.03.25.586437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Transposable elements (TEs) make up the bulk of eukaryotic genomes and examples abound of TE-derived sequences repurposed for organismal function. The process by which TEs become coopted remains obscure because most cases involve ancient, transpositionally inactive elements. Reports of active TEs serving beneficial functions are scarce and often contentious due to difficulties in manipulating repetitive sequences. Here we show that recently active TEs in zebrafish encode products critical for embryonic development. Knockdown and rescue experiments demonstrate that the endogenous retrovirus family BHIKHARI-1 (Bik-1) encodes a Gag protein essential for mesoderm development. Mechanistically, Bik-1 Gag associates with the cell membrane and its ectopic expression in chicken embryos alters cell migration. Similarly, depletion of BHIKHARI-2 Gag, a relative of Bik-1, causes defects in neural crest development in zebrafish. We propose an "addiction" model to explain how active TEs can be integrated into conserved developmental processes.
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Affiliation(s)
- Ni-Chen Chang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
| | - Jonathan N Wells
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
| | - Andrew Y Wang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
| | - Phillip Schofield
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
| | - Yi-Chia Huang
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
- Department of Pathology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Vinh H Truong
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
| | - Marcos Simoes-Costa
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
- Department of Pathology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
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8
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Lin L, Huang Y, McIntyre J, Chang CH, Colmenares S, Lee YCG. Prevalent fast evolution of genes involved in heterochromatin functions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.03.583199. [PMID: 38496614 PMCID: PMC10942301 DOI: 10.1101/2024.03.03.583199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Heterochromatin is a gene-poor and repeat-rich genomic compartment ubiquitously found in eukaryotes. Despite its low transcriptional activity, heterochromatin plays important roles in maintaining genome stability, organizing chromosomes, and suppressing transposable elements (TEs). Given the importance of these functions, it is expected that the genes involved in heterochromatin regulation would be highly conserved. Yet, a handful of these genes have been found to evolve rapidly. To investigate whether these previous findings are anecdotal or general to genes modulating heterochromatin, we compiled an exhaustive list of 106 candidate genes involved in heterochromatin functions and investigated their evolution over both short and long evolutionary time scales in Drosophila. Our analyses found that these genes exhibit significantly more frequent evolutionary changes, both in the forms of amino acid substitutions and gene copy number variation, when compared to genes involved in Polycomb-based repressive chromatin. While positive selection drives amino acid changes within both structured domains with diverse functions and irregular disordered regions (IDRs), purifying selection may have maintained the proportions of IDRs. Together with the observed negative associations between rates of protein evolution of these genes and genomic TE abundance, we propose an evolutionary model where the fast evolution of genes involved in heterochromatin functions is an inevitable outcome of the unique molecular features of the heterochromatin environment, while the rapid evolution of TEs may be an effect rather than cause. Our study provides an important global view of the evolution of genes involved in this critical cellular domain and provides insights into the factors driving the distinctive evolution of heterochromatin.
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Affiliation(s)
- Leila Lin
- Department of Ecology and Evolutionary Biology, University of California, Irvine
| | - Yuheng Huang
- Department of Ecology and Evolutionary Biology, University of California, Irvine
| | - Jennifer McIntyre
- Department of Ecology and Evolutionary Biology, University of California, Irvine
| | | | - Serafin Colmenares
- Department of Cell and Molecular Biology, University of California, Berkeley
| | - Yuh Chwen G. Lee
- Department of Ecology and Evolutionary Biology, University of California, Irvine
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9
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Garcia S, Kovarik A, Maiwald S, Mann L, Schmidt N, Pascual-Díaz JP, Vitales D, Weber B, Heitkam T. The Dynamic Interplay Between Ribosomal DNA and Transposable Elements: A Perspective From Genomics and Cytogenetics. Mol Biol Evol 2024; 41:msae025. [PMID: 38306580 PMCID: PMC10946416 DOI: 10.1093/molbev/msae025] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 12/06/2023] [Accepted: 01/29/2024] [Indexed: 02/04/2024] Open
Abstract
Although both are salient features of genomes, at first glance ribosomal DNAs and transposable elements are genetic elements with not much in common: whereas ribosomal DNAs are mainly viewed as housekeeping genes that uphold all prime genome functions, transposable elements are generally portrayed as selfish and disruptive. These opposing characteristics are also mirrored in other attributes: organization in tandem (ribosomal DNAs) versus organization in a dispersed manner (transposable elements); evolution in a concerted manner (ribosomal DNAs) versus evolution by diversification (transposable elements); and activity that prolongs genomic stability (ribosomal DNAs) versus activity that shortens it (transposable elements). Re-visiting relevant instances in which ribosomal DNA-transposable element interactions have been reported, we note that both repeat types share at least four structural and functional hallmarks: (1) they are repetitive DNAs that shape genomes in evolutionary timescales, (2) they exchange structural motifs and can enter co-evolution processes, (3) they are tightly controlled genomic stress sensors playing key roles in senescence/aging, and (4) they share common epigenetic marks such as DNA methylation and histone modification. Here, we give an overview of the structural, functional, and evolutionary characteristics of both ribosomal DNAs and transposable elements, discuss their roles and interactions, and highlight trends and future directions as we move forward in understanding ribosomal DNA-transposable element associations.
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Affiliation(s)
- Sònia Garcia
- Institut Botànic de Barcelona (IBB), CSIC-CMCNB, 08038 Barcelona, Catalonia, Spain
| | - Ales Kovarik
- Institute of Biophysics, Academy of Sciences of the Czech Republic, 61265 Brno, Czech Republic
| | - Sophie Maiwald
- Faculty of Biology, Technische Universität Dresden, D-01069 Dresden, Germany
| | - Ludwig Mann
- Faculty of Biology, Technische Universität Dresden, D-01069 Dresden, Germany
| | - Nicola Schmidt
- Faculty of Biology, Technische Universität Dresden, D-01069 Dresden, Germany
| | | | - Daniel Vitales
- Institut Botànic de Barcelona (IBB), CSIC-CMCNB, 08038 Barcelona, Catalonia, Spain
- Laboratori de Botànica–Unitat Associada CSIC, Facultat de Farmàcia i Ciències de l’Alimentació, Universitat de Barcelona, 08028 Barcelona, Catalonia, Spain
| | - Beatrice Weber
- Faculty of Biology, Technische Universität Dresden, D-01069 Dresden, Germany
| | - Tony Heitkam
- Faculty of Biology, Technische Universität Dresden, D-01069 Dresden, Germany
- Institute of Biology, NAWI Graz, Karl-Franzens-Universität, A-8010 Graz, Austria
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10
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Nelson JO, Slicko A, Raz AA, Yamashita YM. Insulin signaling regulates R2 retrotransposon expression to orchestrate transgenerational rDNA copy number maintenance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.28.582629. [PMID: 38464041 PMCID: PMC10925281 DOI: 10.1101/2024.02.28.582629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Preserving a large number of essential yet highly unstable ribosomal DNA (rDNA) repeats is critical for the germline to perpetuate the genome through generations. Spontaneous rDNA loss must be countered by rDNA copy number (CN) expansion. Germline rDNA CN expansion is best understood in Drosophila melanogaster, which relies on unequal sister chromatid exchange (USCE) initiated by DNA breaks at rDNA. The rDNA-specific retrotransposon R2 responsible for USCE-inducing DNA breaks is typically expressed only when rDNA CN is low to minimize the danger of DNA breaks; however, the underlying mechanism of R2 regulation remains unclear. Here we identify the insulin receptor (InR) as a major repressor of R2 expression, limiting unnecessary R2 activity. Through single-cell RNA sequencing we find that male germline stem cells (GSCs), the major cell type that undergoes rDNA CN expansion, have reduced InR expression when rDNA CN is low. Reduced InR activity in turn leads to R2 expression and CN expansion. We further find that dietary manipulation alters R2 expression and rDNA CN expansion activity. This work reveals that the insulin pathway integrates rDNA CN surveying with environmental sensing, revealing a potential mechanism by which diet exerts heritable changes to genomic content.
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Affiliation(s)
- Jonathan O Nelson
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY
- Whitehead Institute for Biomedical Research, Cambridge, MA
- Howard Hughes Medical Institute, Cambridge, MA
| | - Alyssa Slicko
- Whitehead Institute for Biomedical Research, Cambridge, MA
- Howard Hughes Medical Institute, Cambridge, MA
| | - Amelie A Raz
- Whitehead Institute for Biomedical Research, Cambridge, MA
- Howard Hughes Medical Institute, Cambridge, MA
| | - Yukiko M Yamashita
- Whitehead Institute for Biomedical Research, Cambridge, MA
- Howard Hughes Medical Institute, Cambridge, MA
- Department of Biology, MIT, Cambridge, MA
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11
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Le Breton A, Bettencourt MP, Gendrel AV. Navigating the brain and aging: exploring the impact of transposable elements from health to disease. Front Cell Dev Biol 2024; 12:1357576. [PMID: 38476259 PMCID: PMC10927736 DOI: 10.3389/fcell.2024.1357576] [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: 12/18/2023] [Accepted: 02/08/2024] [Indexed: 03/14/2024] Open
Abstract
Transposable elements (TEs) are mobile genetic elements that constitute on average 45% of mammalian genomes. Their presence and activity in genomes represent a major source of genetic variability. While this is an important driver of genome evolution, TEs can also have deleterious effects on their hosts. A growing number of studies have focused on the role of TEs in the brain, both in physiological and pathological contexts. In the brain, their activity is believed to be important for neuronal plasticity. In neurological and age-related disorders, aberrant activity of TEs may contribute to disease etiology, although this remains unclear. After providing a comprehensive overview of transposable elements and their interactions with the host, this review summarizes the current understanding of TE activity within the brain, during the aging process, and in the context of neurological and age-related conditions.
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Affiliation(s)
| | | | - Anne-Valerie Gendrel
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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12
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Cranz-Mileva S, Reilly E, Chalhoub N, Patel R, Atanassova T, Cao W, Ellison C, Zaratiegui M. Transposon Removal Reveals Their Adaptive Fitness Contribution. Genome Biol Evol 2024; 16:evae010. [PMID: 38245838 PMCID: PMC10836971 DOI: 10.1093/gbe/evae010] [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: 08/15/2023] [Revised: 01/04/2024] [Accepted: 01/12/2024] [Indexed: 01/22/2024] Open
Abstract
Transposable elements are molecular parasites that persist in their host genome by generating new copies to outpace natural selection. Transposable elements exert a large influence on host genome evolution, in some cases providing adaptive changes. Here we measure the fitness effect of the transposable element insertions in the fission yeast Schizosaccharomyces pombe type strain by removing all insertions of its only native transposable element family, the long terminal repeat retrotransposon Tf2. We show that Tf2 elements provide a positive fitness contribution to its host. Tf2 ablation results in changes to the regulation of a mitochondrial gene and, consistently, the fitness effect are sensitive to growth conditions. We propose that Tf2 influences host fitness in a directed manner by dynamically rewiring the transcriptional response to metabolic stress.
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Affiliation(s)
- Susanne Cranz-Mileva
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Eve Reilly
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Noor Chalhoub
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Rohan Patel
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Tania Atanassova
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Weihuan Cao
- Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Christopher Ellison
- Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Mikel Zaratiegui
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
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13
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Maiwald S, Mann L, Garcia S, Heitkam T. Evolving Together: Cassandra Retrotransposons Gradually Mirror Promoter Mutations of the 5S rRNA Genes. Mol Biol Evol 2024; 41:msae010. [PMID: 38262464 PMCID: PMC10853983 DOI: 10.1093/molbev/msae010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/26/2023] [Accepted: 12/11/2023] [Indexed: 01/25/2024] Open
Abstract
The 5S rRNA genes are among the most conserved nucleotide sequences across all species. Similar to the 5S preservation we observe the occurrence of 5S-related nonautonomous retrotransposons, so-called Cassandras. Cassandras harbor highly conserved 5S rDNA-related sequences within their long terminal repeats, advantageously providing them with the 5S internal promoter. However, the dynamics of Cassandra retrotransposon evolution in the context of 5S rRNA gene sequence information and structural arrangement are still unclear, especially: (1) do we observe repeated or gradual domestication of the highly conserved 5S promoter by Cassandras and (2) do changes in 5S organization such as in the linked 35S-5S rDNA arrangements impact Cassandra evolution? Here, we show evidence for gradual co-evolution of Cassandra sequences with their corresponding 5S rDNAs. To follow the impact of 5S rDNA variability on Cassandra TEs, we investigate the Asteraceae family where highly variable 5S rDNAs, including 5S promoter shifts and both linked and separated 35S-5S rDNA arrangements have been reported. Cassandras within the Asteraceae mirror 5S rDNA promoter mutations of their host genome, likely as an adaptation to the host's specific 5S transcription factors and hence compensating for evolutionary changes in the 5S rDNA sequence. Changes in the 5S rDNA sequence and in Cassandras seem uncorrelated with linked/separated rDNA arrangements. We place all these observations into the context of angiosperm 5S rDNA-Cassandra evolution, discuss Cassandra's origin hypotheses (single or multiple) and Cassandra's possible impact on rDNA and plant genome organization, giving new insights into the interplay of ribosomal genes and transposable elements.
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Affiliation(s)
- Sophie Maiwald
- Faculty of Biology, Technische Universität Dresden, 01069 Dresden, Germany
| | - Ludwig Mann
- Faculty of Biology, Technische Universität Dresden, 01069 Dresden, Germany
| | - Sònia Garcia
- Institut Botànic de Barcelona, IBB (CSIC-MCNB), 08038 Barcelona, Catalonia, Spain
| | - Tony Heitkam
- Faculty of Biology, Technische Universität Dresden, 01069 Dresden, Germany
- Institute of Biology, NAWI Graz, Karl-Franzens-Universität, 8010 Graz, Austria
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Jiang T, Zhou ZM, Ling ZQ, Zhang Q, Wu ZZ, Yang JW, Yang SY, Yang B, Huang LS. Pig H3K4me3, H3K27ac, and gene expression profiles reveal reproductive tissue-specific activity of transposable elements. Zool Res 2024; 45:138-151. [PMID: 38155423 PMCID: PMC10839656 DOI: 10.24272/j.issn.2095-8137.2023.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 09/04/2023] [Indexed: 12/30/2023] Open
Abstract
Regulatory sequences and transposable elements (TEs) account for a large proportion of the genomic sequences of species; however, their roles in gene transcription, especially tissue-specific expression, remain largely unknown. Pigs serve as an excellent animal model for studying genomic sequence biology due to the extensive diversity among their wild and domesticated populations. Here, we conducted an integrated analysis using H3K27ac ChIP-seq, H3K4me3 ChIP-seq, and RNA-seq data from 10 different tissues of seven fetuses and eight closely related adult pigs. We aimed to annotate the regulatory elements and TEs to elucidate their associations with histone modifications and mRNA expression across different tissues and developmental stages. Based on correlation analysis between mRNA expression and H3K27ac and H3K4me3 peak activity, results indicated that H3K27ac exhibited stronger associations with gene expression than H3K4me3. Furthermore, 1.45% of TEs overlapped with either the H3K27ac or H3K4me3 peaks, with the majority displaying tissue-specific activity. Notably, a TE subfamily (LTR4C_SS), containing binding motifs for SIX1 and SIX4, showed specific enrichment in the H3K27ac peaks of the adult and fetal ovaries. RNA-seq analysis also revealed widespread expression of TEs in the exons or promoters of genes, including 4 688 TE-containing transcripts with distinct development stage-specific and tissue-specific expression. Of note, 1 967 TE-containing transcripts were enriched in the testes. We identified a long terminal repeat (LTR), MLT1F1, acting as a testis-specific alternative promoter in SRPK2 (a cell cycle-related protein kinase) in our pig dataset. This element was also conserved in humans and mice, suggesting either an ancient integration of TEs in genes specifically expressed in the testes or parallel evolutionary patterns. Collectively, our findings demonstrate that TEs are deeply embedded in the genome and exhibit important tissue-specific biological functions, particularly in the reproductive organs.
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Affiliation(s)
- Tao Jiang
- National Key Laboratory of Pig Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Zhi-Min Zhou
- National Key Laboratory of Pig Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Zi-Qi Ling
- National Key Laboratory of Pig Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Qing Zhang
- National Key Laboratory of Pig Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Zhong-Zi Wu
- National Key Laboratory of Pig Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Jia-Wen Yang
- National Key Laboratory of Pig Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Si-Yu Yang
- National Key Laboratory of Pig Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Bin Yang
- National Key Laboratory of Pig Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China. E-mail:
| | - Lu-Sheng Huang
- National Key Laboratory of Pig Genetic Improvement and Germplasm Innovation, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China. E-mail:
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15
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Westerberg I, Ament-Velásquez SL, Vogan AA, Johannesson H. Evolutionary dynamics of the LTR-retrotransposon crapaud in the Podospora anserina species complex and the interaction with repeat-induced point mutations. Mob DNA 2024; 15:1. [PMID: 38218923 PMCID: PMC10787394 DOI: 10.1186/s13100-023-00311-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/22/2023] [Indexed: 01/15/2024] Open
Abstract
BACKGROUND The genome of the filamentous ascomycete Podospora anserina shows a relatively high abundance of retrotransposons compared to other interspersed repeats. The LTR-retrotransposon family crapaud is particularly abundant in the genome, and consists of multiple diverged sequence variations specifically localized in the 5' half of both long terminal repeats (LTRs). P. anserina is part of a recently diverged species-complex, which makes the system ideal to classify the crapaud family based on the observed LTR variation and to study the evolutionary dynamics, such as the diversification and bursts of the elements over recent evolutionary time. RESULTS We developed a sequence similarity network approach to classify the crapaud repeats of seven genomes representing the P. anserina species complex into 14 subfamilies. This method does not utilize a consensus sequence, but instead it connects any copies that share enough sequence similarity over a set sequence coverage. Based on phylogenetic analyses, we found that the crapaud repeats likely diversified in the ancestor of the complex and have had activity at different time points for different subfamilies. Furthermore, while we hypothesized that the evolution into multiple subfamilies could have been a direct effect of escaping the genome defense system of repeat induced point mutations, we found this not to be the case. CONCLUSIONS Our study contributes to the development of methods to classify transposable elements in fungi, and also highlights the intricate patterns of retrotransposon evolution over short timescales and under high mutational load caused by nucleotide-altering genome defense.
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Affiliation(s)
- Ivar Westerberg
- Department of Ecology, environmental and Plant Sciences, Stockholm University, Stockholm, 106 91, Sweden
| | - S Lorena Ament-Velásquez
- Division of Population Genetics, Department of Zoology, Stockholm University, Stockholm, 106 91, Sweden
| | - Aaron A Vogan
- Systematic Biology, Department of Organismal Biology, Uppsala University, Norbyvägen 18D, Uppsala, 752 36, Sweden.
| | - Hanna Johannesson
- Department of Ecology, environmental and Plant Sciences, Stockholm University, Stockholm, 106 91, Sweden.
- The Royal Swedish Academy of Sciences, Stockholm, 114 18, Sweden.
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16
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Singh M, Leddy SM, Iñiguez LP, Bendall ML, Nixon DF, Feschotte C. Transposable elements may enhance antiviral resistance in HIV-1 elite controllers. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.11.571123. [PMID: 38168352 PMCID: PMC10760019 DOI: 10.1101/2023.12.11.571123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Less than 0.5% of people living with HIV-1 are elite controllers (ECs) - individuals who have a replication-competent viral reservoir in their CD4+ T cells but maintain undetectable plasma viremia without the help of antiretroviral therapy. While the EC CD4+ T cell transcriptome has been investigated for gene expression signatures associated with disease progression (or, in this case, a lack thereof), the expression and regulatory activity of transposable elements (TEs) in ECs has not been explored. Yet previous studies have established that TEs can directly impact the immune response to pathogens, including HIV-1. Thus, we hypothesize that the regulatory activities of TEs could contribute to the natural resistance of ECs against HIV-1. We perform a TE-centric analysis of previously published multi-omics data derived from EC individuals and other populations. We find that the CD4+ T cell transcriptome and retrotranscriptome of ECs are distinct from healthy controls, treated patients, and viremic progressors. However, there is a substantial level of transcriptomic heterogeneity among ECs. We categorize individuals with distinct chromatin accessibility and expression profiles into four clusters within the EC group, each possessing unique repertoires of TEs and antiviral factors. Notably, several TE families with known immuno-regulatory activity are differentially expressed among ECs. Their transcript levels in ECs positively correlate with their chromatin accessibility and negatively correlate with the expression of their KRAB zinc-finger (KZNF) repressors. This coordinated variation is seen at the level of individual TE loci likely acting or, in some cases, known to act as cis-regulatory elements for nearby genes involved in the immune response and HIV-1 restriction. Based on these results, we propose that the EC phenotype is driven in part by the reduced availability of specific KZNF proteins to repress TE-derived cis-regulatory elements for antiviral genes, thereby heightening their basal level of resistance to HIV-1 infection. Our study reveals considerable heterogeneity in the CD4+ T cell transcriptome of ECs, including variable expression of TEs and their KZNF controllers, that must be taken into consideration to decipher the mechanisms enabling HIV-1 control.
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Affiliation(s)
- Manvendra Singh
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- Clinical Neuroscience, Max Planck Institute for Multidisciplinary Sciences, City Campus, Göttingen, Germany
| | - Sabrina M Leddy
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Luis Pedro Iñiguez
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Matthew L Bendall
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Douglas F Nixon
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
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17
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Ramsoomair CK, Ceccarelli M, Heiss JD, Shah AH. The epitranscriptome of high-grade gliomas: a promising therapeutic target with implications from the tumor microenvironment to endogenous retroviruses. J Transl Med 2023; 21:893. [PMID: 38071304 PMCID: PMC10709919 DOI: 10.1186/s12967-023-04725-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/13/2023] [Indexed: 12/18/2023] Open
Abstract
Glioblastoma (GBM) comprises 45.6% of all primary malignant brain cancers and is one of the most common and aggressive intracranial tumors in adults. Intratumoral heterogeneity with a wide range of proteomic, genetic, and epigenetic dysregulation contributes to treatment resistance and poor prognosis, thus demanding novel therapeutic approaches. To date, numerous clinical trials have been developed to target the proteome and epigenome of high-grade gliomas with promising results. However, studying RNA modifications, or RNA epitranscriptomics, is a new frontier within neuro-oncology. RNA epitranscriptomics was discovered in the 1970s, but in the last decade, the extent of modification of mRNA and various non-coding RNAs has emerged and been implicated in transposable element activation and many other oncogenic processes within the tumor microenvironment. This review provides background information and discusses the therapeutic potential of agents modulating epitranscriptomics in high-grade gliomas. A particular emphasis will be placed on how combination therapies that include immune agents targeting hERV-mediated viral mimicry could improve the treatment of GBM.
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Affiliation(s)
- Christian K Ramsoomair
- Section of Virology and Immunotherapy, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1095 NW 14Th Terrace, Miami, FL, 33136, USA.
- Medical Scientist Training Program, University of Miami Miller School of Medicine, 1095 NW 14Th Terrace, Miami, FL, 33136, USA.
| | - Michele Ceccarelli
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, 1550 N.W. 10Th Avenue, Miami, FL, 33136, USA
| | - John D Heiss
- Surgical Neurology Branch, Disorders and Stroke, National Institute of Neurological, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ashish H Shah
- Section of Virology and Immunotherapy, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, 1095 NW 14Th Terrace, Miami, FL, 33136, USA.
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18
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Vontzou N, Pei Y, Mueller JC, Reifová R, Ruiz-Ruano FJ, Schlebusch SA, Suh A. Songbird germline-restricted chromosome as a potential arena of genetic conflicts. Curr Opin Genet Dev 2023; 83:102113. [PMID: 37734346 DOI: 10.1016/j.gde.2023.102113] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/03/2023] [Accepted: 08/20/2023] [Indexed: 09/23/2023]
Abstract
Genetic conflicts can arise between components of the genome with different inheritance strategies. The germline-restricted chromosome (GRC) of songbirds shows unusual mitotic and meiotic transmission compared with the rest of the genome. It is excluded from somatic cells and maintained only in the germline. It is usually present in one copy in the male germline and eliminated during spermatogenesis, while in the female germline, it usually occurs in two copies and behaves as a regular chromosome. Here, we review what is known about the GRC's evolutionary history, genetic content, and expression and discuss how it may be involved in different types of genetic conflicts. Finally, we interrogate the potential role of the GRC in songbird germline development, highlighting several unsolved mysteries.
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Affiliation(s)
- Niki Vontzou
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Adenauerallee 127, 53113 Bonn, Germany; School of Biological Sciences, University of East Anglia, Norwich, UK.
| | - Yifan Pei
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Adenauerallee 127, 53113 Bonn, Germany; Institute of Evolutionary Biology and Ecology, University of Bonn, An der Immenburg 1, 53121 Bonn, Germany; Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
| | - Jakob C Mueller
- Department of Ornithology, Max Planck Institute for Biological Intelligence, 82319 Seewiesen, Germany
| | - Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Francisco J Ruiz-Ruano
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Adenauerallee 127, 53113 Bonn, Germany; Institute of Evolutionary Biology and Ecology, University of Bonn, An der Immenburg 1, 53121 Bonn, Germany. https://twitter.com/@fjruizruano
| | - Stephen A Schlebusch
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Alexander Suh
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Adenauerallee 127, 53113 Bonn, Germany; Institute of Evolutionary Biology and Ecology, University of Bonn, An der Immenburg 1, 53121 Bonn, Germany; Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
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19
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Wiegand T, Hoffmann FT, Walker MWG, Tang S, Richard E, Le HC, Meers C, Sternberg SH. Emergence of RNA-guided transcription factors via domestication of transposon-encoded TnpB nucleases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569447. [PMID: 38076855 PMCID: PMC10705468 DOI: 10.1101/2023.11.30.569447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Transposon-encoded tnpB genes encode RNA-guided DNA nucleases that promote their own selfish spread through targeted DNA cleavage and homologous recombination1-4. This widespread gene family was repeatedly domesticated over evolutionary timescales, leading to the emergence of diverse CRISPR-associated nucleases including Cas9 and Cas125,6. We set out to test the hypothesis that TnpB nucleases may have also been repurposed for novel, unexpected functions other than CRISPR-Cas. Here, using phylogenetics, structural predictions, comparative genomics, and functional assays, we uncover multiple instances of programmable transcription factors that we name TnpB-like nuclease-dead repressors (TldR). These proteins employ naturally occurring guide RNAs to specifically target conserved promoter regions of the genome, leading to potent gene repression in a mechanism akin to CRISPRi technologies invented by humans7. Focusing on a TldR clade found broadly in Enterobacteriaceae, we discover that bacteriophages exploit the combined action of TldR and an adjacently encoded phage gene to alter the expression and composition of the host flagellar assembly, a transformation with the potential to impact motility8, phage susceptibility9, and host immunity10. Collectively, this work showcases the diverse molecular innovations that were enabled through repeated exaptation of genes encoded by transposable elements, and reveals that RNA-guided transcription factors emerged long before the development of dCas9-based editors.
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Affiliation(s)
- Tanner Wiegand
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Florian T Hoffmann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Matt W G Walker
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Stephen Tang
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Egill Richard
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Hoang C Le
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Chance Meers
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Samuel H Sternberg
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
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20
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Wu Z, Yu X, Zhang S, He Y, Guo W. Novel roles of PIWI proteins and PIWI-interacting RNAs in human health and diseases. Cell Commun Signal 2023; 21:343. [PMID: 38031146 PMCID: PMC10685540 DOI: 10.1186/s12964-023-01368-x] [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: 08/18/2023] [Accepted: 10/26/2023] [Indexed: 12/01/2023] Open
Abstract
Non-coding RNA has aroused great research interest recently, they play a wide range of biological functions, such as regulating cell cycle, cell proliferation, and intracellular substance metabolism. Piwi-interacting RNAs (piRNAs) are emerging small non-coding RNAs that are 24-31 nucleotides in length. Previous studies on piRNAs were mainly limited to evaluating the binding to the PIWI protein family to play the biological role. However, recent studies have shed more lights on piRNA functions; aberrant piRNAs play unique roles in many human diseases, including diverse lethal cancers. Therefore, understanding the mechanism of piRNAs expression and the specific functional roles of piRNAs in human diseases is crucial for developing its clinical applications. Presently, research on piRNAs mainly focuses on their cancer-specific functions but lacks investigation of their expressions and epigenetic modifications. This review discusses piRNA's biogenesis and functional roles and the recent progress of functions of piRNA/PIWI protein complexes in human diseases. Video Abstract.
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Affiliation(s)
- Zeyu Wu
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China
| | - Xiao Yu
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China
| | - Shuijun Zhang
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China
| | - Yuting He
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China.
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China.
| | - Wenzhi Guo
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China.
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China.
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21
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Kalendar R, Karlov GI. Editorial: Mobile elements and plant genome evolution, comparative analyses and computational tools, volume II. FRONTIERS IN PLANT SCIENCE 2023; 14:1308536. [PMID: 38023887 PMCID: PMC10676221 DOI: 10.3389/fpls.2023.1308536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 11/07/2023] [Indexed: 12/01/2023]
Affiliation(s)
- Ruslan Kalendar
- Institute of Biotechnology, Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
- National Laboratory Astana, Nazarbayev University, Astana, Kazakhstan
| | - Gennady I. Karlov
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russia
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22
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Murphy PJ, Berger F. The chromatin source-sink hypothesis: a shared mode of chromatin-mediated regulations. Development 2023; 150:dev201989. [PMID: 38771301 PMCID: PMC10629678 DOI: 10.1242/dev.201989] [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: 05/13/2023] [Accepted: 09/12/2023] [Indexed: 11/05/2023]
Abstract
We propose that several chromatin-mediated regulatory processes are dominated by source-sink relationships in which factors operate as 'sources' to produce or provide a resource and compete with each other to occupy separate 'sinks'. In this model, large portions of genomic DNA operate as 'sinks', which are filled by 'sources', such as available histone variants, covalent modifications to histones, the readers of these modifications and non-coding RNAs. Competing occupation for the sinks by different sources leads to distinct states of genomic equilibrium in differentiated cells. During dynamic developmental events, such as sexual reproduction, we propose that dramatic and rapid reconfiguration of source-sink relationships modifies chromatin states. We envision that re-routing of sources could occur by altering the dimensions of the sink, by reconfiguration of existing sink occupation or by varying the size of the source, providing a central mechanism to explain a plethora of epigenetic phenomena, which contribute to phenotypic variegation, zygotic genome activation and nucleolar dominance.
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Affiliation(s)
- Patrick J. Murphy
- University of Rochester, Department of Biomedical Genetics and Department of Biology, 601 Elmwood Ave., Rochester NY 14620, USA
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter; Dr. Bohr-Gasse 3, 1030 Vienna, Austria
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23
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Meng FW, Murphy KE, Makowski CE, Delatte B, Murphy PJ. Competition for H2A.Z underlies the developmental impacts of repetitive element de-repression. Development 2023; 150:dev202338. [PMID: 37938830 PMCID: PMC10651094 DOI: 10.1242/dev.202338] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/10/2023] [Indexed: 11/10/2023]
Abstract
The histone variant H2A.Z is central to early embryonic development, determining transcriptional competency through chromatin regulation of gene promoters and enhancers. In addition to genic loci, we find that H2A.Z resides at a subset of evolutionarily young repetitive elements, including DNA transposons, long interspersed nuclear elements and long terminal repeats, during early zebrafish development. Moreover, increases in H2A.Z occur when repetitive elements become transcriptionally active. Acquisition of H2A.Z corresponds with a reduction in the levels of the repressive histone modification H3K9me3 and a moderate increase in chromatin accessibility. Notably, however, de-repression of repetitive elements also leads to a significant reduction in H2A.Z over non-repetitive genic loci. Genic loss of H2A.Z is accompanied by transcriptional silencing at adjacent coding sequences, but remarkably, these impacts are mitigated by augmentation of total H2A.Z protein via transgenic overexpression. Our study reveals that levels of H2A.Z protein determine embryonic sensitivity to de-repression of repetitive elements, that repetitive elements can function as a nuclear sink for epigenetic factors and that competition for H2A.Z greatly influences overall transcriptional output during development. These findings uncover general mechanisms in which counteractive biological processes underlie phenotypic outcomes.
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Affiliation(s)
- Fanju W. Meng
- University of Rochester Medical Center, Rochester, NY 14642, USA
| | | | | | - Benjamin Delatte
- Advanced Research Laboratory, Active Motif, 1914 Palomar Oaks Way STE 150, Carlsbad, CA 92008, USA
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24
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Kalmykova AI, Sokolova OA. Retrotransposons and Telomeres. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1739-1753. [PMID: 38105195 DOI: 10.1134/s0006297923110068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/24/2023] [Accepted: 08/12/2023] [Indexed: 12/19/2023]
Abstract
Transposable elements (TEs) comprise a significant part of eukaryotic genomes being a major source of genome instability and mutagenesis. Cellular defense systems suppress the TE expansion at all stages of their life cycle. Piwi proteins and Piwi-interacting RNAs (piRNAs) are key elements of the anti-transposon defense system, which control TE activity in metazoan gonads preventing inheritable transpositions and developmental defects. In this review, we discuss various regulatory mechanisms by which small RNAs combat TE activity. However, active transposons persist, suggesting these powerful anti-transposon defense mechanisms have a limited capacity. A growing body of evidence suggests that increased TE activity coincides with genome reprogramming and telomere lengthening in different species. In the Drosophila fruit fly, whose telomeres consist only of retrotransposons, a piRNA-mediated mechanism is required for telomere maintenance and their length control. Therefore, the efficacy of protective mechanisms must be finely balanced in order not only to suppress the activity of transposons, but also to maintain the proper length and stability of telomeres. Structural and functional relationship between the telomere homeostasis and LINE1 retrotransposon in human cells indicates a close link between selfish TEs and the vital structure of the genome, telomere. This relationship, which permits the retention of active TEs in the genome, is reportedly a legacy of the retrotransposon origin of telomeres. The maintenance of telomeres and the execution of other crucial roles that TEs acquired during the process of their domestication in the genome serve as a type of payment for such a "service."
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Affiliation(s)
- Alla I Kalmykova
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
| | - Olesya A Sokolova
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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25
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Lyons DE, Kumar P, Roan NR, Defechereux PA, Feschotte C, Lange UC, Murthy N, Sameshima P, Verdin E, Ake JA, Parsons MS, Nath A, Gianella S, Smith DM, Kallas EG, Villa TJ, Strange R, Mwesigwa B, Furler O’Brien RL, Nixon DF, Ndhlovu LC, Valente ST, Ott M. HIV-1 Remission: Accelerating the Path to Permanent HIV-1 Silencing. Viruses 2023; 15:2171. [PMID: 38005849 PMCID: PMC10674359 DOI: 10.3390/v15112171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/26/2023] [Accepted: 10/26/2023] [Indexed: 11/26/2023] Open
Abstract
Despite remarkable progress, a cure for HIV-1 infection remains elusive. Rebound competent latent and transcriptionally active reservoir cells persevere despite antiretroviral therapy and rekindle infection due to inefficient proviral silencing. We propose a novel "block-lock-stop" approach, entailing long term durable silencing of viral expression towards an irreversible transcriptionally inactive latent provirus to achieve long term antiretroviral free control of the virus. A graded transformation of remnant HIV-1 in PLWH from persistent into silent to permanently defective proviruses is proposed, emulating and accelerating the natural path that human endogenous retroviruses (HERVs) take over millions of years. This hypothesis was based on research into delineating the mechanisms of HIV-1 latency, lessons from latency reversing agents and advances of Tat inhibitors, as well as expertise in the biology of HERVs. Insights from elite controllers and the availability of advanced genome engineering technologies for the direct excision of remnant virus set the stage for a rapid path to an HIV-1 cure.
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Affiliation(s)
- Danielle E. Lyons
- Gladstone Institute of Virology, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Priti Kumar
- Department of Internal Medicine, Section of Infectious Diseases, Yale University School of Medicine, New Haven, CT 06510, USA;
| | - Nadia R. Roan
- Gladstone Institute of Virology, Gladstone Institutes, San Francisco, CA 94158, USA
- Department of Urology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Patricia A. Defechereux
- Department of Medicine, University of California San Francisco, San Francisco, CA 94158, USA
| | - Cedric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | | | - Niren Murthy
- Department of Bioengineering, University of California, Berkeley, CA 94720, USA;
- Innovative Genomics Institute, Berkeley, CA 94720, USA
| | - Pauline Sameshima
- Faculty of Education, Lakehead University, Thunder Bay, ON P7B 5E1, Canada;
| | - Eric Verdin
- Department of Medicine, University of California San Francisco, San Francisco, CA 94158, USA
- Buck Institute for Research on Aging, Novato, CA 94945, USA
| | - Julie A. Ake
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA (M.S.P.)
| | - Matthew S. Parsons
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA (M.S.P.)
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20817, USA
- Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD 20824, USA;
| | - Sara Gianella
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Davey M. Smith
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Esper G. Kallas
- Department of Infectious and Parasitic Diseases, University of Sao Paulo, São Paulo 04023-900, Brazil
| | - Thomas J. Villa
- HOPE Martin Delaney Collaboratory for HIV Cure Research Community Engagement Ambassador, Washinton, DC 20004, USA (R.S.)
- National HIV & Aging Advocacy Network, Washington, DC 20004, USA
| | - Richard Strange
- HOPE Martin Delaney Collaboratory for HIV Cure Research Community Engagement Ambassador, Washinton, DC 20004, USA (R.S.)
| | - Betty Mwesigwa
- Research Department, Makerere University Walter Reed Project, Kampala P.O Box 7062, Uganda
| | - Robert L. Furler O’Brien
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY 10021, USA
| | - Douglas F. Nixon
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY 10021, USA
| | - Lishomwa C. Ndhlovu
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY 10021, USA
| | - Susana T. Valente
- Department of Immunology and Microbiology, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation and Technology, Jupiter, FL 33458, USA
| | - Melanie Ott
- Gladstone Institute of Virology, Gladstone Institutes, San Francisco, CA 94158, USA
- Department of Medicine, University of California San Francisco, San Francisco, CA 94158, USA
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26
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Hisanaga T, Romani F, Wu S, Kowar T, Wu Y, Lintermann R, Fridrich A, Cho CH, Chaumier T, Jamge B, Montgomery SA, Axelsson E, Akimcheva S, Dierschke T, Bowman JL, Fujiwara T, Hirooka S, Miyagishima SY, Dolan L, Tirichine L, Schubert D, Berger F. The Polycomb repressive complex 2 deposits H3K27me3 and represses transposable elements in a broad range of eukaryotes. Curr Biol 2023; 33:4367-4380.e9. [PMID: 37738971 DOI: 10.1016/j.cub.2023.08.073] [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: 10/28/2022] [Revised: 06/19/2023] [Accepted: 08/24/2023] [Indexed: 09/24/2023]
Abstract
The mobility of transposable elements (TEs) contributes to evolution of genomes. Their uncontrolled activity causes genomic instability; therefore, expression of TEs is silenced by host genomes. TEs are marked with DNA and H3K9 methylation, which are associated with silencing in flowering plants, animals, and fungi. However, in distantly related groups of eukaryotes, TEs are marked by H3K27me3 deposited by the Polycomb repressive complex 2 (PRC2), an epigenetic mark associated with gene silencing in flowering plants and animals. The direct silencing of TEs by PRC2 has so far only been shown in one species of ciliates. To test if PRC2 silences TEs in a broader range of eukaryotes, we generated mutants with reduced PRC2 activity and analyzed the role of PRC2 in extant species along the lineage of Archaeplastida and in the diatom P. tricornutum. In this diatom and the red alga C. merolae, a greater proportion of TEs than genes were repressed by PRC2, whereas a greater proportion of genes than TEs were repressed by PRC2 in bryophytes. In flowering plants, TEs contained potential cis-elements recognized by transcription factors and associated with neighbor genes as transcriptional units repressed by PRC2. Thus, silencing of TEs by PRC2 is observed not only in Archaeplastida but also in diatoms and ciliates, suggesting that PRC2 deposited H3K27me3 to silence TEs in the last common ancestor of eukaryotes. We hypothesize that during the evolution of Archaeplastida, TE fragments marked with H3K27me3 were selected to shape transcriptional regulation, controlling networks of genes regulated by PRC2.
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Affiliation(s)
- Tetsuya Hisanaga
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Facundo Romani
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Shuangyang Wu
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Teresa Kowar
- Epigenetics of Plants, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Yue Wu
- Nantes Université, CNRS, US2B, UMR 6286, 44000 Nantes, France
| | - Ruth Lintermann
- Epigenetics of Plants, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Arie Fridrich
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Chung Hyun Cho
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, South Korea
| | | | - Bhagyshree Jamge
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Sean A Montgomery
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Elin Axelsson
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Svetlana Akimcheva
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Tom Dierschke
- School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - John L Bowman
- School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia; ARC Centre of Excellence for Plant Success in Nature and Agriculture, Monash University, Clayton, Melbourne, VIC 3800, Australia
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, Graduate University for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, Graduate University for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan
| | - Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, Graduate University for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan
| | - Liam Dolan
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Leila Tirichine
- Nantes Université, CNRS, US2B, UMR 6286, 44000 Nantes, France
| | - Daniel Schubert
- Epigenetics of Plants, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany.
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
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27
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Baril T, Pym A, Bass C, Hayward A. Transposon accumulation at xenobiotic gene family loci in aphids. Genome Res 2023; 33:1718-1733. [PMID: 37852781 PMCID: PMC10691553 DOI: 10.1101/gr.277820.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 08/29/2023] [Indexed: 10/20/2023]
Abstract
The evolution of resistance is a major challenge for the sustainable control of pests and pathogens. Thus, a deeper understanding of the evolutionary and genomic mechanisms underpinning resistance evolution is required to safeguard health and food production. Several studies have implicated transposable elements (TEs) in xenobiotic-resistance evolution in insects. However, analyses are generally restricted to one insect species and/or one or a few xenobiotic gene families (XGFs). We examine evidence for TE accumulation at XGFs by performing a comparative genomic analysis across 20 aphid genomes, considering major subsets of XGFs involved in metabolic resistance to insecticides: cytochrome P450s, glutathione S-transferases, esterases, UDP-glucuronosyltransferases, and ABC transporters. We find that TEs are significantly enriched at XGFs compared with other genes. XGFs show similar levels of TE enrichment to those of housekeeping genes. But unlike housekeeping genes, XGFs are not constitutively expressed in germline cells, supporting the selective enrichment of TEs at XGFs rather than enrichment owing to chromatin availability. Hotspots of extreme TE enrichment occur around certain XGFs. We find, in aphids of agricultural importance, particular enrichment of TEs around cytochrome P450 genes with known functions in the detoxification of synthetic insecticides. Our results provide evidence supporting a general role for TEs as a source of genomic variation at host XGFs and highlight the existence of considerable variability in TE content across XGFs and host species. These findings show the need for detailed functional verification analyses to clarify the significance of individual TE insertions and elucidate underlying mechanisms at TE-XGF hotspots.
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Affiliation(s)
- Tobias Baril
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, United Kingdom
| | - Adam Pym
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, United Kingdom
| | - Chris Bass
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, United Kingdom
| | - Alex Hayward
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, United Kingdom
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28
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Meers C, Le HC, Pesari SR, Hoffmann FT, Walker MWG, Gezelle J, Tang S, Sternberg SH. Transposon-encoded nucleases use guide RNAs to promote their selfish spread. Nature 2023; 622:863-871. [PMID: 37758954 DOI: 10.1038/s41586-023-06597-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 08/31/2023] [Indexed: 09/29/2023]
Abstract
Insertion sequences are compact and pervasive transposable elements found in bacteria, which encode only the genes necessary for their mobilization and maintenance1. IS200- and IS605-family transposons undergo 'peel-and-paste' transposition catalysed by a TnpA transposase2, but they also encode diverse, TnpB- and IscB-family proteins that are evolutionarily related to the CRISPR-associated effectors Cas12 and Cas9, respectively3,4. Recent studies have demonstrated that TnpB and IscB function as RNA-guided DNA endonucleases5,6, but the broader biological role of this activity has remained enigmatic. Here we show that TnpB and IscB are essential to prevent permanent transposon loss as a consequence of the TnpA transposition mechanism. We selected a family of related insertion sequences from Geobacillus stearothermophilus that encode several TnpB and IscB orthologues, and showed that a single TnpA transposase was broadly active for transposon mobilization. The donor joints formed upon religation of transposon-flanking sequences were efficiently targeted for cleavage by RNA-guided TnpB and IscB nucleases, and co-expression of TnpB and TnpA led to substantially greater transposon retention relative to conditions in which TnpA was expressed alone. Notably, TnpA and TnpB also stimulated recombination frequencies, surpassing rates observed with TnpB alone. Collectively, this study reveals that RNA-guided DNA cleavage arose as a primal biochemical activity to bias the selfish inheritance and spread of transposable elements, which was later co-opted during the evolution of CRISPR-Cas adaptive immunity for antiviral defence.
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Affiliation(s)
- Chance Meers
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Hoang C Le
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Sanjana R Pesari
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
- Biochemistry and Molecular Biophysics Program, University of California, San Diego, CA, USA
| | - Florian T Hoffmann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Matt W G Walker
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Jeanine Gezelle
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Stephen Tang
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Samuel H Sternberg
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
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29
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Lawlor MA, Ellison CE. Evolutionary dynamics between transposable elements and their host genomes: mechanisms of suppression and escape. Curr Opin Genet Dev 2023; 82:102092. [PMID: 37517354 PMCID: PMC10530431 DOI: 10.1016/j.gde.2023.102092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/27/2023] [Accepted: 07/02/2023] [Indexed: 08/01/2023]
Abstract
Transposable elements (TEs) are ubiquitous among eukaryotic species. Their evolutionary persistence is likely due to a combination of tolerogenic, evasive/antagonistic, and cooperative interactions with their host genomes. Here, we focus on metazoan species and review recent advances related to the harmful effects of TE insertions, including how epigenetic effects and TE-derived RNAs can damage host cells. We discuss new findings related to host pathways that silence TEs, such as the piRNA pathway and the APOBEC3 and Kruppel-associated box zinc finger gene families. Finally, we summarize novel strategies used by TEs to evade host silencing, including the Y chromosome as a permissive niche for TE mobilization and TE counterdefense strategies to block host silencing factors.
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30
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Podvalnaya N, Bronkhorst AW, Lichtenberger R, Hellmann S, Nischwitz E, Falk T, Karaulanov E, Butter F, Falk S, Ketting RF. piRNA processing by a trimeric Schlafen-domain nuclease. Nature 2023; 622:402-409. [PMID: 37758951 PMCID: PMC10567574 DOI: 10.1038/s41586-023-06588-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023]
Abstract
Transposable elements are genomic parasites that expand within and spread between genomes1. PIWI proteins control transposon activity, notably in the germline2,3. These proteins recognize their targets through small RNA co-factors named PIWI-interacting RNAs (piRNAs), making piRNA biogenesis a key specificity-determining step in this crucial genome immunity system. Although the processing of piRNA precursors is an essential step in this process, many of the molecular details remain unclear. Here, we identify an endoribonuclease, precursor of 21U RNA 5'-end cleavage holoenzyme (PUCH), that initiates piRNA processing in the nematode Caenorhabditis elegans. Genetic and biochemical studies show that PUCH, a trimer of Schlafen-like-domain proteins (SLFL proteins), executes 5'-end piRNA precursor cleavage. PUCH-mediated processing strictly requires a 7-methyl-G cap (m7G-cap) and a uracil at position three. We also demonstrate how PUCH interacts with PETISCO, a complex that binds to piRNA precursors4, and that this interaction enhances piRNA production in vivo. The identification of PUCH concludes the search for the 5'-end piRNA biogenesis factor in C. elegans and uncovers a type of RNA endonuclease formed by three SLFL proteins. Mammalian Schlafen (SLFN) genes have been associated with immunity5, exposing a molecular link between immune responses in mammals and deeply conserved RNA-based mechanisms that control transposable elements.
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Affiliation(s)
- Nadezda Podvalnaya
- Biology of Non-coding RNA group, Institute of Molecular Biology, Mainz, Germany
- International PhD Programme on Gene Regulation, Epigenetics & Genome Stability, Mainz, Germany
| | - Alfred W Bronkhorst
- Biology of Non-coding RNA group, Institute of Molecular Biology, Mainz, Germany
| | - Raffael Lichtenberger
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Department of Structural and Computational Biology, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Svenja Hellmann
- Biology of Non-coding RNA group, Institute of Molecular Biology, Mainz, Germany
| | - Emily Nischwitz
- International PhD Programme on Gene Regulation, Epigenetics & Genome Stability, Mainz, Germany
- Quantitative Proteomics group, Institute of Molecular Biology, Mainz, Germany
| | - Torben Falk
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Department of Structural and Computational Biology, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Emil Karaulanov
- Bioinformatics Core Facility, Institute of Molecular Biology, Mainz, Germany
| | - Falk Butter
- Department of Structural and Computational Biology, Center for Molecular Biology, University of Vienna, Vienna, Austria
- Institute of Molecular Virology and Cell Biology, Friedrich Loeffler Institute, Greifswald, Germany
| | - Sebastian Falk
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria.
- Department of Structural and Computational Biology, Center for Molecular Biology, University of Vienna, Vienna, Austria.
| | - René F Ketting
- Biology of Non-coding RNA group, Institute of Molecular Biology, Mainz, Germany.
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany.
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31
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Mori T, Nakashima M. Sequence-dependent heterochromatin formation in the human malaria parasite Plasmodium falciparum. Heliyon 2023; 9:e19164. [PMID: 37681121 PMCID: PMC10480601 DOI: 10.1016/j.heliyon.2023.e19164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 07/20/2023] [Accepted: 08/14/2023] [Indexed: 09/09/2023] Open
Abstract
The human malaria parasite Plasmodium falciparum represses transcription of the gene encoding AP2-G, which is the master regulator of germ cell differentiation, via heterochromatin condensation following histone H3 lysine 9 trimethylation (H3K9me3). Although H3K9me3-marked heterochromatin is typically constitutive and its establishment depends on the RNA interference (RNAi) pathway in fission yeast centromeres, malaria parasites lack molecular members essential for RNAi. We developed a strategy to assess heterochromatin establishment on artificial chromosomes introduced into P. falciparum. We show that a particular DNA sequence in the AP2-G promoter is able to induce de novo H3K9me3 nucleosome deposition. In addition, we also found that the AP2-G promoter contains a distinct element required in maintenance of the repression memory. Thus, we speculate that malaria parasites have evolutionarily acquired a sequence-dependent establishment system of non-constitutive, i.e. facultative, H3K9me3-marked heterochromatin.
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Affiliation(s)
- Toshiyuki Mori
- Corresponding author. Department of Molecular Protozoology, Research Institute for Microbial Diseases (RIMD), Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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Papon N, Lasserre-Zuber P, Rimbert H, De Oliveira R, Paux E, Choulet F. All families of transposable elements were active in the recent wheat genome evolution and polyploidy had no impact on their activity. THE PLANT GENOME 2023; 16:e20347. [PMID: 37243411 DOI: 10.1002/tpg2.20347] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 05/28/2023]
Abstract
Bread wheat (Triticum aestivum L.) is a major crop and its genome is one of the largest ever assembled at reference-quality level. It is 15 Gb, hexaploid, with 85% of transposable elements (TEs). Wheat genetic diversity was mainly focused on genes and little is known about the extent of genomic variability affecting TEs, transposition rate, and the impact of polyploidy. Multiple chromosome-scale assemblies are now available for bread wheat and for its tetraploid and diploid wild relatives. In this study, we computed base pair-resolved, gene-anchored, whole genome alignments of A, B, and D lineages at different ploidy levels in order to estimate the variability that affects the TE space. We used assembled genomes of 13 T. aestivum cultivars (6x = AABBDD) and a single genome for Triticum durum (4x = AABB), Triticum dicoccoides (4x = AABB), Triticum urartu (2x = AA), and Aegilops tauschii (2x = DD). We show that 5%-34% of the TE fraction is variable, depending on the species divergence. Between 400 and 13,000 novel TE insertions per subgenome were detected. We found lineage-specific insertions for nearly all TE families in di-, tetra-, and hexaploids. No burst of transposition was observed and polyploidization did not trigger any boost of transposition. This study challenges the prevailing idea of wheat TE dynamics and is more in agreement with an equilibrium model of evolution.
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Affiliation(s)
- Nathan Papon
- INRAE, GDEC, Université Clermont Auvergne, Clermont-Ferrand, France
| | | | - Hélène Rimbert
- INRAE, GDEC, Université Clermont Auvergne, Clermont-Ferrand, France
| | | | - Etienne Paux
- INRAE, GDEC, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Frédéric Choulet
- INRAE, GDEC, Université Clermont Auvergne, Clermont-Ferrand, France
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33
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Genetic 'parasites' hijack a DNA-repair pathway to form circular DNA and replicate. Nature 2023:10.1038/d41586-023-02108-4. [PMID: 37438621 DOI: 10.1038/d41586-023-02108-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
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34
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Ma H, Wang M, Zhang YE, Tan S. The power of "controllers": Transposon-mediated duplicated genes evolve towards neofunctionalization. J Genet Genomics 2023; 50:462-472. [PMID: 37068629 DOI: 10.1016/j.jgg.2023.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 04/19/2023]
Abstract
Since the discovery of the first transposon by Dr. Barbara McClintock, the prevalence and diversity of transposable elements (TEs) have been gradually recognized. As fundamental genetic components, TEs drive organismal evolution not only by contributing functional sequences (e.g., regulatory elements or "controllers" as phrased by Dr. McClintock) but also by shuffling genomic sequences. In the latter respect, TE-mediated gene duplications have contributed to the origination of new genes and attracted extensive interest. In response to the development of this field, we herein attempt to provide an overview of TE-mediated duplication by focusing on common rules emerging across duplications generated by different TE types. Specifically, despite the huge divergence of transposition machinery across TEs, we identify three common features of various TE-mediated duplication mechanisms, including end bypass, template switching, and recurrent transposition. These three features lead to one common functional outcome, namely, TE-mediated duplicates tend to be subjected to exon shuffling and neofunctionalization. Therefore, the intrinsic properties of the mutational mechanism constrain the evolutionary trajectories of these duplicates. We finally discuss the future of this field including an in-depth characterization of both the duplication mechanisms and functions of TE-mediated duplicates.
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Affiliation(s)
- Huijing Ma
- Key Laboratory of Zoological Systematics and Evolution & State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Mengxia Wang
- Key Laboratory of Zoological Systematics and Evolution & State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yong E Zhang
- Key Laboratory of Zoological Systematics and Evolution & State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; CAS Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, Yunnan 650223, China; Chinese Institute for Brain Research, Beijing 102206, China.
| | - Shengjun Tan
- Key Laboratory of Zoological Systematics and Evolution & State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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35
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Enriquez-Gasca R, Gould PA, Tunbak H, Conde L, Herrero J, Chittka A, Beck CR, Gifford R, Rowe HM. Co-option of endogenous retroviruses through genetic escape from TRIM28 repression. Cell Rep 2023; 42:112625. [PMID: 37294634 DOI: 10.1016/j.celrep.2023.112625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 04/04/2023] [Accepted: 05/23/2023] [Indexed: 06/11/2023] Open
Abstract
Endogenous retroviruses (ERVs) have rewired host gene networks. To explore the origins of co-option, we employed an active murine ERV, IAPEz, and an embryonic stem cell (ESC) to neural progenitor cell (NPC) differentiation model. Transcriptional silencing via TRIM28 maps to a 190 bp sequence encoding the intracisternal A-type particle (IAP) signal peptide, which confers retrotransposition activity. A subset of "escapee" IAPs (∼15%) exhibits significant genetic divergence from this sequence. Canonical repressed IAPs succumb to a previously undocumented demarcation by H3K9me3 and H3K27me3 in NPCs. Escapee IAPs, in contrast, evade repression in both cell types, resulting in their transcriptional derepression, particularly in NPCs. We validate the enhancer function of a 47 bp sequence within the U3 region of the long terminal repeat (LTR) and show that escapee IAPs convey an activating effect on nearby neural genes. In sum, co-opted ERVs stem from genetic escapees that have lost vital sequences required for both TRIM28 restriction and autonomous retrotransposition.
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Affiliation(s)
- Rocio Enriquez-Gasca
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK.
| | - Poppy A Gould
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK
| | - Hale Tunbak
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK
| | - Lucia Conde
- Bill Lyons Informatics Centre, UCL Cancer Institute, London WC1E 6DD, UK
| | - Javier Herrero
- Bill Lyons Informatics Centre, UCL Cancer Institute, London WC1E 6DD, UK
| | - Alexandra Chittka
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK
| | - Christine R Beck
- Department of Genetics and Genome Sciences, University of Connecticut Health Center, The Jackson Laboratory for Genomic Medicine, Connecticut, JAX CT, Farmington, CT 06032, USA
| | - Robert Gifford
- MRC-University of Glasgow Centre for Virus Research, Glasgow G611QH, UK
| | - Helen M Rowe
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK.
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36
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De Luca C, Gupta A, Bortvin A. Retrotransposon LINE-1 bodies in the cytoplasm of piRNA-deficient mouse spermatocytes: Ribonucleoproteins overcoming the integrated stress response. PLoS Genet 2023; 19:e1010797. [PMID: 37307272 DOI: 10.1371/journal.pgen.1010797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 05/23/2023] [Indexed: 06/14/2023] Open
Abstract
Transposable elements (TE) are mobile DNA sequences whose excessive proliferation endangers the host. Although animals have evolved robust TE-targeting defenses, including Piwi-interacting (pi)RNAs, retrotransposon LINE-1 (L1) still thrives in humans and mice. To gain insights into L1 endurance, we characterized L1 Bodies (LBs) and ORF1p complexes in germ cells of piRNA-deficient Maelstrom null mice. We report that ORF1p interacts with TE RNAs, genic mRNAs, and stress granule proteins, consistent with earlier studies. We also show that ORF1p associates with the CCR4-NOT deadenylation complex and PRKRA, a Protein Kinase R factor. Despite ORF1p interactions with these negative regulators of RNA expression, the stability and translation of LB-localized mRNAs remain unchanged. To scrutinize these findings, we studied the effects of PRKRA on L1 in cultured cells and showed that it elevates ORF1p levels and L1 retrotransposition. These results suggest that ORF1p-driven condensates promote L1 propagation, without affecting the metabolism of endogenous RNAs.
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Affiliation(s)
- Chiara De Luca
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, United States of Americ
| | - Anuj Gupta
- The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alex Bortvin
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, United States of Americ
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37
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Srivastav S, Feschotte C, Clark AG. Rapid evolution of piRNA clusters in the Drosophila melanogaster ovary. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.08.539910. [PMID: 37214865 PMCID: PMC10197564 DOI: 10.1101/2023.05.08.539910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Animal genomes are parasitized by a horde of transposable elements (TEs) whose mutagenic activity can have catastrophic consequences. The piRNA pathway is a conserved mechanism to repress TE activity in the germline via a specialized class of small RNAs associated with effector Piwi proteins called piwi-associated RNAs (piRNAs). piRNAs are produced from discrete genomic regions called piRNA clusters (piCs). While piCs are generally enriched for TE sequences and the molecular processes by which they are transcribed and regulated are relatively well understood in Drosophila melanogaster, much less is known about the origin and evolution of piCs in this or any other species. To investigate piC evolution, we use a population genomics approach to compare piC activity and sequence composition across 8 geographically distant strains of D. melanogaster with high quality long-read genome assemblies. We perform extensive annotations of ovary piCs and TE content in each strain and test predictions of two proposed models of piC evolution. The 'de novo' model posits that individual TE insertions can spontaneously attain the status of a small piC to generate piRNAs silencing the entire TE family. The 'trap' model envisions large and evolutionary stable genomic clusters where TEs tend to accumulate and serves as a long-term "memory" of ancient TE invasions and produce a great variety of piRNAs protecting against related TEs entering the genome. It remains unclear which model best describes the evolution of piCs. Our analysis uncovers extensive variation in piC activity across strains and signatures of rapid birth and death of piCs in natural populations. Most TE families inferred to be recently or currently active show an enrichment of strain-specific insertions into large piCs, consistent with the trap model. By contrast, only a small subset of active LTR retrotransposon families is enriched for the formation of strain-specific piCs, suggesting that these families have an inherent proclivity to form de novo piCs. Thus, our findings support aspects of both 'de novo' and 'trap' models of piC evolution. We propose that these two models represent two extreme stages along an evolutionary continuum, which begins with the emergence of piCs de novo from a few specific LTR retrotransposon insertions that subsequently expand by accretion of other TE insertions during evolution to form larger 'trap' clusters. Our study shows that piCs are evolutionarily labile and that TEs themselves are the major force driving the formation and evolution of piCs.
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Affiliation(s)
- Satyam Srivastav
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, USA
| | - Andrew G. Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, USA
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38
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Hamann MV, Adiba M, Lange UC. Confounding factors in profiling of locus-specific human endogenous retrovirus (HERV) transcript signatures in primary T cells using multi-study-derived datasets. BMC Med Genomics 2023; 16:68. [PMID: 37013607 PMCID: PMC10068191 DOI: 10.1186/s12920-023-01486-y] [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: 01/17/2023] [Accepted: 03/11/2023] [Indexed: 04/05/2023] Open
Abstract
BACKGROUND Human endogenous retroviruses (HERV) are repetitive sequence elements and a substantial part of the human genome. Their role in development has been well documented and there is now mounting evidence that dysregulated HERV expression also contributes to various human diseases. While research on HERV elements has in the past been hampered by their high sequence similarity, advanced sequencing technology and analytical tools have empowered the field. For the first time, we are now able to undertake locus-specific HERV analysis, deciphering expression patterns, regulatory networks and biological functions of these elements. To do so, we inevitable rely on omics datasets available through the public domain. However, technical parameters inevitably differ, making inter-study analysis challenging. We here address the issue of confounding factors for profiling locus-specific HERV transcriptomes using datasets from multiple sources. METHODS We collected RNAseq datasets of CD4 and CD8 primary T cells and extracted HERV expression profiles for 3220 elements, resembling most intact, near full-length proviruses. Looking at sequencing parameters and batch effects, we compared HERV signatures across datasets and determined permissive features for HERV expression analysis from multiple-source data. RESULTS We could demonstrate that considering sequencing parameters, sequencing-depth is most influential on HERV signature outcome. Sequencing samples deeper broadens the spectrum of expressed HERV elements. Sequencing mode and read length are secondary parameters. Nevertheless, we find that HERV signatures from smaller RNAseq datasets do reliably reveal most abundantly expressed HERV elements. Overall, HERV signatures between samples and studies overlap substantially, indicating a robust HERV transcript signature in CD4 and CD8 T cells. Moreover, we find that measures of batch effect reduction are critical to uncover genic and HERV expression differences between cell types. After doing so, differences in the HERV transcriptome between ontologically closely related CD4 and CD8 T cells became apparent. CONCLUSION In our systematic approach to determine sequencing and analysis parameters for detection of locus-specific HERV expression, we provide evidence that analysis of RNAseq datasets from multiple studies can aid confidence of biological findings. When generating de novo HERV expression datasets we recommend increased sequence depth ( > = 100 mio reads) compared to standard genic transcriptome pipelines. Finally, batch effect reduction measures need to be implemented to allow for differential expression analysis.
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Affiliation(s)
| | - Maisha Adiba
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Ulrike C Lange
- Leibniz Institute of Virology (LIV), Hamburg, Germany.
- Institute for Infection Research and Vaccine Development, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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39
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Meers C, Le H, Pesari SR, Hoffmann FT, Walker MW, Gezelle J, Sternberg SH. Transposon-encoded nucleases use guide RNAs to selfishly bias their inheritance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.14.532601. [PMID: 36993599 PMCID: PMC10055086 DOI: 10.1101/2023.03.14.532601] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Insertion sequences (IS) are compact and pervasive transposable elements found in bacteria, which encode only the genes necessary for their mobilization and maintenance. IS 200 /IS 605 elements undergo 'peel-and-paste' transposition catalyzed by a TnpA transposase, but intriguingly, they also encode diverse, TnpB- and IscB-family proteins that are evolutionarily related to the CRISPR-associated effectors Cas12 and Cas9, respectively. Recent studies demonstrated that TnpB-family enzymes function as RNA-guided DNA endonucleases, but the broader biological role of this activity has remained enigmatic. Here we show that TnpB/IscB are essential to prevent permanent transposon loss as a consequence of the TnpA transposition mechanism. We selected a family of related IS elements from Geobacillus stearothermophilus that encode diverse TnpB/IscB orthologs, and showed that a single TnpA transposase was active for transposon excision. The donor joints formed upon religation of IS-flanking sequences were efficiently targeted for cleavage by RNA-guided TnpB/IscB nucleases, and co-expression of TnpB together with TnpA led to significantly greater transposon retention, relative to conditions in which TnpA was expressed alone. Remarkably, TnpA and TnpB/IscB recognize the same AT-rich transposon-adjacent motif (TAM) during transposon excision and RNA-guided DNA cleavage, respectively, revealing a striking convergence in the evolution of DNA sequence specificity between collaborating transposase and nuclease proteins. Collectively, our study reveals that RNA-guided DNA cleavage is a primal biochemical activity that arose to bias the selfish inheritance and spread of transposable elements, which was later co-opted during the evolution of CRISPR-Cas adaptive immunity for antiviral defense.
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Affiliation(s)
- Chance Meers
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY
| | - Hoang Le
- Department of Biology, University of Pennsylvania, Philadelphia, PA
| | - Sanjana R. Pesari
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY
| | - Florian T. Hoffmann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY
| | - Matt W.G. Walker
- Department of Biological Sciences, Columbia University, New York, NY
| | - Jeanine Gezelle
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY
| | - Samuel H. Sternberg
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY
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40
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Nguyen PQ, Huecas S, Asif-Laidin A, Plaza-Pegueroles A, Capuzzi B, Palmic N, Conesa C, Acker J, Reguera J, Lesage P, Fernández-Tornero C. Structural basis of Ty1 integrase tethering to RNA polymerase III for targeted retrotransposon integration. Nat Commun 2023; 14:1729. [PMID: 36977686 PMCID: PMC10050235 DOI: 10.1038/s41467-023-37109-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 03/02/2023] [Indexed: 03/30/2023] Open
Abstract
The yeast Ty1 retrotransposon integrates upstream of genes transcribed by RNA polymerase III (Pol III). Specificity of integration is mediated by an interaction between the Ty1 integrase (IN1) and Pol III, currently uncharacterized at the atomic level. We report cryo-EM structures of Pol III in complex with IN1, revealing a 16-residue segment at the IN1 C-terminus that contacts Pol III subunits AC40 and AC19, an interaction that we validate by in vivo mutational analysis. Binding to IN1 associates with allosteric changes in Pol III that may affect its transcriptional activity. The C-terminal domain of subunit C11, involved in RNA cleavage, inserts into the Pol III funnel pore, providing evidence for a two-metal mechanism during RNA cleavage. Additionally, ordering next to C11 of an N-terminal portion from subunit C53 may explain the connection between these subunits during termination and reinitiation. Deletion of the C53 N-terminal region leads to reduced chromatin association of Pol III and IN1, and a major fall in Ty1 integration events. Our data support a model in which IN1 binding induces a Pol III configuration that may favor its retention on chromatin, thereby improving the likelihood of Ty1 integration.
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Affiliation(s)
- Phong Quoc Nguyen
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, 28040, Madrid, Spain
- Aix-Marseille Université, CNRS, AFMB UMR 7257, 13288, Marseille, France
| | - Sonia Huecas
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, 28040, Madrid, Spain
| | - Amna Asif-Laidin
- Université Paris Cité, IRSL, Inserm, U944, CNRS, UMR7212, 75010, Paris, France
| | | | - Beatrice Capuzzi
- Université Paris Cité, IRSL, Inserm, U944, CNRS, UMR7212, 75010, Paris, France
| | - Noé Palmic
- Université Paris Cité, IRSL, Inserm, U944, CNRS, UMR7212, 75010, Paris, France
| | - Christine Conesa
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Joël Acker
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Juan Reguera
- Aix-Marseille Université, CNRS, AFMB UMR 7257, 13288, Marseille, France
- INSERM, AFMB UMR7257, 13288, Marseille, France
| | - Pascale Lesage
- Université Paris Cité, IRSL, Inserm, U944, CNRS, UMR7212, 75010, Paris, France.
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41
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Evering TH, Marston JL, Gan L, Nixon DF. Transposable elements and Alzheimer's disease pathogenesis. Trends Neurosci 2023; 46:170-172. [PMID: 36588011 DOI: 10.1016/j.tins.2022.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 12/13/2022] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease (AD) is characterized by the pathological accumulation of amyloid β (Aβ) plaques and neurofibrillary tangles composed of hyperphosphorylated tau. Microglia and astrocytes respond to the abnormal presence of tau protein with induced transposable element (TE) transcription. In this Forum, we discuss new data that link dysregulated TE expression to AD pathogenesis.
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Affiliation(s)
- Teresa H Evering
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Jez L Marston
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Li Gan
- Helen and Robert Appel Alzheimer's Disease Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Douglas F Nixon
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY, 10021, USA.
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42
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Berger F, Muegge K, Richards EJ. Seminars in cell and development biology on histone variants remodelers of H2A variants associated with heterochromatin. Semin Cell Dev Biol 2023; 135:93-101. [PMID: 35249811 PMCID: PMC9440159 DOI: 10.1016/j.semcdb.2022.02.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 01/04/2023]
Abstract
Variants of the histone H2A occupy distinct locations in the genome. There is relatively little known about the mechanisms responsible for deposition of specific H2A variants. Notable exceptions are chromatin remodelers that control the dynamics of H2A.Z at promoters. Here we review the steps that identified the role of a specific class of chromatin remodelers, including LSH and DDM1 that deposit the variants macroH2A in mammals and H2A.W in plants, respectively. The function of these remodelers in heterochromatin is discussed together with their multiple roles in genome stability.
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Affiliation(s)
- Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
| | - Kathrin Muegge
- Epigenetics Section, Frederick National Laboratory for Cancer Research in the Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD, USA.
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43
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Sun YH, Cui H, Song C, Shen JT, Zhuo X, Wang RH, Yu X, Ndamba R, Mu Q, Gu H, Wang D, Murthy GG, Li P, Liang F, Liu L, Tao Q, Wang Y, Orlowski S, Xu Q, Zhou H, Jagne J, Gokcumen O, Anthony N, Zhao X, Li XZ. Amniotes co-opt intrinsic genetic instability to protect germ-line genome integrity. Nat Commun 2023; 14:812. [PMID: 36781861 PMCID: PMC9925758 DOI: 10.1038/s41467-023-36354-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 01/27/2023] [Indexed: 02/15/2023] Open
Abstract
Unlike PIWI-interacting RNA (piRNA) in other species that mostly target transposable elements (TEs), >80% of piRNAs in adult mammalian testes lack obvious targets. However, mammalian piRNA sequences and piRNA-producing loci evolve more rapidly than the rest of the genome for unknown reasons. Here, through comparative studies of chickens, ducks, mice, and humans, as well as long-read nanopore sequencing on diverse chicken breeds, we find that piRNA loci across amniotes experience: (1) a high local mutation rate of structural variations (SVs, mutations ≥ 50 bp in size); (2) positive selection to suppress young and actively mobilizing TEs commencing at the pachytene stage of meiosis during germ cell development; and (3) negative selection to purge deleterious SV hotspots. Our results indicate that genetic instability at pachytene piRNA loci, while producing certain pathogenic SVs, also protects genome integrity against TE mobilization by driving the formation of rapid-evolving piRNA sequences.
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Affiliation(s)
- Yu H Sun
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Hongxiao Cui
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Chi Song
- College of Public Health, Division of Biostatistics, The Ohio State University, Columbus, OH, 43210, USA
| | - Jiafei Teng Shen
- International Institutes of Medicine, The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, Zhejiang, 322000, China
| | - Xiaoyu Zhuo
- Department of Genetics, The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Ruoqiao Huiyi Wang
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, 14642, USA
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Xiaohui Yu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Rudo Ndamba
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Qian Mu
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Hanwen Gu
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Duolin Wang
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Gayathri Guru Murthy
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Pidong Li
- Grandomics Biosciences Co., Ltd, Beijing, 102206, China
| | - Fan Liang
- Grandomics Biosciences Co., Ltd, Beijing, 102206, China
| | - Lei Liu
- Grandomics Biosciences Co., Ltd, Beijing, 102206, China
| | - Qing Tao
- Grandomics Biosciences Co., Ltd, Beijing, 102206, China
| | - Ying Wang
- Department of Animal Science, University of California, Davis, CA, 95616, USA
| | - Sara Orlowski
- Department of Poultry Science, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Qi Xu
- Department of Animal Science, McGill University, Quebec, H9X 3V9, Canada
| | - Huaijun Zhou
- Department of Animal Science, University of California, Davis, CA, 95616, USA
| | - Jarra Jagne
- Animal Health Diagnostic Center, Cornell University College of Veterinary Medicine, Ithaca, NY, 14850, USA
| | - Omer Gokcumen
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA
| | - Nick Anthony
- Department of Poultry Science, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Xin Zhao
- Department of Animal Science, McGill University, Quebec, H9X 3V9, Canada.
| | - Xin Zhiguo Li
- Center for RNA Biology: From Genome to Therapeutics, Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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44
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Rogers RL, Grizzard SL, Garner JT. Strong, Recent Selective Sweeps Reshape Genetic Diversity in Freshwater Bivalve Megalonaias nervosa. Mol Biol Evol 2023; 40:7026026. [PMID: 36738170 PMCID: PMC9976758 DOI: 10.1093/molbev/msad024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 01/16/2023] [Accepted: 01/24/2023] [Indexed: 02/05/2023] Open
Abstract
Freshwater Unionid bivalves have recently faced ecological upheaval through pollution, barriers to dispersal, harvesting, and changes in fish-host prevalence. Currently, over 70% of species in North America are threatened, endangered or extinct. To characterize the genetic response to recent selective pressures, we collected population genetic data for one successful bivalve species, Megalonaias nervosa. We identify megabase-sized regions that are nearly monomorphic across the population, signals of strong, recent selection reshaping diversity across 73 Mb total. These signatures of selection are greater than is commonly seen in population genetic models. We observe 102 duplicate genes with high dN/dS on terminal branches among regions with sweeps, suggesting that gene duplication is a causative mechanism of recent adaptation in M. nervosa. Genes in sweeps reflect functional classes important for Unionid survival, including anticoagulation genes important for fish host parasitization, detox genes, mitochondria management, and shell formation. We identify sweeps in regions with no known functional impacts, suggesting mechanisms of adaptation that deserve greater attention in future work on species survival. In contrast, polymorphic transposable elements (TEs) appear to be detrimental and underrepresented among regions with sweeps. TE site frequency spectra are skewed toward singleton variants, and TEs among regions with sweeps are present at low frequency. Our work suggests that duplicate genes are an essential source of genetic novelty that has helped this species succeed in environments where others have struggled. These results suggest that gene duplications deserve greater attention in non-model population genomics, especially in species that have recently faced sudden environmental challenges.
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Affiliation(s)
- Rebekah L Rogers
- Department of Bioinformatics and Genomics, University of North Carolina, Charlotte, NC 28223, USA
| | | | - Jeffrey T Garner
- Division of Wildlife and Freshwater Fisheries, Alabama Department of Conservation and Natural Resources, Florence, AL, USA
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45
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Luca CD, Gupta A, Bortvin A. Ribonucleoprotein condensation driven by retrotransposon LINE-1 sustains RNA integrity and translation in mouse spermatocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523313. [PMID: 36712121 PMCID: PMC9882024 DOI: 10.1101/2023.01.09.523313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Transposable elements (TE) are mobile DNA sequences whose excessive proliferation endangers the host. Although animals have evolved robust TE-targeting defenses, including Piwi-interacting (pi)RNAs, retrotransposon LINE-1 (L1) still thrives in humans and mice. To gain insights into L1 endurance, we characterized L1 Bodies (LBs) and ORF1p complexes in germ cells of piRNA-deficient Maelstrom null mice. We report that ORF1p interacts with TE RNAs, genic mRNAs, and stress granule proteins, consistent with earlier studies. We also show that ORF1p associates with the CCR4-NOT deadenylation complex and PRKRA, a Protein Kinase R factor. Despite ORF1p interactions with these negative regulators of RNA expression, the stability and translation of LB-localized mRNAs remain unchanged. To scrutinize these findings, we studied the effects of PRKRA on L1 in cultured cells and showed that it elevates ORF1p levels and L1 retrotransposition. These results suggest that ORF1p-driven condensates promote L1 propagation, without affecting the metabolism of endogenous RNAs.
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46
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Ahn HW, Worman ZF, Lechsinska A, Payer LM, Wang T, Malik N, Li W, Burns KH, Nath A, Levin HL. Retrotransposon insertions associated with risk of neurologic and psychiatric diseases. EMBO Rep 2023; 24:e55197. [PMID: 36367221 PMCID: PMC9827563 DOI: 10.15252/embr.202255197] [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: 04/08/2022] [Revised: 10/11/2022] [Accepted: 10/20/2022] [Indexed: 11/13/2022] Open
Abstract
Transposable elements (TEs) are active in neuronal cells raising the question whether TE insertions contribute to risk of neuropsychiatric disease. While genome-wide association studies (GWAS) serve as a tool to discover genetic loci associated with neuropsychiatric diseases, unfortunately GWAS do not directly detect structural variants such as TEs. To examine the role of TEs in psychiatric and neurologic disease, we evaluated 17,000 polymorphic TEs and find 76 are in linkage disequilibrium with disease haplotypes (P < 10-6 ) defined by GWAS. From these 76 polymorphic TEs, we identify potentially causal candidates based on having insertions in genomic regions of regulatory chromatin and on having associations with altered gene expression in brain tissues. We show that lead candidate insertions have regulatory effects on gene expression in human neural stem cells altering the activity of a minimal promoter. Taken together, we identify 10 polymorphic TE insertions that are potential candidates on par with other variants for having a causal role in neurologic and psychiatric disorders.
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Affiliation(s)
- Hyo Won Ahn
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
| | - Zelia F Worman
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
- Present address:
Seven BridgesCharlestownMAUSA
| | - Arianna Lechsinska
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
| | - Lindsay M Payer
- Department of PathologyJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Tongguang Wang
- Translational Neuroscience CenterNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Nasir Malik
- Translational Neuroscience CenterNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Wenxue Li
- Section of Infections of the Nervous SystemNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Kathleen H Burns
- Department of Oncologic PathologyDana‐Farber Cancer InstituteBostonMAUSA
| | - Avindra Nath
- Translational Neuroscience CenterNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
- Section of Infections of the Nervous SystemNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMDUSA
| | - Henry L Levin
- Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaMDUSA
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47
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Sadler KC. Epigenetics across the evolutionary tree: New paradigms from non-model animals. Bioessays 2023; 45:e2200036. [PMID: 36403219 DOI: 10.1002/bies.202200036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 10/28/2022] [Accepted: 11/03/2022] [Indexed: 11/21/2022]
Abstract
All animals have evolved solutions to manage their genomes, enabling the efficient organization of meters of DNA strands in the nucleus and allowing for nuanced regulation of gene expression while keeping transposable elements suppressed. Epigenetic modifications are central to accomplishing all these. Recent advances in sequencing technologies and the development of techniques that profile epigenetic marks and chromatin accessibility using reagents that can be used in any species has catapulted epigenomic studies in diverse animal species, shedding light on the multitude of epigenomic mechanisms utilized across the evolutionary tree. Now, comparative epigenomics is a rapidly growing field that is uncovering mechanistic aspects of epigenetic modifications and chromatin organization in non-model invertebrates, ranging from octopus to sponges. This review puts recent discoveries in the epigenetics of non-model invertebrates in historical context, and describes new insight into the patterning and functions of DNA methylation and other highly conserved epigenetic modifications.
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Affiliation(s)
- Kirsten C Sadler
- Program in Biology, New York University, Abu Dhabi, United Arab Emirates
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48
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Carelli FN, Cerrato C, Dong Y, Appert A, Dernburg A, Ahringer J. Widespread transposon co-option in the Caenorhabditis germline regulatory network. SCIENCE ADVANCES 2022; 8:eabo4082. [PMID: 36525485 PMCID: PMC9757741 DOI: 10.1126/sciadv.abo4082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 11/18/2022] [Indexed: 06/17/2023]
Abstract
The movement of selfish DNA elements can lead to widespread genomic alterations with potential to create novel functions. We show that transposon expansions in Caenorhabditis nematodes led to extensive rewiring of germline transcriptional regulation. We find that about one-third of Caenorhabditis elegans germline-specific promoters have been co-opted from two related miniature inverted repeat transposable elements (TEs), CERP2 and CELE2. These promoters are regulated by HIM-17, a THAP domain-containing transcription factor related to a transposase. Expansion of CERP2 occurred before radiation of the Caenorhabditis genus, as did fixation of mutations in HIM-17 through positive selection, whereas CELE2 expanded only in C. elegans. Through comparative analyses in Caenorhabditis briggsae, we find not only evolutionary conservation of most CERP2 co-opted promoters but also a substantial fraction that are species-specific. Our work reveals the emergence and evolutionary conservation of a novel transcriptional network driven by TE co-option with a major impact on regulatory evolution.
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Affiliation(s)
- Francesco Nicola Carelli
- Wellcome Trust/Cancer Research UK Gurdon Institute, Cambridge, UK
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Chiara Cerrato
- Wellcome Trust/Cancer Research UK Gurdon Institute, Cambridge, UK
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Yan Dong
- Wellcome Trust/Cancer Research UK Gurdon Institute, Cambridge, UK
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Alex Appert
- Wellcome Trust/Cancer Research UK Gurdon Institute, Cambridge, UK
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Abby Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815, USA
- Biological Sciences and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, Berkeley, CA 94720, USA
| | - Julie Ahringer
- Wellcome Trust/Cancer Research UK Gurdon Institute, Cambridge, UK
- Department of Genetics, University of Cambridge, Cambridge, UK
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49
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Wang L, Tracy L, Su W, Yang F, Feng Y, Silverman N, Zhang ZZZ. Retrotransposon activation during Drosophila metamorphosis conditions adult antiviral responses. Nat Genet 2022; 54:1933-1945. [PMID: 36396707 PMCID: PMC9795486 DOI: 10.1038/s41588-022-01214-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 09/29/2022] [Indexed: 11/18/2022]
Abstract
Retrotransposons are one type of mobile genetic element that abundantly reside in the genomes of nearly all animals. Their uncontrolled activation is linked to sterility, cancer and other pathologies, thereby being largely considered detrimental. Here we report that, within a specific time window of development, retrotransposon activation can license the host's immune system for future antiviral responses. We found that the mdg4 (also known as Gypsy) retrotransposon selectively becomes active during metamorphosis at the Drosophila pupal stage. At this stage, mdg4 activation educates the host's innate immune system by inducing the systemic antiviral function of the nuclear factor-κB protein Relish in a dSTING-dependent manner. Consequently, adult flies with mdg4, Relish or dSTING silenced at the pupal stage are unable to clear exogenous viruses and succumb to viral infection. Altogether, our data reveal that hosts can establish a protective antiviral response that endows a long-term benefit in pathogen warfare due to the developmental activation of mobile genetic elements.
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Affiliation(s)
- Lu Wang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA.
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.
| | - Lauren Tracy
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Weijia Su
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Fu Yang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - Yu Feng
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Neal Silverman
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Z Z Zhao Zhang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA.
- Duke Regeneration Center, Duke University School of Medicine, Durham, NC, USA.
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50
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Liu P, Cuerda-Gil D, Shahid S, Slotkin RK. The Epigenetic Control of the Transposable Element Life Cycle in Plant Genomes and Beyond. Annu Rev Genet 2022; 56:63-87. [DOI: 10.1146/annurev-genet-072920-015534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Within the life cycle of a living organism, another life cycle exists for the selfish genome inhabitants, which are called transposable elements (TEs). These mobile sequences invade, duplicate, amplify, and diversify within a genome, increasing the genome's size and generating new mutations. Cells act to defend their genome, but rather than permanently destroying TEs, they use chromatin-level repression and epigenetic inheritance to silence TE activity. This level of silencing is ephemeral and reversible, leading to a dynamic equilibrium between TE suppression and reactivation within a host genome. The coexistence of the TE and host genome can also lead to the domestication of the TE to serve in host genome evolution and function. In this review, we describe the life cycle of a TE, with emphasis on how epigenetic regulation is harnessed to control TEs for host genome stability and innovation.
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Affiliation(s)
- Peng Liu
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
| | - Diego Cuerda-Gil
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
- Graduate Program in the Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, USA
| | - Saima Shahid
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
| | - R. Keith Slotkin
- Donald Danforth Plant Science Center, St. Louis, Missouri, USA
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
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