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Scarpa A, Pianezza R, Wierzbicki F, Kofler R. Genomes of historical specimens reveal multiple invasions of LTR retrotransposons in Drosophila melanogaster during the 19th century. Proc Natl Acad Sci U S A 2024; 121:e2313866121. [PMID: 38564639 PMCID: PMC11009621 DOI: 10.1073/pnas.2313866121] [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: 01/05/2024] [Indexed: 04/04/2024] Open
Abstract
Transposable element invasions have a profound impact on the evolution of genomes and phenotypes. It is thus an important open question how often such TE invasions occur. To address this question, we utilize the genomes of historical specimens, sampled about 200 y ago. We found that the LTR retrotransposons Blood, Opus, and 412 spread in Drosophila melanogaster in the 19th century. These invasions constitute second waves, as degraded fragments were found for all three TEs. The composition of Opus and 412, but not of Blood, shows a pronounced geographic heterogeneity, likely due to founder effects during the invasions. Finally, we identified species from the Drosophila simulans complex as the likely origin of the TEs. We show that in total, seven TE families invaded D. melanogaster during the last 200y, thereby increasing the genome size by up to 1.2Mbp. We suggest that this high rate of TE invasions was likely triggered by human activity. Based on the analysis of strains and specimens sampled at different times, we provide a detailed timeline of TE invasions, making D. melanogaster the first organism where the invasion history of TEs during the last two centuries could be inferred.
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Affiliation(s)
- Almorò Scarpa
- Institut für Populationsgenetik, Vetmeduni Vienna, Wien1210, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna1210, Austria
| | - Riccardo Pianezza
- Institut für Populationsgenetik, Vetmeduni Vienna, Wien1210, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna1210, Austria
| | - Filip Wierzbicki
- Institut für Populationsgenetik, Vetmeduni Vienna, Wien1210, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna1210, Austria
| | - Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Wien1210, Austria
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2
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Pianezza R, Scarpa A, Narayanan P, Signor S, Kofler R. Spoink, a LTR retrotransposon, invaded D. melanogaster populations in the 1990s. PLoS Genet 2024; 20:e1011201. [PMID: 38530818 DOI: 10.1371/journal.pgen.1011201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 02/27/2024] [Indexed: 03/28/2024] Open
Abstract
During the last few centuries D. melanogaster populations were invaded by several transposable elements, the most recent of which was thought to be the P-element between 1950 and 1980. Here we describe a novel TE, which we named Spoink, that has invaded D. melanogaster. It is a 5216nt LTR retrotransposon of the Ty3/gypsy superfamily. Relying on strains sampled at different times during the last century we show that Spoink invaded worldwide D. melanogaster populations after the P-element between 1983 and 1993. This invasion was likely triggered by a horizontal transfer from the D. willistoni group, much as the P-element. Spoink is probably silenced by the piRNA pathway in natural populations and about 1/3 of the examined strains have an insertion into a canonical piRNA cluster such as 42AB. Given the degree of genetic investigation of D. melanogaster it is perhaps surprising that Spoink was able to invade unnoticed.
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Affiliation(s)
- Riccardo Pianezza
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Almorò Scarpa
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Prakash Narayanan
- Biological Sciences, North Dakota State University, Fargo, North Dakota, United States of America
| | - Sarah Signor
- Biological Sciences, North Dakota State University, Fargo, North Dakota, United States of America
| | - Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
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3
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Rieseberg L, Warschefsky E, Burton J, Huang K, Sibbett B. Editorial 2024. Mol Ecol 2024; 33:e17239. [PMID: 38146175 DOI: 10.1111/mec.17239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Affiliation(s)
- Loren Rieseberg
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Emily Warschefsky
- William L. Brown Center, Missouri Botanical Garden, Saint Louis, MO, USA
| | - Jade Burton
- John Wiley & Sons, Atrium Southern Gate, Chichester, West Sussex, UK
| | - Kaichi Huang
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Benjamin Sibbett
- John Wiley & Sons, Atrium Southern Gate, Chichester, West Sussex, UK
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4
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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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van Lopik J, Alizada A, Trapotsi MA, Hannon GJ, Bornelöv S, Czech Nicholson B. Unistrand piRNA clusters are an evolutionarily conserved mechanism to suppress endogenous retroviruses across the Drosophila genus. Nat Commun 2023; 14:7337. [PMID: 37957172 PMCID: PMC10643416 DOI: 10.1038/s41467-023-42787-1] [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: 04/04/2023] [Accepted: 10/18/2023] [Indexed: 11/15/2023] Open
Abstract
The PIWI-interacting RNA (piRNA) pathway prevents endogenous genomic parasites, i.e. transposable elements, from damaging the genetic material of animal gonadal cells. Specific regions in the genome, called piRNA clusters, are thought to define each species' piRNA repertoire and therefore its capacity to recognize and silence specific transposon families. The unistrand cluster flamenco (flam) is essential in the somatic compartment of the Drosophila ovary to restrict Gypsy-family transposons from infecting the neighbouring germ cells. Disruption of flam results in transposon de-repression and sterility, yet it remains unknown whether this silencing mechanism is present more widely. Here, we systematically characterise 119 Drosophila species and identify five additional flam-like clusters separated by up to 45 million years of evolution. Small RNA-sequencing validated these as bona-fide unistrand piRNA clusters expressed in somatic cells of the ovary, where they selectively target transposons of the Gypsy family. Together, our study provides compelling evidence of a widely conserved transposon silencing mechanism that co-evolved with virus-like Gypsy-family transposons.
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Affiliation(s)
- Jasper van Lopik
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Azad Alizada
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Maria-Anna Trapotsi
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Gregory J Hannon
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK
| | - Susanne Bornelöv
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK.
| | - Benjamin Czech Nicholson
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK.
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Bodelón A, Fablet M, Siqueira de Oliveira D, Vieira C, García Guerreiro MP. Impact of Heat Stress on Transposable Element Expression and Derived Small RNAs in Drosophila subobscura. Genome Biol Evol 2023; 15:evad189. [PMID: 37847062 PMCID: PMC10627563 DOI: 10.1093/gbe/evad189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 10/02/2023] [Accepted: 10/09/2023] [Indexed: 10/18/2023] Open
Abstract
Global warming is forcing insect populations to move and adapt, triggering adaptive genetic responses. Thermal stress is known to alter gene expression, repressing the transcription of active genes, and inducing others, such as those encoding heat shock proteins. It has also been related to the activation of some specific transposable element (TE) families. However, the actual magnitude of this stress on the whole genome and the factors involved in these genomic changes are still unclear. We studied mRNAs and small RNAs in gonads of two Drosophila subobscura populations, considered a good model to study adaptation to temperature changes. In control conditions, we found that a few genes and TE families were differentially expressed between populations, pointing out their putative involvement in the adaptation of populations to their different environments. Under heat stress, sex-specific changes in gene expression together with a trend toward overexpression, mainly of heat shock response-related genes, were observed. We did not observe large changes of TE expression nor small RNA production due to stress. Only population and sex-specific expression changes of some TE families (mainly retrotransposons), or the amounts of siRNAs and piRNAs, derived from specific TE families were observed, as well as the piRNA production from some piRNA clusters. Changes in small RNA amounts and TE expression could not be clearly correlated, indicating that other factors as chromatin modulation could also be involved. This work provides the first whole transcriptomic study including genes, TEs, and small RNAs after a heat stress in D. subobscura.
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Affiliation(s)
- Alejandra Bodelón
- Grup de Genòmica, Bioinformática i Biologia Evolutiva, Departament de Genètica i Microbiologia (Edifici C), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Marie Fablet
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon; Université Lyon 1; CNRS; UMR 5558, Villeurbanne, France
- Institut universitaire de France, Paris, France
| | - Daniel Siqueira de Oliveira
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon; Université Lyon 1; CNRS; UMR 5558, Villeurbanne, France
- Institute of Biosciences, Humanities and Exact Sciences, São Paulo State University (Unesp), São Paulo, Brazil
| | - Cristina Vieira
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon; Université Lyon 1; CNRS; UMR 5558, Villeurbanne, France
| | - Maria Pilar García Guerreiro
- Grup de Genòmica, Bioinformática i Biologia Evolutiva, Departament de Genètica i Microbiologia (Edifici C), Universitat Autònoma de Barcelona, Barcelona, Spain
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Wierzbicki F, Kofler R. The composition of piRNA clusters in Drosophila melanogaster deviates from expectations under the trap model. BMC Biol 2023; 21:224. [PMID: 37858221 PMCID: PMC10588112 DOI: 10.1186/s12915-023-01727-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 10/06/2023] [Indexed: 10/21/2023] Open
Abstract
BACKGROUND It is widely assumed that the invasion of a transposable element (TE) in mammals and invertebrates is stopped when a copy of the TE jumps into a piRNA cluster (i.e., the trap model). However, recent works, which for example showed that deletion of three major piRNA clusters has no effect on TE activity, cast doubt on the trap model. RESULTS Here, we test the trap model from a population genetics perspective. Our simulations show that the composition of regions that act as transposon traps (i.e., potentially piRNA clusters) ought to deviate from regions that have no effect on TE activity. We investigated TEs in five Drosophila melanogaster strains using three complementary approaches to test whether the composition of piRNA clusters matches these expectations. We found that the abundance of TE families inside and outside of piRNA clusters is highly correlated, although this is not expected under the trap model. Furthermore, the distribution of the number of TE insertions in piRNA clusters is also much broader than expected. CONCLUSIONS We found that the observed composition of piRNA clusters is not in agreement with expectations under the simple trap model. Dispersed piRNA producing TE insertions and temporal as well as spatial heterogeneity of piRNA clusters may account for these deviations.
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Affiliation(s)
- Filip Wierzbicki
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vienna, Austria
| | - Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria.
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Yoth M, Maupetit-Méhouas S, Akkouche A, Gueguen N, Bertin B, Jensen S, Brasset E. Reactivation of a somatic errantivirus and germline invasion in Drosophila ovaries. Nat Commun 2023; 14:6096. [PMID: 37773253 PMCID: PMC10541861 DOI: 10.1038/s41467-023-41733-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 09/15/2023] [Indexed: 10/01/2023] Open
Abstract
Most Drosophila transposable elements are LTR retrotransposons, some of which belong to the genus Errantivirus and share structural and functional characteristics with vertebrate endogenous retroviruses. Like endogenous retroviruses, it is unclear whether errantiviruses retain some infectivity and transposition capacity. We created conditions where control of the Drosophila ZAM errantivirus through the piRNA pathway was abolished leading to its de novo reactivation in somatic gonadal cells. After reactivation, ZAM invaded the oocytes and severe fertility defects were observed. While ZAM expression persists in the somatic gonadal cells, the germline then set up its own adaptive genomic immune response by producing piRNAs against the constantly invading errantivirus, restricting invasion. Our results suggest that although errantiviruses are continuously repressed by the piRNA pathway, they may retain their ability to infect the germline and transpose, thus allowing them to efficiently invade the germline if they are expressed.
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Affiliation(s)
- Marianne Yoth
- iGReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000, Clermont-Ferrand, France
| | | | - Abdou Akkouche
- iGReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000, Clermont-Ferrand, France
| | - Nathalie Gueguen
- iGReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000, Clermont-Ferrand, France
| | - Benjamin Bertin
- LIMAGRAIN EUROPE, Centre de recherche, 63720, Chappes, France
| | - Silke Jensen
- iGReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000, Clermont-Ferrand, France.
| | - Emilie Brasset
- iGReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, 63000, Clermont-Ferrand, France.
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Signor S, Vedanayagam J, Kim BY, Wierzbicki F, Kofler R, Lai EC. Rapid evolutionary diversification of the flamenco locus across simulans clade Drosophila species. PLoS Genet 2023; 19:e1010914. [PMID: 37643184 PMCID: PMC10495008 DOI: 10.1371/journal.pgen.1010914] [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: 03/07/2023] [Revised: 09/11/2023] [Accepted: 08/09/2023] [Indexed: 08/31/2023] Open
Abstract
Suppression of transposable elements (TEs) is paramount to maintain genomic integrity and organismal fitness. In D. melanogaster, the flamenco locus is a master suppressor of TEs, preventing the mobilization of certain endogenous retrovirus-like TEs from somatic ovarian support cells to the germline. It is transcribed by Pol II as a long (100s of kb), single-stranded, primary transcript, and metabolized into ~24-32 nt Piwi-interacting RNAs (piRNAs) that target active TEs via antisense complementarity. flamenco is thought to operate as a trap, owing to its high content of recent horizontally transferred TEs that are enriched in antisense orientation. Using newly-generated long read genome data, which is critical for accurate assembly of repetitive sequences, we find that flamenco has undergone radical transformations in sequence content and even copy number across simulans clade Drosophilid species. Drosophila simulans flamenco has duplicated and diverged, and neither copy exhibits synteny with D. melanogaster beyond the core promoter. Moreover, flamenco organization is highly variable across D. simulans individuals. Next, we find that D. simulans and D. mauritiana flamenco display signatures of a dual-stranded cluster, with ping-pong signals in the testis and/or embryo. This is accompanied by increased copy numbers of germline TEs, consistent with these regions operating as functional dual-stranded clusters. Overall, the physical and functional diversity of flamenco orthologs is testament to the extremely dynamic consequences of TE arms races on genome organization, not only amongst highly related species, but even amongst individuals.
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Affiliation(s)
- Sarah Signor
- Biological Sciences, North Dakota State University, Fargo, North Dakota, United States of America
| | - Jeffrey Vedanayagam
- Developmental Biology Program, Sloan-Kettering Institute, New York, New York, United States of America
- Department of Neuroscience, Developmental and Regenerative Biology, University of Texas at San Antonio, Texas, United States of America
| | - Bernard Y. Kim
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Filip Wierzbicki
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vienna, Austria
| | - Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
| | - Eric C. Lai
- Developmental Biology Program, Sloan-Kettering Institute, New York, New York, United States of America
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Asif-Laidin A, Casier K, Ziriat Z, Boivin A, Viodé E, Delmarre V, Ronsseray S, Carré C, Teysset L. Modeling early germline immunization after horizontal transfer of transposable elements reveals internal piRNA cluster heterogeneity. BMC Biol 2023; 21:117. [PMID: 37226160 DOI: 10.1186/s12915-023-01616-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 05/05/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND A fraction of all genomes is composed of transposable elements (TEs) whose mobility needs to be carefully controlled. In gonads, TE activity is repressed by PIWI-interacting RNAs (piRNAs), a class of small RNAs synthesized by heterochromatic loci enriched in TE fragments, called piRNA clusters. Maintenance of active piRNA clusters across generations is secured by maternal piRNA inheritance providing the memory for TE repression. On rare occasions, genomes encounter horizontal transfer (HT) of new TEs with no piRNA targeting them, threatening the host genome integrity. Naïve genomes can eventually start to produce new piRNAs against these genomic invaders, but the timing of their emergence remains elusive. RESULTS Using a set of TE-derived transgenes inserted in different germline piRNA clusters and functional assays, we have modeled a TE HT in Drosophila melanogaster. We have found that the complete co-option of these transgenes by a germline piRNA cluster can occur within four generations associated with the production of new piRNAs all along the transgenes and the germline silencing of piRNA sensors. Synthesis of new transgenic TE piRNAs is linked to piRNA cluster transcription dependent on Moonshiner and heterochromatin mark deposition that propagates more efficiently on short sequences. Moreover, we found that sequences located within piRNA clusters can have different piRNA profiles and can influence transcript accumulation of nearby sequences. CONCLUSIONS Our study reveals that genetic and epigenetic properties, such as transcription, piRNA profiles, heterochromatin, and conversion efficiency along piRNA clusters, could be heterogeneous depending on the sequences that compose them. These findings suggest that the capacity of transcriptional signal erasure induced by the chromatin complex specific of the piRNA cluster can be incomplete through the piRNA cluster loci. Finally, these results have revealed an unexpected level of complexity that highlights a new magnitude of piRNA cluster plasticity fundamental for the maintenance of genome integrity.
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Affiliation(s)
- Amna Asif-Laidin
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Karine Casier
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
- Present Address: CNRS, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, UMR8226, Telomere Biology, Paris, F-75005, France
| | - Zoheir Ziriat
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Antoine Boivin
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Elise Viodé
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Valérie Delmarre
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Stéphane Ronsseray
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Clément Carré
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France
| | - Laure Teysset
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & Small RNA Biology", Paris, F-75005, France.
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11
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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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Qu J, Betting V, van Iterson R, Kwaschik FM, van Rij RP. Chromatin profiling identifies transcriptional readthrough as a conserved mechanism for piRNA biogenesis in mosquitoes. Cell Rep 2023; 42:112257. [PMID: 36930642 DOI: 10.1016/j.celrep.2023.112257] [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: 09/16/2022] [Revised: 12/21/2022] [Accepted: 02/27/2023] [Indexed: 03/18/2023] Open
Abstract
The piRNA pathway in mosquitoes differs substantially from other model organisms, with an expanded PIWI gene family and functions in antiviral defense. Here, we define core piRNA clusters as genomic loci that show ubiquitous piRNA expression in both somatic and germline tissues. These core piRNA clusters are enriched for non-retroviral endogenous viral elements (nrEVEs) in antisense orientation and depend on key biogenesis factors, Veneno, Tejas, Yb, and Shutdown. Combined transcriptome and chromatin state analyses identify transcriptional readthrough as a conserved mechanism for cluster-derived piRNA biogenesis in the vector mosquitoes Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles gambiae. Comparative analyses between the two Aedes species suggest that piRNA clusters function as traps for nrEVEs, allowing adaptation to environmental challenges such as virus infection. Our systematic transcriptome and chromatin state analyses lay the foundation for studies of gene regulation, genome evolution, and piRNA function in these important vector species.
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Affiliation(s)
- Jieqiong Qu
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Valerie Betting
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Ruben van Iterson
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Florence M Kwaschik
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Ronald P van Rij
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands.
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Bock DG, Liu J, Novikova P, Rieseberg LH. Long-read sequencing in ecology and evolution: Understanding how complex genetic and epigenetic variants shape biodiversity. Mol Ecol 2023; 32:1229-1235. [PMID: 36855925 DOI: 10.1111/mec.16884] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/13/2023] [Indexed: 03/02/2023]
Affiliation(s)
- Dan G Bock
- Department of Botany, Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jianquan Liu
- State Key Laboratory of Grassland and Agro-ecosystems, Institute of Innovation Ecology, School of Life Science and the Supercomputing Center, Lanzhou University, Lanzhou, China.,Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Polina Novikova
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Loren H Rieseberg
- Department of Botany, Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
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Liu X, Majid M, Yuan H, Chang H, Zhao L, Nie Y, He L, Liu X, He X, Huang Y. Transposable element expansion and low-level piRNA silencing in grasshoppers may cause genome gigantism. BMC Biol 2022; 20:243. [PMID: 36307800 PMCID: PMC9615261 DOI: 10.1186/s12915-022-01441-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/17/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Transposable elements (TEs) have been likened to parasites in the genome that reproduce and move ceaselessly in the host, continuously enlarging the host genome. However, the Piwi-interacting RNA (piRNA) pathway defends animal genomes against the harmful consequences of TE invasion by imposing small-RNA-mediated silencing. Here we compare the TE activity of two grasshopper species with different genome sizes in Acrididae (Locusta migratoria manilensis♀1C = 6.60 pg, Angaracris rhodopa♀1C = 16.36 pg) to ascertain the influence of piRNAs.
Results
We discovered that repetitive sequences accounted for 74.56% of the genome in A. rhodopa, more than 56.83% in L. migratoria, and the large-genome grasshopper contained a higher TEs proportions. The comparative analysis revealed that 41 TEs (copy number > 500) were shared in both species. The two species exhibited distinct “landscapes” of TE divergence. The TEs outbreaks in the small-genome grasshopper occurred at more ancient times, while the large-genome grasshopper maintains active transposition events in the recent past. Evolutionary history studies on TEs suggest that TEs may be subject to different dynamics and resistances in these two species. We found that TE transcript abundance was higher in the large-genome grasshopper and the TE-derived piRNAs abundance was lower than in the small-genome grasshopper. In addition, we found that the piRNA methylase HENMT, which is underexpressed in the large-genome grasshopper, impedes the piRNA silencing to a lower level.
Conclusions
Our study revealed that the abundance of piRNAs is lower in the gigantic genome grasshopper than in the small genome grasshopper. In addition, the key gene HENMT in the piRNA biogenesis pathway (Ping-Pong cycle) in the gigantic genome grasshopper is underexpressed. We hypothesize that low-level piRNA silencing unbalances the original positive correlation between TEs and piRNAs, and triggers TEs to proliferate out of control, which may be one of the reasons for the gigantism of grasshopper genomes.
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Carlson CR, ter Horst AM, Johnston JS, Henry E, Falk BW, Kuo YW. High-quality, chromosome-scale genome assemblies: comparisons of three Diaphorina citri (Asian citrus psyllid) geographic populations. DNA Res 2022; 29:6648404. [PMID: 35866687 PMCID: PMC9338690 DOI: 10.1093/dnares/dsac027] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Indexed: 11/13/2022] Open
Abstract
The Asian citrus psyllid, Diaphorina citri, is the insect vector of the causal agent of huanglongbing (HLB), a devastating bacterial disease of commercial citrus. Presently, few genomic resources exist for D. citri. In this study, we utilized PacBio HiFi and chromatin confirmation contact (Hi-C) sequencing to sequence, assemble, and compare three high-quality, chromosome-scale genome assemblies of D. citri collected from California, Taiwan, and Uruguay. Our assemblies had final sizes of 282.67 Mb (California), 282.89 Mb (Taiwan), and 266.67 Mb (Uruguay) assembled into 13 pseudomolecules—a reduction in assembly size of 41–45% compared with previous assemblies which we validated using flow cytometry. We identified the X chromosome in D. citri and annotated each assembly for repetitive elements, protein-coding genes, transfer RNAs, ribosomal RNAs, piwi-interacting RNA clusters, and endogenous viral elements. Between 19,083 and 20,357 protein-coding genes were predicted. Repetitive DNA accounts for 36.87–38.26% of each assembly. Comparative analyses and mitochondrial haplotype networks suggest that Taiwan and Uruguay D. citri are more closely related, while California D. citri are closely related to Florida D. citri. These high-quality, chromosome-scale assemblies provide new genomic resources to researchers to further D. citri and HLB research.
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Affiliation(s)
- Curtis R Carlson
- Department of Plant Pathology, University of California Davis , Davis, CA 95616, USA
| | - Anneliek M ter Horst
- Department of Plant Pathology, University of California Davis , Davis, CA 95616, USA
| | - J Spencer Johnston
- Department of Entomology, Texas A&M University , College Station, TX 77843, USA
| | - Elizabeth Henry
- Department of Plant Pathology, University of California Davis , Davis, CA 95616, USA
| | - Bryce W Falk
- Department of Plant Pathology, University of California Davis , Davis, CA 95616, USA
| | - Yen-Wen Kuo
- Department of Plant Pathology, University of California Davis , Davis, CA 95616, USA
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Yoth M, Jensen S, Brasset E. The Intricate Evolutionary Balance between Transposable Elements and Their Host: Who Will Kick at Goal and Convert the Next Try? BIOLOGY 2022; 11:710. [PMID: 35625438 PMCID: PMC9138309 DOI: 10.3390/biology11050710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/15/2022] [Accepted: 04/26/2022] [Indexed: 11/29/2022]
Abstract
Transposable elements (TEs) are mobile DNA sequences that can jump from one genomic locus to another and that have colonized the genomes of all living organisms. TE mobilization and accumulation are an important source of genomic innovations that greatly contribute to the host species evolution. To ensure their maintenance and amplification, TE transposition must occur in the germ cell genome. As TE transposition is also a major threat to genome integrity, the outcome of TE mobility in germ cell genomes could be highly dangerous because such mutations are inheritable. Thus, organisms have developed specialized strategies to protect the genome integrity from TE transposition, particularly in germ cells. Such effective TE silencing, together with ongoing mutations and negative selection, should result in the complete elimination of functional TEs from genomes. However, TEs have developed efficient strategies for their maintenance and spreading in populations, particularly by using horizontal transfer to invade the genome of novel species. Here, we discuss how TEs manage to bypass the host's silencing machineries to propagate in its genome and how hosts engage in a fightback against TE invasion and propagation. This shows how TEs and their hosts have been evolving together to achieve a fine balance between transposition and repression.
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Affiliation(s)
| | | | - Emilie Brasset
- iGReD, CNRS, INSERM, Faculté de Médecine, Université Clermont Auvergne, 63000 Clermont-Ferrand, France; (M.Y.); (S.J.)
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