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Srivastav SP, Feschotte C, Clark AG. Rapid evolution of piRNA clusters in the Drosophila melanogaster ovary. Genome Res 2024; 34:711-724. [PMID: 38749655 PMCID: PMC11216404 DOI: 10.1101/gr.278062.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 05/07/2024] [Indexed: 05/28/2024]
Abstract
The piRNA pathway is a highly conserved mechanism to repress transposable element (TE) activity in the animal germline via a specialized class of small RNAs called piwi-interacting RNAs (piRNAs). piRNAs are produced from discrete genomic regions called piRNA clusters (piCs). Although the molecular processes by which piCs function are relatively well understood in Drosophila melanogaster, much less is known about the origin and evolution of piCs in this or any other species. To investigate piC origin and evolution, we use a population genomic approach to compare piC activity and sequence composition across eight geographically distant strains of D. melanogaster with high-quality long-read genome assemblies. We perform annotations of ovary piCs and genome-wide TE content in each strain. Our analysis uncovers extensive variation in piC activity across strains and signatures of rapid birth and death of piCs. Most TEs inferred to be recently active show an enrichment of insertions into old and large piCs, consistent with the previously proposed "trap" model of piC evolution. In contrast, a small subset of active LTR families is enriched for the formation of new piCs, suggesting that these TEs have higher proclivity to form piCs. Thus, our findings uncover processes leading to the origin of piCs. We propose that piC evolution begins with the emergence of piRNAs from individual insertions of a few select TE families prone to seed new piCs that subsequently expand by accretion of insertions from most other TE families during evolution to form larger "trap" clusters. Our study shows that TEs themselves are the major force driving the rapid evolution of piCs.
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Affiliation(s)
- Satyam P Srivastav
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
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2
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He YJ, Lu G, Xu BJ, Mao QZ, Qi YH, Jiao GY, Weng HT, Tian YZ, Huang HJ, Zhang CX, Chen JP, Li JM. Maintenance of persistent transmission of a plant arbovirus in its insect vector mediated by the Toll-Dorsal immune pathway. Proc Natl Acad Sci U S A 2024; 121:e2315982121. [PMID: 38536757 PMCID: PMC10998634 DOI: 10.1073/pnas.2315982121] [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: 09/14/2023] [Accepted: 03/01/2024] [Indexed: 04/08/2024] Open
Abstract
Throughout evolution, arboviruses have developed various strategies to counteract the host's innate immune defenses to maintain persistent transmission. Recent studies have shown that, in addition to bacteria and fungi, the innate Toll-Dorsal immune system also plays an essential role in preventing viral infections in invertebrates. However, whether the classical Toll immune pathway is involved in maintaining the homeostatic process to ensure the persistent and propagative transmission of arboviruses in insect vectors remain unclear. In this study, we revealed that the transcription factor Dorsal is actively involved in the antiviral defense of an insect vector (Laodelphax striatellus) by regulating the target gene, zinc finger protein 708 (LsZN708), which mediates downstream immune-related effectors against infection with the plant virus (Rice stripe virus, RSV). In contrast, an antidefense strategy involving the use of the nonstructural-protein (NS4) to antagonize host antiviral defense through competitive binding to Dorsal from the MSK2 kinase was employed by RSV; this competitive binding inhibited Dorsal phosphorylation and reduced the antiviral response of the host insect. Our study revealed the molecular mechanism through which Toll-Dorsal-ZN708 mediates the maintenance of an arbovirus homeostasis in insect vectors. Specifically, ZN708 is a newly documented zinc finger protein targeted by Dorsal that mediates the downstream antiviral response. This study will contribute to our understanding of the successful transmission and spread of arboviruses in plant or invertebrate hosts.
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Affiliation(s)
- Yu-Juan He
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Gang Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Bo-Jie Xu
- School of Basic Medical Sciences, Health Science Center, Ningbo University, Ningbo315211, China
| | - Qian-Zhuo Mao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Yu-Hua Qi
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Gao-Yang Jiao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Hai-Tao Weng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Yan-Zhen Tian
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Hai-Jian Huang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Chuan-Xi Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Jian-Ping Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
| | - Jun-Min Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo315211, China
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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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4
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Bladen J, Cooper JC, Ridges JT, Guo P, Phadnis N. A new hybrid incompatibility locus between Drosophila melanogaster and Drosophila sechellia. Genetics 2024; 226:iyae001. [PMID: 38184848 PMCID: PMC10917521 DOI: 10.1093/genetics/iyae001] [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: 11/11/2023] [Revised: 11/11/2023] [Accepted: 12/15/2023] [Indexed: 01/09/2024] Open
Abstract
Despite the fundamental importance of hybrid incompatibilities to the process of speciation, there are few cases where the evolution and genetic architecture of hybrid incompatibilities are understood. One of the longest studied hybrid incompatibilities causes F1 hybrid male inviability in crosses between Drosophila melanogaster females and males from the Drosophila simulans clade of species-Drosophila simulans, Drosophila mauritiana, and Drosophila sechellia. Here, we discover dramatic differences in the manifestation of this lethal hybrid incompatibility among the D. simulans clade of species. In particular, F1 hybrid males between D. melanogaster and D. sechellia are resistant to hybrid rescue through RNAi knockdown of an essential hybrid incompatibility gene. To understand the genetic basis of this inter-species difference in hybrid rescue, we developed a triple-hybrid mapping method. Our results show that 2 discrete large effect loci and many dispersed small effect changes across the genome underlie D. sechellia aversion to hybrid rescue. The large effect loci encompass a known incompatibility gene Lethal hybrid rescue (Lhr) and previously unknown factor, Sechellia aversion to hybrid rescue (Satyr). These results show that the genetic architecture of F1 hybrid male inviability is overlapping but not identical in the 3 inter-species crosses. Our results raise questions about whether new hybrid incompatibility genes can integrate into an existing hybrid incompatibility thus increasing in complexity over time, or if the continued evolution of genes can gradually strengthen an existing hybrid incompatibility.
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Affiliation(s)
- Jackson Bladen
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Jacob C Cooper
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Jackson T Ridges
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Ping Guo
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Nitin Phadnis
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
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5
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Estevez-Castro CF, Rodrigues MF, Babarit A, Ferreira FV, de Andrade EG, Marois E, Cogni R, Aguiar ERGR, Marques JT, Olmo RP. Neofunctionalization driven by positive selection led to the retention of the loqs2 gene encoding an Aedes specific dsRNA binding protein. BMC Biol 2024; 22:14. [PMID: 38273313 PMCID: PMC10809485 DOI: 10.1186/s12915-024-01821-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 01/10/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Mosquito borne viruses, such as dengue, Zika, yellow fever and Chikungunya, cause millions of infections every year. These viruses are mostly transmitted by two urban-adapted mosquito species, Aedes aegypti and Aedes albopictus. Although mechanistic understanding remains largely unknown, Aedes mosquitoes may have unique adaptations that lower the impact of viral infection. Recently, we reported the identification of an Aedes specific double-stranded RNA binding protein (dsRBP), named Loqs2, that is involved in the control of infection by dengue and Zika viruses in mosquitoes. Preliminary analyses suggested that the loqs2 gene is a paralog of loquacious (loqs) and r2d2, two co-factors of the RNA interference (RNAi) pathway, a major antiviral mechanism in insects. RESULTS Here we analyzed the origin and evolution of loqs2. Our data suggest that loqs2 originated from two independent duplications of the first double-stranded RNA binding domain of loqs that occurred before the origin of the Aedes Stegomyia subgenus, around 31 million years ago. We show that the loqs2 gene is evolving under relaxed purifying selection at a faster pace than loqs, with evidence of neofunctionalization driven by positive selection. Accordingly, we observed that Loqs2 is localized mainly in the nucleus, different from R2D2 and both isoforms of Loqs that are cytoplasmic. In contrast to r2d2 and loqs, loqs2 expression is stage- and tissue-specific, restricted mostly to reproductive tissues in adult Ae. aegypti and Ae. albopictus. Transgenic mosquitoes engineered to express loqs2 ubiquitously undergo developmental arrest at larval stages that correlates with massive dysregulation of gene expression without major effects on microRNAs or other endogenous small RNAs, classically associated with RNA interference. CONCLUSIONS Our results uncover the peculiar origin and neofunctionalization of loqs2 driven by positive selection. This study shows an example of unique adaptations in Aedes mosquitoes that could ultimately help explain their effectiveness as virus vectors.
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Affiliation(s)
- Carlos F Estevez-Castro
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France
| | - Murillo F Rodrigues
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403-5289, USA
| | - Antinéa Babarit
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France
| | - Flávia V Ferreira
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Elisa G de Andrade
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France
| | - Eric Marois
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France
| | - Rodrigo Cogni
- Department of Ecology, Institute of Biosciences, University of São Paulo, São Paulo, 05508-090, Brazil
| | - Eric R G R Aguiar
- Department of Biological Science, Center of Biotechnology and Genetics, State University of Santa Cruz, Ilhéus, 45662-900, Brazil
| | - João T Marques
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil.
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France.
| | - Roenick P Olmo
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil.
- CNRS UPR9022, Inserm U1257, Université de Strasbourg, 67084, Strasbourg, France.
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Pan J, Qiu Q, Kumar D, Xu J, Tong X, Shen Z, Zhu M, Hu X, Gong C. Interaction between Bombyx mori Cytoplasmic Polyhedrosis Virus NSP8 and BmAgo2 Inhibits RNA Interference and Enhances Virus Proliferation. Microbiol Spectr 2023; 11:e0493822. [PMID: 37341621 PMCID: PMC10434170 DOI: 10.1128/spectrum.04938-22] [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: 12/01/2022] [Accepted: 05/28/2023] [Indexed: 06/22/2023] Open
Abstract
Some insect viruses encode suppressors of RNA interference (RNAi) to counteract the antiviral RNAi pathway. However, it is unknown whether Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) encodes an RNAi suppressor. In this study, the presence of viral small interfering RNA (vsiRNA) in BmN cells infected with BmCPV was confirmed by small RNA sequencing. The Dual-Luciferase reporter test demonstrated that BmCPV infection may prevent firefly luciferase (Luc) gene silencing caused by particular short RNA. It was also established that the inhibition relied on the nonstructural protein NSP8, which suggests that NSP8 was a possible RNAi suppressor. In cultured BmN cells, the expressions of viral structural protein 1 (vp1) and NSP9 were triggered by overexpression of nsp8, suggesting that BmCPV proliferation was enhanced by NSP8. A pulldown assay was conducted with BmCPV genomic double-stranded RNA (dsRNA) labeled with biotin. The mass spectral detection of NSP8 in the pulldown complex suggests that NSP8 is capable of direct binding to BmCPV genomic dsRNA. The colocalization of NSP8 and B. mori Argonaute 2 (BmAgo2) was detected by an immunofluorescence assay, leading to the hypothesis that NSP8 interacts with BmAgo2. Coimmunoprecipitation further supported the present investigation. Moreover, vasa intronic protein, a component of RNA-induced silencing complex (RISC), could be detected in the coprecipitation complex of NSP8 by mass spectrum analysis. NSP8 and the mRNA decapping protein (Dcp2) were also discovered to colocalize to processing bodies (P bodies) for RNAi-mediated gene silencing in Saccharomyces cerevisiae. These findings revealed that by interacting with BmAgo2 and suppressing RNAi, NSP8 promoted BmCPV growth. IMPORTANCE It has been reported that the RNAi pathway is inhibited by binding RNAi suppressors encoded by some insect-specific viruses belonging to Dicistroviridae, Nodaviridae, or Birnaviridae to dsRNAs to protect dsRNAs from being cut by Dicer-2. However, it is unknown whether BmCPV, belonging to Spinareoviridae, encodes an RNAi suppressor. In this study, we found that nonstructural protein NSP8 encoded by BmCPV inhibits small interfering RNA (siRNA)-induced RNAi and that NSP8, as an RNAi suppressor, can bind to viral dsRNAs and interact with BmAgo2. Moreover, vasa intronic protein, a component of RISC, was found to interact with NSP8. Heterologously expressed NSP8 and Dcp2 were colocalized to P bodies in yeast. These results indicated that NSP8 promoted BmCPV proliferation by binding itself to BmCPV genomic dsRNAs and interacting with BmAgo2 through suppression of siRNA-induced RNAi. Our findings deepen our understanding of the game between BmCPV and silkworm in regulating viral infection.
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Affiliation(s)
- Jun Pan
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Qunnan Qiu
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Dhiraj Kumar
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China
- Department of Zoology, Hansraj College, University of Delhi, Delhi, India
| | - Jian Xu
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Xinyu Tong
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Zeen Shen
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Min Zhu
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Xiaolong Hu
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China
- Agricultural Biotechnology Research Institute, Agricultural Biotechnology and Ecological Research Institute, Soochow University, Suzhou, China
| | - Chengliang Gong
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu, China
- Agricultural Biotechnology Research Institute, Agricultural Biotechnology and Ecological Research Institute, Soochow University, Suzhou, China
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7
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Palmer WH, Norman PJ. The impact of HLA polymorphism on herpesvirus infection and disease. Immunogenetics 2023; 75:231-247. [PMID: 36595060 PMCID: PMC10205880 DOI: 10.1007/s00251-022-01288-z] [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: 08/18/2022] [Accepted: 11/24/2022] [Indexed: 01/04/2023]
Abstract
Human Leukocyte Antigens (HLA) are cell surface molecules, central in coordinating innate and adaptive immune responses, that are targets of strong diversifying natural selection by pathogens. Of these pathogens, human herpesviruses have a uniquely ancient relationship with our species, where coevolution likely has reciprocating impact on HLA and viral genomic diversity. Consistent with this notion, genetic variation at multiple HLA loci is strongly associated with modulating immunity to herpesvirus infection. Here, we synthesize published genetic associations of HLA with herpesvirus infection and disease, both from case/control and genome-wide association studies. We analyze genetic associations across the eight human herpesviruses and identify HLA alleles that are associated with diverse herpesvirus-related phenotypes. We find that whereas most HLA genetic associations are virus- or disease-specific, HLA-A*01 and HLA-A*02 allotypes may be more generally associated with immune susceptibility and control, respectively, across multiple herpesviruses. Connecting genetic association data with functional corroboration, we discuss mechanisms by which diverse HLA and cognate receptor allotypes direct variable immune responses during herpesvirus infection and pathogenesis. Together, this review examines the complexity of HLA-herpesvirus interactions driven by differential T cell and Natural Killer cell immune responses.
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Affiliation(s)
- William H. Palmer
- Department of Biomedical Informatics, University of Colorado, Aurora, CO USA
- Department of Immunology & Microbiology, University of Colorado, Aurora, CO USA
| | - Paul J. Norman
- Department of Biomedical Informatics, University of Colorado, Aurora, CO USA
- Department of Immunology & Microbiology, University of Colorado, Aurora, CO USA
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8
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Li Y, Kim EJ, Voshall A, Moriyama EN, Cerutti H. Small RNAs >26 nt in length associate with AGO1 and are upregulated by nutrient deprivation in the alga Chlamydomonas. THE PLANT CELL 2023; 35:1868-1887. [PMID: 36945744 DOI: 10.1093/plcell/koad093] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/14/2023] [Accepted: 02/17/2023] [Indexed: 05/30/2023]
Abstract
Small RNAs (sRNAs) associate with ARGONAUTE (AGO) proteins forming effector complexes with key roles in gene regulation and defense responses against molecular parasites. In multicellular eukaryotes, extensive duplication and diversification of RNA interference (RNAi) components have resulted in intricate pathways for epigenetic control of gene expression. The unicellular alga Chlamydomonas reinhardtii also has a complex RNAi machinery, including 3 AGOs and 3 DICER-like proteins. However, little is known about the biogenesis and function of most endogenous sRNAs. We demonstrate here that Chlamydomonas contains uncommonly long (>26 nt) sRNAs that associate preferentially with AGO1. Somewhat reminiscent of animal PIWI-interacting RNAs, these >26 nt sRNAs are derived from moderately repetitive genomic clusters and their biogenesis is DICER-independent. Interestingly, the sequences generating these >26-nt sRNAs have been conserved and amplified in several Chlamydomonas species. Moreover, expression of these longer sRNAs increases substantially under nitrogen or sulfur deprivation, concurrently with the downregulation of predicted target transcripts. We hypothesize that the transposon-like sequences from which >26-nt sRNAs are produced might have been ancestrally targeted for silencing by the RNAi machinery but, during evolution, certain sRNAs might have fortuitously acquired endogenous target genes and become integrated into gene regulatory networks.
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Affiliation(s)
- Yingshan Li
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska-Lincoln, Nebraska-Lincoln, NE 68588-0666, USA
| | - Eun-Jeong Kim
- Department of Life Science, Chung-Ang University, Seoul 06974, Korea
| | - Adam Voshall
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska-Lincoln, Nebraska-Lincoln, NE 68588-0666, USA
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Etsuko N Moriyama
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska-Lincoln, Nebraska-Lincoln, NE 68588-0666, USA
| | - Heriberto Cerutti
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska-Lincoln, Nebraska-Lincoln, NE 68588-0666, USA
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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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10
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Origins and diversification of animal innate immune responses against viral infections. Nat Ecol Evol 2023; 7:182-193. [PMID: 36635343 DOI: 10.1038/s41559-022-01951-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 11/11/2022] [Indexed: 01/14/2023]
Abstract
Immune systems are of pivotal importance to any living organism on Earth, as they protect the organism against deleterious effects of viral infections. Though the current knowledge about these systems is still biased towards the immune response in vertebrates, some studies have focused on the identification and characterization of components of invertebrate antiviral immune systems. Two classic model organisms, the insect Drosophila melanogaster and the nematode Caenorhabditis elegans, were instrumental in the discovery of several important components of the innate immune system, such as the Toll-like receptors and the RNA interference pathway. However, these two model organisms provide only a limited view of the evolutionary history of the immune system, as they both are ecdysozoan protostomes. Recent functional studies in non-classic models such as unicellular holozoans (for example, choanoflagellates), lophotrochozoans (for example, oysters) and cnidarians (for example, sea anemones) have added crucial information for understanding the evolution of antiviral systems, as they revealed unexpected ancestral complexity. This Review aims to summarize this information and present the ancestral nature of the antiviral immune response in animals. We also discuss lineage-specific adaptations and future perspectives for the comparative study of the innate immune system that are essential for understanding its evolution.
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11
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Palmer WH, Telford M, Navarro A, Santpere G, Norman PJ. Human herpesvirus diversity is altered in HLA class I binding peptides. Proc Natl Acad Sci U S A 2022; 119:e2123248119. [PMID: 35486690 PMCID: PMC9170163 DOI: 10.1073/pnas.2123248119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 03/30/2022] [Indexed: 11/18/2022] Open
Abstract
Herpesviruses are ubiquitous, genetically diverse DNA viruses, with long-term presence in humans associated with infrequent but significant pathology. Human leukocyte antigen (HLA) class I presents intracellularly derived peptide fragments from infected tissue cells to CD8+ T and natural killer cells, thereby directing antiviral immunity. Allotypes of highly polymorphic HLA class I are distinguished by their peptide binding repertoires. Because this HLA class I variation is a major determinant of herpesvirus disease, we examined if sequence diversity of virus proteins reflects evasion of HLA presentation. Using population genomic data from Epstein–Barr virus (EBV), human cytomegalovirus (HCMV), and Varicella–Zoster virus, we tested whether diversity differed between the regions of herpesvirus proteins that can be recognized, or not, by HLA class I. Herpesviruses exhibit lytic and latent infection stages, with the latter better enabling immune evasion. Whereas HLA binding peptides of lytic proteins are conserved, we found that EBV and HCMV proteins expressed during latency have increased peptide sequence diversity. Similarly, latent, but not lytic, herpesvirus proteins have greater population structure in HLA binding than nonbinding peptides. Finally, we found patterns consistent with EBV adaption to the local HLA environment, with less efficient recognition of EBV isolates by high-frequency HLA class I allotypes. Here, the frequency of CD8+ T cell epitopes inversely correlated with the frequency of HLA class I recognition. Previous analyses have shown that pathogen-mediated natural selection maintains exceptional polymorphism in HLA residues that determine peptide recognition. Here, we show that HLA class I peptide recognition impacts diversity of globally widespread pathogens.
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Affiliation(s)
- William H. Palmer
- Division of Biomedical Informatics and Personalized Medicine, University of Colorado, Aurora, CO 80045
- Department of Immunology and Microbiology, University of Colorado, Aurora, CO 80045
| | - Marco Telford
- Neurogenomics Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM), Department of Medicine and Life Sciences (MELIS), Universitat Pompeu Fabra, 08003 Barcelona, Catalonia, Spain
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510
| | - Arcadi Navarro
- Institut de Biologia Evolutiva (Universitat Pompeu Fabra - Consejo Superior de Investigaciones Científicas), Department of Medicine and Life Sciences (MELIS), Barcelona Biomedical Research Park, Universitat Pompeu Fabra, 08003 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats and Universitat Pompeu Fabra, 08010 Barcelona, Spain
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
- Barcelona Beta Brain Research Center, Pasqual Maragall Foundation, 08005 Barcelona, Spain
| | - Gabriel Santpere
- Neurogenomics Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM), Department of Medicine and Life Sciences (MELIS), Universitat Pompeu Fabra, 08003 Barcelona, Catalonia, Spain
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510
| | - Paul J. Norman
- Division of Biomedical Informatics and Personalized Medicine, University of Colorado, Aurora, CO 80045
- Department of Immunology and Microbiology, University of Colorado, Aurora, CO 80045
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12
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Fields PD, McTaggart S, Reisser CMO, Haag C, Palmer WH, Little TJ, Ebert D, Obbard DJ. Population-genomic analysis identifies a low rate of global adaptive fixation in the proteins of the cyclical parthenogen Daphnia magna. Mol Biol Evol 2022; 39:6542319. [PMID: 35244177 PMCID: PMC8963301 DOI: 10.1093/molbev/msac048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Daphnia are well-established ecological and evolutionary models, and the interaction between D. magna and its microparasites is widely considered a paragon of the host-parasite coevolutionary process. Like other well-studied arthropods such as Drosophila melanogaster and Anopheles gambiae, D. magna is a small, widespread, and abundant species that is therefore expected to display a large long-term population size and high rates of adaptive protein evolution. However, unlike these other species, D. magna is cyclically asexual and lives in a highly structured environment (ponds and lakes) with moderate levels of dispersal, both of which are predicted to impact upon long-term effective population size and adaptive protein evolution. To investigate patterns of adaptive protein fixation, we produced the complete coding genomes of 36 D. magna clones sampled from across the European range (Western Palaearctic), along with draft sequences for the close relatives D. similis and D. lumholtzi, used as outgroups. We analyzed genome-wide patterns of adaptive fixation, with a particular focus on genes that have an a priori expectation of high rates, such as those likely to mediate immune responses, RNA interference against viruses and transposable elements, and those with a strongly male-biased expression pattern. We find that, as expected, D. magna displays high levels of diversity and that this is highly structured among populations. However, compared with Drosophila, we find that D. magna proteins appear to have a high proportion of weakly deleterious variants and do not show evidence of pervasive adaptive fixation across its entire range. This is true of the genome as a whole, and also of putative ‘arms race’ genes that often show elevated levels of adaptive substitution in other species. In addition to the likely impact of extensive, and previously documented, local adaptation, we speculate that these findings may reflect reduced efficacy of selection associated with cyclical asexual reproduction.
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Affiliation(s)
- Peter D Fields
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, Basel, CH-4051, Switzerland
| | - Seanna McTaggart
- Institute of Evolutionary Biology; School of Biological Sciences University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom
| | - Céline M O Reisser
- Centre d'Ecologie Fonctionnelle et Evolutive CEFE UMR 5175, Univ Montpellier, CNRS, EPHE, IRD, Univ Paul Valéry Montpellier 3, campus CNRS, 1919, route de Mende, 34293 Montpellier Cedex 5, France.,MARBEC, Univ Montpellier, CNRS, IFREMER, IRD, Montpellier, France
| | - Christoph Haag
- Centre d'Ecologie Fonctionnelle et Evolutive CEFE UMR 5175, Univ Montpellier, CNRS, EPHE, IRD, Univ Paul Valéry Montpellier 3, campus CNRS, 1919, route de Mende, 34293 Montpellier Cedex 5, France
| | - William H Palmer
- Institute of Evolutionary Biology; School of Biological Sciences University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom
| | - Tom J Little
- Institute of Evolutionary Biology; School of Biological Sciences University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom
| | - Dieter Ebert
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, Basel, CH-4051, Switzerland
| | - Darren J Obbard
- Institute of Evolutionary Biology; School of Biological Sciences University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom
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13
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Almeida MV, Vernaz G, Putman AL, Miska EA. Taming transposable elements in vertebrates: from epigenetic silencing to domestication. Trends Genet 2022; 38:529-553. [DOI: 10.1016/j.tig.2022.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 02/14/2022] [Accepted: 02/15/2022] [Indexed: 12/20/2022]
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14
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Khanal S, Zancanela BS, Peter JO, Flynt AS. The Small RNA Universe of Capitella teleta. Front Mol Biosci 2022; 9:802814. [PMID: 35281272 PMCID: PMC8915122 DOI: 10.3389/fmolb.2022.802814] [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: 10/27/2021] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
RNAi is an evolutionarily fluid mechanism with dramatically different activities across animal phyla. One major group where there has been little investigation is annelid worms. Here, the small RNAs of the polychaete developmental model Capitella teleta are profiled across development. As is seen with nearly all animals, nearly 200 microRNAs were found with 58 high-confidence novel species. Greater miRNA diversity was associated with later stages consistent with differentiation of tissues. Outside miRNA, a distinct composition of other small RNA pathways was found. Unlike many invertebrates, an endogenous siRNA pathway was not observed, indicating pathway loss relative to basal planarians. No processively generated siRNA-class RNAs could be found arising from dsRNA precursors. This has a significant impact on RNAi technology development for this group of animals. Unlike the apparent absence of siRNAs, a significant population of piRNAs was observed. For many piRNAs, phasing and ping-pong biogenesis pathways were identified. Interestingly, piRNAs were found to be highly expressed during early development, suggesting a potential role in regulation in metamorphosis. Critically, the configuration of RNAi factors in C. teleta is found in other annelids and mollusks, suggesting that similar biology is likely to be present in the wider clade. This study is the first in providing comprehensive analysis of small RNAs in annelids.
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15
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Sweeny AR, Corripio-Miyar Y, Bal X, Hayward AD, Pilkington JG, McNeilly TN, Nussey DH, Kenyon F. Longitudinal dynamics of co-infecting gastrointestinal parasites in a wild sheep population. Parasitology 2022; 149:1-12. [PMID: 35264257 PMCID: PMC10090596 DOI: 10.1017/s0031182021001980] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/09/2021] [Accepted: 11/01/2021] [Indexed: 11/07/2022]
Abstract
Within-year variation in infection is a ubiquitous feature of natural populations, but is determined by a complex interplay of environmental, parasitological and host factors. At the same time, co-infection is the norm in the wild. Longitudinal dynamics of co-infecting parasites may therefore be further complicated by covariation across multiple parasites. Here, we used fecal parasite egg and oocyst counts collected repeatedly from individually marked wild Soay sheep to investigate seasonal dynamics of six gastrointestinal parasite groups. Prevalence and abundance tended to be higher in spring and summer, and abundance was higher in lambs compared to adults. We found that within-year variation in highly prevalent strongyle nematode counts was dependent on adult reproductive status, where reproductive ewes had distinct dynamics compared to males and barren ewes. For similarly prevalent coccidia we found an overall peak in oocyst counts in spring but no differences among males, barren and pregnant ewes. Using multivariate mixed-effects models, we further show that apparent positive correlation between strongyle and coccidia counts was driven by short-term within-individual changes in both counts rather than long-term among-individual covariation. Overall, these results demonstrate that seasonality varies across demographic and parasite groups and highlight the value of investigating co-infection dynamics over time.
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Affiliation(s)
- Amy R. Sweeny
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | | | - Xavier Bal
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | | | - Jill G. Pilkington
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | | | - Daniel H. Nussey
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
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16
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Hill T, Unckless RL, Perlmutter JI. Positive Selection and Horizontal Gene Transfer in the Genome of a Male-Killing Wolbachia. Mol Biol Evol 2022; 39:msab303. [PMID: 34662426 PMCID: PMC8763111 DOI: 10.1093/molbev/msab303] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Wolbachia are a genus of widespread bacterial endosymbionts in which some strains can hijack or manipulate arthropod host reproduction. Male killing is one such manipulation in which these maternally transmitted bacteria benefit surviving daughters in part by removing competition with the sons for scarce resources. Despite previous findings of interesting genome features of microbial sex ratio distorters, the population genomics of male-killers remain largely uncharacterized. Here, we uncover several unique features of the genome and population genomics of four Arizonan populations of a male-killing Wolbachia strain, wInn, that infects mushroom-feeding Drosophila innubila. We first compared the wInn genome with other closely related Wolbachia genomes of Drosophila hosts in terms of genome content and confirm that the wInn genome is largely similar in overall gene content to the wMel strain infecting D. melanogaster. However, it also contains many unique genes and repetitive genetic elements that indicate lateral gene transfers between wInn and non-Drosophila eukaryotes. We also find that, in line with literature precedent, genes in the Wolbachia prophage and Octomom regions are under positive selection. Of all the genes under positive selection, many also show evidence of recent horizontal transfer among Wolbachia symbiont genomes. These dynamics of selection and horizontal gene transfer across the genomes of several Wolbachia strains and diverse host species may be important underlying factors in Wolbachia's success as a male-killer of divergent host species.
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Affiliation(s)
- Tom Hill
- NIAID Collaborative Bioinformatics Resource, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Robert L Unckless
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, USA
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17
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Tsouris A, Schacherer J, Ishchuk OP. RNA Interference (RNAi ) as a Tool for High-Resolution Phenotypic Screening of the Pathogenic Yeast Candida glabrata. Methods Mol Biol 2022; 2477:313-330. [PMID: 35524125 DOI: 10.1007/978-1-0716-2257-5_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
After its discovery RNA interference (RNAi) has become a powerful tool to study gene functions in different organisms. RNAi has been applied at genome-wide scale and can be nowadays performed using high-throughput automated systems (robotics). The simplest RNAi process requires the expression of two genes (Dicer and Argonaute) to function. To initiate the silencing, constructs generating either double-strand RNA or antisense RNA are required. Recently, RNAi was reconstituted by expressing Saccharomyces castellii genes in the human pathogenic yeast Candida glabrata and was used to identify new genes related to the virulence of this pathogen.In this chapter, we describe a method to make the C. glabrata pathogenic yeast competent for RNAi and to use RNA silencing as a tool for low- or high-resolution phenotypic screening in this species.
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Affiliation(s)
- Andreas Tsouris
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - Joseph Schacherer
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
- Institut Universitaire de France (IUF), Paris, France
| | - Olena P Ishchuk
- Department of Biology and Biological Engineering, Systems and Synthetic Biology, Chalmers University of Technology, Gothenburg, Sweden.
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18
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Peng J, Svetec N, Zhao L. Intermolecular interactions drive protein adaptive and co-adaptive evolution at both species and population levels. Mol Biol Evol 2021; 39:6456312. [PMID: 34878126 PMCID: PMC8789070 DOI: 10.1093/molbev/msab350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Proteins are the building blocks for almost all the functions in cells. Understanding the molecular evolution of proteins and the forces that shape protein evolution is essential in understanding the basis of function and evolution. Previous studies have shown that adaptation frequently occurs at the protein surface, such as in genes involved in host–pathogen interactions. However, it remains unclear whether adaptive sites are distributed randomly or at regions associated with particular structural or functional characteristics across the genome, since many proteins lack structural or functional annotations. Here, we seek to tackle this question by combining large-scale bioinformatic prediction, structural analysis, phylogenetic inference, and population genomic analysis of Drosophila protein-coding genes. We found that protein sequence adaptation is more relevant to function-related rather than structure-related properties. Interestingly, intermolecular interactions contribute significantly to protein adaptation. We further showed that intermolecular interactions, such as physical interactions, may play a role in the coadaptation of fast-adaptive proteins. We found that strongly differentiated amino acids across geographic regions in protein-coding genes are mostly adaptive, which may contribute to the long-term adaptive evolution. This strongly indicates that a number of adaptive sites tend to be repeatedly mutated and selected throughout evolution in the past, present, and maybe future. Our results highlight the important roles of intermolecular interactions and coadaptation in the adaptive evolution of proteins both at the species and population levels.
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Affiliation(s)
- Junhui Peng
- Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, NY, 10065, USA
| | - Nicolas Svetec
- Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, NY, 10065, USA
| | - Li Zhao
- Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, NY, 10065, USA
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19
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McMenamin AJ, Brutscher LM, Daughenbaugh KF, Flenniken ML. The Honey Bee Gene Bee Antiviral Protein-1 Is a Taxonomically Restricted Antiviral Immune Gene. FRONTIERS IN INSECT SCIENCE 2021; 1:749781. [PMID: 38468887 PMCID: PMC10926557 DOI: 10.3389/finsc.2021.749781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/20/2021] [Indexed: 03/13/2024]
Abstract
Insects have evolved a wide range of strategies to combat invading pathogens, including viruses. Genes that encode proteins involved in immune responses often evolve under positive selection due to their co-evolution with pathogens. Insect antiviral defense includes the RNA interference (RNAi) mechanism, which is triggered by recognition of non-self, virally produced, double-stranded RNAs. Indeed, insect RNAi genes (e.g., dicer and argonaute-2) are under high selective pressure. Honey bees (Apis mellifera) are eusocial insects that respond to viral infections via both sequence specific RNAi and a non-sequence specific dsRNA triggered pathway, which is less well-characterized. A transcriptome-level study of virus-infected and/or dsRNA-treated honey bees revealed increased expression of a novel antiviral gene, GenBank: MF116383, and in vivo experiments confirmed its antiviral function. Due to in silico annotation and sequence similarity, MF116383 was originally annotated as a probable cyclin-dependent serine/threonine-protein kinase. In this study, we confirmed that MF116383 limits virus infection, and carried out further bioinformatic and phylogenetic analyses to better characterize this important gene-which we renamed bee antiviral protein-1 (bap1). Phylogenetic analysis revealed that bap1 is taxonomically restricted to Hymenoptera and Blatella germanica (the German cockroach) and that the majority of bap1 amino acids are evolving under neutral selection. This is in-line with the results from structural prediction tools that indicate Bap1 is a highly disordered protein, which likely has relaxed structural constraints. Assessment of honey bee gene expression using a weighted gene correlation network analysis revealed that bap1 expression was highly correlated with several immune genes-most notably argonaute-2. The coexpression of bap1 and argonaute-2 was confirmed in an independent dataset that accounted for the effect of virus abundance. Together, these data demonstrate that bap1 is a taxonomically restricted, rapidly evolving antiviral immune gene. Future work will determine the role of bap1 in limiting replication of other viruses and examine the signal cascade responsible for regulating the expression of bap1 and other honey bee antiviral defense genes, including coexpressed ago-2, and determine whether the virus limiting function of bap1 acts in parallel or in tandem with RNAi.
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Affiliation(s)
- Alexander J. McMenamin
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, United States
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
- Pollinator Health Center, Montana State University, Bozeman, MT, United States
| | - Laura M. Brutscher
- Pollinator Health Center, Montana State University, Bozeman, MT, United States
| | - Katie F. Daughenbaugh
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, United States
- Pollinator Health Center, Montana State University, Bozeman, MT, United States
| | - Michelle L. Flenniken
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, United States
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
- Pollinator Health Center, Montana State University, Bozeman, MT, United States
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20
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Roy M, Viginier B, Mayeux CA, Ratinier M, Fablet M. Infections by Transovarially Transmitted DMelSV in Drosophila Have No Impact on Ovarian Transposable Element Transcripts but Increase Their Amounts in the Soma. Genome Biol Evol 2021; 13:evab207. [PMID: 34498066 PMCID: PMC8459167 DOI: 10.1093/gbe/evab207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2021] [Indexed: 12/21/2022] Open
Abstract
Transposable elements (TEs) are genomic parasites, which activity is tightly controlled in germline cells. Using Sindbis virus, it was recently demonstrated that viral infections affect TE transcript amounts in somatic tissues. However, the strongest evolutionary impacts are expected in gonads, because that is where the genomes of the next generations lie. Here, we investigated this aspect using the Drosophila melanogaster Sigma virus. It is particularly relevant in the genome/TE interaction given its tropism to ovaries, which is the organ displaying the more sophisticated TE control pathways. Our results in Drosophila simulans flies allowed us to confirm the existence of a strong homeostasis of the TE transcriptome in ovaries upon infection, which, however, rely on TE-derived small RNA modulations. In addition, we performed a meta-analysis of RNA-seq data and propose that the immune pathway that is triggered upon viral infection determines the direction of TE transcript modulation in somatic tissues.
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Affiliation(s)
- Marlène Roy
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Villeurbanne, France
- EPHE, PSL Research University, INRA, Université de Lyon, Université Claude Bernard Lyon1, UMR754, IVPC, Lyon, France
| | - Barbara Viginier
- EPHE, PSL Research University, INRA, Université de Lyon, Université Claude Bernard Lyon1, UMR754, IVPC, Lyon, France
| | - Camille A Mayeux
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Villeurbanne, France
| | - Maxime Ratinier
- EPHE, PSL Research University, INRA, Université de Lyon, Université Claude Bernard Lyon1, UMR754, IVPC, Lyon, France
| | - Marie Fablet
- Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Villeurbanne, France
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21
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Kelleher ES. Protein-Protein Interactions Shape Genomic Autoimmunity in the Adaptively Evolving Rhino-Deadlock-Cutoff Complex. Genome Biol Evol 2021; 13:6296839. [PMID: 34115120 PMCID: PMC8290110 DOI: 10.1093/gbe/evab132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2021] [Indexed: 12/23/2022] Open
Abstract
The Piwi-interacting RNA (piRNA) pathway is a genomic defense system that controls the movement of transposable elements (TEs) through transcriptional and post-transcriptional silencing. Although TE defense is critical to ensuring germline genome integrity, it is equally critical that the piRNA pathway avoids autoimmunity in the form of silencing host genes. Ongoing cycles of selection for expanded control of invading TEs, followed by selection for increased specificity to reduce impacts on host genes, are proposed to explain the frequent signatures of adaptive evolution among piRNA pathway proteins. However, empirical tests of this model remain limited, particularly with regards to selection against genomic autoimmunity. I examined three adaptively evolving piRNA proteins, Rhino, Deadlock, and Cutoff, for evidence of interspecific divergence in autoimmunity between Drosophila melanogaster and Drosophila simulans. I tested a key prediction of the autoimmunity hypothesis that foreign heterospecific piRNA proteins will exhibit enhanced autoimmunity, due to the absence of historical selection against off-target effects. Consistent with this prediction, full-length D. simulans Cutoff, as well as the D. simulans hinge and chromo domains of Rhino, exhibit expanded regulation of D. melanogaster genes. I further demonstrate that this autoimmunity is dependent on known incompatibilities between D. simulans proteins or domains and their interacting partners in D. melanogaster. My observations reveal that the same protein–protein interaction domains that are interfaces of adaptive evolution in Rhino and Cutoff also determine their potential for autoimmunity.
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Rosendo Machado S, van der Most T, Miesen P. Genetic determinants of antiviral immunity in dipteran insects - Compiling the experimental evidence. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 119:104010. [PMID: 33476667 DOI: 10.1016/j.dci.2021.104010] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 06/12/2023]
Abstract
The genetic basis of antiviral immunity in dipteran insects is extensively studied in Drosophila melanogaster and advanced technologies for genetic manipulation allow a better characterization of immune responses also in non-model insect species. Especially, immunity in vector mosquitoes is recently in the spotlight, due to the medical impact that these insects have by transmitting viruses and other pathogens. Here, we review the current state of experimental evidence that supports antiviral functions for immune genes acting in different cellular pathways. We discuss the well-characterized RNA interference mechanism along with the less well-defined JAK-STAT, Toll, and IMD signaling pathways. Furthermore, we highlight the initial evidence for antiviral activity observed for the autophagy pathway, transcriptional pausing, as well as piRNA production from endogenous viral elements. We focus our review on studies from Drosophila and mosquito species from the lineages Aedes, Culex, and Anopheles, which contain major vector species responsible for virus transmission.
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Affiliation(s)
- Samara Rosendo Machado
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, the Netherlands
| | - Tom van der Most
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, the Netherlands
| | - Pascal Miesen
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, the Netherlands.
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Miller WB, Enguita FJ, Leitão AL. Non-Random Genome Editing and Natural Cellular Engineering in Cognition-Based Evolution. Cells 2021; 10:1125. [PMID: 34066959 PMCID: PMC8148535 DOI: 10.3390/cells10051125] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 04/27/2021] [Accepted: 05/05/2021] [Indexed: 12/16/2022] Open
Abstract
Neo-Darwinism presumes that biological variation is a product of random genetic replication errors and natural selection. Cognition-Based Evolution (CBE) asserts a comprehensive alternative approach to phenotypic variation and the generation of biological novelty. In CBE, evolutionary variation is the product of natural cellular engineering that permits purposive genetic adjustments as cellular problem-solving. CBE upholds that the cornerstone of biology is the intelligent measuring cell. Since all biological information that is available to cells is ambiguous, multicellularity arises from the cellular requirement to maximize the validity of available environmental information. This is best accomplished through collective measurement purposed towards maintaining and optimizing individual cellular states of homeorhesis as dynamic flux that sustains cellular equipoise. The collective action of the multicellular measurement and assessment of information and its collaborative communication is natural cellular engineering. Its yield is linked cellular ecologies and mutualized niche constructions that comprise biofilms and holobionts. In this context, biological variation is the product of collective differential assessment of ambiguous environmental cues by networking intelligent cells. Such concerted action is enabled by non-random natural genomic editing in response to epigenetic impacts and environmental stresses. Random genetic activity can be either constrained or deployed as a 'harnessing of stochasticity'. Therefore, genes are cellular tools. Selection filters cellular solutions to environmental stresses to assure continuous cellular-organismal-environmental complementarity. Since all multicellular eukaryotes are holobionts as vast assemblages of participants of each of the three cellular domains (Prokaryota, Archaea, Eukaryota) and the virome, multicellular variation is necessarily a product of co-engineering among them.
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Affiliation(s)
| | - Francisco J. Enguita
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal;
| | - Ana Lúcia Leitão
- MEtRICs, Department of Sciences and Technology of Biomass, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal;
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Goettsch W, Beerenwinkel N, Deng L, Dölken L, Dutilh BE, Erhard F, Kaderali L, von Kleist M, Marquet R, Matthijnssens J, McCallin S, McMahon D, Rattei T, Van Rij RP, Robertson DL, Schwemmle M, Stern-Ginossar N, Marz M. ITN-VIROINF: Understanding (Harmful) Virus-Host Interactions by Linking Virology and Bioinformatics. Viruses 2021; 13:v13050766. [PMID: 33925452 PMCID: PMC8145447 DOI: 10.3390/v13050766] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/15/2021] [Accepted: 04/22/2021] [Indexed: 11/16/2022] Open
Abstract
Many recent studies highlight the fundamental importance of viruses. Besides their important role as human and animal pathogens, their beneficial, commensal or harmful functions are poorly understood. By developing and applying tailored bioinformatical tools in important virological models, the Marie Skłodowska-Curie Initiative International Training Network VIROINF will provide a better understanding of viruses and the interaction with their hosts. This will open the door to validate methods of improving viral growth, morphogenesis and development, as well as to control strategies against unwanted microorganisms. The key feature of VIROINF is its interdisciplinary nature, which brings together virologists and bioinformaticians to achieve common goals.
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Affiliation(s)
- Winfried Goettsch
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, 07743 Jena, Germany;
| | - Niko Beerenwinkel
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland;
| | - Li Deng
- Institute of Virology, Helmholtz Centre Munich and Technical University Munich, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany;
| | - Lars Dölken
- Institut für Virologie und Immunbiologie, Julius-Maximilians-Universität Würzburg, 97078 Würzburg, Germany; (L.D.); (F.E.)
| | - Bas E. Dutilh
- Theoretical Biology and Bioinformatics, Science for Life, Utrecht University, Hugo R. Kruytgebouw, Padualaan 8, 3584 CH Utrecht, The Netherlands;
| | - Florian Erhard
- Institut für Virologie und Immunbiologie, Julius-Maximilians-Universität Würzburg, 97078 Würzburg, Germany; (L.D.); (F.E.)
| | - Lars Kaderali
- Institute of Bioinformatics, University Medicine Greifswald, 17475 Greifswald, Germany;
| | - Max von Kleist
- MF1 Bioinformatics, Robert Koch-Institute, 13353 Berlin, Germany;
| | - Roland Marquet
- CNRS, Architecture et Réactivité de l’ARN, Université de Strasbourg, UPR 9002 Strasbourg, France;
| | - Jelle Matthijnssens
- Department of Microbiology and Immunology, Katholieke Universiteit Leuven, Herestraat 49 Box 1040, 3000 Leuven, Belgium;
| | - Shawna McCallin
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Forchstrasse 340, 8008 Zürich, Switzerland;
| | - Dino McMahon
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195 Berlin, Germany;
| | - Thomas Rattei
- Division of Computational Systems Biology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Althanstraße 14, 1090 Vienna, Austria;
| | - 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;
| | - David L. Robertson
- MRC, University of Glasgow Centre for Virus Research (CVR), 464 Bearsden Road, Glasgow G61 1QH, UK;
| | - Martin Schwemmle
- Institute of Virology, Medical Center—University of Freiburg, Hermann-Herder-Strasse 11, 79104 Freiburg, Germany;
| | - Noam Stern-Ginossar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel;
| | - Manja Marz
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, 07743 Jena, Germany;
- FLI Leibniz Institute for Age Research, 07745 Jena, Germany
- Correspondence: ; Tel.: +49-3641-9-46480
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Sweeny AR, Albery GF, Venkatesan S, Fenton A, Pedersen AB. Spatiotemporal variation in drivers of parasitism in a wild wood mouse population. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13786] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amy R. Sweeny
- Institute of Evolutionary Biology, School of Biological Sciences University of Edinburgh Edinburgh UK
| | | | - Saudamini Venkatesan
- Institute of Evolutionary Biology, School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Andy Fenton
- Institute of Infection, Veterinary and Ecological Sciences University of Liverpool Liverpool UK
| | - Amy B. Pedersen
- Institute of Evolutionary Biology, School of Biological Sciences University of Edinburgh Edinburgh UK
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Wang L, Barbash DA, Kelleher ES. Adaptive evolution among cytoplasmic piRNA proteins leads to decreased genomic auto-immunity. PLoS Genet 2020; 16:e1008861. [PMID: 32525870 PMCID: PMC7310878 DOI: 10.1371/journal.pgen.1008861] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 06/23/2020] [Accepted: 05/14/2020] [Indexed: 02/05/2023] Open
Abstract
In metazoan germlines, the piRNA pathway acts as a genomic immune system, employing small RNA-mediated silencing to defend host DNA from the harmful effects of transposable elements (TEs). Expression of genomic TEs is proposed to initiate self regulation by increasing the production of repressive piRNAs, thereby “adapting” piRNA-mediated control to the most active TE families. Surprisingly, however, piRNA pathway proteins, which execute piRNA biogenesis and enforce silencing of targeted sequences, evolve rapidly and adaptively in animals. If TE silencing is ensured through piRNA biogenesis, what necessitates changes in piRNA pathway proteins? Here we used interspecific complementation to test for functional differences between Drosophila melanogaster and D. simulans alleles of three adaptively evolving piRNA pathway proteins: Armitage, Aubergine and Spindle-E. In contrast to piRNA-mediated transcriptional regulators examined in previous studies, these three proteins have cytoplasmic functions in piRNA maturation and post-transcriptional silencing. Across all three proteins we observed interspecific divergence in the regulation of only a handful of TE families, which were more robustly silenced by the heterospecific piRNA pathway protein. This unexpected result suggests that unlike transcriptional regulators, positive selection has not acted on cytoplasmic piRNA effector proteins to enhance their function in TE repression. Rather, TEs may evolve to “escape” silencing by host proteins. We further discovered that D. simulans alleles of aub and armi exhibit enhanced off-target effects on host transcripts in a D. melanogaster background, as well as modest reductions in the efficiency of piRNA biogenesis, suggesting that promiscuous binding of D. simulans Aub and Armi proteins to host transcripts reduces their participation in piRNA production. Avoidance of genomic auto-immunity may therefore be a critical target of selection. Our observations suggest that piRNA effector proteins are subject to an evolutionary trade-off between defending the host genome from the harmful effect of TEs while also minimizing collateral damage to host genes. Transposable elements are mobile fragments of selfish DNA that burden host genomes with deleterious mutations and incite genome instability. Host cells employ a specialized small-RNA mediated silencing pathway, the piRNA pathway, to act as a genomic immune system suppressing the mobilization of TEs. Changes in genomic TE content are met with rapid changes in the piRNA pool, thereby maintaining host control over transposition. However, piRNA pathway proteins—which enact piRNA biogenesis and silence target TEs—also evolve adaptively. To isolate forces that underlie this adaptive evolution, we examined functional divergence between two Drosophila species for three adaptively evolving piRNA pathway proteins. To our surprise, we found very few differences in TE regulation, suggesting that evolution has not generally acted to enhance control of TE parasites. Rather, we discovered interspecific differences in the regulation of host mRNAs for two proteins, which suggested that proteins evolve to avoid off-target silencing of host transcripts. We propose that the avoidance of such “genomic autoimmunity” is an important and underappreciated force driving the adaptive evolution of piRNA proteins.
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Affiliation(s)
- Luyang Wang
- Dept. Biology & Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Daniel A. Barbash
- Dept. Molecular Biology & Genetics, Cornell University, Ithaca, New York, United States of America
| | - Erin S. Kelleher
- Dept. Biology & Biochemistry, University of Houston, Houston, Texas, United States of America
- * E-mail:
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Brosseau C, Bolaji A, Roussin-Léveillée C, Zhao Z, Biga S, Moffett P. Natural variation in the Arabidopsis AGO2 gene is associated with susceptibility to potato virus X. THE NEW PHYTOLOGIST 2020; 226:866-878. [PMID: 31880814 DOI: 10.1111/nph.16397] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 12/12/2019] [Indexed: 06/10/2023]
Abstract
RNA silencing functions as an anti-viral defence in plants through the action of DICER-like (DCL) and ARGONAUTE (AGO) proteins. Despite the importance of this mechanism, little is known about the functional consequences of variation in genes encoding RNA silencing components. The AGO2 protein has been shown to be important for defense against multiple viruses, and we investigated how naturally occurring differences in AGO2 between and within species affects its antiviral activities. We find that the AGO2 protein from Arabidopsis thaliana, but not Nicotiana benthamiana, effectively limits potato virus X (PVX). Consistent with this, we find that the A. thaliana AGO2 gene shows a high incidence of polymorphisms between accessions, with evidence of selective pressure. Using functional analyses, we identify polymorphisms that specifically affect AGO2 antiviral activity, without interfering with other AGO2-associated functions such as anti-bacterial resistance or DNA methylation. Our results suggest that viruses adapt to overcome RNA silencing in their hosts. Furthermore, they indicate that plant-virus interactions have influenced natural variation in RNA-silencing components and that the latter may be a source of genetically encoded virus resistance.
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Affiliation(s)
- Chantal Brosseau
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Ayooluwa Bolaji
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | | | - Zhenxing Zhao
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Sébastien Biga
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Peter Moffett
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
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28
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Drosophila Interspecific Hybridization Causes A Deregulation of the piRNA Pathway Genes. Genes (Basel) 2020; 11:genes11020215. [PMID: 32092860 PMCID: PMC7073935 DOI: 10.3390/genes11020215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/11/2020] [Accepted: 02/14/2020] [Indexed: 12/17/2022] Open
Abstract
Almost all eukaryotes have transposable elements (TEs) against which they have developed defense mechanisms. In the Drosophila germline, the main transposable element (TE) regulation pathway is mediated by specific Piwi-interacting small RNAs (piRNAs). Nonetheless, for unknown reasons, TEs sometimes escape cellular control during interspecific hybridization processes. Because the piRNA pathway genes are involved in piRNA biogenesis and TE control, we sequenced and characterized nine key genes from this pathway in Drosophila buzzatii and Drosophila koepferae species and studied their expression pattern in ovaries of both species and their F1 hybrids. We found that gene structure is, in general, maintained between both species and that two genes—armitage and aubergine—are under positive selection. Three genes—krimper, methyltransferase 2, and zucchini—displayed higher expression values in hybrids than both parental species, while others had RNA levels similar to the parental species with the highest expression. This suggests that the overexpression of some piRNA pathway genes can be a primary response to hybrid stress. Therefore, these results reinforce the hypothesis that TE deregulation may be due to the protein incompatibility caused by the rapid evolution of these genes, leading to a TE silencing failure, rather than to an underexpression of piRNA pathway genes.
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29
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Song H, Xing C, Lu W, Liu Z, Wang X, Cheng J, Zhang Q. Rapid evolution of piRNA pathway and its transposon targets in Japanese flounder (Paralichthys olivaceus). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2019; 31:100609. [PMID: 31362144 DOI: 10.1016/j.cbd.2019.100609] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/06/2019] [Accepted: 07/18/2019] [Indexed: 11/16/2022]
Abstract
Piwi-interacting RNA (piRNA) pathway is essential for germline specification, gametogenesis, and genome integrity as defense against transposable elements (TEs). This pathway has been suggested to have undergone rapid adaptive evolution in spite of its conserved role in TE silencing. However, with diverse sexual development patterns, piRNA pathway evolution and its adaptation to transposon activity in teleost lineages remain less known. This study illustrated the evolutionary significance of piRNA pathway via a systematic comparative analysis on diverse teleosts, including flatfish lineages. Molecular evolution of piRNA pathway and microRNA/small interfering RNA pathway genes indicated a faster evolution of piRNA pathway in teleosts than in mammals. Positive selection was detected at the PAZ (Piwi-Argonaute-Zwille) domain involved in Piwi-piRNA interaction, thereby suggesting that the amino acid substitutions were adaptive to their functions in teleost piRNA pathway. Notably, Piwil1 evolved faster in Japanese flounder than in other teleosts, and the piRNA pathway genes expressed higher in testes than in ovaries. In addition, gonadal transcriptomic analysis revealed male under-represented TE families mainly from DNA transposons, which were the potential targets of the complex formed by male-biased Piwi genes and male over-represented piRNAs in Japanese flounder testes. The potential piRNA-TE regulatory relationships suggested that the rapidly evolved piRNA pathway in Japanese flounder was likely involved in the regulation of transposon activity in germlines and could play important roles in Japanese flounder gonadal development and spermatogenesis.
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Affiliation(s)
- Haofei Song
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, 5 Yushan Road, Qingdao 266003, China
| | - Changjin Xing
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, 5 Yushan Road, Qingdao 266003, China
| | - Wei Lu
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, 5 Yushan Road, Qingdao 266003, China
| | - Zeyu Liu
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, 5 Yushan Road, Qingdao 266003, China
| | - Xubo Wang
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, 5 Yushan Road, Qingdao 266003, China
| | - Jie Cheng
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, 5 Yushan Road, Qingdao 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology (Qingdao), 1 Wenhai Road, Qingdao 266237, China.
| | - Quanqi Zhang
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, 5 Yushan Road, Qingdao 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology (Qingdao), 1 Wenhai Road, Qingdao 266237, China
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Ozata DM, Gainetdinov I, Zoch A, O'Carroll D, Zamore PD. PIWI-interacting RNAs: small RNAs with big functions. Nat Rev Genet 2019; 20:89-108. [PMID: 30446728 DOI: 10.1038/s41576-018-0073-3] [Citation(s) in RCA: 641] [Impact Index Per Article: 128.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In animals, PIWI-interacting RNAs (piRNAs) of 21-35 nucleotides in length silence transposable elements, regulate gene expression and fight viral infection. piRNAs guide PIWI proteins to cleave target RNA, promote heterochromatin assembly and methylate DNA. The architecture of the piRNA pathway allows it both to provide adaptive, sequence-based immunity to rapidly evolving viruses and transposons and to regulate conserved host genes. piRNAs silence transposons in the germ line of most animals, whereas somatic piRNA functions have been lost, gained and lost again across evolution. Moreover, most piRNA pathway proteins are deeply conserved, but different animals employ remarkably divergent strategies to produce piRNA precursor transcripts. Here, we discuss how a common piRNA pathway allows animals to recognize diverse targets, ranging from selfish genetic elements to genes essential for gametogenesis.
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Affiliation(s)
- Deniz M Ozata
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Ildar Gainetdinov
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Ansgar Zoch
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Dónal O'Carroll
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | - Phillip D Zamore
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA.
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Bourgeois Y, Boissinot S. On the Population Dynamics of Junk: A Review on the Population Genomics of Transposable Elements. Genes (Basel) 2019; 10:genes10060419. [PMID: 31151307 PMCID: PMC6627506 DOI: 10.3390/genes10060419] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/05/2019] [Accepted: 05/21/2019] [Indexed: 01/18/2023] Open
Abstract
Transposable elements (TEs) play an important role in shaping genomic organization and structure, and may cause dramatic changes in phenotypes. Despite the genetic load they may impose on their host and their importance in microevolutionary processes such as adaptation and speciation, the number of population genetics studies focused on TEs has been rather limited so far compared to single nucleotide polymorphisms (SNPs). Here, we review the current knowledge about the dynamics of transposable elements at recent evolutionary time scales, and discuss the mechanisms that condition their abundance and frequency. We first discuss non-adaptive mechanisms such as purifying selection and the variable rates of transposition and elimination, and then focus on positive and balancing selection, to finally conclude on the potential role of TEs in causing genomic incompatibilities and eventually speciation. We also suggest possible ways to better model TEs dynamics in a population genomics context by incorporating recent advances in TEs into the rich information provided by SNPs about the demography, selection, and intrinsic properties of genomes.
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Affiliation(s)
- Yann Bourgeois
- New York University Abu Dhabi, P.O. 129188, Saadiyat Island, Abu Dhabi, United Arab Emirates.
| | - Stéphane Boissinot
- New York University Abu Dhabi, P.O. 129188, Saadiyat Island, Abu Dhabi, United Arab Emirates.
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32
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Crysnanto D, Obbard DJ. Widespread gene duplication and adaptive evolution in the RNA interference pathways of the Drosophila obscura group. BMC Evol Biol 2019; 19:99. [PMID: 31068148 PMCID: PMC6505081 DOI: 10.1186/s12862-019-1425-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 04/18/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND RNA interference (RNAi) related pathways provide defense against viruses and transposable elements, and have been implicated in the suppression of meiotic drive elements. Genes in these pathways often exhibit high levels of adaptive substitution, and over longer timescales show gene duplication and loss-most likely as a consequence of their role in mediating conflict with these parasites. This is particularly striking for Argonaute 2 (Ago2), which is ancestrally the key effector of antiviral RNAi in insects, but has repeatedly formed new testis-specific duplicates in the recent history of the obscura species-group of Drosophila. RESULTS Here we take advantage of publicly available genomic and transcriptomic data to identify six further RNAi-pathway genes that have duplicated in this clade of Drosophila, and examine their evolutionary history. As seen for Ago2, we observe high levels of adaptive amino-acid substitution and changes in sex-biased expression in many of the paralogs. However, our phylogenetic analysis suggests that co-duplications of the RNAi machinery were not synchronous, and our expression analysis fails to identify consistent male-specific expression. CONCLUSIONS These results confirm that RNAi genes, including genes of the antiviral and piRNA pathways, have undergone multiple independent duplications and that their history has been particularly labile within the obscura group. However, they also suggest that the selective pressures driving these changes have not been consistent, implying that more than one selective agent may be responsible.
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Affiliation(s)
- Danang Crysnanto
- Institute of Evolutionary Biology, University of Edinburgh, Charlotte Auerbach Road, Edinburgh, UK
- Animal Genomics, ETH Zurich, Zurich, Switzerland
| | - Darren J. Obbard
- Institute of Evolutionary Biology, University of Edinburgh, Charlotte Auerbach Road, Edinburgh, UK
- Centre for Infection, Evolution and Immunity, University of Edinburgh, Edinburgh, UK
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Abstract
Among the multitude of papers published yearly in scientific journals, precious few publications may be worth looking back in half a century to appreciate the significance of the discoveries that would later become common knowledge and get a chance to shape a field or several adjacent fields. Here, Kimura's fundamental concept of neutral mutation-random drift, which was published 50 years ago, is re-examined in light of its pervasive influence on comparative genomics and, more specifically, on the contribution of transposable elements to eukaryotic genome evolution.
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Affiliation(s)
- Irina R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA
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Almeida MV, Andrade-Navarro MA, Ketting RF. Function and Evolution of Nematode RNAi Pathways. Noncoding RNA 2019; 5:E8. [PMID: 30650636 PMCID: PMC6468775 DOI: 10.3390/ncrna5010008] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 12/11/2022] Open
Abstract
Selfish genetic elements, like transposable elements or viruses, are a threat to genomic stability. A variety of processes, including small RNA-based RNA interference (RNAi)-like pathways, has evolved to counteract these elements. Amongst these, endogenous small interfering RNA and Piwi-interacting RNA (piRNA) pathways were implicated in silencing selfish genetic elements in a variety of organisms. Nematodes have several incredibly specialized, rapidly evolving endogenous RNAi-like pathways serving such purposes. Here, we review recent research regarding the RNAi-like pathways of Caenorhabditis elegans as well as those of other nematodes, to provide an evolutionary perspective. We argue that multiple nematode RNAi-like pathways share piRNA-like properties and together form a broad nematode toolkit that allows for silencing of foreign genetic elements.
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Affiliation(s)
| | - Miguel A Andrade-Navarro
- Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.
- Faculty of Biology, Johannes Gutenberg Universität, 55122 Mainz, Germany.
| | - René F Ketting
- Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.
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35
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Fontdevila A. Hybrid Genome Evolution by Transposition: An Update. J Hered 2019; 110:124-136. [PMID: 30107415 DOI: 10.1093/jhered/esy040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/06/2018] [Indexed: 02/02/2023] Open
Abstract
Contrary to the view that hybrids are lineages devoid of evolutionary value, a number of case studies that have been lately reported show how hybrids are at the origin of many species. Some well-documented cases demonstrate that bursts of transposition often follow hybridization, generating new genetic variability. Studies in hybrid transposition strongly suggest that epigenetic changes and divergence in piRNA pathways drive deregulation in TE landscapes. Here, I have focused on mechanisms acting in Drosophila hybrids between two cactophilic species. The results reported here show that while hybrid instability by transposition is a genome-wide event, deregulation by TE overexpression in hybrid ovaries is not a general rule. When piRNA pools of ovaries are studied, results show that TEs with parental differences higher than 2-fold in their piRNA amounts are not more commonly deregulated in hybrids than TEs with similar levels, partially discrediting the generality of the maternal cytotype hypothesis. Some promising results on the piRNA pathway global failure hypothesis, which states that accumulated divergence of piRNA effector proteins is responsible for hybrid TE deregulation, have also been obtained. Altogether, these results suggest that TE deregulation might be driven by several interacting mechanisms. A natural scenario is proposed in which genome instability by transposition leads to hybrid genome reorganization. Small hybrid populations, subjected to natural selection helped by genetic drift, evolve new adaptations adapted to novel environments. The final step is either introgression or even a new hybrid species.
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Affiliation(s)
- Antonio Fontdevila
- Grup de Genòmica, Bioinformàtica i Biologia Evolutiva, Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Bellaterra, Spain
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36
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Detecting Adaptation with Genome-Scale Molecule Evolutionary Analysis: An Educational Primer for Use with "RNA Interference Pathways Display High Rates of Adaptive Protein Evolution in Multiple Invertebrates". Genetics 2018; 210:773-780. [PMID: 30401763 PMCID: PMC6218227 DOI: 10.1534/genetics.118.301453] [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: 08/03/2018] [Accepted: 08/30/2018] [Indexed: 11/18/2022] Open
Abstract
Hosts and pathogens impose coevolutionary pressure on each other as pathogens strive to establish themselves and hosts seek to suppress infection. RNA interference (RNAi) is a mechanism by which cells repress viruses and transposable elements, thereby serving as a form of immune defense. Previous studies have shown that antiviral RNAi genes evolve extraordinarily quickly in the fruit fly Drosophila melanogaster, suggesting that they may adaptively coevolve with viruses and transposable elements. An article by Palmer and colleagues extends this observation to nematodes and multiple insects. Their article can be combined with this Primer to demonstrate the use of comparative genomics and molecular evolutionary analyses in the measurement of natural selection.
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37
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Im JH, Lazzaro BP. Population genetic analysis of autophagy and phagocytosis genes in Drosophila melanogaster and D. simulans. PLoS One 2018; 13:e0205024. [PMID: 30281656 PMCID: PMC6169979 DOI: 10.1371/journal.pone.0205024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 09/18/2018] [Indexed: 12/03/2022] Open
Abstract
Autophagy and phagocytosis are cellular immune mechanisms for internalization and elimination of intracellular and extracellular pathogens. Some pathogens have evolved the ability to inhibit or manipulate these processes, raising the prospect of adaptive reciprocal co-evolution by the host. We performed population genetic analyses on phagocytosis and autophagy genes in Drosophila melanogaster and D. simulans to test for molecular evolutionary signatures of immune adaptation. We found that phagocytosis and autophagy genes as a whole exhibited an elevated level of haplotype homozygosity in both species. In addition, we detected signatures of recent selection, notably in the Atg14 and Ykt6 genes in D. melanogaster and a pattern of elevated sequence divergence in the genderblind (gb) gene on the D. simulans lineage. These results suggest that the evolution of the host cellular immune system as a whole may be shaped by a dynamic conflict between Drosophila and its pathogens even without pervasive evidence of strong adaptive evolution at the individual gene level.
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Affiliation(s)
- Joo Hyun Im
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, United States of America.,Graduate Field of Genetics, Genomics, and Development, Cornell University, Ithaca, NY, United States of America.,Department of Entomology, Cornell University, Ithaca, NY, United States of America
| | - Brian P Lazzaro
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, United States of America.,Graduate Field of Genetics, Genomics, and Development, Cornell University, Ithaca, NY, United States of America.,Department of Entomology, Cornell University, Ithaca, NY, United States of America
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38
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Leggewie M, Schnettler E. RNAi-mediated antiviral immunity in insects and their possible application. Curr Opin Virol 2018; 32:108-114. [DOI: 10.1016/j.coviro.2018.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/16/2018] [Accepted: 10/23/2018] [Indexed: 01/09/2023]
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39
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Albery GF, Kenyon F, Morris A, Morris S, Nussey DH, Pemberton JM. Seasonality of helminth infection in wild red deer varies between individuals and between parasite taxa. Parasitology 2018; 145:1410-1420. [PMID: 29519265 PMCID: PMC6137381 DOI: 10.1017/s0031182018000185] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 01/19/2018] [Accepted: 01/20/2018] [Indexed: 12/03/2022]
Abstract
Parasitism in wild mammals can vary according to myriad intrinsic and extrinsic factors, many of which vary seasonally. However, seasonal variation in parasitism is rarely studied using repeated samples from known individuals. Here we used a wild population of individually recognized red deer (Cervus elaphus) on the Isle of Rum to quantify seasonality and intrinsic factors affecting gastrointestinal helminth parasitism over the course of a year. We collected 1020 non-invasive faecal samples from 328 known individuals which we then analysed for propagules of three helminth taxa: strongyle nematodes, the common liver fluke Fasciola hepatica and the tissue nematode Elaphostrongylus cervi. Zero-inflated Poisson models were used to investigate how season, age and sex were associated with parasite prevalence and count intensity, while Poisson models were used to quantify individual repeatability within and between sampling seasons. Parasite intensity and prevalence varied according to all investigated factors, with opposing seasonality, age profiles and sex biases between parasite taxa. Repeatability was moderate, decreased between seasons and varied between parasites; both F. hepatica and E. cervi showed significant between-season repeatability, while strongyle nematode counts were only repeatable within-season and showed no repeatability within individuals across the year.
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Affiliation(s)
- Gregory F. Albery
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Fiona Kenyon
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, UK
| | - Alison Morris
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Sean Morris
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Daniel H. Nussey
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Josephine M. Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
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40
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GWAS with Heterogeneous Data: Estimating the Fraction of Phenotypic Variation Mediated by Gene Expression Data. G3-GENES GENOMES GENETICS 2018; 8:3059-3068. [PMID: 30068524 PMCID: PMC6118313 DOI: 10.1534/g3.118.200571] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Intermediate phenotypes such as gene expression values can be used to elucidate the mechanisms by which genetic variation causes phenotypic variation, but jointly analyzing such heterogeneous data are far from trivial. Here we extend a so-called mediation model to handle the confounding effects of genetic background, and use it to analyze flowering time variation in Arabidopsis thaliana, focusing in particular on the central role played by the key regulator FLOWERING TIME LOCUS C (FLC). FLC polymorphism and FLC expression are both strongly correlated with flowering time variation, but the effect of the former is only partly mediated through the latter. Furthermore, the latter also reflects genetic background effects. We demonstrate that it is possible to partition these effects, shedding light on the complex regulatory network that underlies flowering time variation.
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41
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Abstract
The power and ease of Drosophila genetics and the medical relevance of mosquito-transmitted viruses have made dipterans important model organisms in antiviral immunology. Studies of virus-host interactions at the molecular and population levels have illuminated determinants of resistance to virus infection. Here, we review the sources and nature of variation in antiviral immunity and virus susceptibility in model dipteran insects, specifically the fruit fly Drosophila melanogaster and vector mosquitoes of the genera Aedes and Culex. We first discuss antiviral immune mechanisms and describe the virus-specificity of these responses. In the following sections, we review genetic and microbiota-dependent variation in antiviral immunity. In the final sections, we explore less well-studied sources of variation, including abiotic factors, sexual dimorphism, infection history, and endogenous viral elements. We borrow from work on other pathogen types and non-dipteran species when it parallels or complements studies in dipterans. Understanding natural variation in virus-host interactions may lead to the identification of novel restriction factors and immune mechanisms and shed light on the molecular determinants of vector competence.
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Affiliation(s)
- William H Palmer
- Institute of Evolutionary Biology and Centre for Infection, Evolution and Immunity, University of Edinburgh, Edinburgh EH9 3FL UK.
| | - Finny S Varghese
- Department of Medical Microbiology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, P.O. Box 9101, Nijmegen 6500 HB, The Netherlands.
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen 6525 GA, The Netherlands.
| | - Ronald P van Rij
- Department of Medical Microbiology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, P.O. Box 9101, Nijmegen 6500 HB, The Netherlands.
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen 6525 GA, The Netherlands.
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