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Zhong D, Bu L, Habib MR, Lu L, Yan G, Zhang SM. A haplotype-like, chromosome-level assembled and annotated genome of Biomphalaria glabrata, an important intermediate host of schistosomiasis and the best studied model of schistosomiasis vector snails. PLoS Negl Trop Dis 2024; 18:e0011983. [PMID: 38421953 PMCID: PMC10903818 DOI: 10.1371/journal.pntd.0011983] [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: 06/09/2023] [Accepted: 02/08/2024] [Indexed: 03/02/2024] Open
Abstract
Schistosomiasis is one of the world's most devastating parasitic diseases, afflicting 251 million people globally. The Neotropical snail Biomphalaria glabrata is an important intermediate host of the human blood fluke Schistosoma mansoni and a predominant model for schistosomiasis research. To fully exploit this model snail for biomedical research, here we report a haplotype-like, chromosome-level assembled and annotated genome of the homozygous iM line of B. glabrata that we developed at the University of New Mexico. Using multiple sequencing platforms, including Illumina, PacBio, and Omni-C sequencing, 18 sequence contact matrices representing 18 haploid chromosomes (2n = 36) were generated (337x genome coverage), and 96.5% of the scaffold sequences were anchored to the 18 chromosomes. Protein-coding genes (n = 34,559), non-coding RNAs (n = 2,406), and repetitive elements (42.52% of the genome) were predicted for the whole genome, and detailed annotations for individual chromosomes were also provided. Using this genomic resource, we have investigated the genomic structure and organization of the Toll-like receptor (TLR) and fibrinogen-domain containing protein (FReD) genes, the two important immune-related gene families. Notably, TLR-like genes are scattered on 13 chromosomes. In contrast, almost all (39 of 40) fibrinogen-related genes (FREPs) (immunoglobulin superfamily (IgSF) + fibrinogen (FBG)) are clustered within a 5-million nucleotide region on chromosome 13, yielding insight into mechanisms involved in the diversification of FREPs. This is the first genome of schistosomiasis vector snails that has been assembled at the chromosome level, annotated, and analyzed. It serves as a valuable resource for a deeper understanding of the biology of vector snails, especially Biomphalaria snails.
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Affiliation(s)
- Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California, Irvine, California, United States of America
| | - Lijing Bu
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Mohamed R. Habib
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Lijun Lu
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California, Irvine, California, United States of America
| | - Si-Ming Zhang
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
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2
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Al-Moussawy M, Abdelsamed HA, Lakkis FG. Immunoglobulin-like receptors and the generation of innate immune memory. Immunogenetics 2022; 74:179-195. [PMID: 35034136 PMCID: PMC10074160 DOI: 10.1007/s00251-021-01240-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 11/25/2021] [Indexed: 12/22/2022]
Abstract
Host immunity is classically divided into "innate" and "adaptive." While the former has always been regarded as the first, rapid, and antigen-nonspecific reaction to invading pathogens, the latter represents the more sophisticated and antigen-specific response that has the potential to persist and generate memory. Recent work however has challenged this dogma, where murine studies have successfully demonstrated the ability of innate immune cells (monocytes and macrophages) to acquire antigen-specific memory to allogeneic major histocompatibility complex (MHC) molecules. The immunoreceptors so far identified that mediate innate immune memory are the paired immunoglobulin-like receptors (PIRs) in mice, which are orthologous to human leukocyte immunoglobulin-like receptors (LILRs). These receptor families are mainly expressed by the myelomonocytic cell lineage, suggesting an important role in the innate immune response. In this review, we will discuss the role of immunoglobulin-like receptors in the development of innate immune memory across species.
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Affiliation(s)
- Mouhamad Al-Moussawy
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA.
| | - Hossam A Abdelsamed
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA. .,Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, USA.
| | - Fadi G Lakkis
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, USA. .,Department of Immunology, University of Pittsburgh, Pittsburgh, USA. .,Department of Medicine, University of Pittsburgh, Pittsburgh, USA.
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3
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Magadán S, Mikelez-Alonso I, Borrego F, González-Fernández Á. Nanoparticles and trained immunity: Glimpse into the future. Adv Drug Deliv Rev 2021; 175:113821. [PMID: 34087325 DOI: 10.1016/j.addr.2021.05.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/27/2021] [Accepted: 05/29/2021] [Indexed: 12/17/2022]
Abstract
Emerging evidences show that innate immune cells can display changes in their functional programs after infection or vaccination, which lead to immunomodulation (increased or reduced responsiveness) upon secondary activation to the same stimuli or even to a different one. Innate cells acquire features of immunological memory, nowadays using the new term of "trained immunity" or "innate immune memory", which is different from the specific memory immune response elicited by B and T lymphocytes. The review focused on the concept of trained immunity, mostly on myeloid cells. Special attention is dedicated to the pathogen recognition along the evolution (bacteria, plants, invertebrate and vertebrate animals), and to techniques used to study epigenetic reprogramming and metabolic rewiring. Nanomaterials can be recognized by immune cells offering a very promising way to learn about trained immunity. Nanomaterials could be modified in order to immunomodulate the responses ad hoc. Many therapeutic possibilities are opened, and they should be explored.
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Kraus A, Buckley KM, Salinas I. Sensing the world and its dangers: An evolutionary perspective in neuroimmunology. eLife 2021; 10:66706. [PMID: 33900197 PMCID: PMC8075586 DOI: 10.7554/elife.66706] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/09/2021] [Indexed: 12/14/2022] Open
Abstract
Detecting danger is key to the survival and success of all species. Animal nervous and immune systems cooperate to optimize danger detection. Preceding studies have highlighted the benefits of bringing neurons into the defense game, including regulation of immune responses, wound healing, pathogen control, and survival. Here, we summarize the body of knowledge in neuroimmune communication and assert that neuronal participation in the immune response is deeply beneficial in each step of combating infection, from inception to resolution. Despite the documented tight association between the immune and nervous systems in mammals or invertebrate model organisms, interdependence of these two systems is largely unexplored across metazoans. This review brings a phylogenetic perspective of the nervous and immune systems in the context of danger detection and advocates for the use of non-model organisms to diversify the field of neuroimmunology. We identify key taxa that are ripe for investigation due to the emergence of key evolutionary innovations in their immune and nervous systems. This novel perspective will help define the primordial principles that govern neuroimmune communication across taxa.
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Affiliation(s)
- Aurora Kraus
- Department of Biology, University of New Mexico, Albuquerque, United States
| | | | - Irene Salinas
- Department of Biology, University of New Mexico, Albuquerque, United States
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5
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Abstract
The composition of insect hemolymph can change depending on many factors, e.g. access to nutrients, stress conditions, and current needs of the insect. In this chapter, insect immune-related polypeptides, which can be permanently or occasionally present in the hemolymph, are described. Their division into peptides or low-molecular weight proteins is not always determined by the length or secondary structure of a given molecule but also depends on the mode of action in insect immunity and, therefore, it is rather arbitrary. Antimicrobial peptides (AMPs) with their role in immunity, modes of action, and classification are presented in the chapter, followed by a short description of some examples: cecropins, moricins, defensins, proline- and glycine-rich peptides. Further, we will describe selected immune-related proteins that may participate in immune recognition, may possess direct antimicrobial properties, or can be involved in the modulation of insect immunity by both abiotic and biotic factors. We briefly cover Fibrinogen-Related Proteins (FREPs), Down Syndrome Cell Adhesion Molecules (Dscam), Hemolin, Lipophorins, Lysozyme, Insect Metalloproteinase Inhibitor (IMPI), and Heat Shock Proteins. The reader will obtain a partial picture presenting molecules participating in one of the most efficient immune strategies found in the animal world, which allow insects to inhabit all ecological land niches in the world.
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Affiliation(s)
- Iwona Wojda
- Department of Immunobiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland.
| | - Małgorzata Cytryńska
- Department of Immunobiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Agnieszka Zdybicka-Barabas
- Department of Immunobiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Jakub Kordaczuk
- Department of Immunobiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
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6
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Apitanyasai K, Huang SW, Ng TH, He ST, Huang YH, Chiu SP, Tseng KC, Lin SS, Chang WC, Baldwin-Brown JG, Long AD, Lo CF, Yu HT, Wang HC. The gene structure and hypervariability of the complete Penaeus monodon Dscam gene. Sci Rep 2019; 9:16595. [PMID: 31719551 PMCID: PMC6851185 DOI: 10.1038/s41598-019-52656-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/17/2019] [Indexed: 12/19/2022] Open
Abstract
Using two advanced sequencing approaches, Illumina and PacBio, we derive the entire Dscam gene from an M2 assembly of the complete Penaeus monodon genome. The P. monodon Dscam (PmDscam) gene is ~266 kbp, with a total of 44 exons, 5 of which are subject to alternative splicing. PmDscam has a conserved architectural structure consisting of an extracellular region with hypervariable Ig domains, a transmembrane domain, and a cytoplasmic tail. We show that, contrary to a previous report, there are in fact 26, 81 and 26 alternative exons in N-terminal Ig2, N-terminal Ig3 and the entirety of Ig7, respectively. We also identified two alternatively spliced exons in the cytoplasmic tail, with transmembrane domains in exon variants 32.1 and 32.2, and stop codons in exon variants 44.1 and 44.2. This means that alternative splicing is involved in the selection of the stop codon. There are also 7 non-constitutive cytoplasmic tail exons that can either be included or skipped. Alternative splicing and the non-constitutive exons together produce more than 21 million isoform combinations from one PmDscam locus in the P. monodon gene. A public-facing database that allows BLAST searches of all 175 exons in the PmDscam gene has been established at http://pmdscam.dbbs.ncku.edu.tw/.
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Affiliation(s)
- Kantamas Apitanyasai
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Shiao-Wei Huang
- Department of Life Sciences, National Taiwan University, Taipei, Taiwan
| | - Tze Hann Ng
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Shu-Ting He
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Hsun Huang
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Shen-Po Chiu
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Kuan-Chien Tseng
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Shih-Shun Lin
- Institute of Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Wen-Chi Chang
- Institute of Tropical Plant Sciences, National Cheng Kung University, Tainan, Taiwan
| | - James G Baldwin-Brown
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, USA
| | - Anthony D Long
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, USA
| | - Chu-Fang Lo
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Hon-Tsen Yu
- Department of Life Sciences, National Taiwan University, Taipei, Taiwan
| | - Han-Ching Wang
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan. .,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan.
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7
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Dong X, Chaisiri K, Xia D, Armstrong SD, Fang Y, Donnelly MJ, Kadowaki T, McGarry JW, Darby AC, Makepeace BL. Genomes of trombidid mites reveal novel predicted allergens and laterally transferred genes associated with secondary metabolism. Gigascience 2018; 7:5160133. [PMID: 30445460 PMCID: PMC6275457 DOI: 10.1093/gigascience/giy127] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 10/18/2018] [Indexed: 12/21/2022] Open
Abstract
Background Trombidid mites have a unique life cycle in which only the larval stage is ectoparasitic. In the superfamily Trombiculoidea ("chiggers"), the larvae feed preferentially on vertebrates, including humans. Species in the genus Leptotrombidium are vectors of a potentially fatal bacterial infection, scrub typhus, that affects 1 million people annually. Moreover, chiggers can cause pruritic dermatitis (trombiculiasis) in humans and domesticated animals. In the Trombidioidea (velvet mites), the larvae feed on other arthropods and are potential biological control agents for agricultural pests. Here, we present the first trombidid mites genomes, obtained both for a chigger, Leptotrombidium deliense, and for a velvet mite, Dinothrombium tinctorium. Results Sequencing was performed using Illumina technology. A 180 Mb draft assembly for D. tinctorium was generated from two paired-end and one mate-pair library using a single adult specimen. For L. deliense, a lower-coverage draft assembly (117 Mb) was obtained using pooled, engorged larvae with a single paired-end library. Remarkably, both genomes exhibited evidence of ancient lateral gene transfer from soil-derived bacteria or fungi. The transferred genes confer functions that are rare in animals, including terpene and carotenoid synthesis. Thirty-seven allergenic protein families were predicted in the L. deliense genome, of which nine were unique. Preliminary proteomic analyses identified several of these putative allergens in larvae. Conclusions Trombidid mite genomes appear to be more dynamic than those of other acariform mites. A priority for future research is to determine the biological function of terpene synthesis in this taxon and its potential for exploitation in disease control.
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Affiliation(s)
- Xiaofeng Dong
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom.,Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China.,School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China.,Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom
| | - Kittipong Chaisiri
- Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom.,Faculty of Tropical Medicine, Mahidol University, Ratchathewi Bangkok 10400, Thailand
| | - Dong Xia
- Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom.,The Royal Veterinary College, London NW1 0TU, United Kingdom
| | - Stuart D Armstrong
- Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom
| | - Yongxiang Fang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Tatsuhiko Kadowaki
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China
| | - John W McGarry
- Institute of Veterinary Science, University of Liverpool, Liverpool L3 5RP, United Kingdom
| | - Alistair C Darby
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Benjamin L Makepeace
- Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom
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8
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Castro R, Navelsaker S, Krasnov A, Du Pasquier L, Boudinot P. Describing the diversity of Ag specific receptors in vertebrates: Contribution of repertoire deep sequencing. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 75:28-37. [PMID: 28259700 DOI: 10.1016/j.dci.2017.02.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/16/2017] [Accepted: 02/22/2017] [Indexed: 06/06/2023]
Abstract
During the last decades, gene and cDNA cloning identified TCR and Ig genes across vertebrates; genome sequencing of TCR and Ig loci in many species revealed the different organizations selected during evolution under the pressure of generating diverse repertoires of Ag receptors. By detecting clonotypes over a wide range of frequency, deep sequencing of Ig and TCR transcripts provides a new way to compare the structure of expressed repertoires in species of various sizes, at different stages of development, with different physiologies, and displaying multiple adaptations to the environment. In this review, we provide a short overview of the technologies currently used to produce global description of immune repertoires, describe how they have already been used in comparative immunology, and we discuss the future potential of such approaches. The development of these methodologies in new species holds promise for new discoveries concerning particular adaptations. As an example, understanding the development of adaptive immunity across metamorphosis in frogs has been made possible by such approaches. Repertoire sequencing is now widely used, not only in basic research but also in the context of immunotherapy and vaccination. Analysis of fish responses to pathogens and vaccines has already benefited from these methods. Finally, we also discuss potential advances based on repertoire sequencing of multigene families of immune sensors and effectors in invertebrates.
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Affiliation(s)
- Rosario Castro
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
| | - Sofie Navelsaker
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Department of Basic Sciences and Aquatic Medicine, Adamstuen Campus, Oslo 0454, Norway; Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | | | | | - Pierre Boudinot
- Virologie et Immunologie Moléculaires, INRA, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
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9
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Müller V, de Boer RJ, Bonhoeffer S, Szathmáry E. An evolutionary perspective on the systems of adaptive immunity. Biol Rev Camb Philos Soc 2017; 93:505-528. [PMID: 28745003 DOI: 10.1111/brv.12355] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 06/28/2017] [Accepted: 06/30/2017] [Indexed: 12/22/2022]
Abstract
We propose an evolutionary perspective to classify and characterize the diverse systems of adaptive immunity that have been discovered across all major domains of life. We put forward a new function-based classification according to the way information is acquired by the immune systems: Darwinian immunity (currently known from, but not necessarily limited to, vertebrates) relies on the Darwinian process of clonal selection to 'learn' by cumulative trial-and-error feedback; Lamarckian immunity uses templated targeting (guided adaptation) to internalize heritable information on potential threats; finally, shotgun immunity operates through somatic mechanisms of variable targeting without feedback. We argue that the origin of Darwinian (but not Lamarckian or shotgun) immunity represents a radical innovation in the evolution of individuality and complexity, and propose to add it to the list of major evolutionary transitions. While transitions to higher-level units entail the suppression of selection at lower levels, Darwinian immunity re-opens cell-level selection within the multicellular organism, under the control of mechanisms that direct, rather than suppress, cell-level evolution for the benefit of the individual. From a conceptual point of view, the origin of Darwinian immunity can be regarded as the most radical transition in the history of life, in which evolution by natural selection has literally re-invented itself. Furthermore, the combination of clonal selection and somatic receptor diversity enabled a transition from limited to practically unlimited capacity to store information about the antigenic environment. The origin of Darwinian immunity therefore comprises both a transition in individuality and the emergence of a new information system - the two hallmarks of major evolutionary transitions. Finally, we present an evolutionary scenario for the origin of Darwinian immunity in vertebrates. We propose a revival of the concept of the 'Big Bang' of vertebrate immunity, arguing that its origin involved a 'difficult' (i.e. low-probability) evolutionary transition that might have occurred only once, in a common ancestor of all vertebrates. In contrast to the original concept, we argue that the limiting innovation was not the generation of somatic diversity, but the regulatory circuitry needed for the safe operation of amplifiable immune responses with somatically acquired targeting. Regulatory complexity increased abruptly by genomic duplications at the root of the vertebrate lineage, creating a rare opportunity to establish such circuitry. We discuss the selection forces that might have acted at the origin of the transition, and in the subsequent stepwise evolution leading to the modern immune systems of extant vertebrates.
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Affiliation(s)
- Viktor Müller
- Parmenides Center for the Conceptual Foundations of Science, 82049 Pullach/Munich, Germany.,Department of Plant Systematics, Ecology and Theoretical Biology, Institute of Biology, Eötvös Loránd University, 1117 Budapest, Hungary.,Evolutionary Systems Research Group, MTA Centre for Ecological Research, 8237 Tihany, Hungary
| | - Rob J de Boer
- Theoretical Biology, Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Sebastian Bonhoeffer
- Institute of Integrative Biology, Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Eörs Szathmáry
- Parmenides Center for the Conceptual Foundations of Science, 82049 Pullach/Munich, Germany.,Department of Plant Systematics, Ecology and Theoretical Biology, Institute of Biology, Eötvös Loránd University, 1117 Budapest, Hungary.,Evolutionary Systems Research Group, MTA Centre for Ecological Research, 8237 Tihany, Hungary
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10
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Armitage SAO, Kurtz J, Brites D, Dong Y, Du Pasquier L, Wang HC. Dscam1 in Pancrustacean Immunity: Current Status and a Look to the Future. Front Immunol 2017. [PMID: 28649249 PMCID: PMC5465998 DOI: 10.3389/fimmu.2017.00662] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Down syndrome cell adhesion molecule 1 (Dscam1) gene is an extraordinary example of diversity: by combining alternatively spliced exons, thousands of isoforms can be produced from just one gene. So far, such diversity in this gene has only been found in insects and crustaceans, and its essential part in neural wiring has been well-characterized for Drosophila melanogaster. Ten years ago evidence from D. melanogaster showed that the Dscam1 gene is involved in insect immune defense and work on Anopheles gambiae indicated that it is a hypervariable immune receptor. These exciting findings showed that via processes of somatic diversification insects have the possibility to produce unexpected immune molecule diversity, and it was hypothesized that Dscam1 could provide the mechanistic underpinnings of specific immune responses. Since these first publications the quest to understand the function of this gene has uncovered fascinating insights from insects and crustaceans. However, we are still far from a complete understanding of how Dscam1 functions in relation to parasites and pathogens and its full relevance for the immune system. In this Hypothesis and Theory article, we first briefly introduce Dscam1 and what we know so far about how it might function in immunity. By focusing on seven questions, we then share our sometimes contrasting thoughts on what the evidence tells us so far, what essential experiments remain to be done, and the future prospects, with the aim to provide a multiangled view on what this fascinating gene has to do with immune defense.
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Affiliation(s)
- Sophie A O Armitage
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Joachim Kurtz
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Daniela Brites
- Tuberculosis Research Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland.,Zoological Institute, University of Basel, Basel, Switzerland
| | - Yuemei Dong
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, John Hopkins University, Baltimore, MD, United States
| | | | - Han-Ching Wang
- Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
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11
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Cooper D, Eleftherianos I. Memory and Specificity in the Insect Immune System: Current Perspectives and Future Challenges. Front Immunol 2017; 8:539. [PMID: 28536580 PMCID: PMC5422463 DOI: 10.3389/fimmu.2017.00539] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 04/21/2017] [Indexed: 11/13/2022] Open
Abstract
The immune response of a host to a pathogen is typically described as either innate or adaptive. The innate form of the immune response is conserved across all organisms, including insects. Previous and recent research has focused on the nature of the insect immune system and the results imply that the innate immune response of insects is more robust and specific than previously thought. Priming of the insect innate immune system involves the exposure of insects to dead or a sublethal dose of microbes in order to elicit an initial response. Comparing subsequent infections in primed insects to non-primed individuals indicates that the insect innate immune response may possess some of the qualities of an adaptive immune system. Although some studies demonstrate that the protective effects of priming are due to a "loitering" innate immune response, others have presented more convincing elements of adaptivity. While an immune mechanism capable of producing the same degree of recognition specificity as seen in vertebrates has yet to be discovered in insects, a few interesting cases have been identified and discussed.
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Affiliation(s)
- Dustin Cooper
- Department of Biological Sciences, The George Washington University, Washington, DC, United States
| | - Ioannis Eleftherianos
- Department of Biological Sciences, The George Washington University, Washington, DC, United States
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12
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Characterization of a Single Genomic Locus Encoding the Clustered Protocadherin Receptor Diversity in Xenopus tropicalis. G3-GENES GENOMES GENETICS 2016; 6:2309-18. [PMID: 27261006 PMCID: PMC4978886 DOI: 10.1534/g3.116.027995] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Clustered protocadherins (cPcdhs) constitute the largest subgroup of the cadherin superfamily, and in mammals are grouped into clusters of α-, β-, and γ-types. Tens of tandemly arranged paralogous Pcdh genes of the Pcdh clusters generate a substantial diversity of receptor isoforms. cPcdhs are known to have important roles in neuronal development, and genetic alterations of cPcdhs have been found to be associated with several neurological diseases. Here, we present a first characterization of cPcdhs in Xenopus tropicalis. We determined and annotated all cPcdh isoforms, revealing that they are present in a single chromosomal locus. We validated a total of 96 isoforms, which we show are organized in three distinct clusters. The X. tropicalis cPcdh locus is composed of one α- and two distinct γ-Pcdh clusters (pcdh-γ1 and pcdh-γ2). Bioinformatics analyses assisted by genomic BAC clone sequencing showed that the X. tropicalis α- and γ-Pcdhs are conserved at the cluster level, but, unlike mammals, X. tropicalis does not contain a β-Pcdh cluster. In contrast, the number of γ-Pcdh isoforms has expanded, possibly due to lineage-specific gene duplications. Interestingly, the number of X. tropicalis α-Pcdhs is identical between X. tropicalis and mouse. Moreover, we find highly conserved as well as novel promoter elements potentially involved in regulating the cluster-specific expression of cPcdh isoforms. This study provides important information for the understanding of the evolutionary history of cPcdh genes and future mechanistic studies. It provides an annotated X. tropicalis cPcdh genomic map and a first molecular characterization essential for functional and comparative studies.
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