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Darby AM, Lazzaro BP. Interactions between innate immunity and insulin signaling affect resistance to infection in insects. Front Immunol 2023; 14:1276357. [PMID: 37915572 PMCID: PMC10616485 DOI: 10.3389/fimmu.2023.1276357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 10/03/2023] [Indexed: 11/03/2023] Open
Abstract
An active immune response is energetically demanding and requires reallocation of nutrients to support resistance to and tolerance of infection. Insulin signaling is a critical global regulator of metabolism and whole-body homeostasis in response to nutrient availability and energetic needs, including those required for mobilization of energy in support of the immune system. In this review, we share findings that demonstrate interactions between innate immune activity and insulin signaling primarily in the insect model Drosophila melanogaster as well as other insects like Bombyx mori and Anopheles mosquitos. These studies indicate that insulin signaling and innate immune activation have reciprocal effects on each other, but that those effects vary depending on the type of pathogen, route of infection, and nutritional status of the host. Future research will be required to further understand the detailed mechanisms by which innate immunity and insulin signaling activity impact each other.
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Affiliation(s)
- Andrea M. Darby
- Department of Entomology, Cornell University, Ithaca, NY, United States
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, United States
| | - Brian P. Lazzaro
- Department of Entomology, Cornell University, Ithaca, NY, United States
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, United States
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2
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Sheffield L, Sciambra N, Evans A, Hagedorn E, Goltz C, Delfeld M, Kuhns H, Fierst JL, Chtarbanova S. Age-dependent impairment of disease tolerance is associated with a robust transcriptional response following RNA virus infection in Drosophila. G3-GENES GENOMES GENETICS 2021; 11:6219303. [PMID: 33836060 PMCID: PMC8495950 DOI: 10.1093/g3journal/jkab116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/26/2021] [Indexed: 12/18/2022]
Abstract
Advanced age in humans is associated with greater susceptibility to and higher mortality rates from infections, including infections with some RNA viruses. The underlying innate immune mechanisms, which represent the first line of defense against pathogens, remain incompletely understood. Drosophila melanogaster is able to mount potent and evolutionarily conserved innate immune defenses against a variety of microorganisms including viruses and serves as an excellent model organism for studying host–pathogen interactions. With its relatively short lifespan, Drosophila also is an organism of choice for aging studies. Despite numerous advantages that this model offers, Drosophila has not been used to its full potential to investigate the response of the aged host to viral infection. Here, we show that, in comparison to younger flies, aged Drosophila succumb more rapidly to infection with the RNA-containing Flock House virus due to an age-dependent defect in disease tolerance. Relative to younger individuals, we find that older Drosophila mount transcriptional responses characterized by differential regulation of more genes and genes regulated to a greater extent. We show that loss of disease tolerance to Flock House virus with age associates with a stronger regulation of genes involved in apoptosis, some genes of the Drosophila immune deficiency NF-kB pathway, and genes whose products function in mitochondria and mitochondrial respiration. Our work shows that Drosophila can serve as a model to investigate host–virus interactions during aging and furthermore sets the stage for future analysis of the age-dependent mechanisms that govern survival and control of virus infections at older age.
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Affiliation(s)
- Lakbira Sheffield
- Department of Biological Sciences, University of Alabama, 300, Hackberry lane, Tuscaloosa, AL-35487, USA.,Graduate Biomedical Sciences program, University of Alabama at Birmingham, Birmingham, AL- 35294, USA
| | - Noah Sciambra
- Department of Biological Sciences, University of Alabama, 300, Hackberry lane, Tuscaloosa, AL-35487, USA
| | - Alysa Evans
- Department of Biological Sciences, University of Alabama, 300, Hackberry lane, Tuscaloosa, AL-35487, USA
| | - Eli Hagedorn
- Department of Biological Sciences, University of Alabama, 300, Hackberry lane, Tuscaloosa, AL-35487, USA
| | - Casey Goltz
- Department of Biological Sciences, University of Alabama, 300, Hackberry lane, Tuscaloosa, AL-35487, USA
| | - Megan Delfeld
- Department of Biological Sciences, University of Alabama, 300, Hackberry lane, Tuscaloosa, AL-35487, USA
| | - Haley Kuhns
- Department of Biological Sciences, University of Alabama, 300, Hackberry lane, Tuscaloosa, AL-35487, USA
| | - Janna L Fierst
- Department of Biological Sciences, University of Alabama, 300, Hackberry lane, Tuscaloosa, AL-35487, USA
| | - Stanislava Chtarbanova
- Department of Biological Sciences, University of Alabama, 300, Hackberry lane, Tuscaloosa, AL-35487, USA
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3
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Kaur R, Martinez J, Rota-Stabelli O, Jiggins FM, Miller WJ. Age, tissue, genotype and virus infection regulate Wolbachia levels in Drosophila. Mol Ecol 2020; 29:2063-2079. [PMID: 32391935 DOI: 10.1111/mec.15462] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/28/2020] [Indexed: 12/13/2022]
Abstract
The bacterial symbiont Wolbachia can protect insects against viral pathogens, and the varying levels of antiviral protection are correlated with the endosymbiont load within the insects. To understand why Wolbachia strains differ in their antiviral effects, we investigated the factors controlling Wolbachia density in five closely related strains in their natural Drosophila hosts. We found that Wolbachia density varied greatly across different tissues and between flies of different ages, and these effects depended on the host-symbiont association. Some endosymbionts maintained largely stable densities as flies aged while others increased, and these effects in turn depended on the tissue being examined. Measuring Wolbachia rRNA levels in response to viral infection, we found that viral infection itself also altered Wolbachia levels, with Flock House virus causing substantial reductions in symbiont loads late in the infection. This effect, however, was virus-specific as Drosophila C virus had little impact on Wolbachia in all of the five host systems. Because viruses have strong tissue tropisms and antiviral protection is thought to be cell-autonomous, these effects are likely to affect the virus-blocking phenomenon. However, we were unable to find any evidence of a correlation between Wolbachia and viral titres within the same tissues. We conclude that Wolbachia levels within flies are regulated in a complex host-symbiont-virus-dependent manner and this trinity is likely to influence the antiviral effects of Wolbachia.
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Affiliation(s)
- Rupinder Kaur
- Division of Cell and Developmental Biology, Medical University of Vienna, Vienna, Austria.,Department of Sustainable Agro-Ecosystems and Bioresources, Fondazione Edmund Mach, San Michele all'Adige, Italy.,Department of Neurobiology, University of Vienna, Vienna, Austria.,Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Julien Martinez
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow, UK
| | - Omar Rota-Stabelli
- Department of Sustainable Agro-Ecosystems and Bioresources, Fondazione Edmund Mach, San Michele all'Adige, Italy
| | | | - Wolfgang J Miller
- Division of Cell and Developmental Biology, Medical University of Vienna, Vienna, Austria
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4
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Harsh S, Fu Y, Kenney E, Han Z, Eleftherianos I. Zika virus non-structural protein NS4A restricts eye growth in Drosophila through regulation of JAK/STAT signaling. Dis Model Mech 2020; 13:dmm040816. [PMID: 32152180 PMCID: PMC7197722 DOI: 10.1242/dmm.040816] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 02/24/2020] [Indexed: 01/08/2023] Open
Abstract
To gain a comprehensive view of the changes in host gene expression underlying Zika virus (ZIKV) pathogenesis, we performed whole-genome RNA sequencing (RNA-seq) of ZIKV-infected Drosophila adult flies. RNA-seq analysis revealed that ZIKV infection alters several and diverse biological processes, including stress, locomotion, lipid metabolism, imaginal disc morphogenesis and regulation of JAK/STAT signaling. To explore the interaction between ZIKV infection and JAK/STAT signaling regulation, we generated genetic constructs overexpressing ZIKV-specific non-structural proteins NS2A, NS2B, NS4A and NS4B. We found that ectopic expression of non-structural proteins in the developing Drosophila eye significantly restricts growth of the larval and adult eye and correlates with considerable repression of the in vivo JAK/STAT reporter, 10XStat92E-GFP At the cellular level, eye growth defects are associated with reduced rate of proliferation without affecting the overall rate of apoptosis. In addition, ZIKV NS4A genetically interacts with the JAK/STAT signaling components; co-expression of NS4A along with the dominant-negative form of domeless or StatRNAi results in aggravated reduction in eye size, while co-expression of NS4A in HopTuml (also known as hopTum ) mutant background partially rescues the hop-induced eye overgrowth phenotype. The function of ZIKV NS4A in regulating growth is maintained in the wing, where ZIKV NS4A overexpression in the pouch domain results in reduced growth linked with diminished expression of Notch targets, Wingless (Wg) and Cut, and the Notch reporter, NRE-GFP Thus, our study provides evidence that ZIKV infection in Drosophila results in restricted growth of the developing eye and wing, wherein eye phenotype is induced through regulation of JAK/STAT signaling, whereas restricted wing growth is induced through regulation of Notch signaling. The interaction of ZIKV non-structural proteins with the conserved host signaling pathways further advance our understanding of ZIKV-induced pathogenesis.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sneh Harsh
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
- NYU Langone Health, Alexandria Center for Life Science, New York, NY 10016, USA
| | - Yulong Fu
- Center for Genetic Medicine Research, Children's National Health System. Department of Genomics and Precision Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA
| | - Eric Kenney
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - Zhe Han
- Center for Genetic Medicine Research, Children's National Health System. Department of Genomics and Precision Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA
| | - Ioannis Eleftherianos
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
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5
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Belmonte RL, Corbally MK, Duneau DF, Regan JC. Sexual Dimorphisms in Innate Immunity and Responses to Infection in Drosophila melanogaster. Front Immunol 2020; 10:3075. [PMID: 32076419 PMCID: PMC7006818 DOI: 10.3389/fimmu.2019.03075] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 12/16/2019] [Indexed: 12/20/2022] Open
Abstract
The sexes show profound differences in responses to infection and the development of autoimmunity. Dimorphisms in immune responses are ubiquitous across taxa, from arthropods to vertebrates. Drosophila melanogaster shows strong sex dimorphisms in immune system responses at baseline, upon pathogenic challenge, and over aging. We have performed an exhaustive survey of peer-reviewed literature on Drosophila immunity, and present a database of publications indicating the sex(es) analyzed in each study. While we found a growing interest in the community in adult immunity and in reporting both sexes, the main body of work in this field uses only one sex, or does not stratify by sex. We synthesize evidence for sexually dimorphic responses to bacterial, viral, and fungal infections. Dimorphisms may be mediated by distinct immune compartments, and we review work on sex differences in behavioral, epithelial, cellular, and systemic (fat body-mediated) immunity. Emerging work on sexually dimorphic aging of immune tissues, immune senescence, and inflammation are examined. We consider evolutionary drivers for sex differences in immune investment, highlight the features of Drosophila biology that make it particularly amenable to studies of immune dimorphisms, and discuss areas for future exploration.
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Affiliation(s)
- Rebecca L. Belmonte
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Mary-Kate Corbally
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - David F. Duneau
- Laboratoire Evolution & Diversite Biologique, UMR5174 EDB, CNRS, Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Jennifer C. Regan
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, United Kingdom
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A Transgenic Flock House Virus Replicon Reveals an RNAi Independent Antiviral Mechanism Acting in Drosophila Follicular Somatic Cells. G3-GENES GENOMES GENETICS 2019; 9:403-412. [PMID: 30530643 PMCID: PMC6385967 DOI: 10.1534/g3.118.200872] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The small interfering RNA (siRNA) pathway is the main and best studied invertebrate antiviral response. Other poorly characterized protein based antiviral mechanisms also contribute to the control of viral replication in insects. In addition, it remains unclear whether tissue specific factors contribute to RNA and protein-based antiviral immunity mechanisms. In vivo screens to identify such factors are challenging and time consuming. In addition, the scored phenotype is usually limited to survival and/or viral load. Transgenic viral replicons are valuable tools to overcome these limitations and screen for novel antiviral factors. Here we describe transgenic Drosophila melanogaster lines encoding a Flock House Virus-derived replicon (FHV∆B2eGFP), expressing GFP as a reporter of viral replication. This replicon is efficiently controlled by the siRNA pathway in most somatic tissues, with GFP fluorescence providing a reliable marker for the activity of antiviral RNAi. Interestingly, in follicular somatic cells (FSC) of ovaries, this replicon is still partially repressed in an siRNA independent manner. We did not detect replicon derived Piwi-interacting RNAs in FSCs and identified 31 differentially expressed genes between restrictive and permissive FSCs. Altogether, our results uncovered a yet unidentified RNAi-independent mechanism controlling FHV replication in FSCs of ovaries and validate the FHV∆B2eGFP replicon as a tool to screen for novel tissue specific antiviral mechanisms.
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7
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Harsh S, Ozakman Y, Kitchen SM, Paquin-Proulx D, Nixon DF, Eleftherianos I. Dicer-2 Regulates Resistance and Maintains Homeostasis against Zika Virus Infection in Drosophila. THE JOURNAL OF IMMUNOLOGY 2018; 201:3058-3072. [PMID: 30305326 DOI: 10.4049/jimmunol.1800597] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 09/17/2018] [Indexed: 12/13/2022]
Abstract
Zika virus (ZIKV) outbreaks pose a massive public health threat in several countries. We have developed an in vivo model to investigate the host-ZIKV interaction in Drosophila We have found that a strain of ZIKV replicates in wild-type flies without reducing their survival ability. We have shown that ZIKV infection triggers RNA interference and that mutating Dicer-2 results in enhanced ZIKV load and increased susceptibility to ZIKV infection. Using a flavivirus-specific Ab, we have found that ZIKV is localized in the gut and fat body cells of the infected wild-type flies and results in their perturbed homeostasis. In addition, Dicer-2 mutants display severely reduced insulin activity, which could contribute toward the increased mortality of these flies. Our work establishes the suitability of Drosophila as the model system to study host-ZIKV dynamics, which is expected to greatly advance our understanding of the molecular and physiological processes that determine the outcome of this disease.
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Affiliation(s)
- Sneh Harsh
- Department of Biological Sciences, The Institute for Biomedical Sciences, The George Washington University, Washington, DC 20052; and
| | - Yaprak Ozakman
- Department of Biological Sciences, The Institute for Biomedical Sciences, The George Washington University, Washington, DC 20052; and
| | - Shannon M Kitchen
- Department of Microbiology, Immunology, and Tropical Medicine, GW School of Medicine & Health Sciences, The George Washington University, Washington, DC 20052
| | - Dominic Paquin-Proulx
- Department of Microbiology, Immunology, and Tropical Medicine, GW School of Medicine & Health Sciences, The George Washington University, Washington, DC 20052
| | - Douglas F Nixon
- Department of Microbiology, Immunology, and Tropical Medicine, GW School of Medicine & Health Sciences, The George Washington University, Washington, DC 20052
| | - Ioannis Eleftherianos
- Department of Biological Sciences, The Institute for Biomedical Sciences, The George Washington University, Washington, DC 20052; and
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8
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Elmaci İ, Altinoz MA. Recrudescence of herpes virus infections following resection of schwannomas. An antiviral role of merlin? Med Hypotheses 2017; 102:128-129. [PMID: 28478817 DOI: 10.1016/j.mehy.2017.03.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 01/21/2017] [Accepted: 03/21/2017] [Indexed: 10/19/2022]
Abstract
After schwannoma resection, reactivation of herpes infections were reported. Also, IgM antibody titers against Herpes viri increase among 30% of patients, who develop fascial palsy following schwannoma resection. Merlin interacts with p53 pathway and seems to function as a suppressor of viral propagation. Loss of merlin may increase viral particles in nerve fascicles, yet these may fail to cause infections due to immunostimulation by other aberrant antigens present in schwannoma cells. Removal of schwannomas may decrease the antigenic diversity and trigger viral recrudescence. Understanding the viral etiology - molecular merlin interactions in schwannoma tissues may also help to develop strategies against delayed fascial palsy seen following schwannoma resection.
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piRNA pathway is not required for antiviral defense in Drosophila melanogaster. Proc Natl Acad Sci U S A 2016; 113:E4218-27. [PMID: 27357659 DOI: 10.1073/pnas.1607952113] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Since its discovery, RNA interference has been identified as involved in many different cellular processes, and as a natural antiviral response in plants, nematodes, and insects. In insects, the small interfering RNA (siRNA) pathway is the major antiviral response. In recent years, the Piwi-interacting RNA (piRNA) pathway also has been implicated in antiviral defense in mosquitoes infected with arboviruses. Using Drosophila melanogaster and an array of viruses that infect the fruit fly acutely or persistently or are vertically transmitted through the germ line, we investigated in detail the extent to which the piRNA pathway contributes to antiviral defense in adult flies. Following virus infection, the survival and viral titers of Piwi, Aubergine, Argonaute-3, and Zucchini mutant flies were similar to those of wild type flies. Using next-generation sequencing of small RNAs from wild type and siRNA mutant flies, we showed that no viral-derived piRNAs were produced in fruit flies during different types of viral infection. Our study provides the first evidence, to our knowledge, that the piRNA pathway does not play a major role in antiviral defense in adult Drosophila and demonstrates that viral-derived piRNA production depends on the biology of the host-virus combination rather than being part of a general antiviral process in insects.
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10
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Peterson JS, Timmons AK, Mondragon AA, McCall K. The End of the Beginning: Cell Death in the Germline. Curr Top Dev Biol 2015; 114:93-119. [PMID: 26431565 DOI: 10.1016/bs.ctdb.2015.07.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Programmed cell death occurs in the germline of many organisms, both as an essential part of development and throughout adult life. Germline cell death can be apoptotic or nonapoptotic, depending on the stimulus or stage of development. Here, we focus on the Drosophila ovary, which is a powerful model for studying diverse types of cell death. In Drosophila, the death of primordial germ cells occurs normally during embryonic development, and germline nurse cells are programmed to die during oocyte development in adult flies. Cell death of previtellogenic egg chambers in adults can also be induced by starvation or other environmental cues. Mid-oogenesis seems to be particularly sensitive to such cues and has been proposed to serve as a checkpoint to avoid the energetically expensive cost of egg production. After the germline dies in mid-oogenesis, the remnants are engulfed by an epithelial layer of follicle cells; thus, the fly ovary also serves as a highly tractable model for engulfment by epithelial cells. These examples of cell death in the fly ovary share many similarities to the types of cell death seen in the mammalian germline. Recent progress in elucidating the molecular mechanisms of cell death in the germline is discussed.
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Affiliation(s)
- Jeanne S Peterson
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Allison K Timmons
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | | | - Kimberly McCall
- Department of Biology, Boston University, Boston, Massachusetts, USA.
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11
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Bashir-Tanoli S, Tinsley MC. Immune response costs are associated with changes in resource acquisition and not resource reallocation. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12236] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | - Matthew C. Tinsley
- Biological and Environmental Sciences; University of Stirling; Stirling FK9 4LA UK
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12
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Xu J, Cherry S. Viruses and antiviral immunity in Drosophila. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 42:67-84. [PMID: 23680639 PMCID: PMC3826445 DOI: 10.1016/j.dci.2013.05.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/26/2013] [Accepted: 05/02/2013] [Indexed: 05/10/2023]
Abstract
Viral pathogens present many challenges to organisms, driving the evolution of a myriad of antiviral strategies to combat infections. A wide variety of viruses infect invertebrates, including both natural pathogens that are insect-restricted, and viruses that are transmitted to vertebrates. Studies using the powerful tools in the model organism Drosophila have expanded our understanding of antiviral defenses against diverse viruses. In this review, we will cover three major areas. First, we will describe the tools used to study viruses in Drosophila. Second, we will survey the major viruses that have been studied in Drosophila. And lastly, we will discuss the well-characterized mechanisms that are active against these diverse pathogens, focusing on non-RNAi mediated antiviral mechanisms. Antiviral RNAi is discussed in another paper in this issue.
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Affiliation(s)
- Jie Xu
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Kanda RK, Tristem M, Coulson T. Exploring the effects of immunity and life history on the dynamics of an endogenous retrovirus. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120505. [PMID: 23938754 DOI: 10.1098/rstb.2012.0505] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mammalian DNA is littered with the signatures of past retroviral infections. For example, at least 8% of the human genome can be attributed to endogenous retroviruses (ERVs). We take a single-locus approach to develop a simple susceptible-infected-recovered model to investigate the circumstances under which a disease-causing retrovirus can become incorporated into the host genome and spread through the host population if it were to confer an immunological advantage. In the absence of any fitness benefit provided by the long terminal repeat (LTR), we conclude that signatures of ERVs are likely to go to fixation within a population when the probability of evolving cellular/humoral immunity to a related exogenous version of the virus is extremely small. We extend this model to examine whether changing the speed of the host life history influences the likelihood that an exogenous retrovirus will incorporate and spread to fixation. Our results reveal the parameter space under which incorporation of exogenous retroviruses into a host genome may be beneficial to the host. In our final model, we find that the likelihood of an LTR reaching fixation in a host population is not strongly affected by host life history.
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Affiliation(s)
- R K Kanda
- Department of Zoology, University of Oxford, , Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
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Kurus M, Karakaya C, Karalok MH, To G, Johnson J. The Control of Oocyte Survival by Intrinsic and Extrinsic Factors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 761:7-18. [DOI: 10.1007/978-1-4614-8214-7_2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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