scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Infection patterns of o'nyong nyong virus in the malaria-transmitting mosquito, Anopheles gambiae.

TL;DR: A series of recombinant alphaviruses, based upon the genome of ONNV, designed for the expression of heterologous genes, that will be a valuable asset in parasite–mosquito interaction and interference research and to serve as tools for antimalaria studies.
Abstract: Arthropod-borne alphaviruses transmitted by mosquitoes almost exclusively use culicines; however, the alphavirus o'nyong-nyong (ONNV) has the unusual characteristic of being transmitted primarily by anopheline mosquitoes This unusual attribute makes ONNV a valuable tool in the characterization of mosquito determinants of infection as well as a useful expression system in Anopheles species We developed a series of recombinant alphaviruses, based upon the genome of ONNV, designed for the expression of heterologous genes The backbone genome is a full-length infectious cDNA clone of ONNV from which wild-type virus can be rescued Additional constructs are variants of the primary clone and contain the complete genome plus a duplicated subgenomic promoter element with a multiple cloning site for insertion of heterologous genes We inserted a green fluorescent protein (GFP) gene downstream of this promoter and used it to characterize infection and dissemination patterns of ONNV within An gambiae mosquitoes These experiments allowed us to identify atypical sites of initial infection and dissemination patterns in this mosquito species not frequently observed in comparable culicine infections The utility of these ONNVs for studies in anopheline mosquitoes includes the potential for identification of vector infection determinants and to serve as tools for antimalaria studies Viruses that can express a heterologous gene in a vector and rapidly and efficiently infect numerous tissues in An gambiae mosquitoes will be a valuable asset in parasite-mosquito interaction and interference research
Citations
More filters
Journal ArticleDOI
30 Jan 2014-Nature
TL;DR: Comparative analysis reveals that the screened ISGs target positive-sense single-stranded RNA viruses more effectively than negative-sensesingle-strander RNA viruses.
Abstract: The type I interferon (IFN) response protects cells from viral infection by inducing hundreds of interferon-stimulated genes (ISGs), some of which encode direct antiviral effectors. Recent screening studies have begun to catalogue ISGs with antiviral activity against several RNA and DNA viruses. However, antiviral ISG specificity across multiple distinct classes of viruses remains largely unexplored. Here we used an ectopic expression assay to screen a library of more than 350 human ISGs for effects on 14 viruses representing 7 families and 11 genera. We show that 47 genes inhibit one or more viruses, and 25 genes enhance virus infectivity. Comparative analysis reveals that the screened ISGs target positive-sense single-stranded RNA viruses more effectively than negative-sense single-stranded RNA viruses. Gene clustering highlights the cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS, also known as MB21D1) as a gene whose expression also broadly inhibits several RNA viruses. In vitro, lentiviral delivery of enzymatically active cGAS triggers a STING-dependent, IRF3-mediated antiviral program that functions independently of canonical IFN/STAT1 signalling. In vivo, genetic ablation of murine cGAS reveals its requirement in the antiviral response to two DNA viruses, and an unappreciated contribution to the innate control of an RNA virus. These studies uncover new paradigms for the preferential specificity of IFN-mediated antiviral pathways spanning several virus families.

765 citations

Journal ArticleDOI
08 Jul 2015-Viruses
TL;DR: The nature of the tissue barriers that arboviruses are confronted with in a mosquito vector and how they might surmount these barriers are explained.
Abstract: Arthropod-borne viruses (arboviruses) circulate in nature between arthropod vectors and vertebrate hosts. Arboviruses often cause devastating diseases in vertebrate hosts, but they typically do not cause significant pathology in their arthropod vectors. Following oral acquisition of a viremic bloodmeal from a vertebrate host, the arbovirus disease cycle requires replication in the cellular environment of the arthropod vector. Once the vector has become systemically and persistently infected, the vector is able to transmit the virus to an uninfected vertebrate host. In order to systemically infect the vector, the virus must cope with innate immune responses and overcome several tissue barriers associated with the midgut and the salivary glands. In this review we describe, in detail, the typical arbovirus infection route in competent mosquito vectors. Based on what is known from the literature, we explain the nature of the tissue barriers that arboviruses are confronted with in a mosquito vector and how arboviruses might surmount these barriers. We also point out controversial findings to highlight particular areas that are not well understood and require further research efforts.

332 citations

Journal ArticleDOI
TL;DR: It is shown that silencing RNAi components in Ae.
Abstract: RNA interference (RNAi) is an important anti-viral defense mechanism. The Aedes aegypti genome encodes RNAi component orthologs, however, most populations of this mosquito are readily infected by, and subsequently transmit flaviviruses and alphaviruses. The goal of this study was to use Ae. aegypti as a model system to determine how the mosquito's anti-viral RNAi pathway interacts with recombinant Sindbis virus (SINV; family Togaviridae, genus Alphavirus). SINV (TR339-eGFP) (+) strand RNA, infectious virus titers and infection rates transiently increased in mosquitoes following dsRNA injection to cognate Ago2, Dcr2, or TSN mRNAs. Detection of SINV RNA-derived small RNAs at 2 and 7 days post-infection in non-silenced mosquitoes provided important confirmation of RNAi pathway activity. Two different recombinant SINV viruses (MRE16-eGFP and TR339-eGFP) with significant differences in infection kinetics were used to delineate vector/virus interactions in the midgut. We show virus-dependent effects on RNAi component transcript and protein levels during infection. Monitoring midgut Ago2, Dcr2, and TSN transcript levels during infection revealed that only TSN transcripts were significantly increased in midguts over blood-fed controls. Ago2 protein levels were depleted immediately following a non-infectious bloodmeal and varied during SINV infection in a virus-dependent manner. We show that silencing RNAi components in Ae. aegypti results in transient increases in SINV replication. Furthermore, Ae. aegypti RNAi is active during SINV infection as indicated by production of virus-specific siRNAs. Lastly, the RNAi response varies in a virus-dependent manner. These data define important features of RNAi anti-viral defense in Ae. aegypti.

229 citations


Cites methods from "Infection patterns of o'nyong nyong..."

  • ...We used MRE16-eGFP whole genome capture probes, as these two viruses share about 75% nucleotide identity [43]....

    [...]

Journal ArticleDOI
TL;DR: It is suggested that an exogenous siRNA pathway is essential to the survival of mosquitoes infected with alphaviruses and, thus, the maintenance of these viruses in nature.
Abstract: Mosquito-borne viruses cause significant levels of morbidity and mortality in humans and domesticated animals. Maintenance of mosquito-borne viruses in nature requires a biological transmission cycle that involves alternating virus replication in a susceptible vertebrate and mosquito host. Although the vertebrate infection is acute and often associated with disease, continual transmission of these viruses in nature depends on the establishment of a persistent, nonpathogenic infection in the mosquito vector. An antiviral RNAi response has been shown to limit the replication of RNA viruses in flies. However, the importance of the RNAi pathway as an antiviral defense in mammals is unclear. Differences in the immune responses of mammals and mosquitoes may explain why these viruses are not generally associated with pathology in the invertebrate host. We identified virus-derived small interfering RNAs (viRNAs), 21 nt in length, in Aedes aegypti infected with the mosquito-borne virus, Sindbis (SINV). viRNAs had an asymmetric distribution that spanned the length of the SINV genome. To determine the role of viRNAs in controlling pathogenic potential, mosquitoes were infected with recombinant alphaviruses expressing suppressors of RNA silencing. Decreased survival was observed in mosquitoes in which the accumulation of viRNAs was suppressed. These results suggest that an exogenous siRNA pathway is essential to the survival of mosquitoes infected with alphaviruses and, thus, the maintenance of these viruses in nature.

228 citations


Cites background from "Infection patterns of o'nyong nyong..."

  • ...To investigate whether other vectors would also be sensitive to alphaviruses expressing SRS proteins, we injected Anopheles gambiae with double subgenomic o’nyong-nyong virus (dsONNV) derived from the infectious cDNA clone p5 dsONNic/foy (32), or dsONNV expressing the NoV B2 protein [dsONNV-B2 (NoV)]....

    [...]

  • ...0058; Fisher’s exact test) (32), 8 (P 0....

    [...]

  • ...gambiae 7 days after virus ingestion (32)....

    [...]

Journal ArticleDOI
TL;DR: Comparison of the growth kinetics and infection rates of the viral isolate CHIKV strain LR2006 OPY1 (CHIKV-LR) and a full-length infectious clone indicate that the infectious clone has retained the viral phenotypes of the original isolate.
Abstract: The recent outbreak of Chikungunya virus (CHIKV) on several islands in the Indian Ocean and in India has focused attention on this reemerging virus and highlighted the need for development of new tools to study vector-virus-host interactions. We have constructed and characterized, in cell culture, Aedes aegypti and Ae. albopictus mosquitoes, infectious cDNA clones of CHIKV using a recent isolate from La Reunion Island. Comparison of the growth kinetics and infection rates of the viral isolate CHIKV strain LR2006 OPY1 (CHIKV-LR) and a full-length infectious clone (CHIKV-LR ic) indicate that the infectious clone has retained the viral phenotypes of the original isolate. Infectious clones that express green fluorescent protein (GFP) were also produced and characterized in cell culture and in Aedes mosquitoes. The CHIKV-LR 5'GFP infected Ae. aegypti and Ae. albopictus mosquitoes at a similar rate to the original virus and to the full length infectious clone. The CHIKV-LR 3'GFP only infected Ae. albopictus mosquitoes at similar rates. The development of these authentic infectious clones will enable targeted studies of the molecular determinants of infection, pathogenesis and transmission competence by Ae. aegypti and Ae. albopictus mosquitoes.

198 citations

References
More filters
Journal ArticleDOI
TL;DR: Phylogenetic trees corroborated historical evidence that CHIK virus originated in Africa and subsequently was introduced into Asia and revealed that ONN virus is indeed distinct from CHIK viruses, and these viruses probably diverged thousands of years ago.
Abstract: Chikungunya (CHIK) virus is a member of the genus Alphavirus in the family Togaviridae. Serologically, it is most closely related to o’nyong-nyong (ONN) virus and is a member of the Semliki Forest antigenic complex. CHIK virus is believed to be enzootic throughout much of Africa and historical evidence indicates that it spread to other parts of the world from this origin. Strains from Africa and Asia are reported to differ biologically, indicating that distinct lineages may exist. To examine the relatedness of CHIK and ONN viruses using genetic data, we conducted phylogenetic studies on isolates obtained throughout Africa and Southeast Asia. Analyses revealed that ONN virus is indeed distinct from CHIK viruses, and these viruses probably diverged thousands of years ago. Two distinct CHIK virus lineages were delineated, one containing all isolates from western Africa and the second comprising all southern and East African strains, as well as isolates from Asia. Phylogenetic trees corroborated historical evidence that CHIK virus originated in Africa and subsequently was introduced into Asia. Within the eastern Africa and southern Africa/Asia lineage, Asian strains grouped together in a genotype distinct from the African groups. These different geographical genotypes exhibit differences in their transmission cycles: in Asia, the virus appears to be maintained in an urban cycle with Aedes aegypti mosquito vectors, while CHIK virus transmission in Africa involves a sylvatic cycle, primarily with Ae. furcifer and Ae. africanus mosquitoes.

586 citations

08 Nov 1994

397 citations


"Infection patterns of o'nyong nyong..." refers methods in this paper

  • ...Mosquitoes were maintained in colonies and reared under standard conditions (Gerber et al., 1994)....

    [...]

Journal ArticleDOI
22 Jun 2000-Nature
TL;DR: A transposon, based on the Minos element and bearing exogenous DNA, can integrate efficiently and stably into the germ line of the human malaria vector Anopheles stephensi, through a transposase-mediated process.
Abstract: Anopheline mosquito species are obligatory vectors for human malaria, an infectious disease that affects hundreds of millions of people living in tropical and subtropical countries. The lack of a suitable gene transfer technology for these mosquitoes has hampered the molecular genetic analysis of their physiology, including the molecular interactions between the vector and the malaria parasite. Here we show that a transposon, based on the Minos element and bearing exogenous DNA, can integrate efficiently and stably into the germ line of the human malaria vector Anopheles stephensi, through a transposase-mediated process.

395 citations


"Infection patterns of o'nyong nyong..." refers background in this paper

  • ...Recently, many vector biology studies in Anopheles species mosquitoes have relied on labour-intensive germline transformation of the vectors (Catteruccia et al., 2000; Grossman et al., 2001; Nolan et al., 2002; Perera et al., 2002) or the use of vectors designed to integrate into the mosquito…...

    [...]

Journal ArticleDOI
TL;DR: An improvement in the injection technique at the end of the studies resulted in increased G0 hatching, transient expression and EGFP‐expression rates among G1 progeny, and genetic cross data suggest that the insertion site of the element either resulted in, or is tightly linked to, a recessive lethal.
Abstract: Germline transformation of the major African malaria vector, Anopheles gambiae, was achieved using the piggyBac transposable element marked with the enhanced green fluorescent protein (EGFP) injected into mosquito embryos. Two G1 generation male mosquitoes expressing EGFP were identified among 34 143 larvae screened. Genomic Southern data and sequencing of the piggyBac insertion boundaries showed that these two males arose from one piggyBac insertion event in the injected G0 embryos. Genetic cross data suggest that the insertion site of the element either resulted in, or is tightly linked to, a recessive lethal. This was demonstrated by a deficiency in the number of EGFP-expressing offspring from inbred crosses but expected ratios in outcrosses to non-transformed individuals and failure to establish a pure-breeding line. The insertion was weakly linked to the collarless locus on chromosome 2 and was shown by in situ hybridization to be located in division 28D of that chromosome. Particularly high levels of expression were observed uniformly in salivary glands and, in most individuals, in the anterior stomach. An improvement in the injection technique at the end of the studies resulted in increased G0 hatching, transient expression and EGFP-expression rates among G1 progeny.

241 citations


"Infection patterns of o'nyong nyong..." refers background in this paper

  • ...Recently, many vector biology studies in Anopheles species mosquitoes have relied on labour-intensive germline transformation of the vectors (Catteruccia et al., 2000; Grossman et al., 2001; Nolan et al., 2002; Perera et al., 2002) or the use of vectors designed to integrate into the mosquito genome (Matsubara et al....

    [...]

  • ...…biology studies in Anopheles species mosquitoes have relied on labour-intensive germline transformation of the vectors (Catteruccia et al., 2000; Grossman et al., 2001; Nolan et al., 2002; Perera et al., 2002) or the use of vectors designed to integrate into the mosquito genome (Matsubara et…...

    [...]

Journal ArticleDOI
TL;DR: The comparative susceptibility of 13 geographic strains of Aedes aegypti to oral infection with dengue viruses was studied by feeding the mosquitoes on a virus-erythrocyte-sugar suspension, suggesting that the factors controlling susceptibility were the same for all types.
Abstract: The comparative susceptibility of 13 geographic strains of Aedes aegypti to oral infection with dengue viruses was studied by feeding the mosquitoes on a virus-erythrocyte-sugar suspension. Significant variation in susceptibility to four dengue serotypes was observed among the geographic strains tested. Mosquito strains which were more susceptible to one serotype were also more susceptible to the other serotypes, suggesting that the factors controlling susceptibility were the same for all types. The amount of virus required to infect mosquitoes orally varied inversely with the susceptibility of the geographic strain. Thresholds of infection were not the same for dengue types 1, 2, 3 and 4. There was no apparent difference in infectivity between prototype and recently isolated strains of dengue types 1 and 3. Crossing experimentibility as the resistant parent. No difference was observed between resistant and susceptible mosquito strains in the rate or the amount of viral replication after infection by the parenteral route, or in their ability to transmit dengue 2 virus after infection by the oral route.

230 citations


"Infection patterns of o'nyong nyong..." refers background in this paper

  • ...gambiae mosquitoes and numerous papers have demonstrated mosquito strain variation in susceptibility to various arboviruses (Gubler et al., 1979; Hayes et al., 1984; Boromisa et al., 1987; Banerjee et al., 1988; Turell et al., 1992; Failloux et al., 2002)....

    [...]

  • ...…study examined only one strain (G3) of An. gambiae mosquitoes and numerous papers have demonstrated mosquito strain variation in susceptibility to various arboviruses (Gubler et al., 1979; Hayes et al., 1984; Boromisa et al., 1987; Banerjee et al., 1988; Turell et al., 1992; Failloux et al., 2002)....

    [...]