Discovery of flavivirus-derived endogenous viral elements in<i>Anopheles</i>mosquito genomes supports the existence of<i>Anopheles</i>-associated insect-specific flaviviruses

Lequime, Sébastian; Lambrechts, Louis

doi:10.1093/ve/vew035

Cited by 48 publications

(32 citation statements)

References 42 publications

(51 reference statements)

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“…Flavivirus endogenous viral elements (EVEs) are fragments of flaviviruses that are known to be integrated within the genomic DNA of a previously infected host (60). Flaviviruses do not encode reverse transcriptase or integrase domains, but flavivirus EVEs are reported in the genomes of two well-known flavivirus vectors, Aedes aegypti and Aedes albopictus (60,61), as well as those of Anopheles mosquitoes (62). We sought to identify previous flavivirus infections in crustacean or cephalopod genomes by identifying these EVEs.…”

Section: Resultsmentioning

confidence: 99%

Discovery of Novel Crustacean and Cephalopod Flaviviruses: Insights into the Evolution and Circulation of Flaviviruses between Marine Invertebrate and Vertebrate Hosts

Parry

Asgari

2019

J Virol

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Most described flaviviruses (family Flaviviridae) are disease-causing pathogens of vertebrates maintained in zoonotic cycles between mosquitoes or ticks and vertebrate hosts. Poor sampling of flaviviruses outside vector-borne flaviviruses such as Zika virus and dengue virus has presented a narrow understanding of flavivirus diversity and evolution. In this study, we discovered three crustacean flaviviruses (Gammarus chevreuxi flavivirus, Gammarus pulex flavivirus, and Crangon crangon flavivirus) and two cephalopod flaviviruses (Southern Pygmy squid flavivirus and Firefly squid flavivirus). Bayesian and maximum likelihood phylogenetic methods demonstrate that crustacean flaviviruses form a well-supported clade and share a more closely related ancestor with terrestrial vector-borne flaviviruses than with classical insect-specific flaviviruses. In addition, we identify variants of Wenzhou shark flavivirus in multiple gazami crab (Portunus trituberculatus) populations, with active replication supported by evidence of an active RNA interference response. This suggests that Wenzhou shark flavivirus moves horizontally between sharks and gazami crabs in ocean ecosystems. Analyses of the mono-and dinucleotide composition of marine flaviviruses compared to that of flaviviruses with known host status suggest that some marine flaviviruses share a nucleotide bias similar to that of vector-borne flaviviruses. Furthermore, we identify crustacean flavivirus endogenous viral elements that are closely related to elements of terrestrial vector-borne flaviviruses. Taken together, these data provide evidence of flaviviruses circulating between marine vertebrates and invertebrates, expand our understanding of flavivirus host range, and offer potential insights into the evolution and emergence of terrestrial vector-borne flaviviruses.IMPORTANCE Some flaviviruses are known to cause disease in vertebrates and are typically transmitted by blood-feeding arthropods such as ticks and mosquitoes. While an ever-increasing number of insect-specific flaviviruses have been described, we have a narrow understanding of flavivirus incidence and evolution. To expand this understanding, we discovered a number of novel flaviviruses that infect a range of crustaceans and cephalopod hosts. Phylogenetic analyses of these novel marine flaviviruses suggest that crustacean flaviviruses share a close ancestor to all terrestrial vector-borne flaviviruses, and squid flaviviruses are the most divergent of all known flaviviruses to date. Additionally, our results indicate horizontal transmission of a marine flavivirus between crabs and sharks. Taken together, these data suggest that flaviviruses move horizontally between invertebrates and vertebrates in ocean ecosystems. This study demonstrates that flavivirus invertebrate-vertebrate host associations have arisen in flaviviruses at least twice and may potentially provide insights into the emergence or origin of terrestrial vector-borne flaviviruses. FIG 2 Translation of a complete polyprotein depends on highly st...

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Section: Resultsmentioning

confidence: 99%

Discovery of Novel Crustacean and Cephalopod Flaviviruses: Insights into the Evolution and Circulation of Flaviviruses between Marine Invertebrate and Vertebrate Hosts

Parry

Asgari

2019

J Virol

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“…Flavivirus infection is a major public health concern worldwide 1 . Duck tembusu virus (DTMUV) is a member of the genus Flavivirus whose incidence exploded in China in 2010 2 .…”

Section: Introductionmentioning

confidence: 99%

Oral Delivery of a DNA Vaccine Expressing the PrM and E Genes: A Promising Vaccine Strategy against Flavivirus in Ducks

Huang

Jia

Shen

et al. 2018

Sci Rep

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A flavivirus, named duck tembusu virus (DTMUV), emerged in China in 2010. This virus has caused great economic losses in the poultry industry in China and may pose a threat to public health. As a safe, efficient and convenient vaccine development strategy, DNA-based vaccines have become a popular approach for both human and veterinary applications. Attenuated bacteria have been widely used as vehicles to deliver heterologous antigens to the immune system. Thus, an efficient and low-cost oral delivery DNA vaccine SL7207 (pVAX1-SME) based on envelope proteins (prM and E) of DTMUV and attenuated Salmonella typhimurium aroA- strain SL7207 was developed and evaluated in this study. The prM and E antigen proteins were successfully expressed from the vaccine SL7207 (pVAX1-SME) both in vitro and in vivo. High titers of the specific antibody against the DTMUV-E protein and the neutralizing antibody against the DTMUV virus were both detected after vaccination with SL7207 (pVAX1-SME). Ducks orally vaccinated with the SL7207 (pVAX-SME) vaccine were efficiently protected from lethal DTMUV infection in this study. Taken together, we demonstrated that prM and E proteins of DTMUV possess strong immunogenicity against the DTMUV infection. Moreover, an oral delivery of the DNA vaccine SL7207 (pVAX1-SME) utilizing Salmonella SL7207 was an efficient way to protect the ducks against DTMUV infection and provides an economic and fast vaccine delivery strategy for a large-scale clinical use.

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“…Viral DNA fragments have been found to be integrated into host genomes [ 8 , 209 , 210 ]. Whereas viral integrations are prevalent in Culicidae genomes, amazingly, Aedes mosquitoes have 10 times more EVEs than other mosquito species [ 211 , 212 , 213 , 214 ]. This striking capacity may reflect on the repetitive genomes of Ae.…”

Section: Viral Pirnas In Drosophila Versus Mosqmentioning

confidence: 99%

Diverse Defenses: A Perspective Comparing Dipteran Piwi-piRNA Pathways

Gamez

Srivastav

Akbari

et al. 2020

Cells

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Animals face the dual threat of virus infections hijacking cellular function and transposons proliferating in germline genomes. For insects, the deeply conserved RNA interference (RNAi) pathways and other chromatin regulators provide an important line of defense against both viruses and transposons. For example, this innate immune system displays adaptiveness to new invasions by generating cognate small RNAs for targeting gene silencing measures against the viral and genomic intruders. However, within the Dipteran clade of insects, Drosophilid fruit flies and Culicids mosquitoes have evolved several unique mechanistic aspects of their RNAi defenses to combat invading transposons and viruses, with the Piwi-piRNA arm of the RNAi pathways showing the greatest degree of novel evolution. Whereas central features of Piwi-piRNA pathways are conserved between Drosophilids and Culicids, multiple lineage-specific innovations have arisen that may reflect distinct genome composition differences and specific ecological and physiological features dividing these two branches of Dipterans. This perspective review focuses on the most recent findings illuminating the Piwi/piRNA pathway distinctions between fruit flies and mosquitoes, and raises open questions that need to be addressed in order to ameliorate human diseases caused by pathogenic viruses that mosquitoes transmit as vectors.

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Discovery of flavivirus-derived endogenous viral elements inAnophelesmosquito genomes supports the existence ofAnopheles-associated insect-specific flaviviruses

Cited by 48 publications

References 42 publications

Discovery of Novel Crustacean and Cephalopod Flaviviruses: Insights into the Evolution and Circulation of Flaviviruses between Marine Invertebrate and Vertebrate Hosts

Discovery of Novel Crustacean and Cephalopod Flaviviruses: Insights into the Evolution and Circulation of Flaviviruses between Marine Invertebrate and Vertebrate Hosts

Oral Delivery of a DNA Vaccine Expressing the PrM and E Genes: A Promising Vaccine Strategy against Flavivirus in Ducks

Diverse Defenses: A Perspective Comparing Dipteran Piwi-piRNA Pathways

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