The Diversity, Structure, and Function of Heritable Adaptive Immunity Sequences in the Aedes aegypti Genome

Whitfield, Zachary J.; Dolan, Patrick; Kunitomi, Mark; Tassetto, Michel; Seetin, Matthew G.; Oh, Steve D.; Heiner, Cheryl; Paxinos, Ellen E.; Andino, Raul

doi:10.1016/j.cub.2017.09.067

Cited by 172 publications

(264 citation statements)

References 58 publications

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“…We then created a custom database comprised of all single-stranded DNA (ssDNA) and nonretroviral RNA virus protein sequences available in GenBank and used this database to identify putative EVEs genome wide in each arthropod genome via BLASTx. As reported previously, we found that a large number of putative EVEs could not be unambiguously classified as viral due to homology with eukaryotic, bacterial, or archaeal sequences (14). We removed the majority of putative EVEs that were homologous to eukaryotic sequences via reverse BLAST searches against the D. melanogaster proteome.…”

Section: Resultsmentioning

confidence: 99%

Endogenous Viral Elements Are Widespread in Arthropod Genomes and Commonly Give Rise to PIWI-Interacting RNAs

Horst

Nigg

Dekker

et al. 2019

J Virol

100

117

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Arthropod genomes contain sequences derived from integrations of DNA and nonretroviral RNA viruses. These sequences, known as endogenous viral elements (EVEs), have been acquired over the course of evolution and have been proposed to serve as a record of past viral infections. Recent evidence indicates that EVEs can function as templates for the biogenesis of PIWI-interacting RNAs (piRNAs) in some mosquito species and cell lines, raising the possibility that EVEs may serve as a source of immunological memory in these organisms. However, whether piRNAs are derived from EVEs or serve an antiviral function in other arthropod species is unknown. Here, we used publicly available genome assemblies and small RNA sequencing data sets to characterize the repertoire and function of EVEs across 48 arthropod genomes. We found that EVEs are widespread in arthropod genomes and primarily correspond to unclassified single-stranded RNA (ssRNA) viruses and viruses belonging to theRhabdoviridaeandParvoviridaefamilies. Additionally, EVEs were enriched in piRNA clusters in a majority of species, and we found that production of primary piRNAs from EVEs is common, particularly for EVEs located within piRNA clusters. While the abundance of EVEs within arthropod genomes and the frequency with which EVEs give rise to primary piRNAs generally support the hypothesis that EVEs contribute to an antiviral response via the piRNA pathway, limited nucleotide identity between currently described viruses and EVEs identified here likely limits the extent to which this process plays a role during infection with known viruses in the arthropod species analyzed.IMPORTANCEOur results greatly expand the knowledge of EVE abundance, diversity, and function in an exceptionally wide range of arthropod species. We found that while previous findings in mosquitoes regarding the potential of EVEs to serve as sources of immunological memory via the piRNA pathway may be generalized to other arthropod species, speculation regarding the antiviral function of EVE-derived piRNAs should take into context the fact that EVEs are, in the vast majority of cases, not similar enough to currently described viruses at the nucleotide level to serve as sources of antiviral piRNAs against them.

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Section: Resultsmentioning

confidence: 99%

Endogenous Viral Elements Are Widespread in Arthropod Genomes and Commonly Give Rise to PIWI-Interacting RNAs

Horst

Nigg

Dekker

et al. 2019

J Virol

100

117

View full text Add to dashboard Cite

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“…BHK cells (Aguirre et al, 2017) (unsexed) were cultured in minimal essential medium α (MEM α) (Thermo Fisher), supplemented with 10% FBS (Thermo Fisher), GlutaMAX (Thermo Fisher), 100 U/mL penicillin (Thermo Fisher), 100 μg/mL streptomycin (Thermo Fisher), and 10 mM HEPES (Thermo Fisher). Aag2 cells (Whitfield et al, 2017) (unknown gender) were culture in Schneider’s Drosophila medium (Invitrogen) supplemented with 10% FBS (Invitrogen), 1% pen/strep and 1% non-essential amino acids. C6/36 cells (Alvarez et al, 2005) (unknown gender) were cultured in L-15 medium supplemented with 10% FBS (Invitrogen), 1% pen/strep and 1% non-essential amino acids.…”

Section: Star Methodsmentioning

confidence: 99%

Comparative Flavivirus-Host Protein Interaction Mapping Reveals Mechanisms of Dengue and Zika Virus Pathogenesis

Shah

Link

Jang

et al. 2018

Cell

Self Cite

287

355

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Mosquito-borne flaviviruses, including dengue virus (DENV) and Zika virus (ZIKV), are a growing public health concern. Systems level analysis of how flaviviruses hijack cellular processes through virus-host protein-protein interactions (PPIs) provide information about their replication and pathogenic mechanisms. We used affinity purification-mass spectrometry (AP-MS) to compare flavivirus-host interactions for two viruses (DENV and ZIKV) in two hosts (human and mosquito). Conserved virus-host PPIs revealed that the flavivirus NS5 protein suppresses interferon stimulated genes by inhibiting recruitment of the transcription complex PAF1C, and that chemical modulation of SEC61 inhibits DENV and ZIKV replication in human and mosquito cells. Finally, we identified a ZIKV-specific interaction between NS4A and ANKLE2, a gene linked to hereditary microcephaly, and showed that ZIKV NS4A causes microcephaly in Drosophila in an ANKLE2-dependent manner. Thus, comparative flavivirus-host PPI mapping provides biological insights, and when coupled with in vivo models, can be used to unravel pathogenic mechanisms.

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“…We were ultimately interested in studying the potential impact of persistent PCLV infection on acute superinfection with arboviruses in our Aag2-derived clonal cell lines, and therefore first investigated whether sequences derived from PCLV specifically are also integrated into the parental Aag2 cell genome. We performed a BLASTn search against the Aag2 reference genome [70] using our previously published full-length genome sequences for the PCLV known to infect the parental Aag2 cell line [57]. We did not identify any statistically significant (E-value <10 −5 ) PCLV-derived sequences from any of the three viral genome segments (L, M, S) in the Aag2 reference genome sequence.…”

Section: Resultsmentioning

confidence: 99%

“…Our previously published full-length PCLV genome sequences from Aag2 cells (Genbank accession numbers KU936055, KU936056 and KU936057) [57] were searched against the Aag2 cell reference genome [70] using the BLAST function at vectorbase.org [71].…”

Section: Methodsmentioning

confidence: 99%

Aedes aegypti (Aag2)-derived clonal mosquito cell lines reveal the impact of pre-existing persistent infection with the insect-specific bunyavirus Phasi Charoen-like virus on arbovirus replication

Fredericks

Wallace

Russell

et al. 2019

Preprint

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BackgroundAedes aegypti is a vector mosquito of major public health importance, transmitting arthropod-borne viruses (arboviruses) such as chikungunya, dengue, yellow fever and Zika viruses. Wild mosquito populations are persistently infected at high prevalence with insect-specific viruses that do not replicate in vertebrate hosts. In experimental settings, acute infections with insect-specific viruses have been shown to modulate arbovirus infection and transmission in Ae. aegypti and other vector mosquitoes. However, the impact of persistent insect-specific virus infections that more closely mimic the situation in nature has not been investigated extensively. Cell lines are useful models for studying virus-host interactions, however the available Ae. aegypti cell lines are poorly defined and heterogenous cultures.Methodology/Principle FindingsWe generated single cell-derived clonal cell lines from the commonly used Ae. aegypti cell line Aag2. Two of the fourteen Aag2-derived clonal cell lines generated harboured markedly and consistently reduced levels of the insect-specific bunyavirus Phasi Charoen-like virus (PCLV) known to persistently infect Aag2 cells. In contrast to studies with acute insect-specific virus infections in cell culture and in vivo, we found that pre-existing persistent PCLV infection had no major impact on the replication of the flaviviruses dengue virus and Zika virus, the alphavirus Sindbis virus, or the rhabdovirus vesicular stomatitis virus. We also performed a detailed characterisation of the morphology, transfection efficiency and immune status of our Aag2-derived clonal cell lines, and have made a clone that we term Aag2-AF5 available to the research community as a well-defined cell culture model for arbovirus-vector interaction studies.Conclusions/SignificanceOur findings highlight the need for further in vivo studies that more closely recapitulate natural arbovirus transmission settings in which arboviruses encounter mosquitoes harbouring persistent rather than acute insect-specific virus infections. Furthermore, we provide the well-characterised Aag2-derived clonal cell line as a valuable resource to the arbovirus research community.AUTHOR SUMMARYMosquito-borne viruses usually only infect humans through the bite of a mosquito that carries the virus. Viruses transmitted by the ‘yellow fever mosquito’ Aedes aegypti, including dengue virus, Zika virus, yellow fever virus and chikungunya virus, are causing an ever-increasing number of human disease cases globally. Mosquito-borne viruses have to infect and replicate inside the mosquito before they are transmitted to humans, and the presence of other infectious agents can change the efficiency of virus transmission. Mosquitoes are known to be infected with ‘insect-specific viruses’ that only infect mosquitoes and cannot cause human disease. We have shown here that in laboratory cell cultures derived from the Aedes aegypti mosquito, pre-existing infection with an insect-specific virus called Phasi Charoen-like virus does not affect the infection and growth of the mosquito-borne viruses dengue virus, Zika virus, Sindbis virus or vesicular stomatitis virus. Compared to previous research, our research is more reflective of conditions that mosquito-borne viruses encounter in nature, and our results provide important new insights into whether and how insect-specific viruses affect mosquito-borne virus transmission. Ultimately, this information could inform ongoing research into whether insect-specific viruses could be used to prevent the transmission of mosquito-borne viruses to reduce global disease burdens.

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The Diversity, Structure, and Function of Heritable Adaptive Immunity Sequences in the Aedes aegypti Genome

Cited by 172 publications

References 58 publications

Endogenous Viral Elements Are Widespread in Arthropod Genomes and Commonly Give Rise to PIWI-Interacting RNAs

Endogenous Viral Elements Are Widespread in Arthropod Genomes and Commonly Give Rise to PIWI-Interacting RNAs

Comparative Flavivirus-Host Protein Interaction Mapping Reveals Mechanisms of Dengue and Zika Virus Pathogenesis

Aedes aegypti (Aag2)-derived clonal mosquito cell lines reveal the impact of pre-existing persistent infection with the insect-specific bunyavirus Phasi Charoen-like virus on arbovirus replication

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