Evolution and biological significance of flaviviral elements in the genome of the arboviral vector Aedes albopictus

Emerg Microbes Infect. 2019;8(1):1265-1279. doi: 10.1080/22221751.2019.1657785.

Abstract

Since its genome details are publically available, the mosquito Aedes albopictus has become the central stage of attention for deciphering multiple biological and evolutionary aspects at the root of its success as an invasive species. Its genome of 1,967 Mb harbours an unusual high number of non-retroviral integrated RNA virus sequences (NIRVS). NIRVS are enriched in piRNA clusters and produce piRNAs, suggesting an antiviral effect. Here, we investigated the evolutionary history of NIRVS in geographically distant Ae. albopictus populations by comparing genetic variation as derived by neutral microsatellite loci and seven selected NIRVS. We found that the evolution of NIRVS was far to be neutral with variations both in their distribution and sequence polymorphism among Ae. albopictus populations. The Flaviviral elements AlbFlavi2 and AlbFlavi36 were more deeply investigated in their association with dissemination rates of dengue virus (DENV) and chikungunya virus (CHIKV) in Ae. albopictus at both population and individual levels. Our results show a complex association between NIRVS and DENV/CHIKV opening a new avenue for investigating the functional role of NIRVS as antiviral elements shaping vector competence of mosquitoes to arboviruses.

Keywords: NIRVS; arboviral diseases; genetic structure; vector competence.

MeSH terms

  • Aedes / genetics*
  • Aedes / immunology
  • Aedes / virology
  • Animals
  • Chikungunya virus / isolation & purification
  • Dengue Virus / isolation & purification
  • Evolution, Molecular*
  • Flaviviridae / genetics*
  • Genome, Insect*
  • Mosquito Vectors / genetics*
  • Mosquito Vectors / immunology
  • Mosquito Vectors / virology
  • RNA, Small Interfering / genetics

Substances

  • RNA, Small Interfering

Grant support

This study was supported by the Institut Pasteur, the French Government’s Investissement d’Avenir program, Laboratoire d’Excellence “Integrative Biology of Emerging Infectious Diseases” (grant number ANR-10-LABX-62-IBEID to A-BF), the European Union’s Horizon 2020 research and innovation program, ZIKAlliance program under ZIKAlliance grant agreement no. 734548 to A-BF, and the European Research Council, NIRV_HOST_INT Council (grant agreement number 682394 – NIRV_HOST_INT to VH and MB).