I investigated the viral genetic determinants underlying the different mosquito-borne transmissibility between Asian and African lineage ZIKV strains by comparing an African strain and an Asian strain using chimeric viruses, in which segments of the parental genomes are swapped.
My results show that the structural genes from the African strain enhance viral internalization, while the non-structural genes improve genome replication and infectious particle production in mosquito cells.
I also performed the artificial blood meal feeding using mosquitoes in vivo. In vivo mosquito transmission is most significantly influenced by the structural genes, although no single viral gene is solely responsible for this effect.
Additionally, I develop a stochastic model of in vivo viral dynamics in mosquitoes that mirrors the observed patterns, suggesting that the primary difference between the African and Asian strains lies in their ability to traverse the mosquito salivary glands.
I conclude that natural ZIKV variation in the efficiency of mosquito-borne transmission is determined by multiple viral genetic factors, predominantly affecting the final stage of propagation within mosquitoes.
I also investigated the Ae. aegypti factors responsible for the susceptibility of ZIKV by comparison of virus-binding mosquito proteins between two mosquito strains displaying different levels of ZIKV susceptibility.
I conducted pilot studies to explore the method for isolating virus-binding mosquito proteins. After mosquito midguts were sonicated by using COVARIS and centrifuged, supernatants were collected as midgut protein lysates.
Midgut protein lysates were incubated with ZIKV, fixed and reacted with anti-ZIKV primary antibodies and secondary fluorescent antibodies.
I then investigated whether ZIKV-midgut protein complex was able to be detected by flow cytometry. Notably, ZIKV particle was able to be detected using anti-E protein monoclonal antibody and some mosquito proteins could be identified by mass spectrometry.
