Conserved molecular mechanisms of replication for mosquito-borne flaviviruses

As obligate intracellular parasites, all viruses replicate by coopting host machinery through virus-host protein interactions. Arthropod-borne viruses, which are transmitted to vertebrates by arthropod vectors, must hijack host machinery in human and arthropod cells to accomplish the same fundamental aspects of virus replication. Thus, arthropod-borne viruses maintain protein interactions with host homologs (interologs) to replicate. Identifying these interologs is critical to understanding how an important group of viruses deals with this unique constraint from a biophysical perspective. For flaviviruses transmitted by Aedes mosquitoes (Aedes-borne flaviviruses), it can also inform therapy development by expanding the list of drug targets since these viruses are a major source of human disease. Using a comparative proteomics approach, we recently found large-scale evidence of interologs for dengue virus (DENV), a major Aedes-borne flavivirus that infects nearly 400 million people annually. These interologs involve processes that are essential for virus replication in human and Aedes cells. We hypothesize that Aedes-borne flaviviruses use the conserved interologs to facilitate replication in human and Aedes cells due to the similar constraints place on these viruses and the complexity of maintaining virus-host protein interactions across multiple divergent hosts. The overall objective of this proposal is to systematically compare the role of interologs in virus replication for two Aedes-borne flaviviruses. We will focus on DENV to take advantage of our existing interolog data and yellow fever virus (YFV), a re-emerging Aedes-borne flavivirus that is distantly related to DENV. In Aim 1, we will systematically identify YFV-human and YFV-Aedes protein interactions using affinity purification and mass spectrometry. We will further identify YFV interologs through computational network integration. In Aim 2, we will identify interologs conserved between YFV and DENV using a similar computational network integration approach. We will then test the role of interologs in Aedes-borne flavivirus replication by measuring virus replication following interolog knockdown. This work will identify the conserved molecular mechanisms by which a medically important group of viruses replicates. It will reveal the biophysical parameters that constrain virus evolution. In the future, the interologs we identify could be leveraged as pharmacological or vector engineering targets to inhibit replication of multiple Aedes-borne flaviviruses. Our work would also lay the foundation to search for more interologs conserved across different arthropod vectors and/or different virus families.