Title: Mechanisms of Host Cell Binding and Neurotropism of Zika Virus

Abstract

26Zika virus (ZIKV) recently emerged in the Western Hemisphere with previously unrecognized or 27unreported clinical presentations. Here, we identify two distinct binding mechanisms of ancestral and 28 emergent ZIKV strains featuring the envelope (E) protein residue ASN154 and viral phosphatidylserine 29 (PS). Short (20-mer) peptides representing the region containing ASN154 from strains PRVABC59 (Puerto 30Rico 2015) and MR_766 (Uganda 1947) were exposed to neuronal cells and fibroblasts, expecting 31interactions to be representative of ZIKV E protein/cell interactions, and bound MDCK or Vero cells and 32 primary neurons significantly above a scrambled PRVABC59 control peptide. Peptides also significantly 33 inhibited Vero cell adsorption by ZIKV strains MR_766 and PRVABC59, indicating that we have identified 34 a binding mechanism of ancestral African ZIKV strains and emergent Western Hemisphere strains. 35Pretreatment of ZIKV MR_766 and PRVABC59 with the PS-binding protein annexin V significantly 36 inhibited replication of PRVABC59, but not MR_766, suggesting that Western hemisphere strains are 37 additionally utilizing PS-mediated entry to infect host cells. Taken together, these data indicate that we 38have identified an ancestral binding mechanism of ZIKV, and a secondary binding mechanism utilized by 39Western Hemisphere strains. 40 41Background 42