N-linked glycosylation of the West Nile virus envelope protein is not a requisite for avian virulence or vector competence

by Payal D. Maharaj, Stanley A. Langevin, Bethany G. Bolling, Christy C. Andrade, Xavier A. Engle, Wanichaya N. Ramey, Angela Bosco-Lauth, Richard A. Bowen, Todd A. Sanders, Claire Y.-H. Huang, William K. Reisen, Aaron C. Brault The N-linked glycosylation motif at amino acid position 154–156 of the envelope (E) protein of West Nile virus (WNV) is linked to enhanced murine neuroinvasiveness, avian pathogenicity and vector competence. Naturally occurring isolates with altered E protein glycosylation patterns have been obs erved in WNV isolates; however, the specific effects of these polymorphisms on avian host pathogenesis and vector competence have not been investigated before. In the present study, amino acid polymorphisms, NYT, NYP, NYF, SYP, SYS, KYS and deletion (A’DEL), were reverse engineered into a parental WNV (NYS) cDNA infectious clone to generate WNV glycosylation mutant viruses. These WNV glycosylation mutant viruses were characterized forin vitro growth, pH-sensitivity, temperature-sensitivity and host competence in American crows (AMCR), house sparrows (HOSP) andCulex quinquefasciatus. The NYS and NYT glycosylated viruses showed higher viral replication, pH and temperature sensitivity than NYP, NYF, SYP, SYS, KYS and A ’DEL virusesin vitro. Interestingly,in vivo results demonstrated asymmetric effects in avian and mosquito competence that were independent of the E-protein glycosylation status. In AMCRs and HOSPs, all viruses showed comparable viremias with...
Source: PLoS Neglected Tropical Diseases - Category: Tropical Medicine Authors: Source Type: research