Modulation of West Nile Virus Capsid Protein and Viral RNA Interaction through Phosphorylation
type: CreativeWork
description: West Nile virus (WNV) is a mosquito-borne flavivirus, which can cause fatal meningoencephalitis. Although studies have been done to examine virus life cycle, the mechanisms that regulate its assembly are unknown. This study aims to characterize the interaction between WNV viral RNA and the capsid (C) protein and also elucidate how the processes of nucleocapsid assembly are regulated. Initial in vitro C protein and viral RNA interaction studies showed that this interaction was not specific. This suggested the presence of a regulatory mechanism to regulate C protein and RNA interaction. There are 5 putative phosphorylation sites on C protein hence; functions of C protein could be regulated by phosphorylation. Western blot analysis with anti-phosphoserine antibodies confirmed that C protein was phosphorylated. Experiments using kinase inhibitors and activators identified protein kinase C to be one of the kinases responsible for the phosphorylation of C protein. Mutations were introduced into C protein to abolish phosphorylation. The effects of hypophosphorylation with regards to the nucleocapsid assembly processes like RNA binding; nuclear localisation and oligomerization were investigated. Phosphorylation of C protein attenuated RNA binding and this study showed that C protein was dephosphorylated later during infection to facilitate C protein and viral RNA interaction. It is also known that WNV C protein localises predominantly in nuclei of infected cells. Hypophosphorylation of C protein was shown to disrupt this process. Tracking of the cellular localisation of C protein during an infection showed that C protein localised in the nucleus during the early phase of infection but was found in the cytoplasm during late phase of infection. This correlated with the gradual dephosphorylation of C protein in infected cells. Capsid protein also oligomerized to form the nucleocapsid but hypophosphorylation did not affect the formation of oligomers. However, the rate of oligom…
abstract: West Nile virus (WNV) is a mosquito-borne flavivirus, which can cause fatal meningoencephalitis. Although studies have been done to examine virus life cycle, the mechanisms that regulate its assembly are unknown. This study aims to characterize the interaction between WNV viral RNA and the capsid (C) protein and also elucidate how the processes of nucleocapsid assembly are regulated. Initial in vitro C protein and viral RNA interaction studies showed that this interaction was not specific. This suggested the presence of a regulatory mechanism to regulate C protein and RNA interaction. There are 5 putative phosphorylation sites on C protein hence; functions of C protein could be regulated by phosphorylation. Western blot analysis with anti-phosphoserine antibodies confirmed that C protein was phosphorylated. Experiments using kinase inhibitors and activators identified protein kinase C to be one of the kinases responsible for the phosphorylation of C protein. Mutations were introduced into C protein to abolish phosphorylation. The effects of hypophosphorylation with regards to the nucleocapsid assembly processes like RNA binding; nuclear localisation and oligomerization were investigated. Phosphorylation of C protein attenuated RNA binding and this study showed that C protein was dephosphorylated later during infection to facilitate C protein and viral RNA interaction. It is also known that WNV C protein localises predominantly in nuclei of infected cells. Hypophosphorylation of C protein was shown to disrupt this process. Tracking of the cellular localisation of C protein during an infection showed that C protein localised in the nucleus during the early phase of infection but was found in the cytoplasm during late phase of infection. This correlated with the gradual dephosphorylation of C protein in infected cells. Capsid protein also oligomerized to form the nucleocapsid but hypophosphorylation did not affect the formation of oligomers. However, the rate of oligom…
author: CHEONG YUEN KUEN
keywords: flavivirus, capsid, phosphorylation, West Nile virus, regulation
date published: 2010-08-11
date modified: 2026-07-24T03:30:34Z
provider: National University of Singapore
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: National University of Singapore