Complete genomic RNA sequence of western equine encephalitis virus and expression of the structural genes

Abstract

The complete nucleotide sequence of the 71V-1658 strain of western equine encephalitis virus (WEE) was determined (minus 25 nucleotides from the 5h end). A 5h RACE reaction was used to sequence the 5h terminus from WEE strain CBA87. The deduced WEE genome was 11 508 nucleotides in length, excluding the 5h cap nucleotide and 3h poly(A) tail. The nucleotide composition was 28 % A, 25 % C, 25 % G and 22 % U. Comparison with partial WEE sequences of strain 5614 (nsP2-nsP3 of the nonstructural region) and strain BFS1703 (26S structural region) revealed comparatively little variation ; a total of 149 nucleotide differences in 8624 bases (1n7% divergence), of which only 28 % (42 nucleotides) altered the encoded amino acids. Comparison of deduced nsP1 and nsP4 amino acid sequences from WEE with the corresponding proteins from eastern equine encephalitis virus (EEE) yielded identities of 84n9 and 83n8 %, respectively. Previously uncharacterized stem-loop structures were identified in the nontranslated terminal regions. A cDNA clone of the 26S region encoding the structural polyprotein of WEE strain 71V-1658 was placed under the control of a cytomegalovirus promoter and transfected into tissue culture cells. The viral envelope proteins were functionally expressed in tissue culture, as determined by histochemical staining with monoclonal antibodies that recognize WEE antigens, thus, forming the initial step in the investigation of subunit vaccines to WEE.

Virulence variation among isolates of western equine encephalitis virus in an outbred mouse model

“…Three of the major changes in E2 were clustered within a 68 aa stretch and could possibly play an important role in the efficiency with which WEEV binds/enters host cells. Previous studies have shown that the secondary structure of the stem-loops in the 59 NTR of other alphavirus genomes plays a role in virus neurovirulence (Evans et al, 1985;Kinney et al, 1993;Logue et al, 2008;Netolitzky et al, 2000). The single nucleotide difference between MCM and IMP at position 34, however, did not affect the secondary structure of the sole stem-loop of the WEEV 59 NTR.…”

Liposome-Antigen-Nucleic Acid Complexes Protect Mice from Lethal Challenge with Western and Eastern Equine Encephalitis Viruses

“…We purposefully chose this protein antigen for our LANAC formulation for several reasons. First, although E2 protein is the major neutralizing antigen, E1 is highly conserved among distinct alphaviral species (9,10), and antibody to E1 is protective (11). Second, the E1 of WEEV is a recent ancestor of the E1 from a Sindbis-like virus, which has been shown to induce cross-reactive and cross-protective antibodies (11,35).…”

“…Subunit vaccines consisting of recombinant forms of WEEV E2 or E1 have been reported to induce significant protection in animal models (6)(7)(8). Although E2 is the major neutralizing antigen, E1 is highly conserved among alphaviruses (9,10). Thus, E1 is an excellent vaccine candidate because it might offer broader ("pan-alphavirus") protection against fatal encephalitis.…”

Bats as Potential Reservoir Hosts for Vector-Borne Diseases

“…The latter authors postulate that bats may become infected, especially during epizootics in other hosts. The prototype virus of the genus Alphavirus is the Sindbis virus (SINV), which belongs together with the Highland J, Fort Morgan, Buggy Creek and Aura virus to the Western equine encephalomyelitis antigenic complex (Hubálek 2008;Lundström and Pfeffer 2010;Netolitzky et al 2000). It was first recognized and isolated from Culex pipiens and Cx.…”