Determinants of attenuation in the envelope protein of the flavivirus Alfuy

Murray Valley encephalitis virus (MVEV) is a mosquito-borne flavivirus endemic to Australia and Papua New Guinea. Most strains of MVEV cause potentially fatal cases of encephalitis in humans and horses, and have been shown to be highly neuroinvasive in weanling mice. In contrast, the naturally occur...

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Main Authors: Prow, N., May, F., Westlake, D., Hurrelbrink, R., Biron, R., Leung, J., McMinn, P., Clark, D., Mackenzie, John, Lobigs, M, Khromykh, A., Hall, R.
Format: Journal Article
Published: Society for General Microbiology 2011
Online Access:http://hdl.handle.net/20.500.11937/34002
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author Prow, N.
May, F.
Westlake, D.
Hurrelbrink, R.
Biron, R.
Leung, J.
McMinn, P.
Clark, D.
Mackenzie, John
Lobigs, M
Khromykh, A.
Hall, R.
author_facet Prow, N.
May, F.
Westlake, D.
Hurrelbrink, R.
Biron, R.
Leung, J.
McMinn, P.
Clark, D.
Mackenzie, John
Lobigs, M
Khromykh, A.
Hall, R.
author_sort Prow, N.
building Curtin Institutional Repository
collection Online Access
description Murray Valley encephalitis virus (MVEV) is a mosquito-borne flavivirus endemic to Australia and Papua New Guinea. Most strains of MVEV cause potentially fatal cases of encephalitis in humans and horses, and have been shown to be highly neuroinvasive in weanling mice. In contrast, the naturally occurring subtype Alfuy virus (ALFV) has never been associated with human disease, nor is it neuroinvasive in weanling mice, even at high doses. To identify viral factors associated with ALFV attenuation, a chimeric infectious clone was constructed containing the structural genes premembrane (prM) and envelope (E) of ALFV swapped into the MVEV genome. The resulting virus (vMVEV/ALFVstr) was no longer neuroinvasive in mice, suggesting that motifs within prM–E of ALFV confer attenuation. To define these motifs further, mutants were constructed by targeting divergent sequences between the MVEV and ALFV E proteins that are known markers of virulence in other encephalitic flaviviruses. MVEV mutants containing a unique ALFV sequence in the flexible hinge region (residues 273–277) or lacking the conserved glycosylation site at position 154 were significantly less neuroinvasive in mice than wild-type MVEV, as determined by delayed time to death or increased LD50. Conversely, when the corresponding MVEV sequences were inserted into the vMVEV/ALFVstr chimera, the mutant containing the MVEV hinge sequence was more neuroinvasive than the parental chimera, though not to the same level as wild-type MVEV. These results identify the hinge region and E protein glycosylation as motifs that contribute to the attenuation of ALFV.
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spelling curtin-20.500.11937-340022017-09-13T16:09:21Z Determinants of attenuation in the envelope protein of the flavivirus Alfuy Prow, N. May, F. Westlake, D. Hurrelbrink, R. Biron, R. Leung, J. McMinn, P. Clark, D. Mackenzie, John Lobigs, M Khromykh, A. Hall, R. Murray Valley encephalitis virus (MVEV) is a mosquito-borne flavivirus endemic to Australia and Papua New Guinea. Most strains of MVEV cause potentially fatal cases of encephalitis in humans and horses, and have been shown to be highly neuroinvasive in weanling mice. In contrast, the naturally occurring subtype Alfuy virus (ALFV) has never been associated with human disease, nor is it neuroinvasive in weanling mice, even at high doses. To identify viral factors associated with ALFV attenuation, a chimeric infectious clone was constructed containing the structural genes premembrane (prM) and envelope (E) of ALFV swapped into the MVEV genome. The resulting virus (vMVEV/ALFVstr) was no longer neuroinvasive in mice, suggesting that motifs within prM–E of ALFV confer attenuation. To define these motifs further, mutants were constructed by targeting divergent sequences between the MVEV and ALFV E proteins that are known markers of virulence in other encephalitic flaviviruses. MVEV mutants containing a unique ALFV sequence in the flexible hinge region (residues 273–277) or lacking the conserved glycosylation site at position 154 were significantly less neuroinvasive in mice than wild-type MVEV, as determined by delayed time to death or increased LD50. Conversely, when the corresponding MVEV sequences were inserted into the vMVEV/ALFVstr chimera, the mutant containing the MVEV hinge sequence was more neuroinvasive than the parental chimera, though not to the same level as wild-type MVEV. These results identify the hinge region and E protein glycosylation as motifs that contribute to the attenuation of ALFV. 2011 Journal Article http://hdl.handle.net/20.500.11937/34002 10.1099/vir.0.034793-0 Society for General Microbiology unknown
spellingShingle Prow, N.
May, F.
Westlake, D.
Hurrelbrink, R.
Biron, R.
Leung, J.
McMinn, P.
Clark, D.
Mackenzie, John
Lobigs, M
Khromykh, A.
Hall, R.
Determinants of attenuation in the envelope protein of the flavivirus Alfuy
title Determinants of attenuation in the envelope protein of the flavivirus Alfuy
title_full Determinants of attenuation in the envelope protein of the flavivirus Alfuy
title_fullStr Determinants of attenuation in the envelope protein of the flavivirus Alfuy
title_full_unstemmed Determinants of attenuation in the envelope protein of the flavivirus Alfuy
title_short Determinants of attenuation in the envelope protein of the flavivirus Alfuy
title_sort determinants of attenuation in the envelope protein of the flavivirus alfuy
url http://hdl.handle.net/20.500.11937/34002