Roy Hall

Publications (3)9.17 Total impact

• Article: NS1' of flaviviruses in the Japanese encephalitis virus serogroup is a product of ribosomal frameshifting and plays a role in viral neuroinvasiveness.

  Ezequiel Balmori Melian, Edward Hinzman, Tomoko Nagasaki, Andrew E Firth, Norma M Wills, Amanda S Nouwens, Bradley J Blitvich, Jason Leung, Anneke Funk, John F Atkins, Roy Hall, Alexander A Khromykh
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  ABSTRACT: Flavivirus NS1 is a nonstructural protein involved in virus replication and regulation of the innate immune response. Interestingly, a larger NS1-related protein, NS1', is often detected during infection with the members of the Japanese encephalitis virus serogroup of flaviviruses. However, how NS1' is made and what role it performs in the viral life cycle have not been determined. Here we provide experimental evidence that NS1' is the product of a -1 ribosomal frameshift event that occurs at a conserved slippery heptanucleotide motif located near the beginning of the NS2A gene and is stimulated by a downstream RNA pseudoknot structure. Using site-directed mutagenesis of these sequence elements in an infectious clone of the Kunjin subtype of West Nile virus, we demonstrate that NS1' plays a role in viral neuroinvasiveness.
  Journal of Virology 11/2009; 84(3):1641-7. · 5.40 Impact Factor
• Article: Universal primers that amplify RNA from all three flavivirus subgroups

  Sheryl Maher-Sturgess, Naomi Forrester, Paul Wayper, Ernest Gould, Roy Hall, Ross Barnard, Mark Gibbs
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  ABSTRACT: Abstract Background Species within the Flavivirus genus pose public health problems around the world. Increasing cases of Dengue and Japanese encephalitis virus in Asia, frequent outbreaks of Yellow fever virus in Africa and South America, and the ongoing spread of West Nile virus throughout the Americas, show the geographical burden of flavivirus diseases. Flavivirus infections are often indistinct from and confused with other febrile illnesses. Here we review the specificity of published primers, and describe a new universal primer pair that can detect a wide range of flaviviruses, including viruses from each of the recognised subgroups. Results Bioinformatic analysis of 257 published full-length Flavivirus genomes revealed conserved regions not previously targeted by primers. Two degenerate primers, Flav100F and Flav200R were designed from these regions and used to generate an 800 base pair cDNA product. The region amplified encoded part of the methyltransferase and most of the RNA-dependent-RNA-polymerase (NS5) coding sequence. One-step RT-PCR testing was successful using standard conditions with RNA from over 60 different flavivirus strains representing about 50 species. The cDNA from each virus isolate was sequenced then used in phylogenetic analyses and database searches to confirm the identity of the template RNA. Conclusion Comprehensive testing has revealed the broad specificity of these primers. We briefly discuss the advantages and uses of these universal primers.
  Virology Journal. 01/2008;
• Article: Cross-protective and infection-enhancing immunity in mice vaccinated against flaviviruses belonging to the Japanese encephalitis virus serocomplex.

  Mario Lobigs, Megan Pavy, Roy Hall
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  ABSTRACT: The Japanese encephalitis virus serocomplex is a group of mosquito-borne flaviviruses that cause severe encephalitic disease in humans. The recent emergence of several members of this serocomplex in geographic regions where other closely related flaviviruses are endemic has raised urgent human health issues. Thus, the impact of vaccination against one of these neurotropic virus on the outcome of infection with a second, serologically related virus is unknown. We show here that immunity against Murray Valley encephalitis virus in vaccinated mice can cross-protect but also augment disease severity following challenge with Japanese encephalitis virus. Immunepotentiation of heterologous flavivirus disease was apparent in animals immunized with a 'killed' virus preparation when humoral antiviral immunity of low magnitude was elicited.
  Vaccine 05/2003; 21(15):1572-9. · 3.77 Impact Factor