Dataset Information

Deep sequencing of WNV isolates collected in Harris County, TX 2013-2016

ABSTRACT: Harris County, Texas experienced its largest outbreak of West Nile (WNV) disease in 2014. Characterization WNV isolates from the outbreak using next generation sequencing approaches, phylogeny, and animal studies revealed a novel genotype characterized by selection of an amino acid substitution, NS2A-R188K. Retrospective analysis of Genbank showed this genotype was first identified in New York and Connecticut in 2008 and then in Texas subsequently. Thus, we have termed this the Northeast 2008 (NE/WN08) genotype. Emergence of this genotype in Texas likely involved the displacement of the SW/WN03 genotype. Quasispecies diversity revealed significant variation occurred among viral isolates, but no phenotypic changes were observed in terms of temperature sensitivity and mouse virulence, suggesting that despite WNV being in North America for 15 years there are strong mutational robustness among naturally occurring WNV isolates. Examination of Genbank showed that convergent evolution of NS2A-R188K was also taking place worldwide.

ORGANISM(S): West Nile virus

PROVIDER: GSE126555 | GEO | 2020/01/01

REPOSITORIES: GEO

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Project description:An array analysis of C. gattii (C. bacillosporus), intended to identify loci associated with the hypervirulence of the Vancouver Island Outbreak (VIO). 23 C. gattii isolates, representing both VIO strains and control strains, were grown for 24 hours in mammalian macrophages. RNA was isolated and gene expression for each strain quantified relative to pooled RNA from all 23 samples. Linear regression was used to identify loci showing positive or negative correlation with "intracellular proliferation rate", a proxy measure for virulence. Data from this analysis is included in Ma et al, 2009, PNAS 106(31) 12980-12985. The abstract is included below. In 1999, the population of Vancouver Island, Canada, began to experience an outbreak of a fatal fungal disease caused by a highly virulent lineage of Cryptococcus gattii. This organism has recently spread to the Canadian mainland and Pacific Northwest, but the molecular cause of the outbreak remains unknown. Here we show that the Vancouver Island outbreak (VIO) isolates have dramatically increased their ability to replicate within macrophages of the mammalian immune system in comparison with other C. gattii strains. We further demonstrate that such enhanced intracellular parasitism is directly linked to virulence in a murine model of cryptococcosis, suggesting that this phenotype may be the cause of the outbreak. Finally, microarray studies on 24 C. gattii strains reveals that the hypervirulence of the VIO isolates is characterized by the up-regulation of a large group of genes, many of which are encoded by mitochondrial genome or associated with mitochondrial activities. This expression profile correlates with an unusual mitochondrial morphology exhibited by the VIO strains after phagocytosis. Our data thus demonstrate that the intracellular parasitism of macrophages is a key driver of a human disease outbreak, a finding that has significant implications for a wide range of other human pathogens. Dual-colour hybridization (each sample was hybridized against pooled RNA), one array per isolate, 23 biological samples, no technical replicates.

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Deep sequencing of WNV isolates collected in Harris County, TX 2013-2016

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