Project description:Detection of viral infection by pattern-recognition receptors triggers production of interferon. Secreted interferon binds to cognate receptors, triggering JAK/STAT signaling, resulting in the transcription and production of hundreds of interferon-stimulated genes (ISGs). Our lab identified lymphocyte antigen 6, locus E (LY6E) as an ISG that enhances infectivity of a subset of enveloped RNA viruses from Flaviviridae, Orthomyxoviridae, and Togaviridae families. To test whether the enhancing effects of LY6E were due to alterations of the global cellular transcriptome, we overexpressed LY6E and a control empty vector and examined global transcription using RNA-Seq.
2018-12-25 | GSE111958 | GEO
Project description:Metagenomic Analysis of Flaviviridae in Mosquito Viromes Isolated from Yunnan Province in China
Project description:Zika virus (ZIKV) is a mosquito-transmitted positive-sense RNA virus in the family Flaviviridae. ZIKV infections are associated with neurodevelopmental deficiencies termed Congenital Zika Syndrome. ZIKV strains are grouped into three phylogenetic lineages: East African, West African, and Asian, which contains the American lineage. RNA virus genomes exist as genetically-related sequences. The heterogeneity of these viral populations is implicated in viral fitness, and genome diversity is correlated to virulence. This study examines genetic diversity of representative ZIKV strains from all lineages utilizing next generation sequencing (NGS). Inter-lineage diversity results indicate that ZIKV lineages differ broadly from each other; however, intra-lineage comparisons of American ZIKV strains isolated from human serum or placenta show differences in diversity when compared to ZIKVs from Asia and West Africa. This study describes the first comprehensive NGS analysis of all ZIKV lineages and posits that sub-consensus-level diversity may provide a framework for understanding ZIKV fitness during infection.
Project description:Zika virus (ZIKV) is a mosquito-transmitted positive-sense RNA virus in the family Flaviviridae. Live attenuated vaccines have been successfully used to combat infection by flaviviruses, such as yellow fever and Japanese encephalitis viruses. A Zika virus harboring combined mutations in the envelope protein glycosylation site and in the nonstructural 4B protein amino acid 36 (ZE4B-36) was generated and assessed for stability, attenuation, and protection against infection. To determine the genetic stability of its RNA genome, ZE4B-36 was serially passaged in vitro in Vero cells. Virus harvested from passages (P)1 to P6 was subjected to next generation sequencing and downstream analysis to determine its nucleotide sequence variability. Specifically, single nucleotide variant analysis showed that the ZE4B-36 genome decreased its genetic diversity and resulted in a more stable nucleotide sequence. Thus, in addition to showing attenuation and protection, ZE4B-36 is a stable live attenuated virus that possesses characteristics important for a vaccine to combat Zika disease.
Project description:The modification N6-methyladenosine (m6A) affects rates of translation and degradation of mRNA transcripts. We analyzed m6A across the transcriptome following infection by dengue virus (DENV), Zika virus (ZIKV), West Nile virus (WNV), and hepatitis C virus (HCV) using MeRIP-seq. We used the uninfected replicates, among which we would expect little biological variation in methylation, as negative controls to validate statistical methods for the detection of m6A changes in MeRIP-seq data. Applying validated statistical methods, we found that innate immune response to Flaviviridae viruses alters m6A modification of specific cellular transcripts compared to uninfected controls. Finally, we find that these changes in m6A can in turn affect splicing or translation of genes relevant to infection.
Project description:In RNA interference (RNAi), long double-stranded RNA (dsRNA) is cleaved by Dicer endonuclease into small RNA interfering RNAs (siRNAs), which guide degradation of complementary RNAs. While RNAi mediates antiviral innate immunity in plants and many invertebrates, vertebrates adopted sequence-independent response and their Dicer produces siRNAs inefficiently because it is adapted to process small hairpin microRNA precursors in the gene-regulating microRNA pathway. Mammalian RNAi is thus a rudimentary pathway of unclear significance. To investigate its antiviral potential, we modified mouse Dicer locus to express a truncated variant (DicerΔHEL1) known to stimulate RNAi. Next, we analyzed how DicerΔHEL1/wt mice respond to four RNA viruses: Coxsackievirus B3 (CVB3) and encephalomyocarditis virus (ECMV) from Picornaviridae; tick-borne encephalitis virus (TBEV) from Flaviviridae; and lymphocytic choriomeningitis virus (LCMV) from Arenaviridae. Increased Dicer activity in DicerΔHEL1/wt mice had no antiviral effect. This result supports insignificant antiviral function of endogenous mammalian RNAi in vivo. However, we also report that sufficiently high expression of DicerΔHEL1 suppressed LCMV in embryonic stem cells and in a transgenic mouse model. Altogether, mice with increased Dicer activity offer a new benchmark for identifying and studying viruses susceptible to mammalian RNAi in vivo.