Project description:The purpose of this experiment was to obtain samples for mRNA analysis in IHH cells infected with Zaire Ebola virus and mutants: Zaire Ebola virus: This wild-type Ebola virus - strain Mayinga - was isolated from a fatal human case in Zaire (now known as the Democratic Republic of Congo) in 1976 Zaire Ebola virus, VP35 R312A possesses a R312A mutation in the VP35 protein. Zaire Ebola virus, delta sGP. Lacks the ability to produce non-structural protein, the secreted glycoprotein (sGP). Zaire Ebola virus, delta mucin. Lacks the mucin-like domain (MLD), which contains both N-linked and O-linked glycosylation sites, for the glycoproteins.
Project description:Dengue and Zika are closely related members of the Flaviviridae family of positive, single-stranded RNA viruses and are of global clinical importance. These viruses utilize an 11kb RNA genome for translation and replication, and much remains to be learnt about how the entire genome folds to enable virus function. Here, we performed high throughput RNA secondary structure and pair-wise interaction mapping on four dengue serotypes and four Zika strains within their virus particles. We identified structures that are associated with translation pausing, and are evolutionary conserved by integrating synonymous mutation rates into our analysis. Genome-wide interaction mapping revealed alternative structures, as well as extensive long-range RNA interactions – including the known circularization signals– within the virus particles. Many of these long-range interactions are conserved across the viruses and/or clustered into “hubs” that are shown to be functionally important. This comprehensive structural resource of dengue and Zika viruses reveals that viral genome organization is much more complex than previously appreciated and deepens our understanding of the molecular basis for viral pathogenesis.
Project description:Zoonotic influenza A viruses of avian origin can cause severe disease in individuals, or even global pandemics, and thus pose a threat to human populations. Waterfowl and shorebirds are believed to be the reservoir for all influenza A viruses, but this has recently been challenged by the identification of novel influenza A viruses in bats. The major bat influenza A virus envelope glycoprotein, haemagglutinin, does not bind the canonical influenza A virus receptor, sialic acid or any other glycan, despite its high sequence and structural homology with conventional haemagglutinins. This functionally uncharacterized plasticity of the bat influenza A virus haemagglutinin means the tropism and zoonotic potential of these viruses has not been fully determined. Here we show, using transcriptomic profiling of susceptible versus non-susceptible cells in combination with genome-wide CRISPR-Cas9 screening, that the major histocompatibility complex class II (MHC-II) human leukocyte antigen DR isotype (HLA-DR) is an essential entry determinant for bat influenza A viruses. Genetic ablation of the HLA-DR α-chain rendered cells resistant to infection by bat influenza A virus, whereas ectopic expression of the HLA-DR complex in non-susceptible cells conferred susceptibility. Expression of MHC-II from different bat species, pigs, mice or chickens also conferred susceptibility to infection. Notably, the infection of mice with bat influenza A virus resulted in robust virus replication in the upper respiratory tract, whereas mice deficient for MHC-II were resistant. Collectively, our data identify MHC-II as a crucial entry mediator for bat influenza A viruses in multiple species, which permits a broad vertebrate tropism.
Project description:Hepatitis C virus (HCV), a major causative agent of acute and chronic liver disease, belongs to the Flaviviridæ family and contains a single-strand positive-sense RNA genome, which upon virus entry and uncoating, functions as mRNAs and thus can be directly translated into proteins by host cell machinery. To date the HCV origin remains unclear and HCV life cycle and pathogenesis are not enlightened processes due to the absence of HCV efficient cell cultures systems or animals models. Here we show that rabbit and hare HCV-like viruses, RHCV and HHCV respectively, are formed after the inoculation of genomic DNA in Madin-Darby bovine kidney cell line cultures. RHCV is closely related to the HCV-1a/HCV-1b genotypes and HHCV is more closely related to the HCV-1b genotype. These findings could contribute to the understanding of HCV origin as well as clarify the virus life cycle, pathogenesis, evolution and diversity.