arbovirus-infections-as-screening-tools-for-identification-viral

Arbovirus Infections As Screening Tools for the Identification of Viral Immunomodulators and Host Antiviral Factors

RNA interference- and genome editing-based screening platforms have been widely used to identify host cell factors that restrict virus replication. ...

University of Texas Southwestern Medical Center

The recent discovery of the positive-sense single-stranded RNA (ssRNA) Orsay virus (OV) as a natural pathogen of the nematode Caenorhabditis elegans has stimulated interest in exploring virus-nematode interactions. However, OV infection is restricted to a small number of intestinal cells, even in nematodes defective in their antiviral RNA interference (RNAi) response, and is neither lethal nor vertically transmitted. Using a fluorescent reporter strain of the negative-sense ssRNA vesicular stomatitis virus (VSV), we show that microinjection of VSV particles leads to a dose-dependent, muscle tissue-tropic, lethal infection in C. elegans. Furthermore, we find nematodes deficient for components of the antiviral RNAi pathway, such as Dicer-related helicase 1 (DRH-1), to display hypersusceptibility to VSV infection as evidenced by elevated infection rates, virus replication in multiple tissue types, and earlier mortality. Strikingly, infection of oocytes and embryos could also be observed in drh-1 mutants. Our results suggest that the antiviral RNAi response not only inhibits vertical VSV transmission but also promotes transgenerational inheritance of antiviral immunity. Our study introduces a new, in vivo virus-host model system for exploring arbovirus pathogenesis and provides the first evidence for vertical pathogen transmission in C. elegans.

The Antiviral RNA Interference Response Provides Resistance to Lethal Arbovirus Infection and Vertical Transmission in Caenorhabditis elegans.

Since 1999,  has been extensively used to study microbe-host interactions due to its simple culture, genetic tractability, and susceptibility to numerous bacterial and fungal pathogens. In contrast, virus studies have been hampered by a lack of convenient virus infection models in nematodes. The recent discovery of a natural viral pathogen of  and development of diverse artificial infection models are providing new opportunities to explore virus-host interplay in this powerful model organism.

Caenorhabditis elegans as an Emerging Model for Virus-Host Interactions.

Over the past 15 years, the free-living nematode,  has become an important model system for exploring eukaryotic innate immunity to bacterial and fungal pathogens. More recently, infection models using either natural or non-natural nematode viruses have also been established in . These models offer new opportunities to use the nematode to understand eukaryotic antiviral defense mechanisms. Here we report protocols for the infection of  with a non-natural viral pathogen, vesicular stomatitis virus (VSV) through microinjection. We also describe how recombinant VSV strains encoding fluorescent or luciferase reporter genes can be used in conjunction with simple fluorescence-, survival-, and luminescence-based assays to identify host genetic backgrounds with differential susceptibilities to virus infection.

Don B. Gammon

Department of Microbiology

University of Texas Southwestern Medical Center

Arbovirus Infections As Screening Tools for the Identification of Viral Immunomodulators and Host Antiviral Factors

Don B. Gammon

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University of Texas Southwestern Medical Center

Arbovirus Infections As Screening Tools for the Identification of Viral Immunomodulators and Host Antiviral Factors

Department of Microbiology