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Establishment of Viral Infection and Analysis of Host-Virus Interaction in Drosophila Melanogaster
Published on: March 14, 2019
Antiviral immunity in Drosophila requires systemic RNA interference spread
Maria-Carla Saleh1, Michel Tassetto, Ronald P van Rij
1Department of Microbiology and Immunology, University of California, San Francisco 94122-2280, USA.
Nature
|February 11, 2009
Summary
Flies require a double-stranded RNA (dsRNA) uptake pathway for effective antiviral immunity. This pathway enables a systemic RNA interference (RNAi) response, crucial for combating viral infections throughout the organism.
Area of Science:
- Immunology
- Molecular Biology
- Virology
Background:
- Multicellular organisms possess sophisticated defense systems against pathogens.
- Insect antiviral immunity, particularly RNA interference (RNAi), was previously considered a localized, cell-autonomous process.
- The ability of immune systems to respond both locally and systemically is a key characteristic.
Purpose of the Study:
- To investigate the role of a double-stranded RNA (dsRNA) uptake pathway in Drosophila melanogaster antiviral immunity.
- To determine if RNAi-mediated antiviral defense in flies can generate a systemic response.
Main Methods:
- Generating mutant flies deficient in the dsRNA uptake pathway.
- Infecting wild-type and mutant flies with Drosophila C virus and Sindbis virus.
- Measuring viral titers and RNA levels.
- Inoculating flies with naked dsRNA to assess immune response.
- Using green fluorescent protein (GFP)-tagged Sindbis virus to track systemic effects.
Main Results:
- Mutant flies lacking the dsRNA uptake pathway exhibited hypersensitivity to viral infections.
- dsRNA uptake-defective flies showed significantly increased viral loads (100- to 10(5)-fold).
- Exogenous dsRNA administration induced a sequence-specific antiviral response dependent on the uptake pathway.
- Viral infection led to the suppression of host-encoded GFP at distal sites, indicating systemic signaling.
Conclusions:
- A dsRNA uptake pathway is essential for effective antiviral RNA interference immunity in adult flies.
- The systemic spread of dsRNA is critical for mounting a comprehensive antiviral defense.
- Antiviral RNAi in flies, like protein-based immunity in vertebrates, relies on the systemic dissemination of immunity signals.
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