Papaya meleira virus (PMeV), a double-stranded RNA (dsRNA) virus present in the latex of papaya (Carica papaya L.), is the causal agent of ‘meleira’ or ‘sticky disease’, which prevails in eastern Brazil. Disease management strategies in the orchards are impaired by the lack of knowledge on PMeV transmission. We have therefore evaluated inoculation methods (five mechanical and one biological) fo...

The treatment of human embryonic kidney 293 cells harboring a hepatitis C virus (HCV) subgenomic replicon with the double-stranded RNA (dsRNA) mimic poly(I . C) inhibits HCV RNA replication through an undefined mechanism. Interferon regulatory factor 3 (IRF 3) has been widely postulated to mediate various antiviral responses, and its role in mediating the response to dsRNA in 293 cells was exam...

During viral infection, extracellular dsRNA is a potent signaling molecule that activates many innate immune cells, including macrophages. TLR3 is a well-known receptor for extracellular dsRNA, and internalization of extracellular dsRNA is required for endosomal TLR3 activation. Preserved inflammatory responses of TLR3-deficient macrophages to extracellular dsRNA strongly support a TLR3-indepen...

We report the structure of the flock house virus B2 protein, a potent suppressor of RNA interference (RNAi) in animals and plants. The B2 protein is a homodimer in solution and contains three alpha-helices per monomer. Chemical shift perturbation shows that an antiparallel arrangement of helices (alpha2/alpha2') forms an elongated binding interface with double-stranded RNA (dsRNA). This implies...

Infectious bursal disease virus (IBDV) is an avian pathogen responsible for an acute immunosuppressive disease that causes major losses to the poultry industry. Despite having a bipartite dsRNA genome, IBDV, as well as other members of the Birnaviridae family, possesses a single capsid layer formed by trimers of the VP2 capsid protein. The capsid encloses a ribonucleoprotein complex formed by t...

A new virus species of the genus Phytoreovirus was isolated from glassy-winged sharpshooter (GWSS), Homalodisca vitripennis Germar (Hemiptera: Cicadellidae), in California and designated here as Homalodisca vitripennis reovirus (HoVRV). Extraction of nucleic acid from GWSS adults collected from three Californian populations revealed an array of double-stranded (ds) RNA species that was soluble ...

A number of avocado (Persea americana) cultivars are known to contain high-molecular-weight double-stranded RNA (dsRNA) molecules for which a viral nature has been suggested, although sequence data are not available. Here we report the cloning and complete sequencing of a 13.5-kbp dsRNA virus isolated from avocado and show that it corresponds to the genome of a new species of the genus Endornav...

dsRNA, as genomic fragment, replicative intermediate, or stem and loop structure in cells infected by viruses, can act to signal the immune system of the presence of viral infections. Although most viral infections are associated with strong Th1 immune responses, Th2-type responses have also been observed. In this study, we characterize the effects of dsRNA on the induction of Th2 responses in ...

In contrast to well-established internal ribosomal entry site (IRES)-mediated translational initiation in animals and plants, no IRESs were established in fungal viral or cellular RNAs. To identify IRES elements in mycoviruses, we developed a luciferase-based dual-reporter detection system in Cryphonectria parasitica, a model filamentous fungus for virus-host interactions. A bicistronic constru...

Abstract Citrus tristeza virus (CTV) is found worldwide wherever citrus cultivated, causing disease resulting in significant yield losses and sometimes the death of plant. Transgenic plants encoding CTV gene sequences have shown to exhibit pathogen-derived resistance CTV. Exogenous application double-stranded RNA (dsRNA) an established strategy for plant control, making this method attractive a...