Viruses are intracellular parasites that must use the host machinery to multiply. Identification of the host factors that perform essential functions in viral replication is thus of crucial importance to the understanding of virus-host interactions. Here we describe Ded1p, a highly conserved DExD/H-box translation factor, as a possible host factor recruited by the yeast L-A double-stranded RNA ...

Viral infection of farmed fish and shellfish represents a major issue within the aquaculture industry. One potential control strategy involves RNA interference viral gene expression through oral delivery specific double-stranded (dsRNA). In previous work, we have shown that recombinant dsRNA can be produced in chloroplast edible microalga Chlamydomonas reinhardtii used to disease shrimp. Here, ...

Interferon (IFN) mediates its antiviral effects by inducing a number of responsive genes, including the double-stranded RNA (dsRNA)-dependent protein kinase, PKR. Here we report that inducible overexpression of functional PKR in murine fibroblasts sensitized cells to apoptosis induced by influenza virus, while in contrast, cells expressing a dominant-negative variant of PKR were completely resi...

RNAi experiments in insects are characterized by great variability in efficiency; for instance beetles and locusts are very amenable to dsRNA-mediated gene silencing, while other insect groups, most notably lepidopterans, are more refractory to RNAi. Several factors can be forwarded that could affect the efficiency of RNAi, such as the composition and function of the intracellular RNAi machiner...

The Ebola virus (EBOV) VP35 protein blocks the virus-induced phosphorylation and activation of interferon regulatory factor 3 (IRF-3), a transcription factor critical for the induction of alpha/beta interferon (IFN-alpha/beta) expression. However, the mechanism(s) by which this blockage occurs remains incompletely defined. We now provide evidence that VP35 possesses double-stranded RNA (dsRNA)-...

Rosellinia necatrix megabirnavirus 1 (RnMBV1) W779 is a bi-segmented dsRNA virus and a strain of the type species Rosellinia necatrix megabirnavirus 1 of the family Megabirnaviridae. RnMBV1 causes severe reduction of both mycelial growth of Rosellinia necatrix in synthetic medium and fungal virulence to plant hosts, and thus has strong potential for virocontrol (biological control using viruses...

Plant and animal viruses employ diverse suppressor proteins to thwart the host antiviral reaction of RNA silencing. Many suppressors bind dsRNA with different size specificity. Here, we examine the dsRNA recognition mechanism of the Rice stripe virus NS3 suppressor using quantitative biochemical approaches, as well as mutagenesis and suppression activity analyses in plants. We show that dimeric...

Double-stranded RNA (dsRNA)-specific endonucleases belonging to RNase III classes 3 and 2 process dsRNA precursors to small interfering RNA (siRNA) or microRNA, respectively, thereby initiating and amplifying RNA silencing-based antiviral defense and gene regulation in eukaryotic cells. However, we now provide evidence that a class 1 RNase III is involved in suppression of RNA silencing. The si...

RNA silencing is a mechanism which higher plants and animals have evolved to defend against viral infection in addition to regulation of gene expression for growth and development. As a counterdefense, many plant and some animal viruses studied to date encode RNA silencing suppressors (RSS) that interfere with various steps of the silencing pathway. In this study, we report the first identifica...