Protein kinase PKR is activated by double-stranded RNA (dsRNA) and phosphorylates translation initiation factor 2alpha to inhibit protein synthesis in virus-infected mammalian cells. PKR contains two dsRNA binding motifs (DRBMs I and II) required for activation by dsRNA. There is strong evidence that PKR activation requires dimerization, but the role of dsRNA in dimer formation is controversial...

Despite decades of research efforts, the nature of the infectious agent causing scrapie and other Transmissible Spongiform Encephalopathies (TSE) remains an enigma. The protein-only prion hypothesis posits that an abnormal conformer of a host protein is the infectious agent. Virus and virino theories include host-independent nucleic acids in the genome of the infectious agent, in addition to th...

The double-stranded RNA content, the production of inactive killer protein, and the presence of virus-like particles were examined in induced nonkiller mutants and nonkiller progeny from a cross between a killer strain and a sensitive strain. A correlation between the loss of the 0.7 x 10(6) daltons dsRNA of the Ustilago maydis P6 virus and the lack of synthesis of the killer protein was establ...

Viruses evolve so rapidly that sequence-based comparison is not suitable for detecting relatedness among distant viruses. Structure-based comparisons suggest that evolution led to a small number of viral classes or lineages that can be grouped by capsid protein (CP) folds. Here, we report that the CP structure of the fungal dsRNA Penicillium chrysogenum virus (PcV) shows the progenitor fold of ...

The dengue virus (DENV) circulates between humans and mosquitoes and requires no other mammals or birds for its maintenance in nature. The virus is well-adapted to humans, as reflected by high-level viraemia in patients. To investigate its high adaptability, the DENV induction of host type-I interferon (IFN) was assessed in vitro in human-derived HeLa cells and compared with that induced by the...

The whitefly Bemisia tabaci (Genn.) is a pest and vector of plant viruses to crop and ornamental plants worldwide. Using RNA interference (RNAi) to down regulate whitefly genes by expressing their homologous double stranded RNAs in plants has great potential for management of whiteflies to reduce plant virus disease spread. Using a Tobacco rattle virus-derived plasmid for in planta transient ex...

Papaya sticky disease, or "meleira", is one of the major diseases of papaya in Brazil and Mexico, capable of causing complete crop loss. The causal agent of sticky disease was identified as an isometric virus with a double stranded RNA (dsRNA) genome, named papaya meleira virus (PMeV). In the present study, PMeV dsRNA and a second RNA band of approximately 4.5 kb, both isolated from latex of pa...

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory infections that can be life-threatening. To establish an infection and spread, MERS-CoV, like most other viruses, must navigate through an intricate network of antiviral host responses. Besides the well-known type I interferon (IFN-α/β) response, the protein kinase R (PKR)-mediated stress response is being recogni...

Y‐satellite RNA (Y‐sat) of cucumber mosaic virus upregulates the expression aphid ABCG4 gene, which promotes wing formation. We used virus‐induced gene silencing (VIGS) to prevent wing‐induction mechanism Y‐sat and thus inhibited Of aphids on plants with VIGS , only about 30% had wings, 60–70% winged were small likely impaired in flying ability. In addition, we showed that double‐stranded RNAs ...

TLR22 occurs exclusively in aquatic animals and its role is unknown. Herein we show that the fugu (Takifugu rubripes) (fg)TLR3 and fgTLR22 link the IFN-inducing pathway via the fg Toll-IL-1R homology domain-containing adaptor protein 1(fgTICAM-1, or TRIF) adaptor in fish cells. fgTLR3 resides in endoplasmic reticulum and recognizes relatively short-sized dsRNA, whereas fgTLR22 recognizes long-s...