Double-stranded RNA (dsRNA) plays essential functions in many biological processes, including the activation of innate immune responses and RNA interference. dsRNA also represents the genetic entity of some viruses and is a hallmark of infections by positive-sense single-stranded RNA viruses. Methods for detecting dsRNA rely essentially on immunological approaches and their use is often limited...

Double-stranded RNA (dsRNA) directs gene-specific, post-transcriptional silencing in many organisms, including vertebrates, and has provided a new tool for studying gene function. The biochemical mechanisms underlying this dsRNA interference (RNAi) are unknown. Here we report the development of a cell-free system from syncytial blastoderm Drosophila embryos that recapitulates many of the featur...

Here we describe studies of double-stranded RNA (dsRNA) adenosine deaminase in Xenopus laevis, in particular during meiotic maturation, the period during which a stage VI oocyte matures to an egg. We show that dsRNA adenosine deaminase is in the nuclei of stage VI oocytes. Most importantly, we demonstrate that the cytoplasm of stage VI oocytes contains a factor that protects microinjected dsRNA...

p68 RNA helicase, a nuclear RNA helicase, was identified 2 decades ago. The protein plays very important roles in cell development and organ maturation. However, the biological functions and enzymology of p68 RNA helicase are not well characterized. We report the expression and purification of recombinant p68 RNA helicase in a bacterial system. The recombinant p68 is an ATP-dependent RNA helica...

The three double-stranded ribonucleic acid (dsRNA) segments of the bacteriophage phi6 were isolated and shown to have similar melting temperatures and base compositions. RNA:RNA hybridization experiments with the isolated segments eliminate the possibility that the two smaller dsRNA segments arise from a cleavage of the large dsRNA segment. The two smaller RNA segments reanneal rapidly even at ...

Hepatitis C virus (HCV) is unique among RNA viruses in its ability to establish chronic infection in the majority of exposed adults. HCV persists in the liver despite interferon (IFN)-stimulated gene (ISG) induction; robust induction actually predicts treatment failure and viral persistence. It is unclear which forms of HCV RNA are associated with ISG induction and IFN resistance during natural...

The herpes simplex virus Us11 gene product inhibits activation of the cellular PKR kinase and associates with a limited number of unrelated viral and cellular RNA molecules via a carboxyl-terminal 68-amino-acid segment rich in arginine and proline. To characterize the determinants underlying the recognition of an RNA target by Us11, we employed an in vitro selection technique to isolate RNA lig...

The nucleotide sequence (2617 nucleotides) of virus-like double-stranded (ds) RNA 3a in a diseased isolate, Log1/3-8d2 (Ld), of the ascomycete fungus Ophiostoma novo-ulmi has been determined. One strand of the dsRNA contains an open reading frame (ORF) with the potential to encode a protein of 718 amino acids, and the complementary strand contains two smaller ORFs with the potential to encode p...

Gene knockdown by RNA interference (RNAi) in Caenorhabditis elegans is readily achieved by feeding bacteria expressing double-stranded RNA (dsRNA). Enhanced RNAi (Eri) mutants facilitate RNAi due to their hypersensitivity to dsRNA. Here, we compare eight Eri mutants for sensitivity to ingested dsRNA, targeting a variety of tissue-specific genes.

Knowledge of the distribution and diversity of RNA viruses is still limited in spite of their possible environmental and epidemiological impacts because RNA virus-specific metagenomic methods have not yet been developed. We herein constructed an effective metagenomic method for RNA viruses by targeting long double-stranded (ds)RNA in cellular organisms, which is a hallmark of infection, or the ...