SEARCH · Search PubMed

Results for “DsRNA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources

PubMed2026

Bacterially produced dsRNA targeting SePGRP-LB reduces population fitness of Spodoptera exigua (Lepidoptera: Noctuidae) and increases its susceptibility to SeMNPV.

The beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), is an important agricultural pest, and S. exigua multiple nucleopolyhedrovirus (SeMNPV) is a host-specific biological control agent. However, baculovirus efficacy can be limited by host antiviral responses. S. exigua peptidoglycan recognition protein LB (SePGRP-LB) has been identified as an antiviral immune factor, suggesting that its suppression may increase larval susceptibility to SeMNPV. In this study, bacterially produced double-stranded RNA targeting SePGRP-LB (bac-dsPGRP-LB) was orally delivered to larvae to induce RNA interference. Feeding bac-dsPGRP-LB reduced SePGRP-LB transcript levels by 24.0% to 65.7% over 7 d. SePGRP-LB knockdown prolonged fifth-instar larval development, reduced female pupal weight, shortened male adult longevity and the oviposition period, and decreased fecundity by approximately 51%. Life table analysis further showed significant reductions in the intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0) following bac-dsPGRP-LB treatment. During SeMNPV infection, co-feeding with bac-dsPGRP-LB significantly suppressed SePGRP-LB expression, increased the SeMNPV genomic load, and reduced larval survival compared with the SeMNPV + bac-dsGFP treatment. These findings identify SePGRP-LB as a promising RNAi target for simultaneously reducing S. exigua fitness and enhancing its susceptibility to SeMNPV under laboratory conditions.

SePGRP-LB↗

PubMed1993

Mapping of the gene for interferon-inducible dsRNA-dependent protein kinase to chromosome region 2p21-22: a site of rearrangements in myeloproliferative disorders.

Recent evidence suggests that the human interferon-inducible double-stranded RNA-dependent protein kinase may function as a tumor suppressor. Here we describe the mapping of the gene for this kinase to chromosome region 2p21-22 by fluorescence in situ hybridization. A combined analysis of cytogenetic data from a series of 341 patients with hematologic disorders that exhibited cytogenetic abnormalities and from published reports indicates that abnormalities involving 2p21-22 occur nonrandomly and are observed among patients with acute myelogenous leukemia, raising the possibility of a role for this protein kinase in leukemogenesis.

Bone Marrow↗

PubMed2002

Efficient delivery of dsRNA into zona-enclosed mouse oocytes and preimplantation embryos by electroporation.

Conditions for the electroporation of mouse oocytes and preimplantation embryos have been optimised by following the incorporation of rhodamine labeled dextran. This procedure includes a step to weaken but not remove the zona pellucida that helps achieve good survival. This approach has been applied to introduce double-stranded RNA for c-mos into oocytes and green fluorescent protein (GFP) into transgenic GFP-expressing embryos at the 1- and 4-cell stages. In both cases we were able to observe sequence-specific interference with the expression of the target gene--a failure of oocytes to arrest at metaphase II and a loss in the green fluorescence of embryos by the morula or blastocyst stages. These effects could be observed in multiple oocytes or embryos allowed to develop together following electroporation.

Animals↗

PubMed2025

Dengue Virus Replicative-Form dsRNA Is Recognized by Both RIG-I and MDA5 to Activate Innate Immunity.

RIG-I like receptors (RLRs) are a family of cytosolic RNA sensors that sense RNA virus infection to activate innate immune response. It is generally believed that different RNA viruses are recognized by either RIG-I or MDA5, two important RLR members, depending on the nature of pathogen-associated molecular patterns (PAMPs) that are generated by RNA virus replication. Dengue virus (DENV) is an important RNA virus causing serious human diseases. Despite extensive investigations, the molecular basis of the DENV PAMP recognized by the host RLR has been poorly defined. Here, we demonstrated that the DENV infection-induced interferon response is dependent upon both RIG-I and MDA5, with RIG-I playing a predominant role. Next we purified the DENV PAMP RNA from the DENV-infected cells, and demonstrated that the purified DENV PAMP is viral full-length double-stranded RNA bearing 5'ppp modifications, likely representing the viral replicative-form RNA. Finally, we confirmed the nature of the DENV PAMP by reconstituting the viral replicative-form RNA from in vitro synthesized DENV genomic RNA. In conclusion, our work not only defined the molecular basis of the RLR-PAMP interaction during DENV infection, but also revealed the previously underappreciated recognition of a distinct moiety of the same PAMP by different RLRs in innate immunity against RNA viruses.

Interferon-Induced Helicase, IFIH1↗

PubMed1994

Sequence of MKT1, needed for propagation of M2 satellite dsRNA of the L-A virus of Saccharomyces cerevisiae.

MKT1 is required for maintenance of K2 above 30 degrees C in strains with the L-A-HN variant of the L-A double-stranded RNA virus of Saccharomyces cerevisiae. We report that MKT1 encodes a 92,979 Da protein with serine-rich regions and the retroviral protease signature, DTG, but with no substantial homology to proteins presently in the databases.

Amino Acid Sequence↗

PubMed1993

Structural studies of the enveloped dsRNA bacteriophage phi 6 of Pseudomonas syringae by Raman spectroscopy. I. The virion and its membrane envelope.

We report and interpret the first Raman spectrum of a double-stranded RNA virus containing a membrane envelope. Spectra of the native bacteriophage phi 6 and of its isolated host-attachment (spike) protein and phospholipid-free core assembly were collected from aqueous solutions over a wide range of temperature. Comparison of the vibrational spectra by digital difference methods permits the following structural conclusions regarding molecular constituents of the fully assembled virion. (1) The double-stranded RNA, phospholipid and protein components of the phage exhibit Raman amplitudes in accordance with their biochemically determined compositions in the native virion (10, 20 and 70%, respectively). (2) alpha-Helix and irregular conformations are the dominant secondary structures in proteins of both the viral membrane and nucleocapsid. This represents a departure from previously examined icosahedral phage and plant viruses, which are dominated by beta-sheet structures. (3) The phospholipids of the viral membrane are liquid crystalline throughout the determined range of virus thermostability (0 to 40 degrees C). (4) The P3 spike protein of phi 6, which is anchored to, but not sequestered within the viral membrane, is largely alpha-helical (approximately 35%) and highly thermolabile. Denaturation of P3 at temperatures above 30 degrees C leads to appreciable loss (approximately 20%) of alpha-helix in favor of beta-strand structure, and alters significantly the environments of many aromatic side-chains. (5) The secondary structures of integral membrane proteins of phi 6 are overwhelmingly alpha-helical (approximately 70 to 80%) and also thermolabile. In contrast to P3, which exhibits aspartate and glutamate carboxyls in the ionized form (CO2-), the integral membrane proteins exhibit only protonated carboxyl groups (COOH). Treatment of phi 6 with butylated hydroxytoluene (BHT), which has been shown to remove the P3 spike protein, does not significantly perturb phospholipids and associated integral proteins of the viral membrane or structural proteins and packaged double-stranded RNA of the nucleocapsid. However, P3 subunits, which are recovered after BHT treatment, exhibit radically altered secondary and tertiary structures, including the loss of most subunit alpha-helices. Among the P3 side-chains affected by BHT treatment, we note a general trend toward greater hydrophilicity and greater solvent exposure of the aromatic residues Trp and Tyr. On the other hand, the cysteine sulfhydryl groups of the BHT-isolated P3 monomer are not solvent exposed and function as strong hydrogen-bond donors in the protein core.(ABSTRACT TRUNCATED AT 400 WORDS)

Bacteriophage phi 6↗

PubMed2001

Purification, crystallization, and preliminary X-ray analysis of L-A: a dsRNA yeast virus.

TheL-A virus (LAV) particle is a specialized compartment for the transcription and replication of double-stranded RNA. It is 390 A in diameter and infects yeast. The particle is formed by a capsid containing 120 copies of a 680-residue gene product arranged with T = 1 icosahedral symmetry, approximately two copies of an RNA-directed RNA polymerase, and a 4.6-kb linear, duplex RNA. LAV crystals diffracting to at least 4.5-A resolution were grown in a combination of polyethylene glycol 8000, ethylene glycol, and lithium chloride. Following crystallization the reservoir solution was replaced by a 2x concentrated reservoir solution in order for ethylene glycol to function as a cryoprotectant even though initial crystals would not grow at sufficiently high concentrations of ethylene glycol for cryoprotection. A complete data set was collected to 6-A resolution from a frozen crystal obtained with this procedure. The crystals belong to space group P2(1). The unit cell dimensions are a = 406.7 A, b = 403.3 A, c = 572.5 A, beta = 90.3 degrees with two virus particles in the unit cell. The particle orientation was determined with the rotation function and the particle center was estimated on the basis of packing considerations.

Capsid↗

PubMed1994

RNA structural requirements for stability and minus-strand synthesis in the dsRNA bacteriophage phi 6.

Bacteriophage phi 6 has a genome consisting of three segments of double-stranded RNA designated L, M, and S. Each virion contains one of each genomic segment. Empty procapsids can package plus-strand transcripts of the genomic segments if the 5' regions are intact. Minus-strand synthesis takes place if all three segments are packaged and if the 3' end of the segment is intact. The 3' ends of the segments contain four hairpin structures within a region of high sequence conservation. We now show that removal of parts of this region leads to progressive but limited loss of ability to support minus-strand synthesis. The defective 3' ends can be corrected by heterologous recombination with the termini of other segments. Segments that have small deletions in the conserved region and that support apparently normal minus-strand synthesis are highly recombinogenic.

Bacteriophage phi 6↗

PubMed1994

A new small low-abundant nonstructural protein encoded by the L segment of the dsRNA bacteriophage phi 6.

A new small low-abundant protein encoded by the large genome segment of bacteriophage phi 6 has been detected in extracts of Escherichia coli bearing phi 6 cDNA clones and in extracts of phage-infected Pseudomonas phaseolicola. This 62 amino acid protein, designated P14, has a net charge of +2 at pH 7.0. Gene 14 has been located by deletion analysis and N-terminal protein sequence. Expression of P14 is down-regulated in E. coli when the complete L segment clone is expressed. Polyclonal antibodies to P14 detected the new protein in small amounts in phage-infected cells but not in phi 6 virions or nucleocapsids, or in procapsids assembled in E. coli. Procapsids assembled in E. coli after expression of phi 6 L segment clones with or without gene 14 had essentially similar protein composition and activity in an in vitro packaging and replication system. Thus P14 does not appear to be essential for the structure or assembly of functional procapsids. P14 might, however, facilitate packaging in vivo. Alternatively this protein could play in a role in repair of host membranes following viral penetration.

Amino Acid Sequence↗

PubMed1994

Reconstitution of active replicase in procapsids of the segmented dsRNA bacteriophage phi 6.

Bacteriophage phi 6 has a genome of three segments of double-stranded RNA enclosed in a procapsid composed of four different proteins. The preformed procapsid is capable of packaging plus strand transcripts of the genomic segments in an in vitro reaction. The plus strands then serve as templates for in vitro minus strand synthesis. Procapsids that are missing protein P2 are incapable of minus strand synthesis. In this report we show that incubation with a cell extract containing P2 results in particles with normal amounts of attached P2 and with packaging and replicase activity. Particles lacking P7 have reduced replicase activity which can be augmented by incubation with extracts containing P7, but the amount of attached P7 is small.

Bacteriophage phi 6↗

PubMed1995

Acquisition of a fourth genomic segment in bacteriophage phi 6, a bacteriophage with a genome of three segments of dsRNA.

Bacteriophage phi 6 has a genome of three segments of double-stranded RNA enclosed in a polyhedral procapsid. Packaging of individual segments is dependent upon unique packaging sequences near the 5' ends of the segments. We have prepared deletions in segments L and M that decrease their size by half. Phages with these deletions can be propagated on host strains carrying plasmids with complementing genes. The deletion segments are present in two copies per virion. Phage carrying a deletion segment can acquire the transcript of the complementing plasmid if the latter has a packaging sequence. If the packaging sequence is homologous to that of the deletion segment, acquisition occurs at high frequency. If it is heterologous, then recombination exchanges the heterologous packaging sequence for a homologous one or it attaches the transcript to one of the other genomic segments.

Bacteriophages↗

PubMed1998