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Total 55 results found since Jan 2013.

Characterization of viral siRNA populations in honey bee colony collapse disorder.
Abstract Colony Collapse Disorder (CCD), a special case of collapse of honey bee colonies, has resulted in significant losses for beekeepers. CCD-colonies show abundance of pathogens which suggests that they have a weakened immune system. Since honey bee viruses are major players in colony collapse and given the important role of viral RNA interference (RNAi) in combating viral infections we investigated if CCD-colonies elicit an RNAi response. Deep-sequencing analysis of samples from CCD-colonies from US and Israel revealed abundant small interfering RNAs (siRNA) of 21-22 nucleotides perfectly matching the Israel...
Source: Virology - April 1, 2014 Category: Virology Authors: Chejanovsky N, Ophir R, Schwager MS, Slabezki Y, Grossman S, Cox-Foster D Tags: Virology Source Type: research

Pathogenesis of Soybean mosaic virus in soybean carrying Rsv1 gene is associated with miRNA and siRNA pathways, and breakdown of AGO1 homeostasis.
Abstract Profiling small RNAs in soybean Williams 82 (rsv), susceptible to Soybean mosaic virus (SMV, the genus Potyvirus, family Potyviridae) strains G2 and G7, and soybean PI96983 (Rsv1), resistant to G2 but susceptible to G7, identified the microRNA miR168 that was highly overexpressed only in G7-infected PI96983 showing a lethal systemic hypersensitive response (LSHR). Overexpression of miR168 was in parallel with the high-level expression of AGO1 mRNA, high-level accumulation of miR168-mediated AGO1 mRNA cleavage products but with severely repressed AGO1 protein. In contrast, AGO1 mRNA, degradation products a...
Source: Virology - January 12, 2015 Category: Virology Authors: Chen H, Zhang L, Yu K, Wang A Tags: Virology Source Type: research

Inhibition of influenza A virus matrix and nonstructural gene expression using RNA interference.
Abstract Influenza antiviral drugs that use protein inhibitors can lose their efficacy as resistant strains emerge. As an alternative strategy, we investigated the use of small interfering RNA molecules (siRNAs) by characterizing three siRNAs (M747, M776 and M832) targeting the influenza matrix 2 gene and three (NS570, NS595 and NS615) targeting the nonstructural protein 1 and 2 genes. We also re-examined two previously reported siRNAs, M331 and M950, which target the matrix 1 and 2 genes. Treatment with M331-, M776-, M832-, and M950-siRNAs attenuated influenza titer. M776-siRNA treated cells had 29.8% less infect...
Source: Virology - July 26, 2016 Category: Virology Authors: McMillen CM, Beezhold DH, Blachere FM, Othumpangat S, Kashon ML, Noti JD Tags: Virology Source Type: research

Protective role of Indoleamine 2,3 dioxygenase in Respiratory Syncytial Virus associated immune response in airway epithelial cells.
Abstract RSV is a major cause of severe lower respiratory infection in infants and young children. With no vaccine yet available, it is important to clarify mechanisms of disease pathogenesis. Since indoleamine-2,3-dioxygenase (IDO) is an immunomodulatory enzyme and is upregulated with RSV infection, we studied it in vivo during infection of BALB/c mice and in vitro in A549 cells. RSV infection upregulated IDO transcripts in vivo and in vitro. IDO siRNA decreased IDO transcripts ~2 fold compared to control siRNA after RSV infection but this decrease did not affect RSV replication. In the presence of IFN-γ, siRNA-...
Source: Virology - September 27, 2017 Category: Virology Authors: Rajan D, Chinnadurai R, Keefe EO, Boyoglu-Barnum S, Todd SO, Hartert TV, Galipeau J, Anderson LJ Tags: Virology Source Type: research

Cytorhabdovirus phosphoprotein shows RNA silencing suppressor activity in plants, but not in insect cells.
Abstract RNA silencing in plants and insects provides an antiviral defense and as a countermeasure most viruses encode RNA silencing suppressors (RSS). For the family Rhabdoviridae, no detailed functional RSS studies have been reported in plant hosts and insect vectors. In agroinfiltrated Nicotiana benthamiana leaves we show for the first time for a cytorhabdovirus, lettuce necrotic yellows virus (LNYV), that one of the nucleocapsid core proteins, phosphoprotein (P) has relatively weak local RSS activity and delays systemic silencing of a GFP reporter. Analysis of GFP small RNAs indicated that the P protein did no...
Source: Virology - January 12, 2015 Category: Virology Authors: Mann KS, Johnson KN, Dietzgen RG Tags: Virology Source Type: research

Mungbean yellow mosaic Indian virus encoded AC2 protein suppresses RNA silencing by inhibiting Arabidopsis RDR6 and AGO1 activities.
Abstract RNA silencing refers to a conserved RNA-directed gene regulatory mechanism in a wide range of eukaryotes. It plays an important role in many processes including growth, development, genome stability, and antiviral defense in the plants. Geminivirus encoded AC2 is identified as an RNA silencing suppressor protein, however, the mechanism of action has not been characterized. In this paper, we elucidate another mechanism of AC2-mediated suppression activity of Mungbean Yellow Mosaic India Virus (MYMIV). The AC2 protein, unlike many other suppressors, does not bind to siRNA or dsRNA species and its suppressio...
Source: Virology - September 30, 2015 Category: Virology Authors: Kumar V, Mishra SK, Rahman J, Taneja J, Sundaresan G, Mishra NS, Mukherjee SK Tags: Virology Source Type: research

Peste des petits ruminants virus exploits cellular autophagy machinery for replication.
Abstract Peste des petits ruminants virus (PPRV) is an important pathogen that seriously influences the productivity of small ruminants worldwide. Although PPRV is known to induce apoptosis in infected cells, the interaction between PPRV and permissive cells requires further elucidation. Here, we provide the first evidence that PPRV infection triggered autophagy in Vero cells based on the appearance of abundant double- and single-membrane vesicles, the accumulation of LC3 fluorescent puncta, the enhancement of LC3-I/-II conversion, and autophagic flux. We further demonstrated that induction of autophagy with rapam...
Source: Virology - January 11, 2013 Category: Virology Authors: Zhang Y, Wu S, Lv J, Feng C, Deng J, Wang C, Yuan X, Zhang T, Lin X Tags: Virology Source Type: research

Dog nectin-4 is an epithelial cell receptor for canine distemper virus that facilitates virus entry and syncytia formation.
Abstract Canine distemper virus (CDV) was shown to use dog nectin-4 as a receptor to gain entry into epithelial cells. RNA from dog placenta or MDCK kidney cells was isolated and cDNAs were prepared. Two splice variants of dog nectin-4 were identified. A deletion of 25 amino acids was found in the cytoplasmic domain of dog nectin-4 from MDCK cells, corresponding to a splice variant that is also seen in murine nectin-4, and did not affect its role as a receptor. Both dog nectin-4 and human nectin-4 could function as an entry factor for CDV containing an EGFP reporter gene. Inhibition of dog nectin-4 expression by R...
Source: Virology - January 27, 2013 Category: Virology Authors: Noyce RS, Delpeut S, Richardson CD Tags: Virology Source Type: research

The modulation of hepatitis C virus 1a replication by PKR is dependent on NF-kB mediated interferon beta response in Huh7.5.1 cells.
Abstract Protein kinase R (PKR), a sensor of double-stranded RNA, plays an important role in the host response to viral infection. Hepatitis C genotype 2a virus (HCV2a) has been shown to induce PKR activation to suppress the translation of antiviral interferon stimulated genes (ISGs), suggesting that PKR inhibitor can be beneficial for treating chronically HCV-infected patients in conjunction with interferon alpha and ribavirin. However, in this study, we found that PKR inhibition using siRNA PKR, shRNA PKR or PKR inhibitor enhanced HCV 1a replication and rendered Huh7.5.1 cells more susceptible to HCV1a infection...
Source: Virology - February 8, 2013 Category: Virology Authors: Zhang L, Alter HJ, Wang H, Jia S, Wang E, Marincola FM, Shih JW, Wang RY Tags: Virology Source Type: research

Amino acids 78 and 79 of Mammalian Orthoreovirus protein µNS are necessary for stress granule localization, core protein λ2 interaction, and de novo virus replication.
We examined the capacity of a μNS(78-79) mutant to associate with known viral protein binding partners of μNS and found that it loses association with viral core protein λ2. Finally, we show that while this mutant cannot support de novo viral replication, it is able to rescue replication following siRNA knockdown of μNS. These data suggest that μNS association with SGs, λ2, or both play roles in MRV replication. PMID: 24314644 [PubMed - in process]
Source: Virology - December 12, 2013 Category: Virology Authors: Carroll K, Hastings C, Miller CL Tags: Virology Source Type: research

hnRNP A2/B1 interacts with influenza A viral protein NS1 and inhibits virus replication potentially through suppressing NS1 RNA/protein levels and NS1 mRNA nuclear export.
In this study, we identified heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) as an interacting partner of NS1 proteins by a proteomic method. Knockdown of hnRNP A2/B1 by small interfering RNA (siRNA) resulted in higher levels of NS vRNA, NS1 mRNA, and NS1 protein in the virus-infected cells. In addition, we demonstrated that hnRNP A2/B1 proteins are associated with NS1 and NS2 mRNAs and that knockdown of hnRNP A2/B1 promotes transport of NS1 mRNA from the nucleus to the cytoplasm in the infected cells. Lastly, we showed that knockdown of hnRNP A2/B1 leads to enhanced virus replication. Our results suggest that ...
Source: Virology - January 18, 2014 Category: Virology Authors: Wang Y, Zhou J, Du Y Tags: Virology Source Type: research

The nucleolar phosphoprotein B23 targets Newcastle disease virus matrix protein to the nucleoli and facilitates viral replication.
In this study, a nucleolar phosphoprotein B23 was identified to interact with Newcastle disease virus (NDV) matrix (M) protein. We found that NDV M protein accumulated in the nucleolus by binding B23 early in infection, but resulted in the redistribution of B23 from the nucleoli to the nucleoplasm later in infection. In vitro binding studies utilizing deletion mutants indicated that amino acids 30-60 of M and amino acids 188-245 of B23 were required for binding. Furthermore, knockdown of B23 by siRNA or overexpression of B23 or M-binding B23-derived polypeptides remarkably reduced cytopathic effect and inhibited NDV replic...
Source: Virology - March 1, 2014 Category: Virology Authors: Duan Z, Chen J, Xu H, Zhu J, Li Q, He L, Liu H, Hu S, Liu X Tags: Virology Source Type: research

Host cell autophagy promotes BK virus infection.
Abstract Autophagy is important for a variety for virus life cycles. We sought to determine the role of autophagy in human BK polyomavirus (BKPyV) infection. The addition excess amino acids during viral infection reduced BKPyV infection. Perturbing autophagy levels using inhibitors, 3-MA, bafilomycin A1, and spautin-1, also reduced infection, while rapamycin treatment of host cells increased infection. siRNA knockdown of autophagy genes, ATG7 and Beclin-1, corresponded to a decrease in BKPyV infection. BKPyV infection not only correlated with autophagosome formation, but also virus particles localized to autophagy...
Source: Virology - May 1, 2014 Category: Virology Authors: Bouley SJ, Maginnis MS, Derdowski A, Gee GV, O׳Hara BA, Nelson CD, Bara AM, Atwood WJ, Dugan AS Tags: Virology Source Type: research

PKCδ is required for porcine reproductive and respiratory syndrome virus replication.
Abstract Protein kinase C (PKC) that transduces signals to modulate a wide range of cellular functions has been shown to regulate a number of viral infections. Herein, we showed that inhibition of PKC with the PKC inhibitor GF109203X significantly impaired porcine reproductive and respiratory syndrome virus (PRRSV) replication. Inhibition of PKC led to virus yield reduction, which was associated with decreased viral RNA synthesis and lowered virus protein expression. And this inhibitory effect by PKC inhibitor was shown to occur at the early stage of PRRSV infection. Subsequently, we found that PRRSV infection act...
Source: Virology - August 22, 2014 Category: Virology Authors: Zhao H, Guo XK, Bi Y, Zhu Y, Feng WH Tags: Virology Source Type: research

Tetherin restricts HSV-2 release and is counteracted by multiple viral glycoproteins.
Abstract Tetherin has been defined as a restriction factor of HIV-1 and several other enveloped viruses. However, the significance of tetherin in viral infection remains to be further addressed. Here, we investigated whether tetherin plays a role in HSV-2 infection. Our study revealed that overexpression of tetherin restricted the release of HSV-2 into the extracellular medium, while knockdown of tetherin by siRNA enhanced its release. We further demonstrated that HSV-2 infection and viral glycoproteins gB, gD, gH and gL but not gM significantly downregulated the endogenous expression of tetherin. Additional study...
Source: Virology - November 26, 2014 Category: Virology Authors: Liu Y, Luo S, He S, Zhang M, Wang P, Li C, Huang W, Hu B, Griffin GE, Shattock RJ, Hu Q Tags: Virology Source Type: research