Project description:Small RNAs play a critical role in host-pathogen interaction. In insects, for instance, small RNA-mediated silencing or RNA interference (RNAi) represents the main antiviral defense system. However, the antiviral role of RNAi has not been clearly proven in higher vertebrates. On the contrary, it is well established that the cell response relies on the recognition of viral RNAs by host pattern recognition receptors (PRR) to trigger the activation of the interferon pathway. Based on this evidence, we wished to contribute to this research field by identifying and characterizing small non-coding RNAs produced in mammalian cells upon RNA virus infection. We focused on Sindbis virus (SINV), the prototypical arbovirus, which by definition, is able to infect both vertebrate hosts and invertebrate vectors and triggers the interferon pathway or RNAi, respectively.
Project description:Small RNAs play a critical role in host-pathogen interaction. In insects, for instance, small RNA-mediated silencing or RNA interference (RNAi) represents the main antiviral defense system. However, the antiviral role of RNAi has not been clearly proven in higher vertebrates. On the contrary, it is well established that the cell response relies on the recognition of viral RNAs by host pattern recognition receptors (PRR) to trigger the activation of the interferon pathway. Based on this evidence, we wished to contribute to this research field by identifying and characterizing small non-coding RNAs produced in mammalian cells upon RNA virus infection. We focused on Sindbis virus (SINV), the prototypical arbovirus, which by definition, is able to infect both vertebrate hosts and invertebrate vectors and triggers the interferon pathway or RNAi, respectively. Taking advantage of large scale sequencing, we cloned and sequenced small RNAs from both mock and SINV-infected mammalian cells (HEK 293 and VERO). We identified a novel population of viral small RNAs (vsRNAs) that accumulate as 20 to 30 nt species during infection. We assessed that this viral small RNA population is modified in 3'end and derived from the activation of the cellular antiviral endoribonuclease RNaseL. Altogether our results indicate a potential role for the SINV-derived small RNAs in the host defense mechanism.
Project description:Viral vectors are attractive tools to express genes in neurons. Transduction of neurons with a recombinant, replication-deficient Sindbis viral vector is a method of choice for studying the effects of short-term protein overexpression on neuronal function. However, to which extent Sindbis by itself may affect neurons is not fully understood. We assessed effects of neuronal transduction with a Sindbis viral vector on the transcriptome and proteome in organotypic hippocampal slice cultures, and analyzed the electrophysiological properties of individual CA1 neurons, at 24h and 72h after viral vector injection. Whereas Sindbis caused substantial gene expression alterations, changes at the protein level were less pronounced. Alterations in transcriptome and proteome were predominantly limited to proteins involved in mediating anti-viral innate immune responses. Sindbis transduction did not affect the electrophysiological properties of individual neurons: the membrane potential, excitability and synaptic currents were similar between transduced and nontransduced CA1 neurons up to 72h after Sindbis injection. We conclude that Sindbis viral vectors are suitable for studying short-term effects of a protein of interest on electrophysiological properties of neurons, but not for studies on the regulation of gene expression.
Project description:A time course of infection of the alphavirus Sindbis virus (SINV) was used to investigate the presence of viral specific vsRNA and the changes in miRNAs profiles in human embryonic kidney 293 cells (HEK293) by high throughput DNA sequencing. Deep sequencing of small RNAs early in SINV infection (4 and 6 hpi) showed low abundance (0.8%) of viral specific RNAs (vsRNAs) , with a random uniform distribution not typical of Dicer products, suggesting they arise from non-specific degradation. Sequencing showed little variation of cellular microRNAs (miRNAs) at 4 and 6 hpi compared to uninfected cells. Twelve miRNAs exhibiting some minor differential expression by sequencing, showed insignificant modulation by Northern blot analysis.
Project description:A time course of infection of the alphavirus Sindbis virus (SINV) was used to investigate the presence of viral specific vsRNA and the changes in miRNAs profiles in human embryonic kidney 293 cells (HEK293) by high throughput DNA sequencing. Deep sequencing of small RNAs early in SINV infection (4 and 6 hpi) showed low abundance (0.8%) of viral specific RNAs (vsRNAs) , with a random uniform distribution not typical of Dicer products, suggesting they arise from non-specific degradation. Sequencing showed little variation of cellular microRNAs (miRNAs) at 4 and 6 hpi compared to uninfected cells. Twelve miRNAs exhibiting some minor differential expression by sequencing, showed insignificant modulation by Northern blot analysis. RNA was isolated from mock infected and SINV inoculated HEK 293 cells at 4hpi and 6hpi cDNA libraries were generated for the small RNA (sRNA) content of the cells and sequenced using Illumina GA II, which yielded between 29.1M and 30.5M reads per sample
Project description:Microarray analysis comparing cells that are resistant to Sindbis virus-induced cell death (clones 9, 43) versus cells that are sensitive to Sindbis virus-induced cell death (WT293) Keywords = Sindbis alphavirus functinal phenotype Keywords: repeat sample
Project description:We focus our analyses on the description of viral small RNAs (FHVdeltaB2 or FHV) and based on genetic and molecular evidende, classify them and discuss their relevance in antiviral defense. Small RNAs from adult Drosophila flies from different genetic backgrounds and infected with FHV-deltaB2 or FHV were sequenced using the illumina platform.
Project description:RNA viruses rely on cellular RNA-binding proteins (RBPs) to infect the host cell. However, the repertoire of the cellular RBPs exploited by viruses is largely unknown. Using the ‘RNA interactome capture’ method, we profiled in a proteome-wide scale the RBP-RNA interactions occurring during sindbis virus (SINV) infection. We discover that SINV affects the activity of hundreds of RBPs, essentially rewiring the host RNA-bound proteome. Such alterations do not relate to changes in protein abundance but are rather due to subcellular redistribution of RBPs and pervasive transcriptome remodelling. Strikingly, RBPs stimulated by SINV accumulate in the cytoplasmic compartments where the virus replicates and interact with viral RNA. Perturbation of these RBPs can restrict or promote infection; for example, GEMIN5 binds to key regulatory regions of SINV RNAs and inhibits viral protein expression. Importantly, we show that drug based RBP intervention may have potential as therapeutic strategy against viruses.
Project description:We focus our analyses on the description of viral small RNAs (FHVdeltaB2 or FHV) and based on genetic and molecular evidende, classify them and discuss their relevance in antiviral defense.