Dataset Information

Cross-species comparative analysis of Dicer proteins during Sindbis virus infection

ABSTRACT: The role of RNA silencing as a defense mechanism against viruses remains to be formerly established in mammalian somatic cells. Here, we determined the antiviral properties of human and Drosophila Dicer proteins in a heterologous setup. We expressed human Dicer (hDicer) in Drosophila, and Drosophila Dicer-2 in human cells, and measured the impact on the response to Sindbis virus (SINV) infection. In flies, hDicer presents a low processing activity, but partially rescues a Dcr2 null mutation in flies. Expression of Dicer-2 in HEK293 cells allows the processing of SINV RNA into 21-nt-long small RNAs. Nevertheless, instead of conferring a protective effect against SINV, Dicer-2 expression increases viral replication in HEK293 cells. We present evidence that this effect is due to a competition with the interferon pathway. Our results therefore suggest that adding functionial RNA silencing machinery in IFN-competent differentiated mammalian cells can be detrimental for antiviral defense.

OTHER RELATED OMICS DATASETS IN: PRJNA266231

ORGANISM(S): Sindbis virus Homo sapiens Drosophila melanogaster

PROVIDER: GSE62934 | GEO | 2015/12/28

SECONDARY ACCESSION(S): PRJNA266231

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:In Drosophila, the siRNA pathway is initiated when exogenous or endogenous double stranded RNA (dsRNA) is processed into siRNAs by Dicer-2 (Dcr-2) and a dsRNA-binding protein (dsRBP) cofactor called Loquacious (Loqs). The siRNAs are then loaded onto Argonaute-2 (Ago2) protein by the action of Dcr-2 with another dsRBP cofactor called R2D2. Loaded Ago2 executes the destruction of target RNAs that have sequence complementarity to the siRNA. Dcr-2, R2D2, and Ago2 have also been shown to be required for innate antiviral defense in Drosophila. However, the biogenesis of virus-derived siRNAs (vsiRNAs) and their targets in virus-infected cells remain unclear. Here, we analyzed the antiviral response in Drosophila by monitoring the replication of different RNA viruses and deep sequencing of small RNAs in infected animals. We show that vsiRNAs are generated by Dcr-2 processing of dsRNA formed during viral genome replication and transcription. These vsiRNAs then directly target viral transcripts but not genomes, to inhibit viral replication. The biogenesis of vsiRNAs was virtually independent of Loqs and R2D2. R2D2, however, was essential for sorting and loading of vsiRNAs onto Ago2 and effective silencing of viral RNA expression. Loqs was completely dispensable for silencing of viruses in contrast to its role in silencing of endogenous targets. Our results suggest the existence of a specific siRNA pathway triggered by viral infection independent of conserved dsRBP cofactors and separate from the endogenous pathway. Inhibition of virus replication resulting from direct injection of viral RNA into Drosophila embryos was also not dependent on Loqs, suggesting the distinction of the two pathways is not related to the mode of entry but recognition of intrinsic features of viral RNA or its mode of replication. We speculate that this unique framework might be necessary for a prompt and efficient antiviral response We analyzed the small RNA reponse to viral infection by deep sequencing of small RNA libraries from wild type and RNAi mutant adult flies infected with Sindbis birus and Vesicular Stomatatis virus.

Dataset Information

Cross-species comparative analysis of Dicer proteins during Sindbis virus infection

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure