Anti-viral RNA silencing: do we look like plants ?

Abstract

The anti-viral function of RNA silencing was first discovered in plants as a natural manifestation of the artificial 'co-suppression', which refers to the extinction of endogenous gene induced by homologous transgene. Because silencing components are conserved among most, if not all, eukaryotes, the question rapidly arose as to determine whether this process fulfils anti-viral functions in animals, such as insects and mammals. It appears that, whereas the anti-viral process seems to be similarly conserved from plants to insects, even in worms, RNA silencing does influence the replication of mammalian viruses but in a particular mode: micro(mi)RNAs, endogenous small RNAs naturally implicated in translational control, rather than virus-derived small interfering (si)RNAs like in other organisms, are involved. In fact, these recent studies even suggest that RNA silencing may be beneficial for viral replication. Accordingly, several large DNA mammalian viruses have been shown to encode their own miRNAs. Here, we summarize the seminal studies that have implicated RNA silencing in viral infection and compare the different eukaryotic responses.

Multimodal analysis of drug transporter expression in gastrointestinal tissue

“…The extent of peripheral immune humanization observed here was consistent with previous studies using these models[34], but this is the first study to quantify human transporter expression in these animals. The detection of some human transporter gene expression should not be surprising given that many of these transporters are expressed on the surface of human lymphocytes, which are abundant in the humanized mouse GI tract, particularly in the ileum.…”

HIV-1 TAR RNA Subverts RNA Interference in Transfected Cells through Sequestration of TAR RNA-binding Protein, TRBP

“…Perhaps not unexpected, there is now increasing evidence that plant and animal viruses can also manipulate the RNAi defense of the cell (2,6,23). Toward the latter goal, viruses can mutate both their primary nucleic acid sequences and secondary RNA structures to evade complementarity-based targeting (24); and many viruses also encode suppressor factors (25)(26)(27)(28)(29)(30) that interfere with discrete steps in the RNA silencing machinery of the cell.…”

Interactions between the HIV-1 Unspliced mRNA and Host mRNA Decay Machineries

“…RNA silencing is a mechanism for regulation of gene expression involving small non-coding RNA [92], as well as an innate host cell defense mechanism against viruses [93]. miRNA biogenesis begins with the RNA polymerase II-mediated transcription of miRNA precursor molecules containing a 5′-end cap structure and a 3′-end poly(A) tail.…”