Studying the RNA silencing pathway with the p19 protein

Abstract

Edited by Wilhelm JustKeywords: p19 protein Viral suppressors of RNA silencing Small RNA detection miRNA-122 Protein engineering Heterologous expression a b s t r a c tThe origins of the RNA silencing pathway are in defense against invading viruses and in response, viruses have evolved counter-measures to interfere with the host pathway. The p19 protein is expressed by tombusviruses as a suppressor of RNA silencing and functions to sequester small RNA duplexes, thereby preventing induction of the pathway. p19 exhibits size-specific and sequence-independent binding of its small RNA ligands, binding with high affinity to duplexes 20-22 nucleotides long. p19's binding specificity and its ability to sequester small RNAs has made it a unique protein-based tool for probing the molecular mechanisms of the highly complex RNA silencing pathway in a variety of systems. Furthermore, protein engineering of this 'molecular caliper' promises novel applications in biotechnology and medicine where small RNA molecules are of remarkable interest given their potent gene regulatory abilities. Crown

Complementation of the human adenovirus type 5 VA RNAI defect by the Vaccinia virus E3L protein and serotype-specific VA RNAIs

“…This is well exemplified in the case of the Tomato bushy stunt virus (TBSV) P19 protein, which in its dimeric form interacts and sequesters siRNA duplexes from being incorporated into RISC (Danielson and Pezacki, 2013). Likewise, a very high affinity of the Rice hoja blanca virus (RHBV) NS3 protein towards siRNA duplexes blocks functional RISC assembly in plants (Hemmes et al, 2007).…”

A Novel p19 Fusion Protein as a Delivery Agent for Short-interfering RNAs

“…21,29,30,31 The utility of p19 has been further enhanced through mutations and protein fusions. 21,32,33,34,35 As reported previously, linking two p19 monomers with a flexible linker gives the protein a higher thermostability and a higher affinity for its bound siRNAs, which are generally beneficial properties for p19's development as a biotechnology tool.…”

Suppressing RNA silencing with small molecules and the viral suppressor of RNA silencing protein p19

“…The affinity of p19 drops off dramatically for any dsRNA longer or shorter than those generated by the dicer enzyme [6]. Because of this p19 is becoming an attractive tool in biotechnology [7], in studies of microRNAs [8e18], in diverse organisms such as human cells, C. elegans, and Drosophila [8,19,20], and protein overexpression [21e26].…”