Enhanced specificity of the viral suppressor of RNA silencing protein p19 toward sequestering of human microRNA-122

  1. Get@NRC: Enhanced specificity of the viral suppressor of RNA silencing protein p19 toward sequestering of human microRNA-122 (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1021/bi2008273
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Journal titleBiochemistry
Pages77457755; # of pages: 11
SubjectBinding surface; Dimeric proteins; Human hepatoma cell lines; Human liver; Hydrogen bonding interactions; MicroRNAs; Mutational analysis; Post-transcriptional; RNA silencing; RNA-induced silencing complexes; Side-chains; Single residue; Site directed mutagenesis; Size selectivity; Small RNA; Wild types; Cell culture; Genes; Hydrogen bonds; Proteins; RNA; hydrogen; microRNA 122; mutant protein; protein p19; RNA; RNA induced silencing complex; siRNA 027; unclassified drug; article; base mispairing; enzyme specificity; gel mobility shift assay; gene control; gene silencing; hepatoma cell; human; human cell; human cell culture; hydrogen bond; mutational analysis; plasmid; posttranscriptional gene silencing; priority journal; protein binding; protein expression; protein purification; site directed mutagenesis; Western blotting; Binding Sites; Cell Line, Tumor; Circular Dichroism; Genome, Viral; Humans; Hydrogen Bonding; MicroRNAs; Models, Molecular; Mutagenesis, Site-Directed; RNA Interference; Tobacco; Tombusvirus; Transfection; Viral Proteins; Eukaryota
AbstractTombusviruses express a 19 kDa protein (p19) that, as a dimeric protein, suppresses the RNAs silencing pathway during infection by binding short-interfering RNA (siRNA) and preventing their association with the RNA-induced silencing complex (RISC). The p19 protein can bind to both endogenous and synthetic siRNAs with a high degree of size selectivity but with little sequence dependence. It also binds to other endogenous small RNAs such as microRNAs (miRNAs) but with lower affinity than to canonical siRNAs. It has become apparent, however, that miRNAs play a large role in gene regulation; their influence extends to expression and processing that affects virtually all eukaryotic processes. In order to develop new tools to study endogenous small RNAs, proteins that suppress specific miRNAs are required. Herein we describe mutational analysis of the p19 binding surface with the aim of creating p19 mutants with increased affinity for miR-122. By site-directed mutagenesis of a single residue, we describe p19 mutants with a nearly 50-fold increased affinity for miR-122 without altering the affinity for siRNA. Upon further mutational analysis of this site, we postulate that the higher affinity relies on hydrogen-bonding interactions but can be sterically hindered by residues with bulky side chains. Finally, we demonstrate the effectiveness of a mutant p19, p19-T111S, at sequestering miR-122 in human hepatoma cell lines, as compared to wild-type p19. Overall, our results suggest that p19 can be engineered to enhance its affinity toward specific small RNA molecules, particularly noncanonical miRNAs that are distinguishable based on locations of base-pair mismatches. The p19-T111S mutant also represents a new tool for the study of the function of miR-122 in post-transcriptional silencing in the human liver. © 2011 American Chemical Society.
Publication date
AffiliationNational Research Council Canada (NRC-CNRC); NRC Steacie Institute for Molecular Sciences (SIMS-ISSM)
Peer reviewedYes
NPARC number21271211
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Record identifierd0b4edd5-343d-445d-b5ec-a829718fbc02
Record created2014-03-24
Record modified2016-05-09
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