eIF1A augments Ago2-mediated Dicer-independent miRNA biogenesis and RNA interference

Nat Commun. 2015 May 28;6:7194. doi: 10.1038/ncomms8194.

Abstract

MicroRNA (miRNA) biogenesis and miRNA-guided RNA interference (RNAi) are essential for gene expression in eukaryotes. Here we report that translation initiation factor eIF1A directly interacts with Ago2 and promotes Ago2 activities in RNAi and miR-451 biogenesis. Biochemical and NMR analyses demonstrate that eIF1A binds to the MID domain of Ago2 and this interaction does not impair translation initiation. Alanine mutation of the Ago2-facing Lys56 in eIF1A impairs RNAi activities in human cells and zebrafish. The eIF1A-Ago2 assembly facilitates Dicer-independent biogenesis of miR-451, which mediates erythrocyte maturation. Human eIF1A (heIF1A), but not heIF1A(K56A), rescues the erythrocyte maturation delay in eif1axb knockdown zebrafish. Consistently, miR-451 partly compensates erythrocyte maturation defects in zebrafish with eif1axb knockdown and eIF1A(K56A) expression, supporting a role of eIF1A in miRNA-451 biogenesis in this model. Our results suggest that eIF1A is a novel component of the Ago2-centred RNA-induced silencing complexes (RISCs) and augments Ago2-dependent RNAi and miRNA biogenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Argonaute Proteins / metabolism*
  • Blotting, Northern
  • Blotting, Western
  • DEAD-box RNA Helicases / metabolism*
  • Eukaryotic Initiation Factor-1 / genetics*
  • Eukaryotic Initiation Factor-1 / metabolism
  • Gene Expression Regulation / genetics*
  • Gene Knockdown Techniques
  • HEK293 Cells
  • Humans
  • Immunoprecipitation
  • In Vitro Techniques
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • MicroRNAs / biosynthesis*
  • Mutagenesis, Site-Directed
  • RNA Interference*
  • Real-Time Polymerase Chain Reaction
  • Ribonuclease III / metabolism*
  • Zebrafish

Substances

  • AGO2 protein, human
  • Argonaute Proteins
  • Eukaryotic Initiation Factor-1
  • MIRN451 microRNA, human
  • MicroRNAs
  • eukaryotic peptide initiation factor-1A
  • DICER1 protein, human
  • Ribonuclease III
  • DEAD-box RNA Helicases