Features of double-stranded RNA-binding domains of RNA helicase A are necessary for selective recognition and translation of complex mRNAs

J Biol Chem. 2011 Feb 18;286(7):5328-37. doi: 10.1074/jbc.M110.176339. Epub 2010 Dec 1.

Abstract

The DExH protein RNA helicase A (RHA) plays numerous roles in cell physiology, and post-transcriptional activation of gene expression is a major role among them. RHA selectively activates translation of complex cellular and retroviral mRNAs. Although RHA requires interaction with structural features of the 5'-UTR of these target mRNAs, the molecular basis of their translation activation by RHA is poorly understood. RHA contains a conserved ATPase-dependent helicase core that is flanked by two α-β-β-β-α double-stranded RNA-binding domains at the N terminus and repeated arginine-glycine residues at the C terminus. The individual recombinant N-terminal, central helicase, and C-terminal domains were evaluated for their ability to specifically interact with cognate RNAs by in vitro biochemical measurements and mRNA translation assays in cells. The results demonstrate that N-terminal residues confer selective interaction with retroviral and junD target RNAs. Conserved lysine residues in the distal α-helix of the double-stranded RNA-binding domains are necessary to engage structural features of retroviral and junD 5'-UTRs. Exogenous expression of the N terminus coprecipitates junD mRNA and inhibits the translation activity of endogenous RHA. The results indicate that the molecular basis for the activation of translation by RHA is recognition of target mRNA by the N-terminal domain that tethers the ATP-dependent helicase for rearrangement of the complex 5'-UTR.

Publication types

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

MeSH terms

  • 5' Untranslated Regions / physiology*
  • Animals
  • DEAD-box RNA Helicases / chemistry
  • DEAD-box RNA Helicases / genetics
  • DEAD-box RNA Helicases / metabolism*
  • HEK293 Cells
  • Humans
  • Neoplasm Proteins / chemistry
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Protein Biosynthesis / physiology*
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins c-jun / chemistry
  • Proto-Oncogene Proteins c-jun / genetics
  • Proto-Oncogene Proteins c-jun / metabolism
  • RNA, Viral / chemistry
  • RNA, Viral / genetics
  • RNA, Viral / metabolism
  • Retroviridae / chemistry
  • Retroviridae / genetics
  • Retroviridae / metabolism

Substances

  • 5' Untranslated Regions
  • Neoplasm Proteins
  • Proto-Oncogene Proteins c-jun
  • RNA, Viral
  • DHX9 protein, human
  • DEAD-box RNA Helicases