Identification of cis-acting elements in the 3'-untranslated region of the dengue virus type 2 RNA that modulate translation and replication

J Biol Chem. 2011 Jun 24;286(25):22521-34. doi: 10.1074/jbc.M111.234302. Epub 2011 Apr 22.

Abstract

Using the massively parallel genetic algorithm for RNA folding, we show that the core region of the 3'-untranslated region of the dengue virus (DENV) RNA can form two dumbbell structures (5'- and 3'-DBs) of unequal frequencies of occurrence. These structures have the propensity to form two potential pseudoknots between identical five-nucleotide terminal loops 1 and 2 (TL1 and TL2) and their complementary pseudoknot motifs, PK2 and PK1. Mutagenesis using a DENV2 replicon RNA encoding the Renilla luciferase reporter indicated that all four motifs and the conserved sequence 2 (CS2) element within the 3'-DB are important for replication. However, for translation, mutation of TL1 alone does not have any effect; TL2 mutation has only a modest effect in translation, but translation is reduced by ∼60% in the TL1/TL2 double mutant, indicating that TL1 exhibits a cooperative synergy with TL2 in translation. Despite the variable contributions of individual TL and PK motifs in translation, WT levels are achieved when the complementarity between TL1/PK2 and TL2/PK1 is maintained even under conditions of inhibition of the translation initiation factor 4E function mediated by LY294002 via a noncanonical pathway. Taken together, our results indicate that the cis-acting RNA elements in the core region of DENV2 RNA that include two DB structures are required not only for RNA replication but also for optimal translation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • 3' Untranslated Regions / genetics*
  • Algorithms
  • Base Sequence
  • Cell Line
  • Conserved Sequence
  • Dengue Virus / genetics*
  • Dengue Virus / metabolism
  • Dengue Virus / physiology*
  • Luciferases, Renilla / genetics
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Protein Biosynthesis / genetics*
  • RNA, Viral / biosynthesis
  • RNA, Viral / chemistry
  • RNA, Viral / genetics*
  • Regulatory Sequences, Ribonucleic Acid / genetics*
  • Replicon / genetics
  • Virus Replication / genetics*

Substances

  • 3' Untranslated Regions
  • RNA, Viral
  • Regulatory Sequences, Ribonucleic Acid
  • Luciferases, Renilla