The 5' non-translated region of Varroa destructor virus 1 (genus Iflavirus): structure prediction and IRES activity in Lymantria dispar cells

J Gen Virol. 2006 Nov;87(Pt 11):3397-407. doi: 10.1099/vir.0.82122-0.


Structure prediction of the 5' non-translated region (NTR) of four iflavirus RNAs revealed two types of potential internal ribosome entry site (IRES), which are discriminated by size and level of complexity, in this group of viruses. In contrast to the intergenic IRES of dicistroviruses, the potential 5' IRES structures of iflaviruses do not have pseudoknots. To test the activity of one of these, a bicistronic construct was made in which the 5' NTR of Varroa destructor virus 1 (VDV-1) containing a putative IRES was cloned in between two reporter genes, enhanced green fluorescent protein and firefly luciferase (Fluc). The presence of the 5' NTR of VDV-1 greatly enhanced the expression levels of the second reporter gene (Fluc) in Lymantria dispar Ld652Y cells. The 5' NTR was active in a host-specific manner, as it showed lower activity in Spodoptera frugiperda Sf21 cells and no activity in Drosophila melanogaster S2 cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5' Untranslated Regions / genetics*
  • 5' Untranslated Regions / metabolism
  • Algorithms
  • Animals
  • Base Composition
  • Base Sequence
  • Blotting, Northern
  • Cells, Cultured
  • Gene Expression Regulation*
  • Genes, Reporter / genetics
  • Genes, Viral / genetics
  • Insecta
  • Luciferases, Firefly / genetics
  • Luciferases, Firefly / metabolism
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Picornaviridae / genetics*
  • RNA, Messenger / analysis
  • RNA, Viral / genetics*
  • Regulatory Sequences, Nucleic Acid
  • Ribosomes / metabolism
  • Species Specificity
  • Transfection


  • 5' Untranslated Regions
  • RNA, Messenger
  • RNA, Viral
  • Luciferases, Firefly