Exportin-5 mediates nuclear export of minihelix-containing RNAs

J Biol Chem. 2003 Feb 21;278(8):5505-8. doi: 10.1074/jbc.C200668200. Epub 2002 Dec 30.

Abstract

The adenovirus VA1 RNA (VA1), a 160-nucleotide (nt)-long RNA transcribed by RNA polymerase III, is efficiently exported from the nucleus to the cytoplasm of infected cells, where it antagonizes the interferon-induced antiviral defense system. We recently reported that nuclear export of VA1 is mediated by a cis-acting RNA export motif, called minihelix, that comprises a double-stranded stem (>14 nt) with a base-paired 5' end and a 3-8-nt protruding 3' end. RNA export mediated by the minihelix motif is Ran-dependent, which indicates the involvement of a karyopherin-related factor (exportin) that remained to be determined. Here we show using microinjection in Xenopus laevis oocytes that VA1 is transported to the cytoplasm by exportin-5, a nuclear transport factor for double-stranded RNA binding proteins. Gel retardation assays revealed that exportin-5 directly interacts with VA1 RNA in a RanGTP-dependent manner. More generally, in vivo and in vitro competition experiments using various VA1-derived, but also artificial and cellular, RNAs lead to the conclusion that exportin-5 preferentially recognizes and transports minihelix motif-containing RNAs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus / physiology*
  • Adenoviridae / genetics
  • Animals
  • Base Sequence
  • Cell Nucleus / physiology
  • Female
  • Karyopherins / metabolism*
  • Nucleic Acid Conformation
  • Oocytes / physiology
  • RNA, Double-Stranded / metabolism
  • RNA, Viral / chemistry*
  • RNA, Viral / metabolism*
  • RNA-Binding Proteins / metabolism
  • Xenopus laevis
  • ran GTP-Binding Protein*

Substances

  • Karyopherins
  • RNA, Double-Stranded
  • RNA, Viral
  • RNA-Binding Proteins
  • XPO5 protein, human
  • ran GTP-Binding Protein