Exportin-5 mediates nuclear export of minihelix-containing RNAs.
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.
Gwizdek
Carole
C
Institut Jacques Monod, Unité Mixte de Recherche 7592, CNRS, Universités Paris VI et VII, 2 Place Jussieu, Tour 43, 75251 Paris Cedex 05, France.
Ossareh-Nazari
Batool
B
Brownawell
Amy M
AM
Doglio
Alain
A
Bertrand
Edouard
E
Macara
Ian G
IG
Dargemont
Catherine
C
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000502:physiology; D005260:Female; D028884:Karyopherins / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D009865:Oocytes / Q000502:physiology; D012330:RNA, Double-Stranded / Q000378:metabolism; D012367:RNA, Viral / Q000737:chemistry* / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D014982:Xenopus laevis; D020931:ran GTP-Binding Protein
D028884:Karyopherins; D012330:RNA, Double-Stranded; D012367:RNA, Viral; D016601:RNA-Binding Proteins; C446511:XPO5 protein, human; D020931:ran GTP-Binding Protein