Exportin-5 mediates nuclear export of minihelix-containing RNAs

C. Gwizdek (1) , B. Ossareh-Nazari (1) , A. M. Brownawell (2) , A. Doglio (3) , Edouard Bertrand (4) , I. G. Macara (2) , C. Dargemont (1)

1 IJM (UMR_7592) - Institut Jacques Monod
2 University of Virginia
3 MICORALIS - Microbiologie Orale, Immunothérapie et Santé
4 IGMM - Institut de Génétique Moléculaire de Montpellier

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 (\textgreater 14 nt) with a base-paired 5' end and a 3-8-nt protruding 3' end. RNA export mediated by the minibelix 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.

Mots clés: protein-synthesis mechanism

Domaines: Génomique, Transcriptomique et Protéomique [q-bio.GN]; Virologie

C. Gwizdek, B. Ossareh-Nazari, A. M. Brownawell, A. Doglio, Edouard Bertrand, et al.. Exportin-5 mediates nuclear export of minihelix-containing RNAs. Journal of Biological Chemistry, 2003, 278 (8), pp.5505--5508. ⟨10.1074/jbc.C200668200⟩. ⟨hal-02239917⟩