Exportin-5 orthologues are functionally divergent among species.
Nucleic Acids Res
; 34(17): 4711-21, 2006.
Article
em En
| MEDLINE
| ID: mdl-16963774
ABSTRACT
Exportin-5, an evolutionarily conserved nuclear export factor belonging to the importin-beta family of proteins, is known to play a role in the nuclear export of small noncoding RNAs such as precursors of microRNA, viral minihelix RNA and a subset of tRNAs in mammalian cells. In this study, we show that the exportin-5 orthologues from different species such as human, fruit fly and yeast exhibit diverged functions. We found that Msn5p, a yeast exportin-5 orthologue, binds double-stranded RNAs and that it prefers a shorter 22 nt, double-stranded RNA to approximately 80 nt pre-miRNA, even though both of these RNAs share a similar terminal structure. Furthermore, we found that Drosophila exportin-5 binds pre-miRNAs and that amongst the exportin-5 orthologues tested, it shows the highest affinity for tRNAs. The knockdown of Drosophila exportin-5 in cultured cells decreased the amounts of tRNA as well as miRNA, whereas the knock down of human exportin-5 in cultured cells affected only miRNA but not tRNA levels. These results indicate that double-stranded RNA binding ability is an inherited functional characteristic of the exportin-5 orthologues and that Drosophila exportin-5 functions as an exporter of tRNAs as well as pre-miRNAs in the fruit fly that lacks the orthologous gene for exportin-t.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
RNA de Cadeia Dupla
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Carioferinas
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Proteínas de Drosophila
Limite:
Animals
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Humans
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Japão