Abstract
MicroRNAs (miRNAs) are initially expressed as long transcripts that are processed in the nucleus to yield approximately 65-nucleotide (nt) RNA hairpin intermediates, termed pre-miRNAs, that are exported to the cytoplasm for additional processing to yield mature, approximately 22-nt miRNAs. Here, we demonstrate that human pre-miRNA nuclear export, and miRNA function, are dependent on Exportin-5. Exportin-5 can bind pre-miRNAs specifically in vitro, but only in the presence of the Ran-GTP cofactor. Short hairpin RNAs, artificial pre-miRNA analogs used to express small interfering RNAs, also depend on Exportin-5 for nuclear export. Together, these findings define an additional cellular cofactor required for miRNA biogenesis and function.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Active Transport, Cell Nucleus
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Cell Line
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Cell Nucleus / genetics
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Cell Nucleus / metabolism*
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Electrophoretic Mobility Shift Assay
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Humans
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Karyopherins / genetics
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Karyopherins / metabolism*
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Luciferases / metabolism
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MicroRNAs / genetics
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MicroRNAs / metabolism*
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Plasmids
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Promoter Regions, Genetic
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RNA / chemistry*
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RNA / metabolism*
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RNA Interference
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RNA Precursors / genetics
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RNA Precursors / metabolism
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RNA Processing, Post-Transcriptional*
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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ran GTP-Binding Protein / metabolism
Substances
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Karyopherins
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MicroRNAs
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RNA Precursors
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RNA, Messenger
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XPO5 protein, human
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RNA
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Luciferases
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ran GTP-Binding Protein