Overexpression of Exportin 5 enhances RNA interference mediated by short hairpin RNAs and microRNAs
Abstract
Plasmids or viral vectors that express short hairpin RNAs (shRNAs) have emerged as important tools for the stable inhibition of specific genes by RNA interference. shRNAs are structural and functional homologs of pre-microRNAs, intermediates in the production of endogenously encoded microRNAs (miRNAs). Therefore, overexpressed shRNAs could inhibit miRNA function by competing for a limiting level of one or more factors involved in miRNA biogenesis or function. Here, we demonstrate that overexpressed shRNAs can saturate the activity of endogenous Exportin 5, a factor required for nuclear export of both shRNAs and pre-miRNAs. While shRNA overexpression can therefore inhibit miRNA function, simultaneous overexpression of Exportin 5 reverses this effect. Moreover, Exportin 5 overexpression can significantly enhance RNA interference mediated by shRNAs. These data have implications for the future clinical utilization of shRNAs and also provide a simple method to enhance RNA interference by shRNAs in culture.
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Footnotes
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↵4 Present address: Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10021, USA
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Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.7233305.
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- Accepted November 11, 2004.
- Received October 31, 2004.
- Copyright 2005 by RNA Society