Structural requirements for pre-microRNA binding and nuclear export by Exportin 5.

Published online

Journal Article

The biogenesis and function of mature human microRNAs is dependent on the nuclear export of pre-microRNA precursors by Exportin 5 (Exp5). The precursor for the human miR-30 microRNA, which is a 63 nt long RNA hairpin bearing a 2 nt 3' overhang, forms a specific complex with Exp5 and the Ran-GTP cofactor. Here, we have examined the structural requirements for pre-microRNA binding by Exp5. Our data indicate that pre-miR-30 binding requires an RNA stem of >16 bp and is facilitated by a 3' overhang. Although a blunt-ended derivative of the pre-miR-30 stem-loop remained capable of binding Exp5, 5' overhangs were inhibitory. miR-30 variants that had lost the ability to bind Exp5 effectively were not efficiently exported from the nucleus and were also expressed at reduced levels. Furthermore, formation of a pre-microRNA/Exp5/Ran-GTP complex inhibited exonucleolytic digestion of the pre-miRNA in vitro. Together, these data demonstrate that pre-microRNA binding by Exp5 involves recognition of almost all of the RNA hairpin, with the exception of the terminal loop. Moreover, these results argue that Exp5 binding not only mediates pre-microRNA nuclear export but also prevents nuclear pre-microRNA degradation.

Full Text

Duke Authors

Cited Authors

  • Zeng, Y; Cullen, BR

Published Date

  • 2004

Published In

Volume / Issue

  • 32 / 16

Start / End Page

  • 4776 - 4785

PubMed ID

  • 15356295

Pubmed Central ID

  • 15356295

Electronic International Standard Serial Number (EISSN)

  • 1362-4962

Digital Object Identifier (DOI)

  • 10.1093/nar/gkh824

Language

  • eng

Conference Location

  • England