Graduate School of Frontier Biosciences, Osaka University

Japanese

A High-Resolution Structure of the Pre-microRNA Nuclear Export Machinery

Journal Science 326, 1275-1279 (2009)
Authors Chimari Okada, Eiki Yamashita, Soo Jae Lee, Satoshi Shibata, Jun Katahira,
Atsushi Nakagawa, Yoshihiro Yoneda, Tomitake Tsukihara
Title A High-Resolution Structure of the Pre-microRNA Nuclear Export Machinery
PubMed 19965479
Abstract Nuclear export of microRNAs (miRNAs) by exportin-5 (Exp-5) is an essential step in miRNA biogenesis. Here, we present the 2.9 angstrom structure of the pre-miRNA nuclear export machinery formed by pre-miRNA complexed with Exp-5 and a guanine triphosphate (GTP)–bound form of the small nuclear guanine triphosphatase (GTPase) Ran (RanGTP). The x-ray structure shows that Exp-5:RanGTP recognizes the 2-nucleotide 3' overhang structure and the double-stranded stem of the pre-miRNA. Exp-5:RanGTP shields the pre-miRNA stem from degradation in a baseball mitt–like structure where it is held by broadly distributed weak interactions, whereas a tunnel-like structure of Exp-5 interacts strongly with the 2-nucleotide 3' overhang through hydrogen bonds and ionic interactions. RNA recognition by Exp-5:RanGTP does not depend on RNA sequence, implying that Exp-5:RanGTP can recognize a variety of pre-miRNAs.

 

Figure.
The structure of the Exportin-5:RanGTP:pre-miRNA complex.



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