Crystal structure of the primary piRNA biogenesis factor Zucchini reveals similarity to the bacterial PLD endonuclease Nuc
- Franka Voigt1,
- Michael Reuter2,3,
- Anisa Kasaruho2,3,
- Eike C. Schulz1,
- Ramesh S. Pillai2,3,4 and
- Orsolya Barabas1,4
- 1European Molecular Biology Laboratory, 69117 Heidelberg, Germany
- 2European Molecular Biology Laboratory, 38042 Grenoble, France
- 3CNRS-UJF-EMBL International Unit (UMI 3265) for Virus Host Cell Interactions (UVHCI), 38042 Grenoble, France
Abstract
Piwi-interacting RNAs (piRNAs) are a gonad-specific class of small RNAs that associate with the Piwi clade of Argonaute proteins and play a key role in transposon silencing in animals. Since biogenesis of piRNAs is independent of the double-stranded RNA-processing enzyme Dicer, an alternative nuclease that can process single-stranded RNA transcripts has been long sought. A Phospholipase D-like protein, Zucchini, that is essential for piRNA processing has been proposed to be a nuclease acting in piRNA biogenesis. Here we describe the crystal structure of Zucchini from Drosophila melanogaster and show that it is very similar to the bacterial endonuclease, Nuc. The structure also reveals that homodimerization induces major conformational changes assembling the active site. The active site is situated on the dimer interface at the bottom of a narrow groove that can likely accommodate single-stranded nucleic acid substrates. Furthermore, biophysical analysis identifies protein segments essential for dimerization and provides insights into regulation of Zucchini's activity.
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Footnotes
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↵4 Corresponding authors
E-mail orsolya.barabas{at}embl.de
E-mail pillai{at}embl.fr
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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.034967.112.
- Received June 16, 2012.
- Accepted September 14, 2012.
- Copyright © 2012 RNA Society
Freely available online through the RNA Open Access option.
