Scientific article
Open access

Metazoan Maelstrom is an RNA-binding protein that has evolved from an ancient nuclease active in protists

Published inRNA, vol. 21, no. 5, p. 833-839
Publication date2015-05-16
First online date2015-03-16

Piwi-interacting RNAs (piRNAs) guide Piwi argonautes to their transposon targets for silencing. The highly conserved protein Maelstrom is linked to both piRNA biogenesis and effector roles in this pathway. One defining feature of Maelstrom is the predicted MAEL domain of unknown molecular function. Here, we present the first crystal structure of the MAEL domain from Bombyx Maelstrom, which reveals a nuclease fold. The overall architecture resembles that found in Mg 2+ - or Mn 2+ -dependent DEDD nucleases, but a clear distinguishing feature is the presence of a structural Zn 2+ ion coordinated by the conserved ECHC residues. Strikingly, metazoan Maelstrom orthologs across the animal kingdom lack the catalytic DEDD residues, and as we show for Bombyx Maelstrom are inactive as nucleases. However, a MAEL domain-containing protein from amoeba having both sequence motifs (DEDD and ECHC) is robustly active as an exoribonuclease. Finally, we show that the MAEL domain of Bombyx Maelstrom displays a strong affinity for single-stranded RNAs. Our studies suggest that the ancient MAEL nuclease domain evolved to function as an RNA-binding module in metazoan Maelstrom.

  • Bombyx
  • E. histolytica
  • EHI_192630
  • MAEL
  • Piwi
  • PiRNA
  • Ribonuclease
Affiliation Not a UNIGE publication
  • National Institutes of Health - Functions of MOV10L1 in piRNA biogenesis and germ cell development [1R01HD069592-01A1]
  • Fondation Recherche Médicale - [DEP20131128529]
  • French Infrastructure for Integrated Structural Biology Initiative FRISBI - [ANR-10-INSB-05-02]
Citation (ISO format)
CHEN, Kuan-Ming et al. Metazoan Maelstrom is an RNA-binding protein that has evolved from an ancient nuclease active in protists. In: RNA, 2015, vol. 21, n° 5, p. 833–839. doi: 10.1261/rna.049437.114
Main files (1)
Article (Published version)
ISSN of the journal1355-8382

Technical informations

Creation01/25/2024 4:09:00 PM
First validation02/29/2024 3:03:06 PM
Update time02/29/2024 3:03:06 PM
Status update02/29/2024 3:03:06 PM
Last indexation05/06/2024 6:03:50 PM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack