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Structural insights into Rhino‐Deadlock complex for germline piRNA cluster specification
Author(s) -
Yu Bowen,
Lin Yu An,
Parhad Swapnil S,
Jin Zhaohui,
Ma Jinbiao,
Theurkauf William E,
Zhang ZZ Zhao,
Huang Ying
Publication year - 2018
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.201745418
Subject(s) - library science , excellence , china , center of excellence , political science , computer science , law
PIWI ‐interacting RNA s (pi RNA s) silence transposons in germ cells to maintain genome stability and animal fertility. Rhino, a rapidly evolving heterochromatin protein 1 ( HP 1) family protein, binds Deadlock in a species‐specific manner and so defines the pi RNA ‐producing loci in the Drosophila genome. Here, we determine the crystal structures of Rhino‐Deadlock complex in Drosophila melanogaster and simulans . In both species, one Rhino binds the N‐terminal helix–hairpin–helix motif of one Deadlock protein through a novel interface formed by the beta‐sheet in the Rhino chromoshadow domain. Disrupting the interface leads to infertility and transposon hyperactivation in flies. Our structural and functional experiments indicate that electrostatic repulsion at the interaction interface causes cross‐species incompatibility between the sibling species. By determining the molecular architecture of this pi RNA ‐producing machinery, we discover a novel HP 1‐partner interacting mode that is crucial to pi RNA biogenesis and transposon silencing. We thus explain the cross‐species incompatibility of two sibling species at the molecular level.