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Requirements for multivalent Yb body assembly in transposon silencing in Drosophila
Author(s) -
Hirakata Shigeki,
Ishizu Hirotsugu,
Fujita Aoi,
Tomoe Yumiko,
Siomi Mikiko C
Publication year - 2019
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.201947708
Subject(s) - biological sciences , library science , medical school , graduate students , biology , medicine , medical education , computer science , microbiology and biotechnology
Female sterile (1) Yb (Yb) is a primary component of Yb bodies, perinuclear foci considered to be the site of PIWI‐interacting RNA (piRNA) biogenesis in Drosophila ovarian somatic cells (OSCs). Yb consists of three domains: Helicase C‐terminal (Hel‐C), RNA helicase, and extended Tudor (eTud) domains. We previously showed that the RNA helicase domain is necessary for Yb–RNA interaction, Yb body formation, and piRNA biogenesis. Here, we investigate the functions of Hel‐C and eTud and reveal that Hel‐C is dedicated to Yb–Yb homotypic interaction, while eTud is necessary for Yb–RNA association, as is the RNA helicase domain. All of these domains are indispensable for Yb body formation and transposon‐repressing piRNA production. Strikingly, however, genic piRNAs unrelated to transposon silencing are produced in OSCs where Yb bodies are disassembled. We also reveal that Yb bodies are liquid‐like multivalent condensates whose assembly depends on Yb–Yb homotypic interaction and Yb binding particularly with flamenco RNA transcripts, the source of transposon‐repressing piRNAs. New insights into Yb body assembly and biological relevance of Yb bodies in transposon silencing have emerged.