TY - JOUR
T1 - Requirements for multivalent Yb body assembly in transposon silencing in Drosophila
AU - Hirakata, Shigeki
AU - Ishizu, Hirotsugu
AU - Fujita, Aoi
AU - Tomoe, Yumiko
AU - Siomi, Mikiko C.
N1 - Funding Information:
We thank J. Brennecke for Shu expression vectors and T. Tajima (OLYMPUS Corporation) for assistance with live imaging. We are grateful to T. Hirose and T. Yamazaki for experimental suggestions and discussions. We also thank other members of the Siomi laboratories for discussions and comments on the manuscript. This work was supported by grants from the Ministry of Education, Culture, Sports, Science and Technology of Japan to H.I. and M.C.S. S.H. is supported by the Japan Society for the Promotion of Science.
Publisher Copyright:
© 2019 The Authors
PY - 2019/7
Y1 - 2019/7
N2 - 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.
AB - 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.
KW - Yb body
KW - female sterile (1) Yb
KW - liquid–liquid phase separation
KW - piRNA
KW - transposon
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U2 - 10.15252/embr.201947708
DO - 10.15252/embr.201947708
M3 - Article
C2 - 31040109
AN - SCOPUS:85065172744
SN - 1469-221X
VL - 20
JO - EMBO Reports
JF - EMBO Reports
IS - 7
M1 - e47708
ER -