2026-01-08 東京大学
アワノメイガと共生しているオス殺しボルバキア(緑は細胞核で、赤がボルバキア)
<関連情報>
- https://www.a.u-tokyo.ac.jp/topics/topics_20260108-1.html
- https://www.nature.com/articles/s41467-025-67993-x
長期にわたるボルバキア共生中の染色体性決定から細胞質性決定への完全な移行 Complete transition from chromosomal to cytoplasmic sex determination during prolonged Wolbachia symbiosis
Takahiro Fukui,Tomohiro Muro,Noriko Matsuda-Imai,Tatsunori Kaneda,Hidetaka Kosako,Hideaki Hiraki,Keisuke Shoji,Takeshi Fujii,Yutaka Suzuki,Atsushi Toyoda,Takehiko Itoh,Takashi Kiuchi & Susumu Katsuma
Nature Communications Published:08 January 2026
DOI:https://doi.org/10.1038/s41467-025-67993-x
Abstract
Wolbachia infection causes male-specific death in Ostrinia furnacalis, but its removal from infected strains results in female-specific death instead of restoring 1:1 sex ratio, suggesting that cytoplasmic Wolbachia, not the host genome, primarily determines femaleness in infected strains. This phenomenon is a striking example of the evolutionary outcome of cytoplasmic sex determination, potentially arising from prolonged host-symbiont co-evolution. Although we recently identified Oscar, the Wolbachia-encoded male-killing effector targeting the host masculinizing factor OfMasc in Ostrinia moths, inactivation or loss of the host’s endogenous feminizer remains unknown. Here we identify a W-linked primary feminizer, OfFem piRNA, which targets an mRNA encoding an OfMasc-interacting protein Ofznf-2. We demonstrate that Ofznf-2 is essential for both masculinization and dosage compensation. We also show that OfFem piRNA is entirely absent in the Wolbachia-infected lineage, providing molecular evidence that a male-killing Wolbachia hijacks the host feminizing piRNA function by acquiring the Oscar protein during prolonged endosymbiosis.
