Insect sexual manipulation by intracellular bacterial endosymbionts

2021 Fiscal Year Final Research Report

• Project Area: Spectrum of the Sex: a continuity of phenotypes between female and male
• Project/Area Number: 17H06431
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: The University of Tokyo
• Principal Investigator: Katsuma Susumu 東京大学, 大学院農学生命科学研究科(農学部), 教授 (20378863)
• Co-Investigator(Kenkyū-buntansha): 木内 隆史 東京大学, 大学院農学生命科学研究科(農学部), 准教授 (60622892)
• Project Period (FY): 2017-06-30 – 2022-03-31
• Keywords: ボルバキア / 性決定 / 性操作 / 昆虫 / オス殺し / 共生細菌 / チョウ目昆虫 / プロテアソーム

Outline of Final Research Achievements

Wolbachia species are the most widespread intracellular bacterial endosymbionts in insects. Male killing is one strategy by which Wolbachia manipulate the male-female sex ratio of their host’s progeny. In a previous study, we showed that Wolbachia infection induces male-specific death in the Asian corn borer Ostrinia furnacalis by inducing a failure of dosage compensation through targeting the host factor Masculinizer (Masc), an essential protein for both masculinization and dosage compensation. However, it remains unknown how a male-killing Wolbachia inhibits the functions of Masc. In this study, we identify a Wolbachia protein, designated Oscar, which interacts with Masc. Embryonic expression of Oscar inhibited Masc-induced masculinization and induced male killing in lepidopteran insects. Our results indicated that Oscar is the long-sought Wolbachia’s male-killing factor for lepidopteran insects.

Free Research Field

昆虫分子生物学、昆虫病理学

Academic Significance and Societal Importance of the Research Achievements

ボルバキアが持つオス殺し因子候補としては、ショウジョウバエに感染するボルバキアが持つwmkが報告されているが、真のオス殺し因子かどうか確証は得られていない。本研究において発見したOscarはチョウ目昆虫において完全なオス殺しを1遺伝子で再現できたことから、世界で初めてボルバキアオス殺し因子を発見した報告となった。今後、本遺伝子を用いたチョウ目昆虫の性操作技術の開発が期待できる。