Study on glidinig motility of Babesia bovis merozoite

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K08021
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Veterinary medical science
• Research Institution: Nagasaki University
• Principal Investigator: ASADA Masahito 長崎大学, 熱帯医学研究所, 助教 (40587028)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: バベシア / ウシ / 滑走運動 / ゲノム編集

Outline of Final Research Achievements

Babesia bovis is an apicomplexan intraerythrocytic protozoan parasite that induces babesiosis in cattle after transmission by ticks. During specific stages of the apicomplexan parasite lifecycle, host cells are targeted for invasion using a unique, active process termed "gliding motility". We have reported gliding motility of B. bovis merozoites, however molecular mechanisms of gliding motility have not been elucidated. In this study, we have searched the genes related to the glideosome, and found 5 thrombospondin-related adhesive protein (TRAP) genes. The single gene knockout experiment revealed that four of the TRAP genes were dispensable. On the contrary, we failed to disrupt one of the TRAP gene. The glmS gene knock down system was developed for Babesia parasites and adopted to the TRAP gene, and we found the gene has an important role for intraerythrocytic stage of the parasite.

Free Research Field

獣医学

Academic Significance and Societal Importance of the Research Achievements

本研究では、バベシア原虫メロゾイト滑走運動の分子機序を明らかにするまでには至らなかったが、同原虫TRAP関連遺伝子の一つが赤内期の生存に重要な役割を果たすことを明らかにした。また、技術的な面からはバベシア原虫において初めて2種類の遺伝子ノックダウン法を確立したほか、CRISPR/Cas9法によるゲノム編集法を確立し、さらにFRETバイオセンサーを用いたイメージングに成功するなど顕著な進捗が見られた。遺伝子ノックダウン法やゲノム編集法は寄生体のゲノム機能解析に非常に有効なツールであるため、今後バベシア病研究の加速が見込まれる。