Establishment of gene knockout Fasciola sp. and identification of genes controlling the timing of insect egg hatching

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K21367
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 42:Veterinary medical science, animal science, and related fields
• Research Institution: Gifu University
• Principal Investigator: TAKASHIMA Yasuhiro 岐阜大学, 応用生物科学部, 准教授 (20333552)
• Project Period (FY): 2020-07-30 – 2024-03-31
• Keywords: 肝蛭 / 遺伝子組換え / 孵化

Outline of Final Research Achievements

Eggs of Fasciola sp. are found to undergo growth and hatching inhibition upon osmotic stimulation. A gene region that is homologous to the gene encoding the osmotic pressure-sensing molecule known in mice and humans was also found to exist in the Fasciola sp. In order to clarify whether the gene product determines the timing of hatching, we developed a technology to knock out the gene. Although we were not able to produce KO parasite until the endo of research period, we succeeded in inducing a large number of sporocyst stage larvae, which are optimal for gene transfer, under culture conditions, and obtaining metacercariae by returning sporocysts in culture to intermediate host mollusks. We also constructed a plasmid vector for expression of foreign genes for liver leech.

Free Research Field

獣医学

Academic Significance and Societal Importance of the Research Achievements

肝蛭をはじめとする吸虫は家畜やヒトの健康被害の原因となる。しかし遺伝子改変技術が確立されておらず、吸虫のさまざまな生命現象を司る責任遺伝子の確認が実験生物学的レベルで実施できないのが現状である。本研究では肝蛭の遺伝子組換えにむけた基盤技術を確立した。また宿主糞便中に排出された肝蛭卵は中間宿主貝の生息する淡水中で孵化する一方、糞便中では孵化しないが、これがなぜ起こるのかは不明であった。本研究により浸透圧が孵化を抑制することが明らかとなり、糞と淡水の浸透圧の差を虫卵が認識している可能性が示された。