2022 Fiscal Year Final Research Report

Molecular basis for the loss of seasonality of reproduction found in the marine snail, Reishia clavigera, living in the vicinity of the Fukushima daiichi nuclear power plant

Research Project

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Project/Area Number	21K19847
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 63:Environmental analyses and evaluation and related fields
Research Institution	Hiroshima University
Principal Investigator	MORISHITA FUMIHIRO 広島大学, 統合生命科学研究科(理), 助教 (20210164)
Co-Investigator(Kenkyū-buntansha)	今村拓也広島大学, 統合生命科学研究科(理), 教授 (90390682) 堀口敏宏国立研究開発法人国立環境研究所, 環境リスク・健康領域, 室長 (30260186)
Project Period (FY)	2021-07-09 – 2023-03-31
Keywords	神経ペプチド / エピゲノム / トランスクリプトーム / 通年成熟 / 巻貝
Outline of Final Research Achievements	To elucidate the molecular mechanism for the consecutive sexual maturation (CSM) found in a marine snail, Reishia clavigera, living near the Fukushima Daiichi Nuclear Power Plant, we examined the changes in gene expression in the CSM snail by the RNA-seq analysis. We identified 88 kinds of neuropeptide-precursor genes from more than 60,00 kinds of gene transcripts in the brain, and found that the expression of neuropeptide precursor gene is down-regulated in CSM snails. We also found the up-regulation of several epigenome-related genes in CSM snails, suggesting that chemical modification of the histone and/or DNA is promoted in CSM snail. We proposed a hypothesis that disturbance of epigenome by unknown environmental factor induced the down-regulation of neuropeptides and CSM. Our results also suggest that modification of gene-expression in this marine snail is applicable for the conventional and sensitive monitoring system for the environmental change by pollution and climate change.
Free Research Field	動物生理学
Academic Significance and Societal Importance of the Research Achievements	巻貝の通年成熟現象は、これまで原因に関する知見がほとんど無く、原発事故との関連性も不明であった。本研究により、何らかの環境因子が遺伝子に傷を付けることなくエピゲノム調節を撹乱することで遺伝子発現を変化させ通年成熟を引き起こした、というエピゲノム攪乱仮説を提唱して研究の方向性を示すことができた。今後、この仮説の検証を通して通年成熟の原因解明と原発事故との関連性の検証、さらにはエピゲノム調節の適正化による通年成熟の解消が期待できる。またに、巻貝の遺伝子発現変動を指標にして環境変化を簡便・高感度に検出する新たな環境モニタリングシステムを開発する基盤を提供できた。