Studies on maternal genetic factors in fish eggs and its relation to the adult age

• Project/Area Number: 15K18738
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Aquatic bioproduction science
• Research Institution: Fisheries Research and Education Agency
• Principal Investigator: NYUJI Mitsuo 国立研究開発法人水産研究・教育機構, 中央水産研究所, 研究員 (50732426)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2015: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 水産資源 / 小型浮魚類 / マサバ / 母性遺伝因子 / 母性年齢 / ミトコンドリアDNA / 母性効果 / 年齢 / 小型浮魚 / 資源 / 母性mRNA / RNA-seq

Outline of Final Research Achievements

Maternally-inherited mRNA expressions and mitochondrial DNA (mtDNA) copy number, and its relation to the adult age were studied in the egg of chub mackerel Scomber japonicus. Female fish were ovulated using hormonal manipulation and eggs were obtained. Transcriptome analysis of chub mackerel eggs was conducted using next-generation sequencing. Four genes that were differently expressed between old adult fish and young adult fish were identified. During active spawning, the number of mtDNA copies in eggs was higher in old adult fish than in young adult fish. During non-active spawning, the number of mtDNA copies in eggs was low in both old and young adult fish.

Academic Significance and Societal Importance of the Research Achievements

本研究の特色は、これまで研究されてこなかった、親魚年齢と母性遺伝因子（mRNA、mtDNA）の関係を解析した点にある。本研究により、雌親魚の年齢によって発現の異なる遺伝子が示された。さらに、産卵群によっては、高齢魚と若齢魚の卵の間でmtDNAコピー数が顕著に異なることが示された。これらの成果は、親魚年齢が卵質に及ぼす影響のメカニズム解明に貢献するとともに、卵から親魚年齢を推定する指標として利用されることが期待される。また、マサバ遺伝子の塩基配列情報を網羅的に解析する本研究の成果は、国際的な小型浮魚類の資源研究分野にとって有益な情報になるものと期待される。

Research Products

• [Journal Article] Photoperiodic regulation of plasma gonadotropin levels in previtellogenic greater amberjack (Seriola dumerili) (2018)
  • Author(s): Nyuji M, Hamada K, Kazeto Y, Mekuchi M, Gen K, Soyano K, Okuzawa K
  • Journal Title: General and Comparative Endocrinology Volume: 269 Pages: 149-155
  • DOI: 10.1016/j.ygcen.2018.09.007
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Spawning cycle and fecundity of a multiple spawner round herring Etrumeus teres off southern Japan: oocyte growth and maturation analysis (2017)
  • Author(s): Nyuji M, Takasuka A
  • Journal Title: Journal of Sea Research Volume: 122 Pages: 11-18
  • DOI: 10.1016/j.seares.2017.02.009
  • Peer Reviewed
• [Journal Article] Greater amberjack Fsh, Lh, and their receptors: Plasma and mRNA (2016)
  • Author(s): Nyuji M, Kazeto Y, Izumida D, Tani K, Suzuki H, Hamada K, Mekuchi M, Gen K, Soyano K, Okuzawa K
  • Journal Title: General and Comparative Endocrinology Volume: 225 Pages: 224-234
  • DOI: 10.1016/j.ygcen.2015.10.008
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Effects of synthetic kisspeptin peptides and GnRH analogue on oocyte growth and circulating sex steroids in prepubertal female chub mackerel (Scomber japonicus) (2013)
  • Author(s): Sdvaraj S., 他6名
  • Journal Title: Aquaculture Research Volume: 2013 Issue: 8 Pages: 1-12
  • DOI: 10.1111/are.12342
  • Peer Reviewed
• [Presentation] 小型浮魚類の生殖内分泌制御機構と繁殖特性に関する研究 (2018)
  • Author(s): 入路光雄
  • Organizer: 平成30年度日本水産学会春季大会
  • Invited
• [Presentation] Development of ELISAs for FSH and LH and their application to a study of reproduction in greater amberjack, Seriola dumerili (2016)
  • Author(s): Nyuji M, Kazeto Y, Hamada K, Yamamoto I, Gen K, Soyano K, Okuzawa K
  • Organizer: 8th International Symposium on Fish Endocrinology
  • Place of Presentation: ヨーテボリ, スウェーデン
  • Year and Date: 2016-06-28
  • Int'l Joint Research
• [Presentation] ウルメイワシの産卵特性 (2016)
  • Author(s): 入路光雄，髙須賀明典
  • Organizer: 日本水産学会春季大会
  • Place of Presentation: 東京海洋大学
  • Year and Date: 2016-03-26