生殖細胞発生研究の新モデルとなるJuji魚 (Juji Fish Becomes Promising Model for Studying Germ Cell Development and Gonadal Differentiation)

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2025-01-26 中国科学院(CAS)

中国科学院水生生物研究所(IHB)の孫永華教授率いる研究チームは、淡水魚ジュジ(Gobiocypris rarus)を用いて、生殖細胞発生と性腺分化を連続的に可視化できるトランスジェニック系統 Tg(ddx4:EGFP-UTRddx4) を構築し、その成果を Communications Biology に発表した。本系統により、全発生段階にわたる生殖細胞系列の追跡が可能となった。解析の結果、ジュジでは初期生殖細胞数が性分化に影響せず、受精後20日齢での蛍光強度が将来の卵巣・精巣分化を正確に予測することが示された。RNA-seq解析から、生殖細胞分化前段階ですでに雌雄で異なる遺伝子発現プログラムが存在することが判明した。さらに dmrt1 欠損実験により、体細胞の性運命転換が生殖細胞の分化運命を再プログラムすることが示され、ジュジが性腺分化研究に優れたモデル生物であることが明確になった。

<関連情報>

生殖細胞の発達と生殖腺の分化を研究するためのモデル魚としてのコイ科魚類ジュウジ(Gobiocypris rarus ) Cyprinid Juji (Gobiocypris rarus) as a model fish to study germ cell development and gonadal differentiation

Naike Su,Zhiqin Ren,Houpeng Wang,Chaofan Wang,Yongkang Hao,Ding Ye,Mudan He & Yonghua Sun
Communications Biology  Published:24 December 2025
DOI:https://doi.org/10.1038/s42003-025-09378-w

生殖細胞発生研究の新モデルとなるJuji魚 (Juji Fish Becomes Promising Model for Studying Germ Cell Development and Gonadal Differentiation)

Abstract

Although the cyprinid zebrafish has been widely used to study gametogenesis and gonadal differentiation, it has remarkable limitations, such as the loss of sex determinants in laboratory strains, a juvenile ovary stage in both sexes, and oocyte defects generally leading to sex reversal. Here, we develop a novel small cyprinid model for studying gonadal differentiation and gametogenesis, Juji (Gobiocypris rarus), which possesses a genetic sex determination system. We generate a transgenic line of Juji, Tg(ddx4:EGFP-UTRddx4), enabling lifetime visualization of germline development, and find that the dimorphic expression of ddx4:EGFP, rather than primordial germ cell number, at early stages determines the sexual fate of adults. RNA-seq analysis of juvenile ovaries and testes prior to germ cell differentiation identifies sexually dimorphic genes and signaling pathways. Several key factors, such as foxl2l and dmrt1, which drive gonadal differentiation, are among the sexually dimorphic genes. Knockout of dmrt1 leads to sex reversal in juvenile males, with all mutants developing into females. Furthermore, transplanting germline stem cells from genetic males into dmrt1 mutants results in all transplants developing into females, highlighting the essential Sertoli-cell-specific role of dmrt1 in triggering spermatogenesis. Our study establishes Juji as a promising model for investigating sex differentiation, gametogenesis, and gonadal development.

細胞遺伝子工学
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