Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan.
International Research Center for Agricultural and Environmental Biology, Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan.
Cells. 2022 Jan 24;11(3):387. doi: 10.3390/cells11030387.
The gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), are secreted from the pituitary and bind to the FSH receptor (FSHR) and LH receptor (LHR) to regulate gonadal development in vertebrates. Previously, using -knockout (KO) medaka (), we demonstrated that FSH regulates ovarian development by elevating estrogen levels. However, the -KO phenotype in medaka is poorly characterized. Here, we generated -KO medaka using the transcription activator-like effector nuclease (TALEN) technique. We analyzed its phenotype and that of -KO, ; double-heterozygotes (double-hetero), and double-KO fish. All genetically male medaka displayed normal testes and were fertile, whereas -KO and double-KO genetically female fish displayed small ovaries containing many early pre-vitellogenic oocytes and were infertile. Although -KO genetically female fish had normal ovaries with full-grown oocytes, ovulation did not occur. Levels of 17α,20β-dihydroxy-4-pregnen-3-one, which is required for meiotic maturation of oocytes and sperm maturation in teleost fish, were significantly decreased in all KO female medaka ovaries except for double-heteros. Further, 17β-estradiol levels in -KO and double-KO ovaries were significantly lower than those in double-heteros. These findings indicate that LH is necessary for oocyte maturation and FSH is necessary for follicle development, but that neither are essential for spermatogenesis in medaka.
促性腺激素，卵泡刺激素 (FSH) 和黄体生成素 (LH)，由垂体分泌，与 FSH 受体 (FSHR) 和 LH 受体 (LHR) 结合，调节脊椎动物的性腺发育。以前，我们使用 - 敲除 (KO) 青鳉鱼 () 表明 FSH 通过提高雌激素水平来调节卵巢发育。然而，青鳉鱼中的 -KO 表型特征描述不足。在这里，我们使用转录激活因子样效应物核酸酶 (TALEN) 技术生成了 -KO 青鳉鱼。我们分析了其表型以及 -KO、; 双杂合体 (double-hetero) 和双 KO 鱼的表型。所有遗传上为雄性的青鳉鱼均显示出正常的睾丸且具有生育能力，而 -KO 和双 KO 遗传上为雌性的鱼则显示出卵巢较小，其中含有许多早期前卵黄生成卵母细胞且不育。尽管 -KO 遗传上为雌性的鱼具有具有成熟卵母细胞的正常卵巢，但未发生排卵。17α,20β-二羟基-4-孕烯-3-酮的水平在所有 KO 雌性青鳉鱼的卵巢中均显著降低，除了 double-heteros 外，17α,20β-二羟基-4-孕烯-3-酮是卵母细胞减数分裂成熟和硬骨鱼精子成熟所必需的。此外，-KO 和双 KO 卵巢中的 17β-雌二醇水平明显低于 double-heteros。这些发现表明 LH 对于卵母细胞成熟是必需的，而 FSH 对于卵泡发育是必需的，但在青鳉鱼中，它们对于精子发生都不是必需的。
