Song Yanlong, Hu Wei, Ge Wei
Centre of Reproduction, Development and Aging (CRDA), Faculty of Health Sciences, University of Macau, Taipa, Macau, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Innovation Academy of Seed Design, Chinese Academy of Sciences, Wuhan 430072, China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Innovation Academy of Seed Design, Chinese Academy of Sciences, Wuhan 430072, China.
Gen Comp Endocrinol. 2021 Dec 1;314:113907. doi: 10.1016/j.ygcen.2021.113907. Epub 2021 Sep 17.
The interaction between gonadal somatic support cells and germ cells plays a crucial role in gonadal development. In fish, the process involves various local growth factors such as growth differentiation factor 9 (Gdf9) and gonadal soma-derived factor (Gsdf), which are both members of the transforming growth factor-β (TGF-β) superfamily. Gdf9, an oocyte-secreted factor, is a potent regulator of folliculogenesis in both mammals and fish. By contrast, Gsdf is expressed by the gonadal somatic cells (i.e., Sertoli cells in the testis and granulosa cells in the ovary) that support germ cell development. In this study, we established two transgenic zebrafish models, and demonstrated that the 2.7-kb proximal promoter region of gdf9 drove mCherry expression specifically in the oocytes, whereas the 2.1-kb proximal promoter region of gsdf drove enhanced green fluorescent protein (eGFP) expression in the Sertoli cells and granulosa cells. These proximal promoters contained sufficient information to respectively mimic the spatiotemporal expression patterns of endogenous gdf9 and gsdf in zebrafish. In the Tg(gdf9:mCherry) fish, mCherry was weakly expressed in the oocytes at primary growth stage but strongly expressed in those entering the secondary growth phase. In the Tg(gsdf:eGFP) fish, eGFP-positive Sertoli cells were distributed around spermatogenic cysts in the testis, whereas eGFP-positive granulosa cells were located at the outer side of the follicle layer in the ovary. The eGFP-positive Sertoli cells and granulosa cells seemed to have originated from the dorsal epithelium of the gonads. These Tg(gdf9:mCherry) and Tg(gsdf:eGFP) zebrafish models are suitable for studying gonadal development and function especially on the interaction between germ cells and supporting somatic cells.
性腺体细胞支持细胞与生殖细胞之间的相互作用在性腺发育中起着至关重要的作用。在鱼类中，这一过程涉及多种局部生长因子，如生长分化因子9（Gdf9）和性腺体细胞衍生因子（Gsdf），它们都是转化生长因子-β（TGF-β）超家族的成员。Gdf9是一种卵母细胞分泌因子，在哺乳动物和鱼类中都是卵泡发生的有效调节因子。相比之下，Gsdf由支持生殖细胞发育的性腺体细胞（即睾丸中的支持细胞和卵巢中的颗粒细胞）表达。在本研究中，我们建立了两种转基因斑马鱼模型，并证明gdf9的2.7 kb近端启动子区域驱动mCherry在卵母细胞中特异性表达，而gsdf的2.1 kb近端启动子区域驱动增强型绿色荧光蛋白（eGFP）在支持细胞和颗粒细胞中表达。这些近端启动子包含足够的信息来分别模拟斑马鱼内源性gdf9和gsdf的时空表达模式。在Tg（gdf9:mCherry）鱼中，mCherry在初级生长阶段的卵母细胞中弱表达，但在进入次级生长阶段的卵母细胞中强表达。在Tg（gsdf:eGFP）鱼中，eGFP阳性的支持细胞分布在睾丸中的生精囊肿周围，而eGFP阳性的颗粒细胞位于卵巢卵泡层的外侧。eGFP阳性的支持细胞和颗粒细胞似乎起源于性腺的背侧上皮。这些Tg（gdf9:mCherry）和Tg（gsdf:eGFP）斑马鱼模型适用于研究性腺发育和功能，特别是生殖细胞与支持体细胞之间的相互作用。
