Sexual dimorphism of gonadal structure and gene expression in germ cell-deficient loach, a teleost fish
Sexual dimorphism of gonadal structure and gene expression in germ cell-deficient loach, a teleost fish
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DOI：
10.1073/pnas.1007032107
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发表时间：
2010-10-05
影响因子：
11.1
通讯作者：
Arai, Katsutoshi
中科院分区：
文献类型：
--
作者：
Fujimoto, Takafumi;Nishimura, Toshiya;Arai, Katsutoshi
生殖细胞缺陷的鱼通常发育成表型雄鱼。因此，生殖细胞的存在通常被认为是女性性腺分化或维持卵巢结构所必需的。然而，生殖细胞在决定性腺体细胞性命运中的作用却知之甚少。我们已经建立了一种小型淡水鱼泥鳅(Misgurnus anguillicaudatus，Cypriniformes：Cobitidae)的可诱导生殖细胞缺陷系统，方法是用吗啉反义寡核苷酸敲除末端基因。有趣的是，缺乏生殖细胞的泥鳅可以发育成表型雄性或雌性，在形态上分别表现为胸鳍中有或没有骨板。表型雄性和雌性分别具有睾丸和卵巢结构，但缺乏生殖细胞。这些雄性和雌性生殖细胞缺陷性腺中的基因表达模式与正常鱼性腺中的基因表达模式基本相同。我们的观察表明，生殖细胞缺陷的泥鳅体内可以发育出性二型性腺。与其他模式鱼不同的是，表型雌鱼的性腺体细胞自主分化为卵巢组织，并在维持性腺结构方面发挥作用。在我们观察的基础上，我们提出了两种可能的模型来解释生殖细胞在鱼类性别决定中的作用。
Germ cell-deficient fish usually develop as phenotypic males. Thus, the presence of germ cells is generally considered to be essential for female gonadal differentiation or the maintenance of ovarian structure. However, little is known of the role of germ cells in the determination of the sexual fate of gonadal somatic cells. We have established an inducible germ cell deficiency system in the loach ( Misgurnus anguillicaudatus, Cypriniformes: Cobitidae), a small freshwater fish, using knockdown of the dead end gene with a morpholino antisense oligonucleotide. Interestingly, loach lacking germ cells could develop as either phenotypic males or females, as characterized morphologically by the presence or absence of bony plates in the pectoral fins, respectively. The phenotypic males and females had testicular and ovarian structures, respectively, but lacked germ cells. Gene expression patterns in these male and female germ cell-deficient gonads were essentially the same as those in gonads of normal fish. Our observations indicate that sexually dimorphic gonads can develop in germ cell-deficient loach. In contrast to the situation in other model fish species, the gonadal somatic cells in phenotypic females autonomously differentiated into ovarian tissues and also played a role in the maintenance of gonadal structure. On the basis of our observations, we propose two possible models to explain the role of germ cells in sex determination in fish.