Germ cells are not the primary factor for sexual fate determination in goldfish
Germ cells are not the primary factor for sexual fate determination in goldfish
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DOI：
10.1016/j.ydbio.2012.07.010
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发表时间：
2012-10-01
影响因子：
2.7
通讯作者：
Yamaha, Etsuto
中科院分区：
文献类型：
--
作者：
Goto, Rie;Saito, Taiju;Yamaha, Etsuto
生殖细胞在脊椎动物早期性腺中的存在对决定性命和性腺发育很重要。最近对斑马鱼和青竹的研究表明，早期性腺中生殖细胞的缺乏会导致性别逆转，有利于男性的表型。然而，目前还不确定性腺体细胞还是生殖细胞是决定其他脊椎动物性腺命运的主要因素。在这里，我们研究了生殖细胞在金鱼性腺分化中的作用，金鱼是一种具有XX-XY遗传性别决定系统的裸色物种。在胚胎发育过程中，通过注射针对死端基因的吗啉寡核苷酸，消除了鱼的原始生殖细胞(PGC)。没有生殖细胞的鱼表现出两种性腺形态：一种有卵巢腔，另一种有生精小管。接下来，我们测试是否可以通过将单个PGC移植到每个胚胎中来恢复这些空的性腺的功能，并确定由此产生的生殖系嵌合体的性腺性别。将单个GFP标记的PGC移植到42.7%的胚胎中，成功地产生了生殖系嵌合体。一些成年生殖系嵌合体的一侧有一个发育的性腺，含有供体来源的生殖细胞，而对侧的性腺缺乏任何早期生殖细胞阶段。雌性生殖系嵌合体的对侧有一个正常的卵巢和一个无生殖细胞的卵巢样结构；这种结构与雌性变种的结构相似。雄性生殖系嵌合体有一个睾丸和一个对侧的空睾丸，管腔中有一些精子。对变异体和生殖系嵌合体的性腺芳香酶、FOXL2和AMH表达的分析表明，没有发生体细胞转分化。可育生殖系嵌合体的后代都具有供体来源的表型，表明生殖系替换已经发生，移植的PGC挽救了雌性和雄性的性腺功能。这些发现表明，生殖细胞的缺失不影响卵巢或睾丸的发育途径，金鱼的表型性别是由遗传性别控制下的体细胞决定的，而不是生殖细胞和体细胞之间的相互作用。(C)2012 Elsevier Inc.保留所有权利。
The presence of germ cells in the early gonad is important for sexual fate determination and gonadal development in vertebrates. Recent studies in zebrafish and medaka have shown that a lack of germ cells in the early gonad induces sex reversal in favor of a male phenotype. However, it is uncertain whether the gonadal somatic cells or the germ cells are predominant in determining gonadal fate in other vertebrate. Here, we investigated the role of germ cells in gonadal differentiation in goldfish, a gonochoristic species that possesses an XX-XY genetic sex determination system. The primordial germ cells (PGCs) of the fish were eliminated during embryogenesis by injection of a morpholino oligonucleotide against the dead end gene. Fish without germ cells showed two types of gonadal morphology: one with an ovarian cavity; the other with seminiferous tubules. Next, we tested whether function could be restored to these empty gonads by transplantation of a single PGC into each embryo, and also determined the gonadal sex of the resulting germline chimeras. Transplantation of a single GFP-labeled PGC successfully produced a germline chimera in 42.7% of the embryos. Some of the adult germline chimeras had a developed gonad on one side that contained donor derived germ cells, while the contralateral gonad lacked any early germ cell stages. Female germline chimeras possessed a normal ovary and a germ-cell free ovary-like structure on the contralateral side; this structure was similar to those seen in female morphants. Male germline chimeras possessed a testis and a contralateral empty testis that contained some sperm in the tubular lumens. Analysis of aromatase, foxl2 and amh expression in gonads of morphants and germline chimeras suggested that somatic transdifferentiation did not occur. The offspring of fertile germline chimeras all had the donor-derived phenotype, indicating that germline replacement had occurred and that the transplanted PGC had rescued both female and male gonadal function. These findings suggest that the absence of germ cells did not affect the pathway for ovary or testis development and that phenotypic sex in goldfish is determined by somatic cells under genetic sex control rather than an interaction between the germ cells and somatic cells. (C) 2012 Elsevier Inc. All rights reserved.