Department of Marine Biosciences, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, Japan.
Development. 2010 Apr;137(8):1227-30. doi: 10.1242/dev.044982. Epub 2010 Mar 10.
The sexual plasticity of fish gonads declines after the sex differentiation period; however, information about the plasticity of the germ cells themselves after sex differentiation is limited. Using rainbow trout (Oncorhynchus mykiss), we recently established a novel germ cell transplantation system that provides a unique platform with which to dissect the developmental and cellular mechanisms underlying gametogenesis. Using this technique, we show here that transplanted ovarian germ cells isolated from 6- to 9-month-old donors can colonize sexually undifferentiated embryonic gonads and resume gametogenesis. Ovarian germ cells containing oogonia and early oocytes isolated from female rainbow trout were transplanted into the peritoneal cavities of hatching-stage fry of both sexes and the behavior of the donor cells was observed. The transplanted ovarian germ cells migrated towards the recipient gonads, interacted with embryonic gonadal somatic cells, proliferated rapidly, and eventually differentiated into eggs in female recipients and sperm in male recipients. Furthermore, the donor-derived eggs and sperm obtained from the recipient fish were functional and were able to produce normal offspring. These findings indicate that mitotic germ cells, the oogonia, possess a high level of sexual plasticity.
鱼类性腺的性可塑性在性别分化期后下降；然而，关于性别分化后生殖细胞本身的可塑性的信息有限。我们最近使用虹鳟（Oncorhynchus mykiss）建立了一种新的生殖细胞移植系统，该系统为剖析配子发生的发育和细胞机制提供了独特的平台。使用该技术，我们在这里表明，从 6 至 9 个月大的供体中分离的移植卵巢生殖细胞可以定植于未分化的胚胎性腺并恢复配子发生。从雌性虹鳟鱼中分离的含有卵原细胞和早期卵母细胞的卵巢生殖细胞被移植到两性孵化阶段鱼苗的腹腔中，并观察供体细胞的行为。移植的卵巢生殖细胞向受者性腺迁移，与胚胎性腺体细胞相互作用，迅速增殖，并最终在雌性受者中分化为卵子，在雄性受者中分化为精子。此外，从受者鱼中获得的供体来源的卵子和精子是有功能的，能够产生正常的后代。这些发现表明有丝分裂生殖细胞，即卵原细胞，具有高度的性可塑性。
