Marine Fisheries Institute of Zhejiang Province, Zhoushan, P.R. China.
Department of Aquatic Biosciences, Tokyo University of Marine Science and Technology, Tokyo, Japan.
Biol Reprod. 2020 Dec 1;103(6):1289-1299. doi: 10.1093/biolre/ioaa168.
In animals, spermatogonial transplantation in sterile adult males is widely developed; however, despite its utility, ovarian germ cell transplantation is not well developed. We previously showed that the interspecific hybrid offspring of sciaenid was a suitable model for germ cell transplantation studies as they have germ cell-less gonads. However, all these gonads have testis-like characteristics. Here, we tested whether triploidization in hybrid embryos could result in germ cell-less ovary development. Gonadal structure dimorphism and sex-specific gene expression patterns were examined in 6-month-old triploid hybrids (3nHybs). Thirty-one percent of 3nHybs had germ cell-less gonads with an ovarian cavity. cyp19a1a and foxl2, ovarian differentiation-related genes, were expressed in these gonads, whereas dmrt1 and vasa were not expressed, suggesting ovary-like germ cell-less gonad development. Some (26%) 3nHybs had testis-like germ cell-less gonads. Ovarian germ cells collected from homozygous green fluorescent protein (GFP) transgenic blue drum (BD) (Nibea mitsukurii) were transplanted into 6-month-old 3nHybs gonads via the urogenital papilla or oviduct. After 9 months, the recipients were crossed with wild type BD. Among the six 3nHyb recipients that survived, one female and one male produced fertile eggs and motile sperm carrying gfp-specific DNA sequences. Progeny tests revealed that all F1 offspring possessed gfp-specific DNA sequences, suggesting that these recipients produced only donor-derived eggs or sperm. Histological observation confirmed donor-derived gametogenesis in the 3nHyb recipients' gonads. Overall, triploidization reduces male-biased sex differentiation in germ cell-less gonads. We report, for the first time, donor-derived egg production in an animal via direct ovarian germ cell transplantation into a germ cell-less ovary.
在动物中，雄性不育成年个体的精原干细胞移植已得到广泛发展；然而，尽管该技术具有实用性，但卵巢生殖细胞移植的发展并不完善。我们之前曾表明，鲷科鱼类的种间杂交后代是生殖细胞移植研究的合适模型，因为它们的性腺中没有生殖细胞。然而，所有这些性腺都具有睾丸样特征。在这里，我们测试了杂交胚胎的三倍体化是否会导致无生殖细胞的卵巢发育。我们在 6 月龄的三倍体杂交鱼（3nHybs）中检查了性腺结构的二态性和性别特异性基因表达模式。31%的 3nHybs 具有无生殖细胞的卵巢，其中有卵巢腔。这些性腺中表达了与卵巢分化相关的基因 cyp19a1a 和 foxl2，而 dmrt1 和 vasa 则未表达，表明存在类似于卵巢的无生殖细胞的性腺发育。一些（26%）3nHybs 具有睾丸样的无生殖细胞的性腺。从纯合绿色荧光蛋白（GFP）转基因蓝鼓鱼（Nibea mitsukurii）中收集的卵巢生殖细胞通过尿殖孔或输卵管移植到 6 月龄的 3nHybs 性腺中。9 个月后，受者与野生型蓝鼓鱼杂交。在存活的 6 名 3nHyb 受者中，有 1 名雌性和 1 名雄性产生了携带 GFP 特异性 DNA 序列的可育卵和游动精子。后代测试表明，所有 F1 后代都具有 GFP 特异性 DNA 序列，这表明这些受者仅产生了供体来源的卵子或精子。组织学观察证实了 3nHyb 受者性腺中的供体源性配子发生。总的来说，三倍体化降低了无生殖细胞性腺中雄性偏性的性别分化。我们首次报道了通过直接将卵巢生殖细胞移植到无生殖细胞的卵巢中，在动物中产生供体来源的卵子。
