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.

中文翻译：

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将卵巢生殖细胞移植到成年、无生殖细胞、三倍体杂交鱼的性腺后，产生供体来源的卵子†。

在动物方面，不育成年雄性的精原细胞移植得到广泛发展；然而，尽管具有实用性，但卵巢生殖细胞移植还没有得到很好的发展。我们之前表明，sciaenid 的种间杂交后代是生殖细胞移植研究的合适模型，因为它们具有无生殖细胞的性腺。然而，所有这些性腺都具有类似睾丸的特征。在这里，我们测试了杂交胚胎中的三倍体化是否会导致无生殖细胞的卵巢发育。在 6 个月大的三倍体杂种 (3nHybs) 中检查了性腺结构二态性和性别特异性基因表达模式。31% 的 3nHybs 具有带卵巢腔的无生殖细胞性腺。cyp19a1a和foxl2卵巢分化相关基因在这些性腺中表达，而dmrt1和vasa不表达，表明卵巢样生殖细胞无性腺发育。一些 (26%) 3nHybs 具有类似睾丸的无生殖细胞性腺。从纯合绿色荧光蛋白 (GFP) 转基因蓝鼓 (BD) ( Nibea mitsukurii )收集的卵巢生殖细胞通过泌尿生殖乳头或输卵管移植到 6 个月大的 3nHybs 性腺中。9 个月后，受体与野生型 BD 杂交。在幸存的六名 3nHyb 接受者中，一名女性和一名男性产生了受精卵和携带gfp特异性 DNA 序列的活动精子。后代测试显示所有 F1 后代都拥有gfp- 特定的 DNA 序列，表明这些接受者只产生了供体来源的卵子或精子。组织学观察证实了 3nHyb 受体性腺中供体来源的配子发生。总体而言，三倍体化减少了无生殖细胞性腺中偏向男性的性别分化。我们首次报告了通过将卵巢生殖细胞直接移植到无生殖细胞卵巢中，在动物体内产生供体来源的卵子。