Piprek Rafal P, Kloc Malgorzata, Tassan Jean-Pierre, Kubiak Jacek Z
Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Krakow, Poland.
The Houston Methodist Research Institute, Houston, TX, USA; Department of Surgery, The Houston Methodist Hospital, Houston, TX, USA; University of Texas, MD Anderson Cancer Center, Houston, TX, USA.
Dev Biol. 2017 Dec 15;432(2):298-310. doi: 10.1016/j.ydbio.2017.10.020. Epub 2017 Nov 7.
Information on the mechanisms orchestrating sexual differentiation of the bipotential gonads into testes or ovaries in amphibians is limited. The aim of this study was to investigate the development of Xenopus laevis gonad, to identify the earliest signs of sexual differentiation, and to describe mechanisms driving these processes. We used light and electron microscopy, immunofluorescence and cell tracing. In order to identify the earliest signs of sexual differentiation the sex of each tadpole was determined using genotyping with the sex markers. Our analysis revealed a series of events participating in the gonadal development, including cell proliferation, migration, cell adhesion, stroma penetration, and basal lamina formation. We found that during the period of sexual differentiation the sites of intensive cell proliferation and migration differ between male and female gonads. In the differentiating ovaries the germ cells remain associated with the gonadal surface epithelium (cortex) and a sterile medulla forms in the ovarian center, whereas in the differentiating testes the germ cells detach from the surface epithelium, disperse, and the cortex and medulla fuse. Cell junctions that are more abundant in the ovarian cortex possibly can favor the persistence of germ cells in the cortex. Also the stroma penetrates the female and male gonads differently. These finding indicate that the crosstalk between the stroma and the coelomic epithelium-derived cells is crucial for development of male and female gonad.
关于两栖动物中双潜能性腺分化为睾丸或卵巢的调控机制的信息有限。本研究的目的是研究非洲爪蟾性腺的发育，确定性别分化的最早迹象，并描述驱动这些过程的机制。我们使用了光学和电子显微镜、免疫荧光和细胞追踪技术。为了确定性别分化的最早迹象，使用性别标记进行基因分型来确定每只蝌蚪的性别。我们的分析揭示了一系列参与性腺发育的事件，包括细胞增殖、迁移、细胞黏附、基质穿透和基膜形成。我们发现，在性别分化期间，雄性和雌性性腺中细胞强烈增殖和迁移的部位不同。在分化中的卵巢中，生殖细胞与性腺表面上皮（皮质）保持关联，卵巢中心形成无生殖细胞的髓质，而在分化中的睾丸中，生殖细胞从表面上皮脱离、分散，皮质和髓质融合。卵巢皮质中更丰富的细胞连接可能有利于生殖细胞在皮质中的存留。此外，基质穿透雌性和雄性性腺的方式也不同。这些发现表明，基质与体腔上皮衍生细胞之间的相互作用对于雄性和雌性性腺的发育至关重要。
