Patek C E, Kerr J B, Gosden R G, Jones K W, Hardy K, Muggleton-Harris A L, Handyside A H, Whittingham D G, Hooper M L
Department of Pathology, University of Edinburgh, UK.
Development. 1991 Sep;113(1):311-25. doi: 10.1242/dev.113.1.311.
Adult intraspecific mouse chimaeras, derived by introducing male embryonal stem cells into unsexed host blastocysts, were examined to determine whether gonadal sex was correlated with the sex chromosome composition of particular cell lineages. The fertility of XX in equilibrium XY and XY in equilibrium XY male chimaeras was also compared. The distribution of XX and XY cells in 34 XX in equilibrium XY ovaries, testes and ovotestes was determined by in situ hybridisation using a Y-chromosome-specific probe. Both XX and XY cells were found in all gonadal somatic tissues but Sertoli cells were predominantly XY and granulosa cells predominantly XX. The sex chromosome composition of the tunica albuginea and testicular surface epithelium could not, in general, be fully resolved, owing to diminished hybridisation efficiency in these tissues, but the ovarian surface epithelium (which like the testicular surface epithelium derives from the coelomic epithelium) was predominantly XX. These findings show that the claim that Sertoli cells were exclusively XY, on which some previous models of gonadal sex determination were based, was incorrect, and indicate instead that in the mechanism of Sertoli cell determination there is a step in which XX cells can be recruited. However, it remains to be established whether the sex chromosome constitution of the coelomic epithelium lineage plays a causal role in gonadal sex determination. Male chimaeras with XX in equilibrium XY testes were either sterile or less fertile than chimaeras with testes composed entirely of XY cells. This impaired fertility was associated with the loss of XY germ cells in atrophic seminiferous tubules. Since this progressive lesion was correlated with a high proportion of XX Leydig cells, we suggest that XX Leydig cells are functionally defective, and unable to support spermatogenesis.
通过将雄性胚胎干细胞引入未分性别的宿主囊胚而获得的成年种内小鼠嵌合体，被用于研究性腺性别是否与特定细胞谱系的性染色体组成相关。同时还比较了XX平衡XY和XY平衡XY雄性嵌合体的生育能力。使用Y染色体特异性探针通过原位杂交确定了34个XX平衡XY卵巢、睾丸和卵睾中XX和XY细胞的分布。在所有性腺体细胞组织中都发现了XX和XY细胞，但支持细胞主要是XY型，颗粒细胞主要是XX型。由于这些组织中的杂交效率降低，白膜和睾丸表面上皮的性染色体组成一般无法完全解析，但卵巢表面上皮（与睾丸表面上皮一样源自体腔上皮）主要是XX型。这些发现表明，一些先前的性腺性别决定模型所基于的支持细胞仅为XY型这一说法是错误的，相反表明在支持细胞决定机制中存在一个可以招募XX细胞的步骤。然而，体腔上皮谱系的性染色体构成在性腺性别决定中是否起因果作用仍有待确定。具有XX平衡XY睾丸的雄性嵌合体要么不育，要么比睾丸完全由XY细胞组成的嵌合体生育能力更低。这种生育能力受损与萎缩的生精小管中XY生殖细胞的丢失有关。由于这种进行性病变与高比例的XX间质细胞相关，我们认为XX间质细胞在功能上存在缺陷，无法支持精子发生。
