Lin L H, DePhilip R M
Department of Cell Biology, Neurobiology, and Anatomy, Ohio State University College of Medicine, Columbus 43210, USA.
Anat Rec. 1996 Dec;246(4):535-44. doi: 10.1002/(SICI)1097-0185(199612)246:4<535::AID-AR12>3.0.CO;2-P.
Placental (P)-cadherin is one of a family of cell adhesion molecules that participate in embryonic sorting and organogenesis. In previous work, P-cadherin was localized to Sertoli cells in the mouse testis as early as postnatal day 1. This early postnatal localization raised questions about when P-cadherin first appeared in the embryonic testis and whether P-cadherin was expressed differentially in the embryonic testis and ovary.
The localization of P-cadherin, epithelial (E)-cadherin, and Müllerian inhibiting substance was determined in frozen sections of mouse gonads between embryonic days 10.5 and 18 using indirect immunohistochemistry. Alkaline phosphatase reactivity was used to identify germ cells.
The expression of P-cadherin was traced back to the indifferent stage of gonadogenesis where uniform distribution was observed in the indifferent gonad of both sexes. However, after sexual differentiation, the expression of P-cadherin in the testis was localized to Sertoli cells in the testicular cords, while its expression in the ovary fell below detectable levels.
The localization of P-cadherin in the male and female indifferent gonad is similar and cannot be used to distinguish the future testis and ovary. The localization of P-cadherin in the testis after sexual differentiation suggests a role for P-cadherin in testicular cord formation. The common temporal pattern of P-cadherin and Müllerian inhibiting substance expression in Sertoli cells is consistent with a shared regulatory mechanism.
胎盘型（P）-钙黏蛋白是参与胚胎分选和器官形成的细胞黏附分子家族之一。在先前的研究中，P-钙黏蛋白早在出生后第1天就定位于小鼠睾丸的支持细胞。这种出生后早期的定位引发了关于P-钙黏蛋白最早何时出现在胚胎睾丸以及它在胚胎睾丸和卵巢中是否差异表达的问题。
使用间接免疫组织化学法，在胚胎第10.5天至18天的小鼠性腺冰冻切片中确定P-钙黏蛋白、上皮型（E）-钙黏蛋白和苗勒氏管抑制物质的定位。用碱性磷酸酶反应性来鉴定生殖细胞。
P-钙黏蛋白的表达可追溯到性腺发生的未分化阶段，在两性的未分化性腺中观察到其均匀分布。然而，性别分化后，P-钙黏蛋白在睾丸中的表达定位于睾丸索中的支持细胞，而其在卵巢中的表达降至可检测水平以下。
P-钙黏蛋白在雄性和雌性未分化性腺中的定位相似，不能用于区分未来的睾丸和卵巢。性别分化后P-钙黏蛋白在睾丸中的定位表明其在睾丸索形成中起作用。支持细胞中P-钙黏蛋白和苗勒氏管抑制物质表达的共同时间模式与共享的调节机制一致。
