Akins R E, Tuan R S
Department of Biology, University of Pennsylvania, Philadelphia 19104.
J Cell Sci. 1993 Jun;105 ( Pt 2):369-79. doi: 10.1242/jcs.105.2.369.
The chicken eggshell supplies approximately 80% of the calcium found in the hatchling chick. The mobilization of eggshell calcium into the developing embryo involves the transepithelial transport of large amounts of calcium in a development-specific manner. The cells responsible for the transport of eggshell calcium into the embryonic circulation are the ectodermal cells of the chorioallantoic membrane. In this report, we present a method for the isolation and culture of chorioallantoic membrane ectodermal cells, which are amenable to direct experimental manipulation. Cell preparations are characterized with respect to the expression of an ectoderm-specific cell surface marker (transcalcin, a calcium-binding protein), and a specific enzymatic activity (elevated Ca(2+)-activated ATPase). Functional assessment of in vitro cellular calcium uptake by 45Ca2+ tracer kinetics indicates the persistence of a temperature-sensitive, rapid-influx pathway similar to that observed in vivo. The preparations of primary ectodermal cells present an in vitro system applicable to the experimental analysis of calcium metabolism and transport by the chick chorioallantoic membrane.
鸡蛋壳提供了刚孵化出的雏鸡体内约80%的钙。蛋壳钙向发育中的胚胎的转运涉及大量钙以发育特异性方式进行的跨上皮运输。负责将蛋壳钙转运到胚胎循环中的细胞是尿囊绒膜的外胚层细胞。在本报告中，我们提出了一种分离和培养尿囊绒膜外胚层细胞的方法，这些细胞适合直接进行实验操作。细胞制剂通过外胚层特异性细胞表面标志物（转钙蛋白，一种钙结合蛋白）的表达以及特定的酶活性（升高的Ca(2+)激活的ATP酶）来表征。通过45Ca2+示踪动力学对体外细胞钙摄取进行功能评估，结果表明存在一种温度敏感的快速内流途径，类似于在体内观察到的情况。原代外胚层细胞制剂提供了一个适用于对雏鸡尿囊绒膜钙代谢和转运进行实验分析的体外系统。
