Carbonic anhydrase and calcium transport function of the chick embryonic chorioallantoic membrane.
Carbonic anhydrase and calcium transport function of the chick embryonic chorioallantoic membrane.
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鸡胚绒毛尿囊膜的碳酸酐酶和钙转运功能。
DOI：
10.1111/j.1749-6632.1984.tb12372.x
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发表时间：
1984
影响因子：
5.2
通讯作者：
Tuan,RS
中科院分区：
文献类型：
--
作者：
Tuan,RS
在鸡胚发育过程中，钙从两个来源供应给胚胎：蛋黄和在妊娠的前半期（即孵化的第9- 10天），蛋黄似乎是唯一的钙供应者。在妊娠后半期，即第11- 12天后，壳钙储备（主要是方解石，CaCO 3）开始被动员，胚胎钙含量迅速增加。以这种方式，壳贡献了孵化小鸡体内总钙（约140-150 mg）的80%以上。负责壳钙易位进入胚胎循环的器官/组织是胚外绒毛尿囊膜（CAM）。4如图1所示，CAM是由于绒毛膜和尿囊膜的逐渐融合而形成的，因此到孵育第10天，它完全包围胚胎和蛋的其他内容物，并附着在壳/壳膜上。CAM的钙转运功能高度发育调节;活性在孵育第12-13天左右开始，此后水平迅速增加，并在第18- 19天左右达到最大水平。5 ± 6功能活性CAM表现出三层结构，由外胚层，中胚层，和内胚层（图2），外胚层与富钙壳和壳膜直接相邻。已经表明，插入毛细血管床的外胚层7是CAM的钙转运区。8 p9 CAM的转运活性对钙具有高度特异性，钙以能量依赖性方式单向动员。4在我们过去几年对CAM钙转运机制的研究中，我们已经确定了几种似乎起功能作用的生化成分。这些包括：（1）一种特异的高分子量钙结合蛋白（CaBP）;（2）碳酸酐酶;（6）以及最近发现的（3）一种Ca ~（2+）激活的、Mg ~（2+）依赖的ATP酶。18其中，CaBP已被最广泛地研究和表征。CaBP是位于面向壳/壳膜的外胚层细胞的细胞表面上的可溶性外周膜蛋白;其以发育调节的方式表达，该方式伴随CAM的钙转运的开始;其表达受维生素K调节，至少由CaBP上的γ-羧基谷氨酸残基的翻译后形成介导;这项工作得到了美国国立卫生研究院（HD 15306，HD 15822，和HD 17887）和美国国家基金会-March of Dimes出生缺陷基金会（Basil奥康纳启动研究资助号5-343）的部分赠款。
During chick embryonic development, calcium is supplied to the embryo from two sources: the yolk and the During the first half of gestation (ie, up to the 9-10th day of incubation), the yolk appears to be the sole calcium supplier. During the second half of gestation, after the 11-12th day, the shell calcium reserve (mainly calcite, CaC03) begins to be mobilized and embryonic calcium content rapidly increase^.^ In this manner, the shell contributes over 80% of the total body calcium (approximately 140-150 mg) of the hatching chick. The organ/tissue responsible for the translocation of the shell calcium into the embryonic circulation is the extraembryonic chorioallantoic membrane (CAM). 4 As shown in FIGURE 1, the CAM is formed as a result of the progressive fusion of the chorionic and allantoic membranes so that by incubation day 10, it completely surrounds the embryo and other contents of the egg and becomes attached to the shell/shell membrane. The calcium transport function of the CAM is highly developmentally regulated; activity begins around incubation day 12-13, rapidly increases in level thereafter, and reaches a maximal level around day 18-19.5+ 6 The functionally active CAM exhibits a three-layered architecture, consisting of the ectoderm, the mesoderm, and the endoderm (FIG. 2) with the ectoderm being directly adjacent to the calcium-rich shell and shell membrane. It has been shown that the ectoderm, which is intercalated with a capillary bed, 7 is the calciumtransporting region of the CAM. 8p9 The transport activity of the CAM is highly specific for calcium which is mobilized unidirectionally and in an energy-dependent manner. 4 During our studies over the last several years on the mechanism of CAM calcium transport, we have identified several biochemical components that appear to play functional roles. These include:(1) a specific, high-molecularweight calcium-binding protein (CaBP); 10-'7 (2) carbonic anhydrase; 6 and, most recently,(3) a Ca2+-activated, Mg2+-dependent ATPase. 18 Of these, the CaBP has been most extensively studied and characterized. The CaBP is a soluble, peripheral membrane protein located on the cell surface of the ectodermal cells that face the shell/shell membrane; it is expressed in a developmentally regulated manner that is concomitant with the onset of calcium transport by the CAM; its expression is regulated by vitamin K, mediated at least by posttranslational formation of y-carboxyglutamate residues on the CaBP; the expression of active a This work is supported in part by grants from the National institutes of Health (HD 15306, HD 15822, and HD 17887) and the National Foundation-March of Dimes Birth Defects Foundation (Basil O'Connor Starter Research Grant No. 5-343.)