Elucidation of mechanism of determination of morphological and structural specificity of amphibia

本研究最重要的贡献是证明了蝌蚪皮肤中存在皮肤预变质转化中心。在这个中心，幼虫的皮肤转变成成体前的皮肤。成体前皮肤首先出现在II期至III期的上外侧区域。该中心先向背侧移动，然后向腹侧、前方和后方移动，显示出独特的连续的皮肤转换模式。转换在第五阶段完成，中心没有扩散到尾部。这清楚地表明，身体和尾巴之间皮肤的变质命运是不同的。从青蛙和蝾螈的表皮和皮肤结缔组织中克隆了以下16种cDNA和基因组克隆；7种爪蟾和牛蛙角蛋白cDNA、1种牛蛙凝集素cDNA、爪蟾组织蛋白酶D cDNA及其基因组克隆、牛蛙骨连接蛋白cDNA、牛蛙ⅰ型胶原α 1和α 2链cDNA、牛蛙ⅱ型胶原α 1和α 2链cDNA。分离得到了蝾螈I型胶原蛋白aipha1和alpha2的cDNA、牛蛙MMP1的基因组克隆和2个可能与再生能力有关的cDNA克隆。从牛蛙皮肤中还鉴定出5种钙结合蛋白。

The most important contribution of this study is to demonstrate the presence of the center for the premetamorphic conversion of the skin in the tadpole skin. In this center the larval skin transforms into the preadult skin. The preadult skin first emerged at stage II to III at a site in the upper lateral region. This center moved dorsally and then ventrally, anteriorly, and posteriorly, showing a unique sequential pattern of the skin conversion. The conversion was completed at stage V. The center did not spread into the tail. This clearly shows that the metamorphic fate of the skin was different between body and tail.We had cloned the following 16 kinds of cDNA and genomic clones from epidermis and skin connective tissues of frogs and newt ; 7 kinds of cDNA of keratins of Xenopus and bullfrog, a cDNA of bullfrog galectin, cDNA and its genomic clone of Xenopus cathepsin D, cDNA of bullfrog osteonectin, cDNA of bullfrog alpha1 and alpha2 chain of type I collagen, cDNA of bullfrog alpha1 and alpha2 of type II collagen. cDNA of newt aipha1 and alpha2 of type I collagen, genomic clone of bullfrog MMP1, and 2 cDNA clones that might be concerned with regenerating ability were isolated. Five calcium-binding proteins were also identified from bullfrog skin.