Dvoráková K, Habrová V, Takác M, Jonák J
Department of Physiology and Developmental Biology, Faculty of Science, Charles University, Prague, Czech Republic.
Folia Biol (Praha). 2000;46(1):3-9.
Aberrant morphogenesis of transgenic Xenopus laevis 5-day embryos carrying Rous sarcoma virus LTR in their DNA and expressing a high level of c-Src protein kinase was found to be accompanied with a profound depression in the level of cadherins and alpha-, beta-, and gamma-(plakoglobin) catenins in their tissues, as revealed by immunohistochemical analysis. Simultaneously, an increased level of phosphotyrosine staining was detected. However, an analogous increase in the level of phosphotyrosine immunostaining and a slightly higher level of Src were also detected in tissues of originally defective but later spontaneously repaired frog embryos that displayed essentially normal patterns of staining for cadherins and catenins. Our results provide evidence that the defective morphogenesis of frog embryos expressing a high level of c-Src is characterized by the loss of the cadherin-catenin complexes. It appears that to induce frog morphogenetic malformations, the c-Src overproduction and the loss of cadherins-catenins are simultaneously required. Phosphorylation is not likely to be the cause of cadherin and catenin disappearance from the tissues of strongly aberrant frog embryos.
通过免疫组织化学分析发现，携带劳氏肉瘤病毒长末端重复序列（LTR）且表达高水平c-Src蛋白激酶的转基因非洲爪蟾5日龄胚胎存在形态发生异常，同时其组织中钙黏蛋白以及α-、β-和γ-（原肌球蛋白）连环蛋白水平显著降低。同时，检测到磷酸酪氨酸染色水平升高。然而，在原本有缺陷但后来自发修复的蛙胚胎组织中也检测到了类似的磷酸酪氨酸免疫染色水平升高以及稍高的Src水平，这些胚胎显示出钙黏蛋白和连环蛋白的染色模式基本正常。我们的结果表明，表达高水平c-Src的蛙胚胎的形态发生缺陷表现为钙黏蛋白-连环蛋白复合物的缺失。似乎要诱导蛙的形态发生畸形，c-Src的过量产生和钙黏蛋白-连环蛋白的缺失是同时需要的。磷酸化不太可能是严重异常蛙胚胎组织中钙黏蛋白和连环蛋白消失的原因。
