Molecular analysis of cell differentiation and morphogenesis by mesoderm inducing factor

有几条证据表明，激活素是非洲爪哇和纽特早期胚胎中诱导中胚层的关键分子。激活素A、B和B的三种亚型在非洲爪哇早期胚胎(阶段1-5)中至少部分以含有丰富的卵泡抑素的复合体的形式存在。非洲爪哇8-细胞期晚期的动物半卵裂球对激活素有反应，腹侧和背侧细胞在非常早期就有前模式。激活素A和维甲酸的混合物诱导了推测外胚层上的前肾小管的组织学分化。与正常胚胎相比，诱导的原肾小管显示出两个标记基因Xlim 1和Xlcaax-1的表达阶段和模式完全相同。激活素和卵泡抑素蛋白均匀分布于卵黄小板内。Sonic Hedgehog、HMG和GS基因是克隆的与神经形成相关的基因。

There are several lines of evidence that activin is a crucial molecules for mesoderm induction in early Xenopus and newt embryos. Three isoforms of activins A,B and B,were demonstrated to be present at least in part as a complex with abundant follistatin in early Xenopus embryos (stage 1-5). Animal-half blastomeres from the late 8-cell stage Xenopus embryo respond to activin, and there are prepatterns in ventral and dorsal cells from very early stages. Histological differentiation of the pronephric tubules on the presumptive ectoderm were induced by the mixture of activin A and retinoic acid. The induced pronephric tubules showed exactly the same expression stage and pattem for both marker genes, Xlim 1 and Xlcaax-1, as compares to that of normal embryos. Activin and follistatin protein were found to be localized uniformly in yolk platelets. Some kind of genes, sonic hedgehog, HMG and GS genes, are cloned related with neural formation.