Bouwmeester T, Leyns L
Howard Hughes Medical Institute, University of California, Los Angeles 90095-1662, USA.
Bioessays. 1997 Oct;19(10):855-63. doi: 10.1002/bies.950191005.
In vertebrates the antero-posterior organization of the embryonic body axis is thought to result from the activity of two separate centers, the head organizer and the trunk organizer, as operationally defined by Spemann in the 1920s. Current molecular studies have supported the existence of a trunk organizer activity while the presence of a distinct head inducing center has remained elusive. Mainly based on analyses of headless mutants in mice, it has been proposed that the anterior axial mesoderm plays a determining role in head induction. Recent gain- and loss-of-function studies in various organisms, however, provide compelling evidence that a largely ignored region, the anterior primitive endoderm, specifies rostral identity. In this review we discuss the emerging concept that the anterior primitive endoderm, rather than the prechordal plate mesoderm, induces head development in the vertebrate embryo.
在脊椎动物中，胚胎体轴的前后组织被认为是由两个独立的中心，即头部组织者和躯干组织者的活动所导致的，这是斯佩曼在20世纪20年代通过操作定义的。目前的分子研究支持躯干组织者活动的存在，而一个独特的头部诱导中心的存在仍然难以捉摸。主要基于对小鼠无头突变体的分析，有人提出前轴中胚层在头部诱导中起决定性作用。然而，最近在各种生物体中的功能获得和功能丧失研究提供了令人信服的证据，表明一个很大程度上被忽视的区域，即前原始内胚层，决定了头端身份。在这篇综述中，我们讨论了一个新出现的概念，即前原始内胚层，而不是脊索前板中胚层，在脊椎动物胚胎中诱导头部发育。
