Lambert J David
Department of Biology, University of Rochester, Rochester, New York 14627, USA.
J Exp Zool B Mol Dev Evol. 2008 Jan 15;310(1):15-23. doi: 10.1002/jez.b.21176.
The Spiralia is a clade of protostome invertebrate phyla that share a highly conserved mode of early development. Spiralian development is characterized by regularities in the arrangement of early cleavages, the fates of the cells that are produced by these divisions, and the development of the distinctive trochophore larva. Because of the strong conservation in early development, homologies can be identified between cells in divergent taxa. Some of the most striking examples of conservation in the spiralian embryo are in the cells that generate the mesoderm. The specification of the mesodermal precursors has been well characterized by embryological approaches, and recently the molecular mechanisms of mesoderm specification are starting to be elucidated. This review examines the development of mesoderm in spiralians in a comparative context, with particular focus on the relationship between the mesendodermal cell 4d and the embryonic organizer.
螺旋动物门是原口无脊椎动物的一个进化枝，它们具有高度保守的早期发育模式。螺旋动物的发育特点是早期卵裂的排列规律、这些分裂产生的细胞的命运以及独特的担轮幼虫的发育。由于早期发育的高度保守性，可以在不同分类群的细胞之间识别出同源性。螺旋动物胚胎中一些最显著的保守例子存在于产生中胚层的细胞中。中胚层前体的特化已通过胚胎学方法得到很好的表征，最近中胚层特化的分子机制也开始得到阐明。本综述在比较的背景下研究了螺旋动物中胚层的发育，特别关注中内胚层细胞4d与胚胎组织者之间的关系。
