Kimelman D, Christian J L, Moon R T
Department of Biochemistry, University of Washington, School of Medicine, Seattle 98195.
Development. 1992 Sep;116(1):1-9. doi: 10.1242/dev.116.Supplement.1.
The first inductive event in Xenopus development establishes the mesoderm at the equator of the developing embryo. As part of this process, the dorsal-ventral and anterior-posterior axes of the embryo are initially established. A number of signalling molecules which may play a role in mesodermal induction and patterning have been identified in the last several years, including members of the FGF, TGF-beta and Wnt gene families. A variety of experiments, using either purified factors or injection of RNA encoding these factors, have added to the wealth of classical embryological experimental data collected over the last century. We have synthesized some recent results with the classical data to provide a framework for examining the process of mesoderm induction, and to formulate putative roles for some of the different factors. We incorporate these ideas into a working model of mesoderm induction that provides a basis for future experimental directions. Finally, we suggest that mesoderm induction may not be a discrete set of well separated events, but instead may be a process involving partially overlapping signals that produce the same pattern.
非洲爪蟾发育过程中的首个诱导事件是在发育中胚胎的赤道处形成中胚层。作为这一过程的一部分，胚胎的背腹轴和前后轴最初得以确立。在过去几年中，已鉴定出一些可能在中胚层诱导和模式形成中发挥作用的信号分子，包括成纤维细胞生长因子（FGF）、转化生长因子-β（TGF-β）和Wnt基因家族的成员。使用纯化因子或注射编码这些因子的RNA进行的各种实验，丰富了上个世纪收集的大量经典胚胎学实验数据。我们将一些近期结果与经典数据相结合，以提供一个用于审视中胚层诱导过程的框架，并阐述一些不同因子的假定作用。我们将这些观点纳入一个中胚层诱导的工作模型，该模型为未来的实验方向提供了基础。最后，我们认为中胚层诱导可能并非是一系列界限分明的离散事件，而是一个涉及部分重叠信号并产生相同模式的过程。
