FGF signalling and the mechanism of mesoderm spreading in Drosophila embryos
FGF signalling and the mechanism of mesoderm spreading in Drosophila embryos
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DOI：
10.1242/dev.01603
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发表时间：
2005-02-01
期刊：
影响因子：
4.6
通讯作者：
Leptin, M
中科院分区：
文献类型：
--
作者：
Wilson, R;Vogelsang, E;Leptin, M
在果蝇胚胎中，成纤维细胞生长因子信号对于中胚层的正确建立是必需的。成纤维细胞生长因子受体的无心激活触发了中胚层MAPK的二磷酸化，MAPK以一种分级的方式积累，最高水平出现在中胚层的背侧边缘。我们研究了在传播过程中对成纤维细胞生长因子信号的具体要求。我们表明，只有扩散的初始步骤，特别是建立外胚层和中胚层之间的联系，依赖于成纤维细胞生长因子信号，并且与成纤维细胞生长因子信号在心脏前体分化中的作用不同，这一功能不能被其他受体酪氨酸激酶所取代。中胚层扩散的启动需要成纤维细胞生长因子受体具有一个功能激活域，但不依赖于MAPK的激活。因此，早期中胚层的扩散受成纤维细胞生长因子受体下游独立于MAPK级联的通路调节。此外，我们证明了无情激活MAPK需要来自外胚层的额外信号。我们认为成纤维细胞生长因子信号在中胚层扩散的初始阶段是必需的，以促进中胚层与外胚层的有效相互作用，而不是具有远程趋化功能，我们讨论了这一点与中胚层扩散的细胞机制有关。
FGF signalling is needed for the proper establishment of the mesodermal cell layer in Drosophila embryos. The activation of the FGF receptor Heartless triggers the diphosphorylation of MAPK in the mesoderm, which accumulates in a graded fashion with the highest levels seen at the dorsal edge of the mesoderm. We have examined the specific requirement for FGF signalling in the spreading process. We show that only the initial step of spreading, specifically the establishment of contact between the ectoderm and the mesoderm, depends upon FGF signalling, and that unlike the role of FGF signalling in the differentiation of heart precursors this function cannot be replaced by other receptor tyrosine kinases. The initiation of mesoderm spreading requires the FGF receptor to possess a functional kinase domain, but does not depend upon the activation of MAPK. Thus, the dispersal of the mesoderm at early stages is regulated by pathways downstream of the FGF receptor that are independent of the MAPK cascade. Furthermore, we demonstrate that the activation of MAPK by Heartless needs additional cues from the ectoderm. We propose that FGF signalling is required during the initial stages of mesoderm spreading to promote the efficient interaction of the mesoderm with the ectoderm rather than having a long range chemotactic function, and we discuss this in relation to the cellular mechanism of mesoderm spreading.