大部分動物胚胎通過身體后部一個生長區(qū)的細(xì)胞積累來生長,，但控制生長的形成及方向性的形態(tài)發(fā)生力量卻不知道。
根據(jù)對在雞胚胎中軀干和尾巴結(jié)構(gòu)的形成過程中的軸伸長所做的一項(xiàng)研究,，Bénazéraf等人提出,，響應(yīng)于由FGF生長因子調(diào)控的信號作用而發(fā)生的組織伸長，是由對分級的,、隨機(jī)的細(xì)胞運(yùn)動的集體調(diào)控而出現(xiàn)的一個特性,，而不是由對個別細(xì)胞運(yùn)動的方向性的調(diào)控所出現(xiàn)的一個特性。(生物谷Bioon.net)
生物谷推薦原文出處：
Nature doi:10.1038/nature09151
A random cell motility gradient downstream of FGF controls elongation of an amniote embryo
Bertrand Bénazéraf,Paul Francois,Ruth E. Baker,Nicolas Denans,Charles D. Little& Olivier Pourquié
Vertebrate embryos are characterized by an elongated antero-posterior (AP) body axis, which forms by progressive cell deposition from a posterior growth zone in the embryo. Here, we used tissue ablation in the chicken embryo to demonstrate that the caudal presomitic mesoderm (PSM) has a key role in axis elongation. Using time-lapse microscopy, we analysed the movements of fluorescently labelled cells in the PSM during embryo elongation, which revealed a clear posterior-to-anterior gradient of cell motility and directionality in the PSM. We tracked the movement of the PSM extracellular matrix in parallel with the labelled cells and subtracted the extracellular matrix movement from the global motion of cells. After subtraction, cell motility remained graded but lacked directionality, indicating that the posterior cell movements associated with axis elongation in the PSM are not intrinsic but reflect tissue deformation. The gradient of cell motion along the PSM parallels the fibroblast growth factor (FGF)/mitogen-activated protein kinase (MAPK) gradient1, which has been implicated in the control of cell motility in this tissue2. Both FGF signalling gain- and loss-of-function experiments lead to disruption of the motility gradient and a slowing down of axis elongation. Furthermore, embryos treated with cell movement inhibitors (blebbistatin or RhoK inhibitor), but not cell cycle inhibitors, show a slower axis elongation rate. We propose that the gradient of random cell motility downstream of FGF signalling in the PSM controls posterior elongation in the amniote embryo. Our data indicate that tissue elongation is an emergent property that arises from the collective regulation of graded, random cell motion rather than by the regulation of directionality of individual cellular movements.
