Amphioxus FGF signaling predicts the acquisition of vertebrate morphological traits
Amphioxus FGF signaling predicts the acquisition of vertebrate morphological traits
复制标题
DOI：
10.1073/pnas.1014235108
复制
发表时间：
2011-05-31
影响因子：
11.1
通讯作者：
Escriva, Hector
中科院分区：
文献类型：
--
作者：
Bertrand, Stephanie;Camasses, Alain;Escriva, Hector
FGF信号传导是在所有后生动物中保守的少数细胞-细胞信号传导途径之一。不同门之间FGF基因含量的多样性表明FGF信号转导的进化可能参与了产生当前各种动物形式。脊椎动物拥有最多数量的FGF基因，其功能进化可能与脊椎动物特异性形态特征的获得有关。在这项研究中，我们已经调查了FGF信号在胚胎发生的头索动物文昌鱼，最好的代理脊索动物的祖先。我们首先分离出完整的FGF基因互补序列，并通过系统发育和同线保守性分析确定文昌鱼和脊椎动物FGF之间的进化关系。利用药物处理，我们在不同的时间窗内抑制文昌鱼胚胎中FGF信号通路。我们的研究结果表明，在原肠胚形成过程中的FGF信号的要求是一个保守的字符之间的脊索动物，而这个信号是不必要的文昌鱼神经诱导，在脊椎动物中是已知的。我们还表明，FGF信号，通过MAPK通路的作用，是必要的文昌鱼最前面的体节的形成，而更多的后体节的形成是不依赖FGF。这一结果使我们提出，修改前近轴中胚层中的文昌鱼样脊椎动物祖先的FGF信号功能可能导致的损失分割的脊椎动物头部的耳前近轴中胚层。
FGF signaling is one of the few cell-cell signaling pathways conserved among all metazoans. The diversity of FGF gene content among different phyla suggests that evolution of FGF signaling may have participated in generating the current variety of animal forms. Vertebrates possess the greatest number of FGF genes, the functional evolution of which may have been implicated in the acquisition of vertebrate-specific morphological traits. In this study, we have investigated the roles of the FGF signal during embryogenesis of the cephalochordate amphioxus, the best proxy for the chordate ancestor. We first isolate the full FGF gene complement and determine the evolutionary relationships between amphioxus and vertebrate FGFs via phylogenetic and synteny conservation analysis. Using pharmacological treatments, we inhibit the FGF signaling pathway in amphioxus embryos in different time windows. Our results show that the requirement for FGF signaling during gastrulation is a conserved character among chordates, whereas this signal is not necessary for neural induction in amphioxus, in contrast to what is known in vertebrates. We also show that FGF signal, acting through the MAPK pathway, is necessary for the formation of the most anterior somites in amphioxus, whereas more posterior somite formation is not FGF-dependent. This result leads us to propose that modification of the FGF signal function in the anterior paraxial mesoderm in an amphioxus-like vertebrate ancestor might have contributed to the loss of segmentation in the preotic paraxial mesoderm of the vertebrate head.