Origins of anteroposterior patterning and Hox gene regulation during chordate evolution.
Origins of anteroposterior patterning and Hox gene regulation during chordate evolution.
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脊索动物进化过程中前后模式的起源和 Hox 基因调控。
DOI：
10.1098/rstb.2001.0918
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Knight,RD
中科院分区：
文献类型：
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作者：
Schilling,TF;Knight,RD
所有脊索动物都有一个基本的身体计划和许多共同的早期发育特征。脊椎动物神经管的前后位（AP）区域是由一种在尾脊索动物和头脊索动物中保守的氧基因表达组合模式指定的。在所有脊索动物中，氧基因调控的另一个原始特征是在胚胎发生期间对视黄酸的敏感性，最近的发育遗传学研究已经证明了类视黄酸信号在脊椎动物中的重要作用。在原肠形成过程中，脊索神经管内发育两个AP区域：由otxgenes指定的前“前脑-中脑”区域和由hoxgenes指定的后“后脑-脊髓”区域。第三个中间区域对应于脊椎动物的中脑或中脑-后脑边界，大约在同一时间发育，比较数据表明这也存在于脊索动物祖先中。然而，在hox表达域的前部，脊椎动物似乎已经进化出了独特的分割基因，如krox - 20，在后脑的模式中。哺乳动物和斑马鱼的遗传方法，加上对海鞘、文昌鱼和七鳃鳗的分子系统发育研究，有望揭示脊椎动物身体计划的复杂机制是如何从一组相对简单的祖先发育成分中产生的。
All chordates share a basic body plan and many common features of early development. Anteroposterior (AP) regions of the vertebrate neural tube are specified by a combinatorial pattern ofHoxgene expression that is conserved in urochordates and cephalochordates. Another primitive feature ofHoxgene regulation in all chordates is a sensitivity to retinoic acid during embryogenesis, and recent developmental genetic studies have demonstrated the essential role for retinoid signalling in vertebrates. Two AP regions develop within the chordate neural tube during gastrulation: an anterior ‘forebrain–midbrain’ region specified byOtxgenes and a posterior ‘hindbrain–spinal cord’ region specified byHoxgenes. A third, intermediate region corresponding to the midbrain or midbrain–hindbrain boundary develops at around the same time in vertebrates, and comparative data suggest that this was also present in the chordate ancestor. Within the anterior part of theHox–expressing domain, however, vertebrates appear to have evolved unique roles for segmentation genes, such asKrox–20, in patterning the hindbrain. Genetic approaches in mammals and zebrafish, coupled with molecular phylogenetic studies in ascidians, amphioxus and lampreys, promise to reveal how the complex mechanisms that specify the vertebrate body plan may have arisen from a relatively simple set of ancestral developmental components.