Developmental gene regulatory network architecture across 500 million years of echinoderm evolution
Developmental gene regulatory network architecture across 500 million years of echinoderm evolution
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DOI：
10.1073/pnas.2235868100
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发表时间：
2003-11-11
影响因子：
11.1
通讯作者：
Davidson, EH
中科院分区：
文献类型：
--
作者：
Hinman, VF;Nguyen, AT;Davidson, EH
形态特征的进化变化必须依赖于发育基因调控网络（GRNs）的结构重组，就像真正的形态特征的保护必须意味着保留祖先的发育GRN功能。临时GRN在海胆胚胎内中胚层发育的关键要素在这里进行比较与那些操作在胚胎的远亲棘皮动物，海星。这些动物在5.2亿至4.8亿年前从它们的共同祖先中分化出来。它们的内中胚层命运图是相似的，除了海胆产生一个骨骼生成细胞谱系，产生一个突出的骨架完全缺乏海星幼虫。一组相关的调控基因被分离出海星星海星，他们的表达模式确定，并对其他基因的干扰表达的每一个被证明。一个三基因的反馈回路，这是一个基本特征的海胆GRN内胚层规格被发现在几乎相同的形式在海星：GRN架构的一个详细的元素已被保留，因为寒武纪时期的棘皮动物谱系。这种保留的重要性也通过观察GRN连接中的许多具体差异而突出。用于驱动海胆骨骼发生的调节基因在海星中的使用完全不同，它对海胆胚胎中不影响它的内中胚层输入做出反应。GRNs的进化变化，因为分歧是有限的急剧某些顺式调控元件，而其他人一直保持不变。
Evolutionary change in morphological features must depend on architectural reorganization of developmental gene regulatory networks (GRNs), just as true conservation of morphological features must imply retention of ancestral developmental GRN features. Key elements of the provisional GRN for embryonic endomesoderm development in the sea urchin are here compared with those operating in embryos of a distantly related echinoderm, a starfish. These animals diverged from their common ancestor 520-480 million years ago. Their endomesodermal fate maps are similar, except that sea urchins generate a skeletogenic cell lineage that produces a prominent skeleton lacking entirely in starfish larvae. A relevant set of regulatory genes was isolated from the starfish Asterina miniata, their expression patterns determined, and effects on the other genes of perturbing the expression of each were demonstrated. A three-gene feedback loop that is a fundamental feature of the sea urchin GRN for endoderm specification is found in almost identical form in the starfish: a detailed element of GRN architecture has been retained since the Cambrian Period in both echinoderm lineages. The significance of this retention is highlighted by the observation of numerous specific differences in the GRN connections as well. A regulatory gene used to drive skeletogenesis in the sea urchin is used entirely differently in the starfish, where it responds to endomesodermal inputs that do not affect it in the sea urchin embryo. Evolutionary changes in the GRNs since divergence are limited sharply to certain cis-regulatory elements, whereas others have persisted unaltered.