Evolutionary rewiring of gene regulatory network linkages at divergence of the echinoid subclasses
Evolutionary rewiring of gene regulatory network linkages at divergence of the echinoid subclasses
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DOI：
10.1073/pnas.1509845112
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发表时间：
2015-07-28
影响因子：
11.1
通讯作者：
Davidson, Eric H.
中科院分区：
文献类型：
--
作者：
Erkenbrack, Eric M.;Davidson, Eric H.
动物身体计划的进化发生在编码的基因组程序的变化，指导发展，通过改变编码的发育基因调控网络（GRNs）的结构。然而，这一最基本的进化过程的研究需要实验上易于处理的，在形态上不同，但属于同一个单系分支，加上在至少一个物种中运作的相关GRNs的知识，遗传学上不同的生物。这些条件是满足在分歧的胚胎发育的两个现存的，形态上不同的，海胆（海胆）的子类，Euechinoidea和Cidaroidea，从一个共同的晚古生代祖先分歧。在这里，我们专注于显着的差异，在一个euechinoid，著名的模式Strongylocentrotus purpuratus（SP），与cidaroid Eucidaris tribuloides（Et）的胚胎骨骼发育模式。在描述性胚胎学的水平上，SP和Et的骨骼发生早已被认为是通过不同的方式发生的。完整的GRN控制这一过程是已知的SP。我们进行了有针对性的功能分析Et的骨骼生成，以确定是否存在，或证明，特定的监管联系和子电路的关键操作的SP骨骼生成GRN。值得注意的是，我们研究的SP成骨GRN的大多数典型设计特征在Et中缺失或以不同的方式运作。这项工作直接意味着一个戏剧性的重组基因组调控电路伴随着分歧的euechinoids，这开始于二叠纪末灭绝。
Evolution of animal body plans occurs with changes in the encoded genomic programs that direct development, by alterations in the structure of encoded developmental gene-regulatory networks (GRNs). However, study of this most fundamental of evolutionary processes requires experimentally tractable, phylogenetically divergent organisms that differ morphologically while belonging to the same monophyletic clade, plus knowledge of the relevant GRNs operating in at least one of the species. These conditions are met in the divergent embryogenesis of the two extant, morphologically distinct, echinoid (sea urchin) subclasses, Euechinoidea and Cidaroidea, which diverged from a common late Paleozoic ancestor. Here we focus on striking differences in the mode of embryonic skeletogenesis in a euechinoid, the well-known model Strongylocentrotus purpuratus (Sp), vs. the cidaroid Eucidaris tribuloides (Et). At the level of descriptive embryology, skeletogenesis in Sp and Et has long been known to occur by distinct means. The complete GRN controlling this process is known for Sp. We carried out targeted functional analyses on Et skeletogenesis to identify the presence, or demonstrate the absence, of specific regulatory linkages and sub-circuits key to the operation of the Sp skeletogenic GRN. Remarkably, most of the canonical design features of the Sp skeletogenic GRN that we examined are either missing or operate differently in Et. This work directly implies a dramatic reorganization of genomic regulatory circuitry concomitant with the divergence of the euechinoids, which began before the end-Permian extinction.