Insights from the amphioxus genome on the origin of vertebrate neural crest
Insights from the amphioxus genome on the origin of vertebrate neural crest
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DOI：
10.1101/gr.076208.108
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发表时间：
2008-07-01
期刊：
影响因子：
7
通讯作者：
Bronner-Fraser, Marianne
中科院分区：
文献类型：
--
作者：
Yu, Jr-Kai;Meulemans, Daniel;Bronner-Fraser, Marianne
神经嵴的出现被认为在早期脊椎动物的进化中起着关键作用，它将脊索动物的头部重塑为一个“新的头部”，使早期脊椎动物能够从滤食转变为主动捕食。在这里，我们表明，基因组的基础脊索动物，文昌鱼，包含同源的大多数脊椎动物基因牵连在一个假定的神经嵴基因调控网络（NC-GRN）神经嵴发育。我们的基因表达调查显示，早期诱导信号，神经板边界图案的基因，黑素细胞分化基因出现保守。此外，外源性BMP影响文昌鱼神经板边界基因的表达，在脊椎动物，这表明保守的信号指定整个脊索动物的神经板边界。与此核心保护相反，许多神经嵴指定基因在文昌鱼神经板/管边界不表达，这一水平的网络在脊椎动物进化过程中被增选的有趣的可能性。与此相一致，AmphiFoxD的调节区，同源的脊椎动物神经嵴指定FoxD 3，驱动组织特异性报告基因表达鸡中胚层，但不是神经嵴。因此，一个新的调控元件的进化可能已经允许该基因的共选择NC-GRN。
The emergence of the neural crest has been proposed to play a key role in early vertebrate evolution by remodeling the chordate head into a "new head" that enabled early vertebrates to shift from filter feeding to active predation. Here we show that the genome of the basal chordate, amphioxus, contains homologs of most vertebrate genes implicated in a putative neural crest gene regulatory network (NC-GRN) for neural crest development. Our survey of gene expression shows that early inducing signals, neural plate border patterning genes, and melanocyte differentiation genes appear conserved. Furthermore, exogenous BMP affects expression of amphioxus neural plate border genes as in vertebrates, suggesting that conserved signals specify the neural plate border throughout chordates. In contrast to this core conservation, many neural crest specifier genes are not expressed at the amphioxus neural plate/tube border, raising the intriguing possibility that this level of the network was co-opted during vertebrate evolution. Consistent with this, the regulatory region of AmphiFoxD, homologous to the vertebrate neural crest specifier FoxD3, drives tissue-specific reporter expression in chick mesoderm, but not neural crest. Thus, evolution of a new regulatory element may have allowed co-option of this gene to the NC-GRN.