Satb2, modularity, and the evolvability of the vertebrate jaw
Satb2, modularity, and the evolvability of the vertebrate jaw
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DOI：
10.1111/j.1525-142x.2011.00511.x
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发表时间：
2011-11-01
影响因子：
2.9
通讯作者：
Depew, Michael J.
中科院分区：
文献类型：
--
作者：
Fish, Jennifer L.;Villmoare, Brian;Depew, Michael J.
模块化是连接开发和进化的关键机制，也是可进化性的基础。在这里，我们调查模块化的脊椎动物颌骨的目的是了解其形态进化的机制。脊椎动物颌骨的基本结构包平面的保护导致了铰链和帽模型，其中极性的图案系统的发展颌骨预测模块化。我们已经测试了Satb2+细胞群描绘了下颌骨内的发育模块的假设。Satb2在颌骨原基的间充质中表达，所述颌骨原基产生上颌骨和下颌骨的远端元件。Satb2的丢失特别影响远端（切牙）域的结构元素，反映了这些元素的整合以及它们与其他下颌域的独立性。减少Satb2剂量导致下颌骨长度的变化增加，从而深入了解产生变化的发育潜力。分类群间的比较表明，Satb2结构域是保守的内gnathostomes。我们补充了以前的功能丧失的研究，在爪蟾基因敲低实验小鼠，Satb2在调节大小的功能保护提供了证据。最后，我们提出的证据表明，下颌骨Satb2+域的相对大小的变化与上皮FGF8的表达，这表明在这个领域的进化变化的机制。两者合计，我们的数据支持铰链和帽模型，并提供证据表明，Satb2调节协调的远颌模块，这些模块受到来自铰链的信号的进化修饰。
Modularity is a key mechanism bridging development and evolution and is fundamental to evolvability. Herein, we investigate modularity of the Vertebrate jaw with the aim of understanding mechanisms of its morphological evolution. Conservation of the basic structural bauplan of Vertebrate jaws led to a Hinge and Caps model, in which polarity in the patterning system of developing jaws predicts modularity. We have tested the hypothesis that the Satb2+ cell population delineates a developmental module within the mandibular jaw. Satb2 is expressed in the mesenchyme of the jaw primordia that gives rise to distal elements of both the upper and lower jaws. Loss of Satb2 specifically affects structural elements of the distal (incisor) domain, reflecting the integration of these elements as well as their independence from other mandibular domains. Reducing Satb2 dosage leads to an increase in variation in mandibular length, providing insight into the developmental potential to generate variation. Inter-taxa comparisons reveal that the Satb2 domain is conserved within gnathostomes. We complement previous loss of function studies in mice with gene knock-down experiments in Xenopus, providing evidence for functional conservation of Satb2 in regulating size. Finally, we present evidence that the relative size of the amniote mandibular Satb2+ domain varies in relation to epithelial Fgf8 expression, suggesting a mechanism for evolutionary change in this domain. Taken together, our data support the Hinge and Caps model and provide evidence that Satb2 regulates coordinated distal jaw modules that are subject to evolutionary modification by signals emanating from the Hinge.