Noncanonical Hox, Etv4, and Gli3 gene activities give insight into unique limb patterning in salamanders
Noncanonical Hox, Etv4, and Gli3 gene activities give insight into unique limb patterning in salamanders
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DOI：
10.1002/jez.b.22798
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发表时间：
2018-05-01
影响因子：
2.2
通讯作者：
Froebisch, Nadia Belinda
中科院分区：
文献类型：
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作者：
Bickelmann, Constanze;Frota-Lima, Gabriela Neiva;Froebisch, Nadia Belinda
蝾螈的四肢发育在四足动物中是独特的。蝾螈不仅可以在其一生中反复再生失去的肢体，而且轴前对足元素和趾在轴后元素和趾之前形成，因此与所有其他四足动物相比具有相反的极性。此外，在蝾螈的自由游泳幼虫阶段，例如蝾螈（Ambystoma mexicanum），每个手指芽独立，而不是经历一个桨阶段。在这里，我们报告的基因表达模式的Hoxa和D簇，以及其他关键的转录因子在蝾螈肢体发育。在肢体发育的早期阶段，表达模式大多与已报道的蝾螈和青蛙的表达模式相似。同样，Hoxd和Shh调控景观在很大程度上是保守的。然而，在后期的数字萌芽阶段，显着的差异是存在的：（i）Hoxd13的表达结构域不包括发展的数字I和IV，（ii）我们扩大了以前的观察，Hoxa11的表达，传统上标志着zeugopodium，远端延伸到发展的数字，和（iii）Gli3和Etv4在发展的数字显示长期的表达。我们的研究结果确定了蝾螈肢体发育后期关键转录因子表达的衍生模式，并为更好地理解蝾螈肢体的独特模式提供了基础。
Limb development in salamanders is unique among tetrapods in significant ways. Not only can salamanders regenerate lost limbs repeatedly and throughout their lives, but also the preaxial zeugopodial element and digits form before the postaxial ones and, hence, with a reversed polarity compared to all other tetrapods. Moreover, in salamanders with free-swimming larval stages, as exemplified by the axolotl (Ambystoma mexicanum), each digit buds independently, instead of undergoing a paddle stage. Here, we report gene expression patterns of Hoxa and d clusters, and other crucial transcription factors during axolotl limb development. During early phases of limb development, expression patterns are mostly similar to those reported for amniotes and frogs. Likewise, Hoxd and Shh regulatory landscapes are largely conserved. However, during late digit-budding phases, remarkable differences are present: (i) the Hoxd13 expression domain excludes developing digits I and IV, (ii) we expand upon previous observation that Hoxa11 expression, which traditionally marks the zeugopodium, extends distally into the developing digits, and (iii) Gli3 and Etv4 show prolonged expression in developing digits. Our findings identify derived patterns in the expression of key transcription factors during late phases of salamander limb development, and provide the basis for a better understanding of the unique patterning of salamander limbs.