Pitx2 promotes development of splanchnic mesoderm-derived branchiomeric muscle
Pitx2 promotes development of splanchnic mesoderm-derived branchiomeric muscle
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DOI：
10.1242/dev.02693
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发表时间：
2006-12-15
期刊：
影响因子：
4.6
通讯作者：
Martin, James F.
中科院分区：
文献类型：
--
作者：
Dong, Feiyan;Sun, Xiaoxia;Martin, James F.
最近的实验表明，颅旁轴质和内脏中胚层都有助于分支肌和心脏流出道（OFT）心肌的发育，揭示了这些肌肉群发育的意想不到的复杂性。Pitx2同源盒基因在颅近轴中胚层中起作用，调节眼肌，在内脏中胚层中调节OFT发育。在这里，我们研究了分支肌中的Pitx2。Pitx2在鳃弓核心中胚层表达，Pitx2无胚和Pitx2半胚均有缺陷的鳃裂肌。用一个Pitx2（cre）等位基因进行谱系追踪表明，Pitx2突变体的后代进入了第一鳃弓。然而，未分化的核心中胚层和特定的鳃裂肌的标记物均缺失。此外，Myf5（cre）等位基因的谱系追踪表明，Pitx2突变体的branchiomial muscle specification和分化存在缺陷。小鼠条件失活和鸡下颌骨培养中Pitx2表达的调控揭示了其在鳃弓中胚层扩张和存活中的自主功能。
Recent experiments, showing that both cranial paraxial and splanchnic mesoderm contribute to branchiomeric muscle and cardiac outflow tract (OFT) myocardium, revealed unexpected complexity in development of these muscle groups. The Pitx2 homeobox gene functions in both cranial paraxial mesoderm, to regulate eye muscle, and in splanchnic mesoderm to regulate OFT development. Here, we investigated Pitx2 in branchiomeric muscle. Pitx2 was expressed in branchial arch core mesoderm and both Pitx2 null and Pitx2 hypomorphic embryos had defective branchiomeric muscle. Lineage tracing with a Pitx2(cre) allele indicated that Pitx2 mutant descendents moved into the first branchial arch. However, markers of both undifferentiated core mesoderm and specified branchiomeric muscle were absent. Moreover, lineage tracing with a Myf5(cre) allele indicated that branchiomeric muscle specification and differentiation were defective in Pitx2 mutants. Conditional inactivation in mice and manipulation of Pitx2 expression in chick mandible cultures revealed an autonomous function in expansion and survival of branchial arch mesoderm.