Prox1 is a marker of ectodermal placodes, endodermal compartments, lymphatic endothelium and lymphangioblasts
Prox1 is a marker of ectodermal placodes, endodermal compartments, lymphatic endothelium and lymphangioblasts
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DOI：
10.1007/s00429-001-0214-9
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发表时间：
2001-11-01
期刊：
影响因子：
--
通讯作者：
Wilting, J
中科院分区：
文献类型：
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作者：
Rodriguez-Niedenführ, M;Papoutsi, M;Wilting, J
淋巴管内皮大多被认为是从专门的静脉中发芽而来的。最近已经表明，同源框转录因子Prox1缺陷的小鼠实际上缺乏同源框。我们研究了鸡胚和人胎中Prox 1 mRNA和蛋白的表达。在鸡中，Prox1在所有胚层的特定隔室中表达。在外胚层中，其存在于神经管、三叉神经节、脊神经节和交感神经节以及视网膜中，并且还存在于基板结构如透镜、嗅觉基板、耳基板、面部基板、舌咽基板和迷走基板以及顶端外胚层脊中。在内胚层中，Prox 1是肝细胞、胆管和胰腺上皮的标志物。在中胚层中，在心肌细胞中观察到弱表达，而在淋巴管内皮中观察到强表达。在19周龄的人类胎儿中发现了相同的表达结构域。在6.5天的鸡胚中，有几个位点的血管与颈静脉接触，其具有Prox 1阳性和阴性细胞的混合内皮。只有非淋巴管内皮细胞表达Prox1被发现在心脏瓣膜的凹侧。为了进一步分析淋巴管的发育，我们研究了早期鸡胚，并观察到散在的Prox 1阳性细胞在皮区，引起Prox 1阳性淋巴网络在随后的发展。此外，在4日龄鸡胚中已可观察到后淋巴囊和成对胸导管的原基。我们的研究表明，植物的发育比以前描述的要早得多，而且它们大多数似乎不是从静脉中发芽而来的。相反，淋巴管母细胞存在于早期中胚层的深和浅隔室中，独立地产生深和浅的淋巴管。
The lymphatic endothelium has mostly been thought to be derived by sprouting from specialized veins. Recently it has been shown that mice deficient for the homeobox transcription factor Prox1 are practically devoid of lymphatics. We have studied the expression of Prox1 mRNA and protein in chick embryos and human fetuses. In the chick, Prox1 is expressed in specific compartments of all germ layers. In the ectoderm, it is found in the neural tube, trigeminal, spinal and sympathetic ganglia and the retina, and also in placodal structures such as the lens, olfactory, otic, facial, glossopharyngeal and vagal placodes, and the apical ectodermal ridge. In the endoderm, Prox1 is a marker of hepatocytes, bile duct and pancreatic epithelium. In the mesoderm, weak expression is observed in cardiomyocytes, and strong expression in lymphatic endothelium. Identical expression domains are found in 19-week-old human fetuses. In day 6.5 chick embryos, there are several sites of contact of lymphatics with the jugular vein, which has a mixed endothelium of Prox1-positive and -negative cells. The only non-lymphatic endothelial cells expressing Prox1 are found on the concave side of the cardiac valves. To further analyse development of lymphatics, we studied early chick embryos and observed scattered Prox1-positive cells in the dermatome, giving rise to Prox1-positive lymphatic networks during subsequent development. Furthermore, the anlagen of the posterior lymph sacs and the paired thoracic duct can already be observed in day-4 chick embryos. Our studies show that lymphatics develop much earlier than previously described, and they mostly do not seem to be derived by sprouting from veins. In contrast, lymphangioblasts are present in the deep and superficial compartments of the early mesoderm, independently giving rise to the deep and superficial lymphatics.