Normal and aberrant cranlofacial myogenesis by grafted trunk somitic and segmental plate mesoderm
Normal and aberrant cranlofacial myogenesis by grafted trunk somitic and segmental plate mesoderm
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DOI：
10.1242/dev.01276
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发表时间：
2004-08-01
期刊：
影响因子：
4.6
通讯作者：
Noden, DM
中科院分区：
文献类型：
--
作者：
Borue, X;Noden, DM
我们的研究评估了三个躯干中胚层群体--新形成的体节的内侧和外侧半部分，以及发育前(节段板)间充质--参与头面部肌肉的分化和形态发生的能力。在鸡的宿主胚胎中，在神经脊迁移开始之前，来自供体胚胎的移植被放置在靠近中脑-后脑边界的中胚层口袋中。这包括外直肌和近端第一鳃弓肌原基的形成部位。用QCPN和Qh1抗体分别鉴定所有的细胞和内皮细胞，检测移植物来源的细胞的分布和分化。1~6天后(1430期)检测嵌合胚胎myf5、myod、pararis和lbx1的表达以及肌球蛋白重链(MyHC)的合成。异位和对照(原位)移植持续产生侵袭性血管母细胞，并促进外直肌和近端第一鳃弓肌肉；许多也促进背斜肌。这些躯干细胞转录因子和MyHC表达的时空模式与正常头部肌肉相似。异位移植物也产生了许多异位肌肉。这些可见于植入部位的体节样凝集、邻近中脑-后脑边界的致密间充质聚集体，以及散布在眼睛背缘深处的许多小凝集。异位凝集的细胞表达树干转录因子，并迅速分化，模仿树干的肌原时间表。一个新的发现是，移植的树干中胚层形成了许多单核肌细胞和眼睛深处不规则取向的肌管。这些结果表明，头部环境能够支持几个不同的躯干肌源性祖细胞群体的渐进分化，推翻了嫁接时存在的任何偏见。头部肌肉分化和形态发生的空间和时间控制是非常特定的部位，而这些部位之外的头部中胚层通常不能或被移植的躯干中胚层细胞启动异位肌肉发生的信号所抑制。
Our research assesses the ability of three trunk mesodermal populations - medial and lateral halves of newly formed somites, and presomitic (segmental plate) mesenchyme - to participate in the differentiation and morphogenesis of craniofacial muscles. Grafts from quail donor embryos were placed in mesodermal pockets adjacent to the midbrain-hindbrain boundary, prior to the onset of neural crest migration, in chick host embryos. This encompasses the site where the lateral rectus and the proximal first branchial arch muscle primordia arise. The distribution and differentiation of graft-derived cells were assayed using QCPN and QH1 antibodies to identify all quail cells and quail endothelial cells, respectively. Chimeric embryos were assayed for expression of myf5, myod, pararis and lbx1, and the synthesis of myosin heavy chain (MyHC), between 1 and 6 days later (stages 1430). Heterotopic and control (orthotopic) transplants consistently produced invasive angioblasts, and contributed to the lateral rectus and proximal first branchial arch muscles; many also contributed to the dorsal oblique muscle. The spatiotemporal patterns of transcription factor and MyHC expression by these trunk cells mimicked those of normal head muscles. Heterotopic grafts also gave rise to many ectopic muscles. These were observed in somite-like condensations at the implant site, in dense mesenchymal aggregates adjacent to the midbrain-hindbrain boundary, and in numerous small condensations scattered deep to the dorsal margin of the eye. Cells in ectopic condensations expressed trunk transcription factors and differentiated rapidly, mimicking the trunk myogenic timetable. A novel discovery was the formation by grafted trunk mesoderm of many mononucleated myocytes and irregularly oriented myotubes deep to the eye. These results establish that the head environment is able to support the progressive differentiation of several distinct trunk myogenic progenitor populations, overriding whatever biases were present at the time of grafting. The spatial and temporal control of head muscle differentiation and morphogenesis are very site specific, and head mesoderm outside of these sites is normally refractory to, or inhibited by, the signals that initiate ectopic myogenesis by grafted trunk mesoderm cells.