DEVELOPMENT OF HEAD NERVES, BLOOD VESSELS, BONES, MUSCLE

我的研究目标是描述所有 鸟类胚胎中的颅面间充质细胞， 通过建立完全分化的组织， 调节间充质细胞组装模式的相互作用 人口到颅面组织和器官。 本供资期内生成的数据显示， 迄今未报道的鸟类颅面发育特征：（1）a 一系列深的，节段性的途径，神经嵴细胞通过这些途径进入 近轴中胚层，（2）多起源和侵入运动， 成血管细胞，以及它们对头部间充质组装线索的依赖性 （3）在血管中发育的间充质细胞群， 内胚层：血管形成前不久的中胚层界面 形成，但仅在SEM制剂中可见，（4）肌管的图案 在肌肉发育的早期出现的排列，在每个 鳃弓肌，并预示着随后的分离模式 （5）细胞运动的精确细节， 三叉神经发育过程中的神经纤维生长模式 感觉运动复合体 拟议中的新实验将扩展对每种组织的分析， 并将更多的注意力集中在定义必要的组织相互作用上 以协调它们的形成。 具体的实验将 检查不同的成血管细胞前体的相对贡献， 颅面血管的发育，特别是 后脑、脸和心壁。 这些将通过研究 移植鹌鹑内皮前体的形成， 免疫细胞化学识别，在鸡宿主胚胎中发育。 到 定义肌源性相互作用，将进行TEM和纤维类型分析 对移植的肌原性前体发育的肌肉， 会表现出不同的特征 最后， 三叉神经感觉神经的特化，证据是它们能够 形成特定的中央和外周投影，将使用 几种纤维示踪方法对胚胎，其中神经节前体 （神经嵴或基板组织）已被移植到不同的 地点或不同时间。

The objectives of my research are to characterize the movements of all craniofacial mesenchymal cells in the avian embryo, from their origins through the establishment of fully differentiated tissues, and to analyze the interactions that regulate patterned assembly of mesenchymal populations into craniofacial tissues and organs. Data generated during the current funding period revealed the following heretofore unreported features of avian craniofacial development: (1) a series of deep, segmental pathways by which neural crest cells move into paraxial mesoderm, (2) multiple origins and invasive movements of angioblasts, and their dependency upon cues in head mesenchyme for assembly into blood vessels, (3) a mesenchymal population that develops at the endoderm:mesoderm interface shortly before the onset of blood vessel formation but is only visible in SEM preparations, (4) patterns of myotube alignment that appear early in muscle development, are unique in each branchial arch muscle, and presage the subsequent patterns of segregation of individual muscles, and (5) precise details of cell movements and patterns of nerve fiber growth during development of the trigeminal sensory-motor complex. The proposed new experiments will extend analyses of each of these tissues, and focus greater attention on defining the tissue interactions necessary for their coordinated formation. Specific proposed experiments will examine the relative contributions of different angioblast precursors in development of craniofacial blood vessels, particularly those in the hindbrain, face, and heart wall. These will be determined by studying the formation of transplanted quail endothelial precursors, which can be recognized immunocytochemically, developing in chick host embryos. To define myogenic interactions, TEM and fiber type analyses will be performed on muscles developing from transplanted myogenic precursors that normally would express different features. Finally, interactions underlying specification of trigeminal sensory nerves, as evidence by their ability to form specific central and peripheral projections, will be assessed using several fiber-tracing methods on embryos in which the ganglionic precursors (neural crest or placodal tissues) have been transplanted to different locations or at different times.