EXTRACELLULAR MOLECULAR INTERACTION IN LIMB DEVELOPMENT

这个项目的主题是概念性的。 我们特别 我认为肢体形态发生是从内部的内在机制开始的， 间充质可以通过分泌的形态发生素进行外源性调节， 邻近组织 我们相信要阐明这些机制， 确定特定的内源性肢体分子， 各种肢体表型的表达。 我们特别寻求识别 用于建立组织结构的主要模式的蛋白质 在此基础上进行肢体形态发生。 高分辨率分子 方法将用于结构和功能特征 特定的蛋白质（一些已经在手）对谱系的影响 肢体间充质的限制、表型表达和组织形成 细胞 所有项目都使用3D培养系统，其中亚群 间充质的细胞可以被分离或探测对组织发生的反应。 感应信号 所有项目包括分子克隆或 染色质结构分析。 对于每个项目， 克隆或染色质结构分析。 对于每个项目，具体 已经提出了假设。 在项目I（Markwald/Krug/Bolender） 将测定外胚层分泌的蛋白质（例如ES-I抗原）， 对软骨形成的调节作用（包括 初级软骨形成中心数量的调节）和组织形成 胶原凝胶中间充质前体细胞群之间的相互作用 文化 在项目III（戈弗雷）中，基底膜分子的作用 在细胞分化之前在间充质细胞上发现的， 测试了它们在肌源性分化、肌管形成和 突触发生 对于其中之一，聚集蛋白，将获得cDNA克隆， 包括外胚层相互作用在内的发育调控研究。 在 项目IV（Fallon），将进行体内分析，以检测 而3D胶原凝胶培养将 用于建立顶端外胚层嵴功能的生物测定， 无肢（11）和无翅突变体。 项目一和项目四的成果 将与模式缺陷Talpid 2获得的结果进行比较 变种人 法伦博士和他的合作者特明博士将继续他们的 正在进行的研究，以开发一种用于细胞标记的鸡遗传标记 在项目I和项目IV中进行实验。 三个核心单元，初级文化核心 （Bolender）、单克隆抗体核心（Yorde）和EM细胞化学核心 沿着一个行政核心将提供研究 提供技术和概念支持的项目。 热情 计划仍然很高，因为进展导致了发展 程序和分子探针，我们可以进行跨学科的研究， 努力阐明肢体形态发生的机制。

The central theme of this program project is conceptual. Specifically, we propose that limb morphogenesis proceeds from intrinsic mechanisms within mesenchyme which can be extrinsically modulated by morphogens secreted by adjacent tissues. We believe to elucidate these mechanisms, it is critical that specific endogenous limb molecules be identified that coordinate expression of the various limb phenotypes. We especially seek to identify proteins that serve to establish the primary pattern of tissue organization upon which limb morphogenesis proceeds. High resolution molecular approaches will be used to structurally and functionally characterize specific proteins (some already in hand) for their effects on lineage restriction, phenotypic expression and tissue formation of limb mesenchymal cells. All projects utilize a 3.d culture system in which subpopulations of mesenchyme can be isolated or probed for response to histogenic inductive signals. All projects include either molecular cloning or chromatin structural analyses. For each projects include either molecular cloning or chromatin structural analyses. For each project, specific hypotheses have been proposed. In Project I (Markwald/Krug/Bolender) ectodermally secreted proteins (e.g. ES-I antigens) will be assayed for effects for their regulatory influence on chondrogenesis (including regulation of the number of primary chondrogenic centers) nd histogenic interactions between mesenchymal precursor cell populations in collagen gel culture. In Project III (Godfrey) the role of basement membrane molecules found on mesenchymal cells before cytodifferentiation will be functionally tested for their role(s) in myogenic differentiation, myotube formation and synaptogenesis. For one of these, agrin, cDNA clones will be obtained for studies of developmental regulation including ectodermal interaction. In Project IV (Fallon), in vivo analyses will be performed to test the roles of ectoderm in patterning mechanisms while the 3d collagen gel culture will be used to establish bioassays of apical ectodermal ridge function using limbless (11) and wingless mutants. Results from both Projects I and IV will compared with findings obtained from the pattern deficient Talpid 2 mutant. Dr. Fallon and his collaborator, Dr. Temin, will continue their ongoing studies to develop a chick heritable marker for use in cell marking experiments in Projects I and IV. Three core units, Primary Culture Core (Bolender), Monoclonal Antibody Core (Yorde) and the EM Cytochemical Core (Riley) along with an Administrative Core will provide the research projects with both technical and conceptual support. Enthusiasm for the program remains high as progress has resulted in the development of procedures and molecular probes with which we can pursue interdisciplinary efforts to elucidate mechanisms of limb morphogenesis.