CELLULAR COMMUNICATION IN MORPHOGENESIS

很少有人知道基因是如何控制这三个- 动物器官的空间结构。 在大多数屏幕中， 影响果蝇发育的突变体，内部组织 已经被忽视，而倾向于外部组织，因为它们不容易 可视化。 本提案的目的是发起一项联合 形态学，遗传学和生物化学研究的发展， 果蝇胚胎气管系统，一个精心设计但规则的分支 管状结构，是动物的呼吸器官。 形成 气管系统包括一组确定的内陷， 上皮细胞，气管前体细胞，在每个胸部和 腹部节形成盲端管;盲端的分支， 分支生长;相邻节的分支融合形成 连续管;和进一步的分支和组织渗透，这些 二级分支。 这项研究的长期目标是确定 控制这些形态发生过程的基因产物， 分支形成的生化机制及分支的生长和融合 的分支。 这项建议的具体目标是： 1.表征胚胎的正常生长和发育 荧光显微镜和高分辨率共聚焦显微镜观察气管系统 使用单克隆抗体染色整个气管的显微镜 胚胎发生 2.阐明气管导管形成、分支和 通过气管发育的实时成像观察分支生长和融合 在光活化气管中的笼状荧光素分子后， 前体细胞 3.分离与气管发育有关的基因， 隐性突变改变气管解剖结构，并通过筛选lacZ 增强子-检测子菌株，以鉴定表达于或接近 发育中的气管 4.启动分子克隆和分子遗传学表征 与气管发育有关的一个或多个已鉴定的基因。 5.用动物整体法纯化气管前体细胞 细胞分选以建立用于气管发育的体外系统。

Very little is known of the means by which genes control the three- dimensional structure of the organs of an animal. In most screens for mutants affecting Drosophila melanogaster development, internal tissues have been ignored in favor of external tissues because they are not easily visualized. The objective of this proposal is to initiate a combined morphological, genetic, and biochemical study of the development of the Drosophila embryonic tracheal system, an elaborate but regular branched tubular structure which is the animal's respiratory organ. Formation of the tracheal system involves the invagination of a defined set of epithelial cells, the tracheal precursor cells, in each thoracic and abdominal segment to form blind-ended tubes; branching of the blind end and branch outgrowth; fusion of branches from adjacent segments to form a continuous tube; and further branching and tissue penetration by these secondary branches. The long-term goals of this research are to identify the gene products that control these morphogenetic processes, focusing on the biochemical mechanisms of branch formation and the outgrowth and fusion of the branches. The specific aims of this proposal are: 1. To characterize the normal growth and development of the embryonic tracheal system by fluorescence microscopy and high resolution confocal microscopy using a monoclonal antibody that stains trachea throughout embryogenesis. 2. To elucidate dynamic aspects of tracheal tube formation, branching, and branch outgrowth and fusion by real-time imaging of tracheal development after photo-activation of a caged fluorescein molecule in tracheal precursor cells. 3. To isolate genes involved in tracheal development, by screening for recessive mutations that alter tracheal anatomy and by screening lacZ enhancer-detector strains to identify genes expressed in or near the developing trachea. 4. To initiate the molecular cloning and molecular genetic characterization of one or more of the identified genes involved in tracheal development. 5. To purify tracheal precursor cells by a new approach called whole animal cell sorting to establish an in vitro system for tracheal development.