SIGNALING CELL MOVEMENT IN DORSAL CLOSURE

胚胎发育过程中复合体模式的建立 不仅依赖于细胞决定，还依赖于形态发生 涉及细胞形状变化和上皮运动的过程 床单。果蝇的背部闭合过程提供了一个 用于细胞多方面研究的优秀模型系统 形态发生。在背部闭合时，侧方上皮细胞 胚胎的每一边向背部移动，以在 背中线形成一层连续的上皮层，包裹着 胚胎。未能完成的突变体的鉴定 背部闭合导致了一种模型的精化，在该模型中，两个 信号通路、Jun激酶盒和DPP/TGFbeta 路径，合作以协调启动和维护 上皮组织运动。上行信号的身份可能 激活Jun通路，从而启动背侧 闭合仍然未知，连接到 细胞形状变化所需的细胞骨架 上皮组织。 这项建议的目的是：1)更好地了解 它们的形态和遗传特征 细胞的独特作用，这些细胞构成了 背上皮，2)确定DPP信号是否 位于外侧的细胞的极化和伸长 上皮细胞，以及3)表征新的基因，所需的 背部闭合过程，重点放在可能 激活Jun通路或可能参与调节 细胞骨架。

The establishment of a complex body pattern during embryogenesis relies not only on cell determination but on morphogenetic processes involving cell shape changes and movement of epithelial sheets. The process of dorsal closure in Drosophila provides an excellent model system for investigating many aspects of cellular morphogenesis. During dorsal closure, the lateral epithelia on each side of the embryo move dorsally to meet and fuse at the dorsal midline forming a continuous epithelial layer encasing the embryo. The identification of mutants that fail to complete dorsal closure has led to the elaboration of a model in which two signaling pathways, the JUN kinase cassette and the DPP/TGFbeta pathway, cooperate to coordinate initiation and maintenance of epithelial movement. The identity of upstream signals that might activate the JUN pathway and thus the initiation of dorsal closure remain unknown as do the molecular links to the cytoskeleton required for cell shape changes within the epithelium. The goals of this proposal are 1) to gain a better understanding of the morphological and genetic characteristics that contribute to the unique role of cells that make up the leading edge of the dorsal epithelium, 2) to determine whether DPP signaling underlies the polarization and elongation of cells in the lateral epithelium, and 3) to characterize new genes required for the process of dorsal closure, focusing on components that may activate the JUN pathway or that may feed into regulation of the cytoskeleton.