Department of Genetics, University of Cambridge , CB2 3EH, Cambridge , UK.
Biol Open. 2012 Apr 15;1(4):353-61. doi: 10.1242/bio.2012497. Epub 2012 Feb 16.
Dorsal closure (DC) is an essential step during Drosophila development whereby a hole is sealed in the dorsal epidermis and serves as a model for cell sheet morphogenesis and wound healing. It involves the orchestrated interplay of transcriptional networks and dynamic regulation of cell machinery to bring about shape changes, mechanical forces, and emergent properties. Here we provide insight into the regulation of dorsal closure by describing novel autonomous and non-autonomous roles for U-shaped (Ush) in the amnioserosa, the epidermis, and in mediation of communication between the tissues. We identified Ush by gene expression microarray analysis of Dpp signaling targets and show that Ush mediates some DC functions of Dpp. By selectively restoring Ush function in either the AS or the epidermis in ush mutants, we show that the AS makes a greater (Ush-dependent) contribution to closure than the epidermis. A signal from the AS induces epidermal cell elongation and JNK activation in the DME, while cable formation requires Ush on both sides of the leading edge, i.e. in both the AS and epidermis. Our study demonstrates that the amnioserosa and epidermis communicate at several steps during the process: sometimes the epidermis instructs the amnioserosa, other times the AS instructs the epidermis, and still other times they appear to collaborate.
背唇闭合（DC）是果蝇发育过程中的一个关键步骤，通过这个过程，背部表皮上的一个孔被封闭，为细胞片层形态发生和伤口愈合提供了模型。它涉及转录网络的协调相互作用和细胞机制的动态调节，以实现形状变化、机械力和涌现性质。在这里，我们通过描述 U 形（Ush）在羊膜和表皮中的自主和非自主作用，以及在组织之间的通讯中介中的作用，提供了对背唇闭合的调控的深入了解。我们通过对 Dpp 信号靶基因的基因表达微阵列分析，鉴定了 Ush，并表明 Ush 介导了 Dpp 的一些 DC 功能。通过在 ush 突变体中选择性地恢复 AS 或表皮中的 Ush 功能，我们表明羊膜对闭合的贡献比表皮更大（依赖于 Ush）。来自羊膜的信号在 DME 中诱导表皮细胞伸长和 JNK 激活，而缆索形成需要前缘两侧的 Ush，即在羊膜和表皮中。我们的研究表明，在这个过程的几个步骤中，羊膜和表皮之间进行了通讯：有时表皮指示羊膜，有时羊膜指示表皮，有时它们似乎在合作。
