We use laser hole drilling to assess the mechanics of an embryonic epithelium during development-in vivo and with subcellular resolution. We ablate a subcellular cylindrical hole clean through the epithelium and track the subsequent recoil of adjacent cells (on ms time scales). We investigate dorsal closure in the fruit fly with emphasis on apical constriction of amnioserosa cells. The mechanic...

Higher cyclorrhaphan flies including Drosophila develop a single extraembryonic epithelium (amnioserosa), which closes the germband dorsally. In most other insects two extraembryonic epithelia, serosa and amnion, line the inner eggshell and the ventral germband, respectively. How the two extraembryonic epithelia evolved into one is unclear. Recent studies have shown that, in the flour beetle Tr...

Apical constriction is a major mechanism underlying tissue internalization during development. This cell constriction typically requires actomyosin contractility. Thus, understanding apical constriction requires characterization of the mechanics and regulation of actomyosin assemblies. We have analyzed the relationship between myosin and the polarity regulators Par-6, aPKC and Bazooka (Par-3) (...

Dorsal closure in the Drosophila embryo occurs during the later stages of embryogenesis and involves changes in cell shape leading to the juxtaposition and subsequent adherence of the lateral epidermal primordia over the amnioserosa. Dorsal closure requires the activation of a conserved c-jun amino-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) module, as it is blocked by null mu...

During development tissue deformations are essential for the generation of organs and to provide the final form of an organism. These deformations rely on the coordination of individual cell behaviours which have their origin in the modulation of subcellular activities. Here we explore the role endocytosis and recycling on tissue deformations that occur during dorsal closure of the Drosophila e...