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BACKGROUND The adhesion of two epithelial sheets is a fundamental process that occurs throughout embryogenesis and during wound repair. Sealing of the dorsal epidermis along the midline of the Drosophila embryo provides a genetically tractable model to analyse the closure of such holes. Several studies indicate that the actin cytoskeleton plays a critical(More)
Throughout development a series of epithelial bendings, sweepings, and fusions occur that collectively give shape to the embryo. These morphogenetic movements are driven by coordinated assembly and contraction of the actomyosin cytoskeleton in restricted populations of epithelial cells. One well-studied example of such a morphogenetic episode is dorsal(More)
Aa robust inflammatory response to tissue damage and infection is conserved across almost all animal phyla. Neutrophils and macrophages, or their equivalents, are drawn to the wound site where they engulf cell and matrix debris and release signals that direct components of the repair process. This orchestrated cell migration is clinically important, and(More)
Drosophila melanogaster hemocytes are highly motile macrophage-like cells that undergo a stereotypic pattern of migration to populate the whole embryo by late embryogenesis. We demonstrate that the migratory patterns of hemocytes at the embryonic ventral midline are orchestrated by chemotactic signals from the PDGF/VEGF ligands Pvf2 and -3 and that these(More)
BACKGROUND The Drosophila segment polarity gene hedgehog encodes a member of a family of secreted proteins that are involved in a variety of patterning processes, in both vertebrates and invertebrates. Some of these processes depend upon short-range or contact-dependent interactions, whereas others seem to involve long-range signalling. Two different models(More)
Throughout development, a series of epithelial movements and fusions occur that collectively shape the embryo. They are dependent on coordinated reorganizations and contractions of the actin cytoskeleton within defined populations of epithelial cells. One paradigm morphogenetic movement, dorsal closure in the Drosophila embryo, involves closure of a dorsal(More)
BACKGROUND Hox genes control animal body plans by directing the morphogenesis of segment-specific structures. As transcription factors, HOX proteins achieve this through the activation of downstream target genes. Much research has been devoted to the search for these targets and the characterization of their roles in organogenesis. This has shown that the(More)
During the final stages of embryogenesis, the Drosophila embryo exhibits a dorsal hole covered by a simple epithelium of large cells termed the amnioserosa (AS). Dorsal closure is the process whereby this hole is closed through the coordination of cellular activities within both the AS and the epidermis. Genetic analysis has shown that signalling through(More)
The wound healing response is an essential mechanism to maintain the integrity of epithelia and protect all organisms from the surrounding milieu. In the "purse-string" mechanism of wound closure, an injured epithelial sheet cinches its hole closed via an intercellular contractile actomyosin cable. This process is conserved across species and utilized by(More)
Epithelial wound healing relies on tissue movements and cell shape changes. Our work shows that, immediately after wounding, there was a dramatic cytoskeleton remodeling consisting of a pulse of actomyosin filaments that assembled in cells around the wound edge and flowed from cell to cell toward the margin of the wound. We show that this actomyosin flow(More)