Bénédicte Sanson

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The Wnt genes encode secreted glycoproteins used in intercellular communication at multiple steps during development. Signalling by Wingless, the Drosophila Wnt-1 homologue, requires the activity of Armadillo, the homologue of vertebrate beta-catenin, which is a component of the cadherin/catenin complex at adherens junctions. The genetic link between(More)
The Drosophila genes dally and dally-like encode glypicans, which are heparan sulphate proteoglycans anchored to the cell membrane by a glycosylphosphatidylinositol link. Genetic studies have implicated Dally and Dally-like in Wingless signalling in embryos and imaginal discs. Here, we test the signalling properties of these molecules in the embryonic(More)
Partitioning tissues into compartments that do not intermix is essential for the correct morphogenesis of animal embryos and organs. Several hypotheses have been proposed to explain compartmental cell sorting, mainly differential adhesion, but also regulation of the cytoskeleton or of cell proliferation. Nevertheless, the molecular and cellular mechanisms(More)
Drosophila germ-band extension (GBE) is an example of the convergence and extension movements that elongate and narrow embryonic tissues. To understand the collective cell behaviours underlying tissue morphogenesis, we have continuously quantified cell intercalation and cell shape change during GBE. We show that the fast, early phase of GBE depends on cell(More)
The dynamic reshaping of tissues during morphogenesis results from a combination of individual cell behaviors and collective cell rearrangements. However, a comprehensive framework to unambiguously measure and link cell behavior to tissue morphogenesis is lacking. Here we introduce such a kinematic framework, bridging cell and tissue behaviors at an(More)
Recent experiments on the wing disc of Drosophila have shown that cells at the interface between the anterior and posterior compartments drive pattern formation by becoming the source of a morphogen. Here we ask whether this model applies to the ventral embryonic epidermis. First, we show that interfaces between posterior (engrailed ON) and anterior(More)
In many instances, remote signaling involves the transport of secreted molecules. Here, we examine the spread of Wingless within the embryonic epidermis of Drosophila. Using two assays for Wingless activity (specification of naked cuticle and repression of rhomboid transcription), we found that Wingless acts at a different range in the anterior and(More)
The adult form of a multicellular organism is shaped by a series of morphogenetic processes that organise the body into tissues and organs. Most of these events involve the deformation of sheets of epithelial cells that are highly polarised along their apical-basal axes and attached to each other by lateral junctions. Here we discuss the role played by(More)
Drosophila Armadillo is a multifunctional protein implicated in both cell adhesion, as a catenin, and cell signaling, as part of the Wingless signal transduction pathway. We have generated viable fly stocks with alterations in the level of Armadillo available for signaling. Flies from one stock overexpress Armadillo and, as a result, have increased vein(More)
How genetic programs generate cell-intrinsic forces to shape embryos is actively studied, but less so how tissue-scale physical forces impact morphogenesis. Here we address the role of the latter during axis extension, using Drosophila germband extension (GBE) as a model. We found previously that cells elongate in the anteroposterior (AP) axis in the(More)