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During germ-band extension in the Drosophila embryo, intercellular communication is required to maintain gene expression patterns initiated at cellular blastoderm. For example, the wingless (wg) single-cell-wide stripe in each parasegment (PS) is dependent on a signal from the adjacent, posterior cells, which express engrailed (eN). This signal is thought(More)
The sloppy paired (slp) locus consists of two genes, slp1 and slp2, both of which encode proteins containing a forkhead domain (a DNA-binding motif). Previous work has shown that a severe segmentation phenotype is obtained only when both slp genes are deleted. Here we examine the functional redundancy of the locus in more detail. The phenotypes of embryos(More)
Wnt proteins are now recognized as one of the major families of developmentally important signaling molecules , with mutations in Wnt genes displaying remarkable phenotypes in the mouse, Caenorhabditis elegans, and Drosophila. Among functions provided by Wnt proteins are such intriguing processes as embryonic induction , the generation of cell polarity, and(More)
In Drosophila wing imaginal discs, the Wingless (Wg) protein acts as a morphogen, emanating from the dorsal/ventral (D/V) boundary of the disc to directly define cell identities along the D/V axis at short and long range. Here, we show that high levels of a Wg receptor, Drosophila frizzled 2 (Dfz2), stabilize Wg, allowing it to reach cells far from its site(More)
In Drosophila embryos the protein Naked cuticle (Nkd) limits the effects of the Wnt signal Wingless (Wg) during early segmentation. nkd loss of function results in segment polarity defects and embryonic death, but how nkd affects Wnt signaling is unknown. Using ectopic expression, we find that Nkd affects, in a cell-autonomous manner, a transduction step(More)
Wnts are secreted proteins that are essential for a wide array of developmental and physiological processes. They signal across the plasma membrane by interacting with serpentine receptors of the Frizzled (Fz) family and members of the low-density-lipoprotein-related protein (LRP) family. Activation of Fz-LRP promotes the stability and nuclear localization(More)
The secreted glycoprotein Wingless (Wg) acts through a conserved signaling pathway to regulate target gene expression. Wg signaling causes nuclear translocation of Armadillo, the fly beta-catenin, which then complexes with the DNA-binding protein TCF, enabling it to activate transcription. Though many nuclear factors have been implicated in modulating(More)
In contrast to the segmentation of the embryonic trunk region which has been extensively studied, relatively little is known about the development and segmentation of the Drosophila head. Proper development of the cephalic region requires the informational input of three of the four maternal coordinate systems. Head-specific gene expression is set up in(More)
Wnt/β-catenin signalling is known to play many roles in metazoan development and tissue homeostasis. Misregulation of the pathway has also been linked to many human diseases. In this review, specific aspects of the pathway's involvement in these processes are discussed, with an emphasis on how Wnt/β-catenin signalling regulates gene expression in a cell and(More)
One of the early surprises in the study of cell adhesion was the discovery that beta-catenin plays dual roles, serving as an essential component of cadherin-based cell-cell adherens junctions and also serving as the key regulated effector of the Wnt signaling pathway. Here, we review our current model of Wnt signaling and discuss how recent work using model(More)