Intestinal stem cell (ISC) self-renewal and proliferation are directed by Wnt/β-catenin signaling in mammals, whereas aberrant Wnt pathway activation in ISCs triggers the development of human colorectal carcinoma. Herein, we have utilized the Drosophila midgut, a powerful model for ISC regulation, to elucidate the mechanisms by which Wingless (Wg)/Wnt regulates intestinal homeostasis and develo...

This case presentation explores how two key Drosophila morphogens, Decapentaplegic (Dpp) and Wingless (Wg), control the expression of two wing disc transcription factors, Vestigial (Vg) and Distalless (Dll). Two simple models for the potential control of Vg and Dll expression by Dpp and Wg in the mature steady state Drosophila wing pouch are explored. Firstly, a model based on the activation me...

The development of the Drosophila leg requires both Decapentaplegic (Dpp) and Wingless (Wg), two signals that establish the proximo-distal (PD) axis by activating target genes such as Distalless (Dll). Dll expression in the leg depends on a Dpp- and Wg-dependent phase and a maintenance phase that is independent of these signals. Here, we show that accurate Dll expression in the leg results from...

BACKGROUND Secreted signaling proteins of the Wingless (Wg)/Wnt, Hedgehog and bone morphogenetic protein (BMP)/Decapentaplegic (Dpp) families function as morphogens to control growth and pattern formation during development. Although these proteins have been shown to act directly on distant cells in the developing limbs of the fruit fly Drosophila, little is known about how ligand gradients for...

Drosophila Wingless (Wg) is a morphogen that determines cell fate during development. Previous studies have shown that endocytic pathways regulate Wg trafficking and signaling. Here, we showed that loss of vamp7, a gene required for vesicle fusion, dramatically increased Wg levels and decreased Wg signaling. Interestingly, we found that levels of Dally-like (Dlp), a glypican that can interact w...

The Frizzled (Fz) receptors contain seven transmembrane helices and an amino-terminal cysteine-rich domain (CRD) that is sufficient and necessary for binding of the ligands, the Wnts. Recent genetic experiments have suggested, however, that the CRD is dispensable for signaling. We engineered fz CRD mutant transgenes and tested them for Wg signaling activity. None of the mutants was functional i...

The objective of the present work was to develop a quantitative risk assessment model in which the exposure and risk of acquiring listeriosis from consumption of packaged smoked or gravad salmon and rainbow trout were estimated. An Excel spreadsheet model was constructed in which variables were represented by distributions based on surveys of L. monocytogenes in these food products, and on demo...

Revision history Revision 0 (3 May 2006) First revision Revision 1 (10 June 2006) Incorporated comments from May 2006 CAP WG changed to SET/REPORT DEVICE IDENTIFIER commands instead of the Device Identification VPD page 83h. Revision 2 (7 September 2006) Incorporated comments from July 2006 CAP WG renamed to SET/REPORT IDENTIFYING INFORMATION to avoid overuse of “identifier”, increased the info...