dishevelled and armadillo act in the Wingless signalling pathway in Drosophila

Abstract

The Wnt genes encode conserved secreted proteins that play a role in normal development and tumorigenesis. Little is known about the signal transduction pathways of Wnt gene products. One of the best characterized Wnt family members is the Drosophila segment polarity gene wingless. We have investigated whether segment polarity genes with a wingless-like phenotype mediate the wingless signal. We used a wingless transgene controlled by a heat-shock promoter for genetic epistasis experiments. We show that wingless acts through dishevelled and armadillo to affect the expression of the homeobox gene engrailed and cuticle differentiation.

Wnt Signaling from Development to Disease: Insights from Model Systems

“…In mammalian and fly cell culture, overexpression may overcome lack of palmitoylation. Consistent with this, whereas Porc is required for endogenous Wg signaling, it is not required when Wg is overexpressed (Noordermeer et al 1994). In exploring relationships between Wnt glycosylation and lipidation, conflicting results were also obtained in culture versus in flies.…”

Wnts as ligands: processing, secretion and reception

“…Numerous studies have shown that the segment polarity gene porcupine (porc) is required for the maintenance of Wg signaling in this tissue. Genetic epistasis analyses demonstrated that porcupine acts upstream of intracellular signaling components in a cell non-autonomous manner (van den Heuvel et al, 1993;Noordermeer et al, 1994;Siegfried et al, 1994;Manoukian et al, 1995;Tanaka et al, 2000). In addition, a genetic screen for maternally expressed genes required for the endoderm induction in Caenorhabditis elegans confirmed the cell non-autonomous role of mom-1 (C. elegans porcupine ortholog) in Wnt signaling (Thorpe et al, 1997).…”

“…In Drosophila, porcupine-mutant cells accumulate Wg protein suggesting that the protein in unable to be released from the producing cells (van den Heuvel et al, 1993;Noordermeer et al, 1994;Siegfried et al, 1994;Tanaka et al, 2000). In porcupine-mutant flies, a much smaller fraction of Wg is found associated with cell membranes as compared to wild-type animals (Zhai et al, 2004).…”

Wnt some lose some: transcriptional governance of stem cells by Wnt/β-catenin signaling

“…Upon the interaction of canonical Wnt ligands to its receptors, Fzd, and coreceptor, LRP5/6, the Dishevelled (Dvl) protein is recruited, the destruction complex is inhibited, and b-catenin is stabilized in the cytoplasm Noordermeer et al 1994;Axelrod et al 1998;Tamai et al 2000;Wehrli et al 2000). Although b-catenin itself has no DNA-binding domain, it can directly impact gene expression if it interacts with a transcriptional cofactor and translocates to the nucleus (Behrens et al 1996).…”