Functional analysis of Wingless reveals a link between intercellular ligand transport and dorsal-cell-specific signaling.

摘要: The Drosophila segment polarity gene wingless (wg) is essential for cell fate decisions in the developing embryonic epidermis. Wg protein produced one row of cells near posterior every and secreted distributed throughout to generate wild-type pattern elements. Ventrally, epidermal secrete a diverse array anterior denticle types expanse naked cuticle; dorsally, stereotyped fine hairs secreted. We describe three new wg alleles that promote cuticle but show reduced diversity dorsal patterning. These mutations cause single amino acid substitutions cluster residues are highly conserved Wnt family. By manipulating expression transgenic proteins, we demonstrate all mutant molecules retain intrinsic capacity signal ventrally fail be across segment. Thus, movement through epithelium proper ventral specification this planar distinct from apical-basal transcytosis previously described polarized epithelia. Furthermore, ectopic overexpression proteins fails rescue Thus have identified region Wingless required both transcytotic process transduction populations, revealing an unexpected link between these two aspects function.