<i>dishevelled</i> is required during <i>wingless</i> signaling to establish both cell polarity and cell identity

TLDR

The Drosophila dishevelled gene encodes a novel intracellular protein with a junction‑associated motif and is essential for establishing polarized cell arrays and embryonic segmentation. The study tests whether the wingless–dishevelled interaction specifies positional values in leg discs and is required for cell polarity and identity. Clonal analysis in leg discs was used to assess whether the wingless–dishevelled interaction determines circumferential positional values predicted by the polar coordinate model. Loss of dishevelled function produces patterning defects that mimic.

Abstract

ABSTRACT The dishevelled gene of Drosophila is required to establish coherent arrays of polarized cells and is also required to establish segments in the embryo. Here, we show that loss of dishevelled function in clones, in double heterozygotes with wingless mutants and in flies bearing a weak dishevelled transgene leads to patterning defects which phenocopy defects observed in wingless mutants alone. Further, polarized cells in all body segments require dishevelled function to establish planar cell polarity, and some wingless alleles and dishevelled; wingless double heterozygotes exhibit bristle polarity defects identical to those seen in dishevelled alone. The requirement for dishevelled in establishing polarity is cell autonomous. The dishevelled gene encodes a novel intracellular protein that shares an amino acid motif with several other proteins that are found associated with cell junctions. Clonal analysis of dishevelled in leg discs provides a unique opportunity to test the hypothesis that the wingless dishevelled interaction specifies at least one of the circumferential positional values predicted by the polar coordinate model. We propose that dishevelled encodes an intracellular protein required to respond to a wingless signal and that this interaction is essential for establishing both cell polarity and cell identity.