The Drosophila tumor suppressor expanded regulates growth, apoptosis, and patterning during development

Mech Dev. 2000 Apr;92(2):251-62. doi: 10.1016/s0925-4773(00)00246-x.


The Drosophila expanded (ex) gene encodes a protein thought to play a role in signaling at apical junctions of epithelial cells. Previous studies have characterized this gene as a tumor suppressor involved in regulating the growth of a subset of Drosophila imaginal discs (Boedigheimer, M., Laughon, A., 1993. expanded: a gene involved in the control of cell proliferation in imaginal discs, Development 118, 1291-1301); although ex negatively regulates cell proliferation in the developing wing, it appeared to have a conflicting role in the eye. In contrast, our analysis of the loss-of-function phenotype indicates that ex does, in fact, regulate growth in the eye. We also show that this gene plays a role in patterning of the eye, mainly at the level of planar polarity. Our studies further demonstrate that, contrary to what was expected based on loss-of-function data, the tissue reduction phenotypes resulting from Ex overexpression are attributable to the induction of apoptotic cell death. Taken together, our data suggest that Ex is a versatile molecule that plays a role in most of the processes that govern disc development.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Apoptosis / genetics
  • Biomarkers
  • Body Patterning / genetics*
  • Cell Division / genetics
  • Dishevelled Proteins
  • Drosophila / genetics*
  • Drosophila / growth & development*
  • Drosophila Proteins*
  • Eye / cytology
  • Eye / growth & development
  • Eye Abnormalities / genetics
  • Frizzled Receptors
  • Gene Expression Regulation, Developmental
  • Insect Proteins / genetics*
  • Insect Proteins / metabolism
  • Membrane Proteins / genetics
  • Mutation
  • Phosphoproteins / genetics
  • Receptors, G-Protein-Coupled
  • Wings, Animal / abnormalities
  • Wings, Animal / growth & development


  • Adaptor Proteins, Signal Transducing
  • Biomarkers
  • Dishevelled Proteins
  • Drosophila Proteins
  • Frizzled Receptors
  • Insect Proteins
  • Membrane Proteins
  • Phosphoproteins
  • Receptors, G-Protein-Coupled
  • ex protein, Drosophila
  • fz protein, Drosophila