The Drosophila tumor suppressor expanded regulates growth, apoptosis, and patterning during development.
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.
Blaumueller
C M
CM
Developmental Biology Programme, EMBL, Meyerhofstrasse 1, 69117, Heidelberg, Germany.
Mlodzik
M
M
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D015415:Biomarkers; D019521:Body Patterning / Q000235:genetics*; D002455:Cell Division / Q000235:genetics; D000072261:Dishevelled Proteins; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development*; D029721:Drosophila Proteins; D005123:Eye / Q000166:cytology / Q000254:growth & development; D005124:Eye Abnormalities / Q000235:genetics; D051157:Frizzled Receptors; D018507:Gene Expression Regulation, Developmental; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics; D043562:Receptors, G-Protein-Coupled; D014921:Wings, Animal / Q000002:abnormalities / Q000254:growth & development
D048868:Adaptor Proteins, Signal Transducing; D015415:Biomarkers; D000072261:Dishevelled Proteins; D029721:Drosophila Proteins; D051157:Frizzled Receptors; D019476:Insect Proteins; D008565:Membrane Proteins; D010750:Phosphoproteins; D043562:Receptors, G-Protein-Coupled; C085090:ex protein, Drosophila; C058784:fz protein, Drosophila