Growth regulation by Dpp: an essential role for Brinker and a non-essential role for graded signaling levels.
Morphogens can control organ development by regulating patterning as well as growth. Here we use the model system of the Drosophila wing imaginal disc to address how the patterning signal Decapentaplegic (Dpp) regulates cell proliferation. Contrary to previous models, which implicated the slope of the Dpp gradient as an essential driver of cell proliferation, we find that the juxtaposition of cells with differential pathway activity is not required for proliferation. Additionally, our results demonstrate that, as is the case for patterning, Dpp controls wing growth entirely via repression of the target gene brinker (brk). The Dpp-Brk system converts an inherently uneven growth program, with excessive cell proliferation in lateral regions and low proliferation in medial regions, into a spatially homogeneous profile of cell divisions throughout the disc.
Schwank
Gerald
G
Institut für Molekularbiologie, Winterthurerstr. 190, CH-8057 Zürich, Switzerland.
Restrepo
Simon
S
Basler
Konrad
K
D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning; D049109:Cell Proliferation; D004330:Drosophila / Q000235:genetics / Q000254:growth & development* / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D017344:Genes, Insect; D009154:Mutation; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D014921:Wings, Animal / Q000166:cytology / Q000254:growth & development
D029721:Drosophila Proteins; D012097:Repressor Proteins; C118082:brk protein, Drosophila; C064196:dpp protein, Drosophila