DPP is not a savior for fly epithelial cells, according to new reports from Matthew Gibson and Norbert Perrimon (Harvard Medical School, Boston, MA) and from Jie Shen and Christian Dahmann (Max Planck Institute, Dresden, Germany). Once thought to be a survival factor in the wing imaginal disc, the DPP morphogen is now shown to regulate cell architecture.
Previous experiments showed that wing imaginal disc cells forced into low DPP signaling were eliminated by apoptosis. But the Dresden and Boston groups now report that clones of DPP-deprived cells are misshapen and thus extrude from the wing disc epithelium. The Harvard group found that some mutant cells did evenutally undergo apoptosis, but this seems to be a secondary effect, perhaps brought on by the mechanical stress of extrusion.Cells lacking DPP signaling (green) are extruded from the epithelial layer.
PERRIMON/AAAS
Gradients of DPP, and other morphogens,...
