Smoothened, thickveins and the genetic control of cell cycle and cell fate in the developing Drosophila eye.

The Hedgehog and Decapentaplegic pathways have several well-characterized functions in the developing Drosophila compound eye, including initiation and progression of the morphogenetic furrow. Other functions involve control of cell cycle and cell survival as well as cell type specification. Here we have used the mosaic clone analysis of null mutations of the smoothened and thickveins genes (which encode the receptors for these two signals) both alone and in combination, to study cell cycle and cell fate in the developing eye. We conclude that both pathways have several, but differing roles in furrow induction and cell fate and survival, but that neither directly affects cell type specification.