Loss of differentiation markers is not due to apoptosis.

Apoptosis does not contribute to the reduction in the number of Sens positive cells. Clones of mutant cells were induced with the FLP-FRT technique and distinguished by the lack of GFP (green). (A) Apoptosis, as detected by the cleaved caspase-3 (C3) antibody (magenta), in the MF of a disc hemizygous for rbf^120a but not in the posterior compartment. (B) Lack of cleaved caspase-3 positive cells, as detected by the C3 antibody (magenta), in clones of rbf^120a wts^x1 double mutant cells within and posterior to the MF. (C) Overexpression of p35 within and posterior to the MF does not rescue the reduced number of Sens positive cells in the posterior of rbf^120a wts^x1 mutant clones.