Figure 2.

Loss of normal apoptosis during pupal development correlates with the NOG eye phenotype observed in the L/Tor;hyx triple heterozygous mutant flies. Normal eye development in Drosophila involves a wave of cellular apoptosis between 35 and 50 h after pupal formation (APF) that eliminates a large fraction of undifferentiated interommatidial cells. The eye discs of L^si/Tor^MB07988 hyx^EY6898/+ triple heterozygotes with a propensity to later develop the NOG phenotype were characterized by a substantial reduction in this usual burst of apoptosis APF compared with w¹¹¹⁸ controls. (a) 4′,6-diamidino-2-phenylindole nuclear staining (left), TUNEL analysis (middle), and merged images (right) of pupal eye discs dissected ∼45 h APF reveal a loss and mis-localization of apoptotic-positive cell nuclei in L^si/Tor^MB07988 hyx^EY6898/+ triple heterozygote flies compared with w¹¹¹⁸ controls. The difference in size between w¹¹¹⁸ control and L^si/Tor^MB07988 hyx^EY6898/+ triple heterozygote eye discs shown represents a random variation and was not reflective of a consistent difference between the two. (b) Quantification of apoptotic cells per pupal eye disc shows significant (∼60%) reduction in total apoptotic-positive cell nuclei in L^si/Tor^MB07988 hyx^EY6898/+ triple heterozygotes compared with w¹¹¹⁸ controls (^***P<0.0001, unpaired Student's t-test; w¹¹¹⁸ control, n=16; L^si/Tor^MB07988 hyx^EY6898/+, n=18)