Figure 4.
mir-11 mutant cells are highly sensitive to dE2F1-dependent irradiation-induced apoptosis and have a higher level of expression of hid and rpr. (A,B) Wild-type (A) or mir-11 mosaic mutant (B) third instar larvae were exposed to 40 Gy of irradiation, and eye discs were harvested at the indicated times following exposure. Apoptosis was detected using the C3 antibody (red), which recognizes active caspases. Clones of mir-11 mutant tissue were generated using ey-FLP. Wild-type tissue is marked by GFP (green). Yellow arrows indicate patches of apoptotic cells that appear in the mir-11 mutant cells at an earlier time point than in the adjacent wild-type tissue. At 4 h after irradiation, the stripe of C3-positive cells anterior to the MF is expanded in the mir-11 mutant tissue. The position of the MF is marked with the arrowhead. (C) C3-positive cells in wild-type or mutant tissue were counted at the indicated times after irradiation. An average of a minimum of six eye discs was counted. Standard deviations are indicated. (D) Canton S or mir-11Δ1 third instar larvae were exposed to 40 Gy of irradiation and then allowed to develop. The number of adults to emerge was counted, and the percentage of survival was calculated. The average and standard deviation of three separate experiments are shown. (*) P = 0.032 in a paired t-test. (E) RNA was extracted from wild-type or mir11 mosaic mutant larval eye discs 1 h following irradiation (40 Gy), and rpr, hid, grim, and skl expression was measured by qRT–PCR. β-tubulin and RpP0 were used as controls in normalization. Expression of rpr and hid is elevated in mir-11 mutant mosaic eye discs before and after irradiation. (**) P < 0.001; (*) P < 0.05 in paired t-tests.