Figure 4.

Reduction or Elevation of pico Levels Does Not Induce Apoptosis

The basal view of wing disc epithelia is shown. Discs expressing pico^IR with ptc-GAL4 have a reduced zone of GFP-labeled cells compared with discs expressing GFP alone (control). Conversely, discs expressing ectopic pico displayed an expanded zone of GFP-labeled cells. Some cells were located basally, but did not show elevated caspase staining and did not have pyknotic nuclei (arrow). Expression of E2F and Dp resulted in high levels of caspase staining and nuclei were pyknotic (arrowhead). Coexpression of pico was unable to suppress E2F/Dp-induced cell death. Merged images show activated caspase staining in blue to visualize apoptotic cells, ptc-GAL4-expressing cells visualized by GFP in green, and propidium-labeled nuclei in red. All images were taken with identical settings to permit comparison of the intensity of activated caspase.