F. There is extensive overlap between the expression of the EB marker Su(H) (green, immunostaining against Beta-galactosidase; white arrow) and the apical caspase reporter DBS-S-QF (red, immunostaining against HA), but it is also present in progenitor cells without Su(H) expression (yellow arrowheads). DAPI (Blue) labels cell nuclei in all the panels. 