Fig. 6. TUNEL analysis of apoptosis in the NB7-3 lineage. Stage 15 embryos were immunostained for TUNEL (green), Eg (red) and Hb (blue). All panels are arranged with anterior at the top and the midline towards the right. (A-A') A wild-type hemisegment showing an extra NB7-3 Eg cell that is apoptotic. (B) A numb¹ hemisegment showing three Eg cells; the two GMC-1 progeny and an apoptotic cell. (C) A numb¹ hemisegment showing apoptosis of the two GMC-1 progeny, these cells are immunostained for all three labels. (D-D') A UAS-Notch^ACT:eg-gal4 hemisegment showing four Eg cells; the two GMC-1 progeny and two apoptotic cells. (E-E') A UAS-Notch^ACT:eg-gal4 hemisegment showing six cells; the two GMC-1 progeny and four closely associated cells that are apoptotic and appear as mitotic pairs. Only one of the apoptotic cells maintains Eg expression. (F-F') A UAS-numb:eggal4 hemisegment showing six Eg cells; the two GMC-1 progeny and paired GMC-2 and GMC-3 progeny (outlined). Only one cell in this hemisegment is apoptotic. Scale bar: 5 µm.