Fig. 2. crol is required for cell cycling. (A-N,P-S) Clones generated using MARCM (positively marked with GFP). (A,B) 120-hour wild-type clones; (C,D) 120-hour crol^-/- clones. (E) 120-hour crol mutant clones expressing UAS-crol. (F-J) crol clones die by apoptosis. (F) Apical section of 96-hour crol clones. (G) Basal section of the disc in H, counterstained with propidium iodide (red). (H) Higher magnification to show pyknotic nuclei with DAPI (blue) and (I) merged with GFP. (J) 120-hour crol^-/- clones overexpressing UAS-p35. In B and D, discs have been co-stained with phalloidin-TRITC to distinguish the hinge from the pouch; the pouch is marked by a white line in A,C,E-G,J. (K-T) Cell cycle analysis of crol mutant clones in the UAS-p35 background. (K-N) 96-hour discs 48 hours after heat-shock. BrdU labelling (red) in control clones (K) and crol^-/- clones (L) or PH3 staining (purple) in control (M) and crol mutant clones (N). (P,Q) crol^-/- clones in 120-hour discs with BrdU (P) and a higher magnification (Q) to show cells flanking the ZNC, which corresponds to the white square in P. (R,S) crol^-/- clones in 120-hour discs with PH3 and a higher magnification (S) to show mitotic cells adjacent to the ZNC, which corresponds to the white square in R. (O,T) Quantification of BrdU (O) and PH3 (T) in 96-hour discs. Counts are from equivalent clone areas (three sets of 70,000 pixels) from control (BrdU 488.6±24.3, PH3 52.0±3.2), crol^-/- (BrdU 84.24±5.2, PH3 7.02±0.6) and crol^-/-; UAS-p35 (BrdU 131.61±7.8, PH3 22.14±2.4). A statistically significant decrease was observed between crol^-/- and control clones for BrdU (P<0.0001) and PH3 (P<0.0001), and for crol^-/-; UAS-p35 and control clones BrdU (P<0.0001) and PH3 (P<0.0002).