Fig. 3. Cut and cell cycle regulation. ct mutant cells are marked by the absence of histone-GFP (hGFP; green in A,B,D,E and white in A'',D''). DAPI is shown in blue (A,B,B',E,e). (A,A',A'') No Cut expression (shown in red in A and white in A') was detected in ct^db7 mutant follicle-cell clones (arrow). The sister clones (outlined and marked by higher levels of GFP) had higher levels of Cut expression than the heterozygous ct^db7 follicle cells. (B,B',B'') ct^db7 mutant follicle cells had larger nuclei and less CycA expression. In a stage 6 egg chamber, DAPI staining showed that ct^db7 mutant follicle cells (outlined) had larger nuclei than the wild-type cells. In the clone, CycA expression is absent (red in B and B''), but in the neighboring wild-type cells about half of the cells were CycA positive. (C) Number of nuclei in ct^db7 mutant clones (blue bars) compared with that in their associated sister clones (purple bars) in stage 10 egg chambers. The x-axis represents the clone number, and the y-axis represents the number of cells per clone or corresponding sister clone. (C') On average, the number of nuclei in the clonal area was one third of that in the associated sister clone. (D,D',D'') CycE (red in D and white in D') had normal oscillating expression pattern in the clone cells (outlined). (E,E') ct^db7 mutant follicle cells properly switched to the gene-amplification stage. A foci-like pattern of BrdU incorporation (red in E and white in E') was found in the cut-mutant follicle cells in a stage 10B egg chamber. (e,e') The circled areas in E and E' show four dots of BrdU incorporation foci (red in e and white in e') in each nucleus.