Fig. 5. Ectopic expression of DMyb promotes mitosis in imaginal discs. Mitotic cells identified with the PH3 antibody were similarly distributed in the anterior and posterior compartments of a control sd-Gal4/+ disc (A), but were more frequent in the posterior compartment when en-Gal4 was used to drive expression of UAS-DMyb (B). White line indicates the compartment boundary, posterior towards the right. (C,D) Higher magnification views of the anterior ZNC in wing discs triply stained with DAPI to visualize nuclei (blue), PH3 antibody to identify mitotic cells (green) and Cyclin B antibody (red). In the control sd-Gal4/+ disc, no mitotic cells were detected in the ventral and dorsal domains of the anterior ZNC, where Cyc B accumulates to high levels (C). By contrast, mitotic cells could be detected in these domains when sd-Gal4 was used to drive expression of UAS-DMyb in the wing pouch (D). Scale bars: in A, 0.05 mm for A,B; in D, 0.05 mm in C,D.