Figure 2

The ZNC is defined by the activity of Notch. Late third instar wing discs labelled to visualize cells in S-phase by BrdU incorporation (antibody to BrdU in red or white (A, C, E, G, I, N, O, P)) or expressing the E2F1-responsive reporter ORC1–GFP (antibody to GFP in pink or white (B, D, F, H, J, Q)). (A, B) Wild-type wing discs labelled to visualize crumbs–lacZ expression (antibody to -gal, green). Note failure to incorporate BrdU (A) or low levels of E2F1 activity (B) in those cells expressing high levels of the Notch-regulated gene crumbs, which corresponds to the ZNC. The DV compartment boundary is marked in this and other panels (d, dorsal; v, ventral). (C, D) Notch^ts2 wing discs reared at the restrictive temperature and labelled to visualize Wg protein expression (green). (E, F) ptc–Gal4; UAS–Delta^DN (E) and sal–Gal4; UAS–mam^DN (F) wing discs labelled to visualize Senseless (Sens, green in E) or Wg (green in F) protein expression. Sens expression was used to label the DV boundary. Red lines label the domain of Delta^DN or mam^DN expression. (G, H) Wing discs with clones of cells lacking Su(H) activity (Su(H)⁸), marked by the absence of GFP (G) or -gal (H) in green. The ZNC is marked by horizontal lines in G. (I) Wing disc with clones of cells lacking arrow activity (arrow²) marked by the absence of GFP. The ZNC is marked by horizontal lines. (J) dpp–Gal4 Gal80ts; UAS–TCF^DN wing disc reared at 29°C during 30 h and labelled to visualize Wg (green) protein expression. The dpp–Gal4 domain is marked by arrowheads. (K–R) Wild-type (K, N), C96–Gal4; UAS–TCF^DN (L, O), C96–Gal4; UAS –TCF^DNUAS–N^intra (M, P, Q) and C96–Gal4; UAS–GFP (R) wing discs labelled to visualize Cut (green, K–M) or GFP (green, R) protein expression, BrdU incorporation (red, N–P) or activity of the E2F1 responsive reporter ORC1–GFP (antibody to GFP in pink, Q). The ZNC is marked by horizontal dashed lines.