Fig. 3. Regulation of hh and tin expression and VM cell number by HH and WG. Lateral (A-K,N,O), ventrolateral (L,M) and ventral (P-S) views of early stage 11 (L,M), mid stage 11 (P-S) and late stage 11 to early stage 12 embryos (A-K,N,O) stained as indicated on various genetic backgrounds. (A,H,L,N) Wild type, (B,K) hh^13C, (C,I) wg^CX4, (D,J) UAS-wg/24B-GAL, (E) twi-GAL4/+; UAS-hh, wg^CX4/+, wg^CX4, (F,G) twi-GAL4/+; UAS-wg, hh^13C/+, hh^13C, (M,O) UAS-hh/+; 24B-GAL4/+. (B,F) Note hh^13C is a point mutation, which enabled us to monitor hh RNA expression. (F,G) Note in hh^13C embryo misexpressing wg, TIN expression in G shows VM is at least partially formed. VM is marked with CON (red; E1) or broken white lines (E2,L,M). Arrowheads in G and H indicate cardiac signals mostly out of focus. (N,O) Drawings in the lower margin show panel interpretation. (P-S) Embryos stained for FAS3. (P) Wild type, (Q) wg^CX, (R) hh^13C and (S) hh^ts (hh^9K/hh^13C) embryos shifted-up from early stage 10 (4.5 AEL) onwards. Broken white lines indicate VM progenitors. Average cell numbers per VM-PS are shown below. meso in E-G,M,O indicates that the expression of target genes is driven by GAL4 drivers. Arrows in A-K indicate VM.