Fig. 1. Expression of Vnd in the pNE and brain NBs of early wild-type embryos. (A-K) Vnd antibody staining at early stage 7 (A), stage 8 (B), stage 9 (C,D,E), stage 10 (F,G,H) and stage 11 (I,J,K). (F-K) Double labeling against Engrailed-lacZ (En) indicates part of the posterior border of brain neuromeres. (C,F,I) Flat preparations displaying the head ectoderm (anterior is upwards). (D,G,J) Higher magnifications of regions framed in C,F,I focusing on NBs; immuno-positive NBs are indicated by white letters, immuno-negative NBs are indicated by black letters. Broken black lines encircle domains of strong levels of Vnd; grey lines circle weak levels of Vnd. (E,H,K) Expression of Vnd and En in brain NBs (dark blue, strong Vnd; light blue, weak Vnd; brown, En). All NBs developing within the Vnd domain have been assigned as ventral NBs [for nomenclature of NBs, see Urbach et al. (Urbach et al., 2003)]. (A,B) Lateral view of anterior half of whole-mount embryos. Broken white line encircles the procephalic Vnd domain, encompassing about 66 cells (A, stage 7) and about 47 cells (B, stage 8), indicating that Vnd is already downregulated in part of the pNE cells (black arrows). The prospective protocerebral Vnd domain (black arrowhead) begins to separate from the trito-/deutocerebral Vnd domain (white arrowhead). (C-E) Vnd has mostly vanished from the anterioventral pNE of the deutocerebrum (DC) and posterioventral pNE of the protocerebrum (PC), and from the ventral NBs Dv3, Dv6 and Pcv1. (F-H) Vnd begins to vanish in the posterior DC and anterior tritocerebrum (TC; area around Dv4 in G). (I-K) Separate Vnd domains are located at the posterioventral border of the TC, DC and PC. as, en antennal stripe; hs, en head spot; is, en intercalary stripe; AN, MD, MX, LA, antennal, mandibular, maxillary, labial segment, respectively; CL, clypeolabrum; CF, cephalic furrow; FG, foregut.