Early specification and developmental autonomy of neuroectodermal progenitor cells. (A') Neuroblast map of a truncal hemisegment at stage 10 (based on ). Anterior to the top; broken line marks midline. Medial (light green), intermediate (medium green) and lateral neuroblasts (dark green) delaminate from particular dorsoventral regions of the neuroectoderm as indicated by corresponding colour code in A''. (A'') Stage 7 neuroectoderm: m (medial, rows 1 to 4), i (intermediate, rows 5 to 9), l, (lateral, rows 10 to 15). Dorsal to the top, midline to the left (mesoderm, white; mesectoderm, black). (B) Proportion of cultured lineages comprising eve-GFP expressing cells. Progenitors derive from specific neuroectodermal domains (as indicated by colour code; compare A'') of the eve-Gal4RRKstrain. (C-E) Semi-schematic presentation of embryonic lineages (horizontal views; anterior to the left; according to ), which include eve-expressing cells (marked in red; see text for further description). Progenitor cells NB1-1a (abdominal), NB7-1, and NB4-2 are highlighted with yellow spots in (A'). (F) Clone derived from a cultured lateral neuroectodermal progenitor (l), comprising glia in addition to neurons. (G) Ventral nerve cord (horizontal view; anterior to the left) of an eve-Gal4RRK/UAS-mCD8::GFP stage 15 embryo double-stained against CD8 (green; aCC/pCC, RP2) and Eve (red; lateral cluster (EL), CQ/U motoneurons, and co-expression in aCC, pCC, and RP2 (yellow nuclei)). (H-N) Clones derived from medial (m) or intermediate (i) neuroectodermal progenitors of wild-type (H,I), eve-Gal4RRK/UAS-mCD8::GFP (J,K,M,N) or M84/P101-lacZ embryos (L) as indicated. (H,I) Cones including four to five (H) and two (I) Eve-expressing cells, respectively. (J) Clone including two cells co-expressing CD8-GFP and Eve. (K) Clone including two Repo-positive glial cells (arrows) and two Eve-positive neurons (cell bodies out of focus)). (L) Clone including two Eve-expressing neurons (brown) and one to two lacZ-expressing cells with flat glia-like shape (green, arrow). (M,N) Clones including one prominent cell double stained against CD8 (green) and Eve (red). Cell sizes in (F,H-N) correspond to 5 to 6 μm. Markers and putative identities of cultured lineages are indicated on top of each picture, and their site of origin in the neuroectoderm at the bottom.