Fig. 6. Neuroectodermal distribution of gfp transcripts in embryos carrying different constructs (B-E,G-J,L-O) in comparison with transcripts of the endogenous gene (A,F,K). Tailbud stage (A-E), two-somite stage (F-J) and 12-somite stage embryos (K-O). Embryos carrying the 6gfp construct (B,G,L) show all the neural expression domains of deltaD with the exception of the early expression of domain 2 and anterior region of domain 3 (A,F,K). Embryos carrying the 63.5-1.3gfp construct show no neural gfp expression at all (C,H,M). gfp expression in neural domains in embryos carrying the 0.5gfp+3' construct (D,I,N) shows a striking delay in comparison with the endogenous gene. Expression domain 2 requires sequence elements located both in the upstream and the downstream regions, as only progeny of transformants carrying the 3.5gfp+3' (E,J,O) and 6gfp+3' construct show gfp transcripts here. Prosencephalic, mesencephalic and rhombencephalic expression domains, 1-4; developing trigeminal ganglion, asterisk; epiphysis, E; medial, intermediary and lateral expression stripes, MS, IS and LS.