GFP/DSRED expression in transient and stable zebrafish transgenic embryos obtained with deletion constructs of pax6b P0 promoter. (A) Restriction map of the zebrafish pax6b genomic locus. The arrow indicates the transcriptional start site at exon 0 (E0, marked in black). Promoter deletion constructs were made by enzymatic digestion at the sites indicated. A, B and C conserved regions of approximately 100-bp long are indicated by blue boxes. (B) These DNA constructs were injected into zebrafish embryos and DSRED (Sce-I transgenesis) or GFP (Tol2 transgenesis) transient expression was analysed at 24, 48 and 75 hours of development. The percentage of embryos expressing DSRED/GFP in the retina, the pancreas and the telencephalon versus the total number of embryos expressing DSRED/GFP (n) is indicated in brackets; the number of DSRED/GFP-expressing cells in each tissue (from +++ to +) is shown in the table. For the stable transgenic lines, n is the number of different transgenic founders obtained, and the level of DSRED expression is indicated (from +++ to -). (C) Transient GFP expression in 75 and 48 hpf embryos injected with the full PO (FullP0), the A-deleted (P0-A) and the C-deleted (PO-C) constructs using Tol2-mediated transgenesis. DSRED expression in stable transgenic embryos at 48 hpf harboring the full P0 construct, the A-deleted construct or the B-deleted construct after Sce-I transgenesis. Abbreviations: A, AccI; B, BclI; Bs, Bst11071I; E, EcoNI; p, pancreas; r, retina; tc, telencephalon. All the embryos are presented in dorsal views with anterior on the left.