Fig. 6

Fig. 6 Gal4-VP16-activator/effector constructs can drive expression in different mesodermal tissues. (A–D) Lateral views of injected zebrafish embryos at 27 hpf; images were taken by using confocal microscopy. Pictures represent merged stacks of 10 individual optical sections covering 90 μm in depth. (A, B) Same twhh-GVP-UG-injected embryo imaged with fluorescent (A, EGFP fluorescence pseudocolored in green) and transmitted light (B) without moving the specimen. (A1, B1) Magnification of notochordal region of images in A and B, respectively, to demonstrate EGFP fluorescence in vacuolated cells (*) in the center of the notochord and notochordal sheath cells (arrowhead) surrounding the vacuolated cell type. (C, D) Same twhh-GVP-UG/EF-GVP-coinjected embryo imaged with fluorescent (C, EGFP fluorescence pseudocolored in green) and transmitted light (D) without moving the specimen. Note intense ubiquitous EGFP expression in comparison to notochord-specific twhh-GVP-UG-injected embryo shown in (A). This indicates that injected twhh-GVP-UG is distributed in cells over all germ layers but activates expression almost exclusively in the notochord. (E–H) Dorsal views of act-GVP-UG-injected embryos at 3 dpf; images were taken by using confocal microscopy and represent single optical sections. Pictures in (E, F) and (G, H) show the same embryo imaged with fluorescent (E and G, EGFP expression pseudocolored in green) and transmitted (F, H) light. Note almost exclusive EGFP expression in muscles of embryo shown in (E and F), while the embryo shown in (G and H) displays also expression in numerous cells of the hindbrain. Abbreviations: c, cerebellum; fp, floorplate; nt, neural tube; rh, rhombencephalon; sm, somitic muscles.