In vivo enhancer assay using EGFP reporter constructs in zebrafish embryos. (A) Representative mosaic G₀ animals, at 5 dpf, for 5 EGFP reporter constructs (CNC4, CNC10, CNC12, and CNC13) as well as for the control plasmid carrying no CNC sequences (Control). The 2-bottom pictures are higher magnification of the areas defined by dashed line of Control and CNC12 constructs, the last one driving EGFP expression in liver (white arrow). (B) CNC12-EGFP and control transgenic representative G₁ animals at 5 dpf. Higher magnification of an 8-dpf CNC12-EGFP transgenic individual depicts clear liver expression of the reporter gene. Embryos are shown in lateral view, anterior to the right in all panels.