Fig. 4.

Predicted Foxc1 binding site is required for fin expression in larvae, juveniles, and adults. GFP reporter gene expression in the left pectoral fin (A) and caudal fin (B) of larvae, juveniles and adults. (A) Expression was detected in the distal edges of the pectoral fin (arrows) in larvae, the base of the pectoral fin rays (asterisk), and the intersegmental joints (arrowheads) of juveniles and adults with the intact sequence of the predicted Foxc1 binding site (left column). Severely reduced expression was seen in the distal edges of the pectoral fin in larvae and the intersegmental joints of juveniles and adults with the scrambled or deleted sequence of the predicted Foxc1 binding site (middle and right columns, respectively), while some expression at the base of the fin rays remained. (B) GFP reporter expression in the caudal fin. In larvae, expression was observed in the distal edge of the median fin fold (arrow) and caudal peduncle (asterisk) with the intact enhancer, but was severely reduced with the scrambled and deleted enhancers. Some peduncle expression remained with the deleted enhancer (right). In juveniles and adults, expression was detected in the peduncle (asterisks) and the intersegmental joints of the caudal fin (arrowheads) for the intact enhancer, but not for the scrambled or deleted enhancer. Scale bars = 500 μm (larva), 1 mm (juvenile), 2 mm (adult).