Fig. 3

creb3l1 mutant zebrafish exhibit perturbations in caudal fin patterning. (A) Tails of age-matched 6 mpf creb3l1+/+,Tg(Sp7:eGFP)/+ and creb3l1ΔbZIP/ΔbZIP,Tg(Sp7:eGFP)/+ fish were imaged by fluorescence and representative images are shown. Orange lines from the caudal peduncle to the tip of third rays mark distance measured as fin length. Blue lines mark the distance of the most proximal bifurcation point from the caudal peduncle of second rays. Scale bar = 1 mm. (B) Images analogous to those in (A) were used to measure the length of second and third ray on both sides of the fin, and the average length/fin is shown. Each data point represents an individual fish. No difference in tail length was detected. n = 15–17. (C) Images analogous to those in (A) were used to measure the distance between the primary proximal bifurcation and the caudal peduncle of the second and third ray on both sides of the fin. The average distance was calculated and is shown. Each data point represents an individual fish. No difference in the proximo-distal position of the bifurcation point was detected. n = 16–17. (D) Higher magnification of images analogous to those in (A) (the images were “stretched” along the x horizontal axis to more clearly visualize the distinct bifurcations). Rays are numbered starting with the most lateral. Secondary bifurcations of the third ray are indicated by yellow arrows, of the fourth ray by sienna arrows, and of the fifth ray by orange arrows. Secondary bifurcations of the sixth and seventh rays are indicated by blue arrows in wild-type fish and are absent in mutant fish. (E, F) Images analogous to those in (A) were used to measure the total number of bifurcations per fin (E), as well as the number of primary (F), and secondary bifurcations per fin (G). The complexity of bifurcations is lower in the creb3l1 mutant fins, with fewer secondary bifurcations per fin than in wild-type creb3l1 fins.