Fig. 4

Fig. 4 Cyp26b1 Is Expressed in Segment Centers and Regulated by FGF Signaling
(A–D) In situ hybridizations to detect the time course of cyp26b1 expression. Images are a merge of confocal stacks of Fast Red staining. Scale bar, 50 μm. White arrowheads indicate segment centers. (D–F) In situ hybridization of cyp26b1 followed by immunostaining with anti-Sox9 antibody. Yellow arrowheads show colocalization of cyp26b1 with Sox9b in segment centers.
(G and H) In situ hybridization of 40 hpf embryos to detect cyp26b1 expression in wt (G) or dominant-negative FGFR1 embryos (Tg(hsp70l:dnfgfr1-EGFP)) (H). Heat shocks were started at the 22 somite stage. Black arrowheads indicate segment centers; open arrowheads indicate the disappearance of cyp26b1 expression from centers. Scale bar, 50 μm.
(I and J) In situ hybridization of 26 hpf embryos to detect cyp26b1 in either wt (I) or constitutively active fgfr1 embryos, Tg(hsp70:ca-fgfr1) (J). Heat shocks were started at 24 hpf and embryos fixed 2 hr later. Black arrowheads indicate segment centers; red arrowheads centers in embryos with cyp26b1 upregulation. Scale bar, 50 μm.