Fig. 1. Expression of FoxF1 during Xenopus development. (A,B) Embryos are shown with anterior to the left and dorsal to the top. (A) Whole-mount in-situ hybridization of a FoxF1 probe to a stage-25 embryo. FoxF1 expression is present in the neural crest-derived structures of the head and in the lateral plate mesoderm. At stage 30 the expression of FoxF1 intensifies and is also present in the ventral mesoderm (B). Letters with lines in (B) indicate the position of sections in (C,D). (C) Section through the head, branchial arches, and heart regions shows the lack of FoxF1 expression in the heart. (D) Section through the mid-trunk region of the embryo shows expression in the lateral plate mesoderm. (E) Ventral view of whole-mount in-situ hybridization of a stage-45 embryo shows FoxF1 expression in the gut. (F) Transverse section through the embryo shown in (E) demonstrates that FoxF1 transcripts are present in the splanchnic mesoderm (arrow).