Fig. 2. fgf24 is expressed in mesodermal precursors during gastrulation in a pattern that overlaps with the expression of fgf8, ntl and spt. Dorsal (A,C,E) and vegetal (B,D,F; dorsal is upwards) views of embryos showing expression of fgf24 at 4 hpf (A,B), 6 hpf (C,D) and 9 hpf (E,F). In addition to the germ ring, fgf24 has weak expression in the developing neural ectoderm (arrow in E), as determined by section analysis (not shown). (G) In situ hybridization and immunohistochemistry show the relationship between the expression of fgf24 (purple) and Ntl (brown) in one-somite-stage embryos. Asterisk indicates the tail bud. The expression pattern of fgf24 (H,L) is compared with that of fgf8 (I,M), spt (J,N) and ntl (K,O) in mid-gastrulation stage embryos (8.5 hpf) by whole-mount in situ hybridization (H-K; dorsal views) and in parasagittal sections (L-O). Arrowheads in H-K indicate approximate position of section though germ ring, and approximate division between the epiblast and hypoblast cell layers in L-O is indicated with a broken line. (L) fgf24 expression is higher in the hypoblast layer (arrow) relative to the epiblast, similar to the localization of spt (N). By contrast, fgf8 expression is highest in the epiblast (M) similar to the localization of ntl (O). In addition to the germ ring staining (arrowheads in H-O), fgf8 is also expressed in the developing hindbrain (arrow in I,M), spt in presomitic mesoderm (arrow in J,N) and ntl in the developing notochord (arrow in K). Scale bars: in A, 100 µm for A-K; in O, 50 µm for L-O.

Return to article