Fig. 5. Endoderm development in sqt^-/-; cyc^+/+ and sqt^-/-; cyc^+/- mutants. Expression of axial/foxa2 (A-F) or sox17 (G-L) in wild-type (A,D,G,J), sqt^-/-; cyc^+/+ (B,E,H,K) and sqt^-/-; cyc^+/- (C,F,I,L) embryos at 6 h (A-C,G-I; animal pole views) and 8 h (D-F,J-L; dorsal views). The reduction of endodermal expression of axial/foxa2 and sox17 in sqt^-/-; cyc^+/+ and sqt^-/-; cyc^+/- embryos is particularly apparent on the dorsal margin (E,F,K,L). Arrows in J-L indicate the position of dorsal forerunner cells. (M) The total number of endodermal precursors expressing axial/foxa2 at 8 h in wild-type embryos (n=3), sqt^-/-; cyc^+/+ embryos (n=4) and sqt^-/-; cyc^+/- embryos (n=5). (N) Reduction of axial/foxa2 expressing endodermal cells at different positions along the dorsoventral axis (dorsal midline set at zero degrees, ventral midline at 180 degrees). Height of each bar indicates the number of marginal cell tiers along the animal-vegetal axis expressing axial/foxa2. No cells at the dorsal midline expressed axial/foxa2 in sqt^-/-; cyc^+/- embryos. The genotype is indicated by color, as shown in M. The genotypes of all embryos shown were determined by PCR after photography.