Altered dorsolateral chordin expression domains in dorsalized and ventralized zebrafish mutants. (A – F) Expression of chordin in dorsalized swr mutants (B, D, F) was expanded ventrally (arrowheads) compared to WT sibs (A, C, E). A and B are animal pole views and C and D are dorsal views at 75% epiboly. E and F are vegetal pole views at 90% epiboly. (G) At shield stage, dorsal organizer expression of chordin was indistinguishable in sbn mutants and WT siblings (dorsal view) and in embryos from intercrosses of all other dorsalizing mutations examined (not shown). (H – L) Animal pole views. Expression was ventrally expanded (arrowheads) compared to WT (H, K) in both sbn (I and J) and snh (L) mutants at 75% epiboly. As described in the text, all embryos from sbn intercrosses had altered expression patterns which fell into two classes (I was the pattern of two-thirds and J was the pattern of one-third of embryos). (M – Q) Dorsal views. (M) chordin expression was indistinguishable in weakly ventralized mes mutants and WT siblings at 75% epiboly. (N, O) However, expression was decreased overall in ventralized ogo mutant embryos (O) compared to WT sibs (N) at 90% epiboly. (P, Q) Dorsolateral domains of chordin expression (arrowheads) were also more dorsally restricted in stl mutants (Q) compared to WT siblings (P) at 80% epiboly. Asterisks indicate the dorsal midline. Scale bar = 20 μm.