Fig. S8

slc25a25b acts upstream of the southpaw (nodal) cascade.

(A-C) southpaw expression in pkd2-morphant zebrafish embryos. Loss of pkd2 caused left–right randomization of southpaw expression. southpaw mRNA in 15-somite stage zebrafish embryos was visualized by in situ hybridization. (D) Comparison of southpaw expression patterns in control and pkd2-morphant (*P = 0.0005) zebrafish. (E-G) Expression of dand5 in 6-somite stage slc25a25b-morphant zebrafish embryos. Asymmetry of dand5 expression was impaired in 6-somite slc25a25b-morphants (wild type: n = 27; left = 4; symmetric = 11; right = 12; Control^MO: n = 28; left = 5; symmetric = 12; right = 11; slc25a25b^MO: n = 18; left = 10; symmetric = 5; right = 3; in comparison to Control^MO *P = 0.03) as well as in (H) 8-somite slc25a25b-morphants (*P = 0.007). (I,J) lefty2 expression in slc25a25b-morphant zebrafish embryos 22 hpf. (K) lefty2 expression was randomized in pkd2- and slc25a25b-morphant zebrafish (*P = 2.2 × 10⁻¹² and *P = 3.4 × 10⁻⁸, respectively). Numbers of embryos are indicated above bars. L = left; S = symmetric; R = right. For numerical values, see S1 Data. hpf, hours post fertilization.