Fig. 1

The phenotype of the s1pr2^as10 mutant.

(A-H) Lateral views of wild-type (WT) (A, C, E and G) and s1pr2^as10 mutants (B, D, F and H). Pericardial edema (B′), small eyes, and tail blisters (B′) were observed in 72-hpf s1pr2^as10 mutant embryos (B). Two separate hearts (white arrows, D) were detected at 24 hpf, whereas a fused heart (white arrow, F) was observed at 48 hpf in s1pr2^as10 mutant embryos. Paraffin sectioning with haematoxylin and eosin staining revealed the presence of two atria and one ventricle in s1pr2^as10 mutant embryos at 72 hpf (H). (I-M) Ventral views of wild-type (WT) (I), s1pr2^as10 (J), mil (K), and the intercross mutant progeny of s1pr2^as10 and mil mutants (L and M) at 24 hpf are shown. The arrows indicate the positions of the hearts. (N) Cardiomyocytes were labeled via cmlc2 staining. Two representative s1pr2^as10 mutant embryos are shown. Both contacting and separated cardiomyocytes were detected in the s1pr2^as10 mutant embryos from the 22 ss to 28 hpf. (O) Percentages of WT and s1pr2^as10 mutants containing contacting myocardia at different developmental stages. Scale bar = 100 μm. The error bars indicate the standard error.