Fig. 1

Cxcl12b–Cxcr4a signaling axis is essential for L–R asymmetric development.

(A–D) WT embryos and cxcr4a^um20 mutants injected with or without 300 pg cxcr4a mRNA at the 256-cell stage were examined for cardiac looping and liver laterality at 48 hpf by WISH against cmlc2 (A) and hhex (C). Embryos with different phenotypes are shown in ventral (A) or dorsal view (C), and the ratios are shown in (B) and (D). Underlying data can be found in  S1 Data. (E–H) Embryo ratios with different expression patterns of cmlc2 and hhex at 48 hpf in WT embryos injected with 8 ng cxcr4a MO (4a MO) at the 256-cell stage (E and F) and cxcl12b mutants (G and H). Underlying data can be found in  S1 Data. (I–N) cxcr4a deficiency alters Nodal gene expression pattern. Representative images of spaw and pitx2c expression in cxcr4a mutants (I and M) and morphants (K). All embryos are shown in dorsal views with anterior on the top. Ratios of embryos are shown in (J), (L), and (N). Underlying data can be found in  S1 Data. cmlc2, cardiac myosin light chain 2; DFC, dorsal forerunner cell; hhex, hematopoietically expressed homeobox; hpf, hours postfertilization; L–R, left–right; MO, morpholino; pitx2c, paired-like homeodomain 2c; spaw, southpaw; WISH, whole-mount in situ hybridization; WT, wild-type.