Figure 5

Nodal-independent regulation of genes in the YSL. Whole mount in situ hybridizations on WT and MZoep embryos at the early-gastrula (6 hpf) stage. Lateral magnifications of the margin and YSL are shown throughout, except for lateral whole-embryo views in M', N', O' and P'. No significant difference was seen in the YSL expression levels of mxtx1 in WT or MZoep embryos, as was previously reported (A-B). Similarly, no significant difference was seen between WT and MZoep embryos for the YSL expression of hnf4a (C-D), gpr137bb (E-F), or camsap1l1 (G-H). The expression of lhx1b (I-J) and sp5 (K-L) was substantially reduced in MZoep mutants. Similarly, concentrated expression of zgc:110712 near the margin was absent in MZoep embryos (M, M', N, N'). The gata6 gene is expressed both in the YSL and margin (O and O') and the margin expression domain is eliminated in MZoep mutants, whereas the YSL expression domain persists (P and P').