Fig. 7. LvSnail functions downstream of LvAlx1 in PMCs. (A) Control embryos. (B) Embryos injected with AlxMASO show no PMC ingression. (C) Excess mesenchyme cells form in embryos overexpressing LvSnail. (D) Co-injection of LvSnail rescues the formation of mesenchyme cells in the absence of LvAlx1. (E) Diagram of experiment in F,G. vv, vegetal view. (F-F'') Chimeric embryos generated by combining one control micromere (green) and one AlxMASO-containing micromere (red) with a control 16-cell stage embryo in which two micromeres were removed. Brightfield (F), fluorescent (F') and merged images (F'') show that the AlxMASO-containing micromere progeny do not ingress, unlike the control micromere progeny in the same embryos. (G-G'') LvSnail can rescue the effects of AlxMASO in PMC ingression. The micromere co-injected with Lvsnail mRNA and AlxMASO (green) ingresses into the blastocoele, whereas the AlxMASO-injected micromere (red) fails to ingress. Brightfield (G), fluorescent (G'), and merged (G'') images are shown.