Fig. 8. Lithium treatment strongly potentiates the mesoderm-inducing activity of NLK. Embryos were injected at the egg stage and treated with LiCl at the two-cell stage and either observed for the phenotype (A-H) or fixed for in situ hybridization (I-X) performed with the probes indicated on the left. (M-P) Mesenchyme blastula (I-L), early gastrula (A-D,Q-T,U-X), late gastrula (E-H), pluteus. vv, vegetal pole view.