Fig. 2. Krm2 overexpression induces NC-derived structures and NC markers in Xenopus. (A-E) Phenotypic analysis of krm2 overexpression. Anterior to the left. (A-C) Embryos at the 16-cell stage were injected in a single animal (A,B) or ventral equatorial (C) blastomere with 400 pg krm2 mRNA and photographed at tadpole stages. Arrowheads indicate ectopic pigment-containing structures. (D) Uninjected control embryo at tadpole stage. (E) Embryos at the four-cell stage were injected equatorially in both dorsal blastomeres with 400 pg krm2 mRNA each. (F-M) Neurula stage embryos, shown in anterior view. Embryos were injected with 400 pg PPL (F-I) or krm2 (J-M) mRNA into one ventral equatorial blastomere at the 16-cell stage (F,H,J,L) or one dorsal animal blastomere at the 8-16-cell stage (G,I,K,M). In situ hybridizations were performed using slug and sox10 probes as indicated. ß-gal lineage tracer is stained in red. Circles indicate lineage-tracer-positive cells. Black and white arrowheads indicate altered and control marker gene expression, respectively. (N) Scheme and statistical overview of experiment shown in F-M. Red area indicates region of krm2-injected cells. (O,P) Embryos were injected as in C and sox10 expression was analyzed at tailbud stage by whole-mount in situ hybridization. Arrowheads indicate ectopic sox10 expression. Co-injected lacZ was used as lineage tracer (red).