Figure 4.

Ectopic expression of AP2α converts neural plate into NC. Whole-mount in situ hybridization of probes for Slug, Sox9 (NC), and Sox2 (neural plate) to embryos injected at the 16-cell stage with 100 pg of RNA encoding AP2α, along with β-galactosidase lineage tracer RNA (5-bromo-4-chloro-3-indolyl-β-d-galactoside, turquoise staining). Discrete domains of intense ectopic expression of both NC marker genes was observed (arrows) within the neural plate. Endogenous Slug and Sox9 expression is indicated by the arrowheads. Concomitant repression of neural plate identity also occurred, as indicated by the reduction in Sox2 expression (arrow). (Magnification: ×22.)