Fig. 1
From: An emerging role for prdm family genes in dorsoventral patterning of the vertebrate nervous system
Schematic diagram of a neural tube cross section. Dorsoventral domains are established by opposing concentration gradients of Shh and BMP (center), which regulate progenitor gene expression (left). The progenitor genes cross-repress each other to establish domain boundaries. Each domain will give rise to a specific cell type that expresses various post-mitotic differentiation genes (right)