PATTERNS OF GENE-EXPRESSION IN THE NEURAL PLATE AND NEURAL-TUBE SUBDIVIDE THE EMBRYONIC FOREBRAIN INTO TRANSVERSE AND LONGITUDINAL DOMAINS

The analysis of gene expression patterns in the neural plate and neura l tube of the embryonic mouse forebrain shows that, at its earliest st ages, the neuroepithelium is subdivided into molecularly distinct doma ins. Here, and in previous publications, we provide evidence that the patterns of gene expression can be related to primary morphogenetic pr ocesses that organize the histological primordia of the embryonic cent ral nervous system into longitudinal and transverse domains. Longitudi nal domains are generated by dorsoventral patterning signals produced by the axial mesendoderm and nonneural ectoderm. Transverse domains (p roneuromeres and neuromeres) expressing distinct combinations of genes are present in the neural plate and neural tube.