Vertebrate Embryo: Neural Patterning

Neural patterning is a process by which neural cells acquire region-specific identity and features during embryogenesis. It takes place during gas- trulation and progressive neural induction and continues after the neural induction for further refined patterns and specification. Tissue inter- actions and signalling play key roles in neural patterning. The main signals include retinoids, fibroblast growth factors, Wnts, BMP (bone mor- phogenetic protein) and Shh (Sonic hedgehog). Following the signalling-based patterning, expres- sion of transcription factors, such as Hox genes for anterior–posterior (rostral–caudal) axis and other homeobox or paired-box containing genes, consol- idate the induced pattern. Combinatorial expres- sion of such genes forms functional compartments or groups of cells in the right position in the devel- oping CNS, providing the basis for further neuronal networking. The knowledge of neural patterning by signalling mechanisms is now used in stem cell technologies, enabling us to obtain specific neu- ronal subtypes in vitro.