Molecular control of cell type diversity in the developing spinal cord

1, During embryonic development, a diverse array of neurons and glia are ge nerated at specific positions along the dorsoventral and rostro-caudal axes of the spinal cord from a common pool of precursor cells. 2. This cell type diversity can be distinguished by the spatially and tempo rally coordinated expression of several transcription factors that are also linked to cell type specification at a very early stage of spinal cord dev elopment. 3, Recent studies have started to uncover that the generation of cell type diversity in the developing spinal cord. Moreover, distinct cell types in t he spinal cord appear to be determined by the spatially and temporally coor dinated expression of transcription factors. 4. The expression of these factors also appears to be controlled by gradien ts of factors expressed by ventral and dorsal midline cells, namely Sonic h edgehog and members of the transforming growth factor-beta family. 5, Changes in the competence of precursor cells and local cell interactions may also play important roles in cell type specification within the develo ping spinal cord.