The expression of neuroepithelial cell fate determinants in rat spinal cord development.

Lineage specification is tightly regulated by a unique combination of extrinsic and intrinsic cues, but exactly how these cues coordinate the timing and position of cell differentiation during spinal cord development needs further investigation. Notch signaling has major roles in lineage specification. Recent evidence also indicates that the combination of transcription factors of the basic helix-loop-helix (Hes3, Hes5) and homeodomain (Pax6) families establish molecular codes that determine both the timing and position of neurons and glia. The precise expression patterns of these genes in vivo in the developing spinal cord from E13 to E18 are not fully known. In this study, the spatial and temporal expression patterns of these genes have been investigated. RT-PCR studies reveal the differential expression of these genes. The dynamic changes detected in the expression of these molecules have an important role in spinal cord cell lineage specification. Moreover, this study clarifies their in vivo expression during spinal cord development, and the expression patterns observed shed light on the generation of the rostro-caudal gradient of development. By understanding how neural stem cells are regulated in spinal cord development in vivo, we may gain insight of relevance to cell replacement strategies to treat spinal cord injuries.