Spatio-temporal dynamics of Roof plate to Radial glial transformation during avian neural development

The development of the dorsal spinal cord is a highly dynamic process. It begins from a neural tube harboring neural crest progenitors that generate the peripheral nervous system. Next, this domain is replaced by the roof plate (RP), a patterning center for dorsal interneurons. Through a process of dorsal collapse, the RP gives rise to radial glial (RG) cells which eventually generate dorsal ependyma, a stem cell niche of the central nervous system.

To investigate the spatio-temporal molecular repertoire and morphological changes that characterize the above transitions, a series of in-situ hybridizations were performed in quail embryos between embryonic days 4 to 10. Expression of BMP inhibitors present in RP, such as Bambi, Raldh2, Hes4, and Grem1, persist in the stretched RG. Likewise, components of the Wnt pathway such as Axin2, Wnt1 and its regulator Rspo1 are present at both stages. In contrast, Fabp7, absent in RG, discriminates between RP and RG stages. By implementing the above genes, we are currently examining the functions of various morphogen signals in selected aspects of RP-to-RG transition.