Developmentally regulated expression of Sox9 and microRNAs 124,128 and 23 in neuroepithelial stem cells in the developing spinal cord

Central nervous system development is a complex process involving many interacting factors. MicroRNAs have recently been identified as playing key intrinsic roles in development however few of their specific targets have been identified in vivo. The transcription factor Sox9 has recently been identified as a target of miR-124 in the adult mouse sub-ventricular zone. Here we investigate the expression of the microRNAs miR-124, miR-128 and miR-23 and that of transcription factor Sox9, in neuroepithelial stem cells in the developing spinal cord. Furthermore we investigate if neurogenesis in embryonic neuroepithelial cells in the spinal cord might also be regulated by the interaction of Sox9 and miR-124. We provide evidence of the spatial and temporal regulation of miR-124, miR-128, miR-23 and Sox9, and taken together with recent findings we provide evidence that Sox9 may also be target of miR-124 in developing spinal cord neuroepithelial cells.

Research highlights▶ miR-124 and miR-23 are both expressed in spinal cord tissue prior to the appearance of astrocytes and neurons, in which they are thought to play a role. ▶ In situ hybridization revealed that miR-124 and Sox9 have a complementary expression pattern in the developing spinal cord. ▶ We provide evidence that transcription factor Sox9 is a target of miR-124 in the developing spinal cord neuroepithelium cells.