Identification of regulators of V2 interneuron diversification and migration during spinal cord development

The locomotion is coordinated by neuronal circuits, named “Central Pattern Generators”, located in the ventral region of the spinal cord. These circuits are composed of motorneurons, and of dorsal or ventral interneurons (INs). Each IN population diversifies and migrates to a precise location into the spinal cord in order to properly integrate into the spinal neuronal circuits. However, the molecular mechanisms that control those processes remain poorly characterized. Recent data obtained in our laboratory have shown that the Onecut (OC) transcription factors are present in several subsets of ventral IN populations. This suggests that they could contribute to the regulation of their development. In this work, we provide evidence that the ventral IN populations diversify in multiple subpopulations regionally distributed along the antero-posterior axis of the spinal cord. We show that the OC factors are necessary for proper diversification and migration of the spinal V2 INs. Moreover, we highlight that the OC factors control the expression of Nkx6.2 and of spinal Pou2f2 isoforms. Thus, we uncover genetic cascades regulate V2 IN migration during embryonic development.%%%%(BIFA - Sciences biomedicales et pharmaceutiques)  – UCL, 2018