In a study published in Cell reports, the group of Laurent Nguyen, WELBIO investigator at GIGA-Neurosciences, Université de Liège, Belgium, has discovered a new molecular mechanism that controls neuronal migration in the developing cerebral cortex. These results uncovered two microRNAs that regulate the expression of a gene implied in projection neuron polarisation and migration.
MicroRNAs are small non-coding RNAs that prevent the translation of about 60% of our genes. These non-coding RNAs are dynamically expressed in most tissues during embryogenesis where their finely tune genetic programs. Some neurodevelopmental disorders are associated with a deregulation of microRNA expression.
The study conducted by the group of Dr Nguyen demonstrated that miR-22 and miR-124, two microRNAs expressed in the developing cortex, target CoREST RNA messengers that encode a subunit of a transcriptional repressor complex that inhibits the expression of genes involved in neuronal specification and maturation. Thus, these microRNAs indirectly regulate the expression of Doublecortin, a target of CoREST, a protein that controls the morphology of cortical neurons during migration.
Overall, these results increase our understanding of the mechanisms that drive neuronal migration in the cerebral cortex, a process whose disruption is often associated with neurological disorders characterized by intellectual disabilities or epilepsy in humans.
Volvert et al. MicroRNA Targeting of CoREST Controls Polarization of Migrating Cortical Neurons, Cell Reports (2014) Vol. 7, Issue 4, pp1168–1183.