Summary

In the adult mouse brain, neural stem cells (NSCs) in the ventricular-subventricular zone (V-SVZ) generate neurons and glia throughout life. microRNAs are important regulators of cell states, frequently acting in a stage- or context-dependent manner. Here, miRNA profiling of FACS-purified populations identified miR-17∼92 as highly upregulated in activated NSCs and transit amplifying cells (TACs) in comparison to quiescent NSCs. Conditional deletion of miR-17∼92 in NSCs reduced stem cell proliferation both in vitro and in vivo . In contrast, in TACs, miR-17∼92 deletion caused a selective shift from neurogenic DLX2 + TACs towards oligodendrogenic OLIG2 + TACs, resulting in increased oligodendrogenesis to the corpus callosum . miR-17∼92 deletion also decreased proliferation and maturation of intraventricular oligodendrocyte progenitor cells. Together, these findings reveal stage- and cell-type-specific functions of the miR-17∼92 cluster within adult V-SVZ neural stem cell lineages.