The molecular mechanisms of neurogenic fate determination are of particular importance in light of the need to regenerate neurons. Here we define the mechanisms of installing neurogenic fate by the transcription factor Pax6 acting together with the Brg1-containing BAF chromatin remodeling complex. We show that Pax6 physically interacts with Brg1-containing BAF complex and genetic deletion of either Pax6 or Brg1, in the neural stem cells in the adult mouse subependymal zone results in a strikingly similar fate conversion from neuronal progenitors to glia. The Pax6-BAF complex drives neurogenesis by directly activating transcription factors Sox11, Nfib and Pou3f4, which form a cross-regulatory network that maintains neurogenic fate downstream of the Pax6-BAF complex in neuroblasts. Our work identifies a novel concept of stratification in neural fate commitment with a strikingly specific role of the Pax6-BAF complex in initiating a cross-regulatory network essential for maintenance of the neurogenic lineage in the adult brain.

Neural stem cells (NSCs) have the remarkable capacity to self-renew and the lifelong ability to generate neurons in the adult mammalian brain. However, the molecular and cellular mechanisms contributing to these behaviors are still not understood. Now that prospective isolation of the NSCs has become feasible, these mechanisms can be studied. Here we describe a protocol for the efficient isolation of adult NSCs, by the application of a dual-labeling strategy on the basis of their glial identity and ciliated nature. The cells are isolated from the lateral ventricular subependymal zone (SEZ) of adult hGFAP-eGFP (human glial fibrillary acidic protein-enhanced green fluorescent protein) transgenic mice by fluorescence-activated cell sorting. Staining against prominin1 (CD133) allows the isolation of the NSCs (hGFAP-eGFP(+)/prominin1(+)), which can be further subdivided by labeling with the fluorescent epidermal growth factor. This protocol, which can be completed in 7 h, allows the assessment of quantitative changes in SEZ NSCs and the examination of their molecular and functional characteristics.