Cell cycle regulation during neurogenesis in the embryonic and adult brain.

Throughout the development of the central nervous system, neural crest cells and the primary neural stem cells originate several non-neuronal and neuronal cell types. Undifferentiated stem cells exist in the adult brain, mainly in the dentate gyrus of the hippocampus and in the subventricular zone of the lateral ventricles, and can produce new neurons, participating in brain plasticity and tissue regeneration. Neurogenesis in the embryonic and adult brain occurs under the control of intrinsic and extrinsic factors. However, the mechanisms, by which cell cycle components control neural stem cell proliferation and consequently neurogenesis, still lack further investigation. We discuss here recent knowledge obtained on cell cycle components as key regulators of neural stem and progenitor cell proliferation and differentiation in the embryonic and adult brain.