system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, RESULTS. Meshes: Animals, Asymmetric Cell Division, Biomarkers, Cell Cycle, Cell Division, Cells, Cultured, Cerebellum, Culture Media, Conditioned, Cyclin-Dependent Kinase Inhibitor p27, Fluorescent Dyes, Genes, Reporter, HEK293 Cells, Hedgehog Proteins, Humans, Mice, Inbred ICR, Microtubule-Associated Proteins, Nerve Tissue Proteins, Neural Stem Cells, Neurogenesis, Neurons, Neuropeptides, Signal Transduction, Time-Lapse Imaging.
user
Are cerebellar granule cells predominantly generated by terminal symmetric divisions of granule cell precursors? Context: Neurons in the central nervous system (CNS) are generated by symmetric and asymmetric cell division of neural stem cells and their derivative progenitor cells. Cerebellar granule cells are the most abundant neurons in the CNS, and are generated by intensive cell division of granule cell precursors (GCPs) during postnatal development. Dysregulation of GCP cell cycle is causal for some subtypes of medulloblastoma. However, the details and mechanisms underlying neurogenesis from GCPs are not well understood. Using long-term live-cell imaging of proliferating GCPs transfected with a fluorescent newborn-granule cell marker, we found that GCPs underwent predominantly symmetric divisions, generating two GCPs or two neurons, while asymmetric divisions generating a GCP and a neuron were only occasionally observed, in both dissociated culture and within tissues of isolated cerebellar lobules. We found no significant difference in cell cycle length between proliferative and neurogenic divisions, or any consistent changes in cell cycle length during repeated proliferative division.
assistant
Unlike neural stem cells in the cerebral cortex and spinal cord, which generate many neurons by repeated asymmetric division, cerebellar GCPs produce neurons predominantly by terminal symmetric division. These results indicate diverse mechanisms of neurogenesis in the mammalian brain. Final Decision: yes