Identification of proliferative progenitors associated with prominent postnatal growth of the pons

The pons controls crucial sensorimotor and autonomic functions. In humans, it grows sixfold postnatally and is a site of paediatric gliomas; however, the mechanisms of pontine growth remain poorly understood. We show that the murine pons quadruples in volume postnatally; growth is fastest during postnatal days 0–4 (P0–P4), preceding most myelination. We identify three postnatal proliferative compartments: ventricular, midline and parenchymal. We find no evidence of postnatal neurogenesis in the pons, but each progenitor compartment produces new astroglia and oligodendroglia; the latter expand 10- to 18-fold postnatally, and are derived mostly from the parenchyma. Nearly all parenchymal progenitors at P4 are Sox2+Olig2+, but by P8 a Sox2- subpopulation emerges, suggesting a lineage progression from Sox2+ ‘early’ to Sox2- ‘late’ oligodendrocyte progenitor. Fate mapping reveals that >90% of adult oligodendrocytes derive from P2–P3 Sox2+ progenitors. These results demonstrate the importance of postnatal Sox2+Olig2+ progenitors in pontine growth and oligodendrogenesis.