Type III neuregulin-1 promotes oligodendrocyte myelination.

The axonal signals that regulate oligodendrocyte myelination during development of the central nervous system (CNS) have not been established. In this study, we have examined the regulation of oligodendrocyte myelination by the type III isoform of neuregulin-1 (NRG1), a neuronal signal essential for Schwann cell differentiation and myelination. In contrast to Schwann cells, primary oligodendrocytes differentiate normally when cocultured with dorsal root ganglia (DRG) neurons deficient in type III NRG1.

Telomerase activity in the subventricular zone of adult mice.

The subventricular zone (SVZ) is the most active site for the production of new neurons in the adult mouse brain. Neural stem cells in the adult SVZ give rise to neuroblasts that travel via the rostral migratory stream (RMS) to the olfactory bulb, where they differentiate into interneurons. The enzyme telomerase has been identified in other population of stem cells and is necessary for the synthesis of telomeric DNA to prevent chromosomal shortening, end-to-end fusions, and apoptosis during successive rounds of cell division.