Abstract
Previous genetic fate-mapping studies have indicated that embryonic glial fibrillary acidic protein-positive (GFAP(+)) cells are multifunctional progenitor/neural stem cells that can produce astrocytes as well as neurons and oligodendrocytes throughout the adult mouse central nervous system (CNS). However, emerging evidence from recent studies indicates that GFAP(+) cells adopt different cell fates and generate different cell types in different regions. Moreover, the fate of GFAP(+) cells in the young adult mouse CNS is not well understood. In the present study, hGFAP-Cre/R26R transgenic mice were used to investigate the lineage of embryonic GFAP(+) cells in the young adult mouse CNS. At postnatal day 21, we found that GFAP(+) cells mainly generated NeuN(+) neurons in the cerebral cortex (both ventral and dorsal), hippocampus, and cerebellum. Strangely, these cells were negative for the Purkinje cell marker calbindin in the cerebellum and the neuronal marker NeuN in the thalamus. Thus, contrary to previous studies, our genetic fate-mapping revealed that the cell fate of embryonic GFAP(+) cells at the young adult stage is significantly different from that at the adult stage.