A CNS-specific POU transcription factor, Brn-2, is required for establishing mammalian neural cell lineages.

The pluripotent embryonal carcinoma cell line P19 can differentiate in vitro into neurons and astrocytes. By employing this neural cell differentiation system, we have studied the expression and function of a POU transcription factor implicated in mammalian neurogenesis. When P19 cells differentiated to the neural cells, one of the CNS-specific POU genes (Brn-2) was selectively induced. The induction of Brn-2 was specific to the neural cell lineages and took place at the early stage of differentiation. When the Brn-2 induction was blocked/delayed by antisense RNA, such cells were unable to differentiate to neurons and astrocytes. Instead they differentiated to nonneural cells, including smooth and skeletal muscle cells. Furthermore, with reduced levels of antisense RNA, differentiation to neural cells occurred. These results indicate that Brn-2 is essential for the neural cell differentiation of P19 cells and suggest that Brn-2 is one of the genes required for establishing neural cell lineages in mammals.