Brn2

Brn-2, also known as Brain-2, is a transcription factor of the POU-domain family in vertebrates. In humans it is encoded by the POU3F2 gene. The Brn-2 protein contains a POU-specific domain and a homeodomain, which together enable binding to POU elements in DNA and the regulation of target gene transcription.

Brn-2 is expressed in the developing central nervous system, including the cerebral cortex, and persists in certain neuronal populations in the adult brain. It participates in neural differentiation and maturation, helping to establish gene expression programs that define neuronal identity during corticogenesis. In the developing cortex Brn-2 contributes to the specification of neuronal subtypes as progenitor cells exit the cell cycle and differentiate.

In biomedical research Brn-2 is used as a neural lineage-determining factor in cellular reprogramming. In combination with other transcription factors, most notably Ascl1 and Myt1l, Brn-2 can drive the conversion of fibroblasts into induced neurons, demonstrating that defined transcription factors can guide direct lineage conversion to a neuronal fate without passing through a pluripotent state.

Brn-2/POU3F2 is conserved across vertebrates and has been studied for its roles in neural development and function. Its activity intersects with broader neural gene regulatory networks and has been leveraged in experimental reprogramming approaches to probe neuronal identity and plasticity.