Activation and repression of gene expression by POU family transcription factors

The POU family transcription factors Oct-2 and Brn-3 utilize different mechanisms to produce a variety of effects on gene expression particularly in the nervous system. In the case of Oct-2, a single gene produces a primary RNA transcript. This transcript then undergoes alternative splicing to yield a variety of different mRNAs encoding Oct-2 isoforms which either activate or repress gene expression. In contrast, three distinct genes encode the closely related Brn-3 factors, Brn-3a, Brn-3b and Brn-3c. Although the proteins encoded by the Brn-Sa and Brn-3c genes activate their target genes Brn-3b represses these genes and can also interfere with activation by Brn-3a or c. These findings indicate that diverse mechanisms are used to generate activating or repressing forms of POU family transcription factors.