THE INHIBITORY DOMAIN IN THE OCT-2 TRANSCRIPTION FACTOR REPRESSES GENE ACTIVITY IN A CELL-TYPE-SPECIFIC AND PROMOTER-INDEPENDENT MANNER

The Oct-2 transcription factor contains an N-terminal inhibitory domain which can act to inhibit promoter activity when linked to either its corresponding DNA-binding POU domain or the heterologous DNA binding domain of the yeast transcription factor GAL4. This inhibitory effect is independent of the number of DNA binding sites or their context in the target promoter. In contrast the effect is cell type-specific and can be relieved by over-expression of the isolated inhibitory domain in the absence of a DNA binding domain. These results suggest that the inhibitory domain acts by decreasing the activity of the basal transcriptional complex but that it operates indirectly by recruiting a second cell type-specific factor to the promoter which then interacts with the basal complex decreasing its activity.