Noncanonical Oct-sequences are targets for mouse Oct-2B transcription factor.

We have suggested a random modification method for determining preferable binding sites of a DNA-binding protein and applied this method to the Oct-2B transcription factor. Our results indicate that the Oct-2B protein interacts with canonical oct sequence ATGC/TAAAT and degenerated sequences which contain TAAT motif in the binding site. We have determined nucleotides in the binding sites, involved in the DNA-protein interaction, and the equilibrium dissociation constants Kd for these sequences. These data show that a much greater number of potential targets for Oct proteins exist on DNA and changed our view on the gene expression regulation by this protein factor.