Identification of novel DNA binding sites recognized by the transcription factor mPOU (POU6F1).

Transcription factors of the POU family recognize DNA through their POU domain which represents a bipartite DNA binding motif consisting of a POU specific domain and a POU homeobox. It is thought that both subdomains make specific contacts with DNA and participate in DNA binding. Here we identify novel DNA binding sites for the POU protein mPOU (POU6F1). The sites contain two TAAT motifs either as palindromes or as direct repeats. DNA binding is mediated through the POU homeobox only. Transactivation experiments revealed that mPOU per se showed no transcriptional activation but could act as a repressor of Oct2A mediated activation.