The POU domain family of transcription factors (TF class 3.1.10.5) regulates developmental processes ranging from specification of the early embryo to terminal differentiation. About half of these factors display substantial affinity for an 8 bp DNA site termed the octamer motif, and are hence known as Oct proteins[1]. Oct4 (Pou5f1) is a well-known Oct factor, with varied and essential roles in development and a key regulator for ESC pluripotency. Reduced expression of Oct4 results in differentiation of ESCs into trophectodermal cells, and ovexpression of Oct4 leads to differentiation of ESCs along the mesodermal and primitive endodermal lineages[2].