Required for the maintenance of pluripotency and self-renewal of embryonic stem cells. Transcriptional activator that binds the DNA consensus sequence 5'-ATGCAAAT-3'. Widely expressed during embryonic development (at protein level). In pre-primitive streak stage embryos, expressed in the epiblast and in a salt-and-pepper fashion in the forming hypoblast (stages XI and XIII) (at protein level). As the primitive streak starts to form, strongly expressed in the epiblast of the streak itself (stage XIV) and in the mesoderm emerging from it, whereas expression in the lower layer tends to decrease (stages 2 through 4+). Expression in the area opaca is lost by stage 3+. At later stages, continues to be expressed in the mesoderm, but not detected in the endoderm (stages 5 through 8). At stage 5, expressed in all cells of the germinal crescent. At stage 8 and subsequently, strongly expressed in the neural plate and neural tube with particularly strong expression in the anterior hindbrain/posterior midbrain. At stage 9 and subsequently, still expressed in neural tissue and in primordial germ cells (at protein level). At stage 33, still expressed in germ cells. At stages 42-43, expressed in male and female gonads, as well as in spleen and brain, but at much lower levels than in proliferating embryonic stem cells. Strongly down-regulated during embryonic stem cell differentiation induced either by retinoic acid treatment, or by cell adhesion prevention leading to embryoid body formation. Belongs to the POU transcription factor family.