Transcription factor that binds to the octamer motif (5'-ATTTGCAT-3'). Antagonizes the activity of nodal/activin signaling during gastrulation to suppress mesendoderm formation. Interacts with the transcription factors tcf7l1/tcf3 and vegt. Initially (stage 9) expressed in all regions of the embryo, becoming localized to the ventroposterior regions by early neurula stages. In adults, expressed at a low level in the brain. Expressed both maternally and zygotically. Expressed at low levels in oocytes, with expression increasing rapidly during gastrulation and peaking during late gastrulation before declining through neurulation. Belongs to the POU transcription factor family. Class-5 subfamily.