Editing Oct-4 (section)

==Expression and function==

Oct-4 transcription factor is initially active as a [[maternal effect|maternal factor]] in the [[oocyte]] and remains active in embryos throughout the preimplantation period. Oct-4 expression is associated with an undifferentiated phenotype and tumors.<ref>{{cite journal | vauthors = Looijenga LH, Stoop H, de Leeuw HP, de Gouveia Brazao CA, Gillis AJ, van Roozendaal KE, van Zoelen EJ, Weber RF, Wolffenbuttel KP, van Dekken H, Honecker F, Bokemeyer C, Perlman EJ, Schneider DT, Kononen J, Sauter G, Oosterhuis JW | title = POU5F1 (OCT3/4) identifies cells with pluripotent potential in human germ cell tumors | journal = Cancer Research | volume = 63 | issue = 9 | pages = 2244–50 | date = May 2003 | pmid = 12727846 }}</ref>  Gene knockdown of Oct-4 promotes [[cellular differentiation|differentiation]], demonstrating a role for these factors in human embryonic stem cell self-renewal.<ref>{{cite journal | vauthors = Zaehres H, Lensch MW, Daheron L, Stewart SA, Itskovitz-Eldor J, Daley GQ | title = High-efficiency RNA interference in human embryonic stem cells | journal = Stem Cells | volume = 23 | issue = 3 | pages = 299–305 | date = March 2005 | pmid = 15749924 | doi = 10.1634/stemcells.2004-0252 | s2cid = 1395518 | doi-access = free }}</ref> Oct-4 can form a heterodimer with [[Sox2]], so that these two proteins bind DNA together.<ref name=Rodda2005>{{cite journal | vauthors = Rodda DJ, Chew JL, Lim LH, Loh YH, Wang B, Ng HH, Robson P | title = Transcriptional regulation of nanog by OCT4 and SOX2 | journal = The Journal of Biological Chemistry | volume = 280 | issue = 26 | pages = 24731–7 | date = July 2005 | pmid = 15860457 | doi = 10.1074/jbc.M502573200 | doi-access = free }}</ref>

Mouse embryos that are Oct-4 deficient or have low expression levels of Oct-4 fail to form the [[inner cell mass]], lose [[pluripotency]], and differentiate into [[trophectoderm]]. Therefore, the level of Oct-4 expression in mice is vital for regulating pluripotency and early cell differentiation since one of its main functions is to keep the embryo from differentiating.