Editing Oct-4 (section)

==In embryonic stem cells==
*In ''in vitro'' experiments of mouse embryonic stem cells, Oct-4 has often been used as a marker of stemness, as differentiated cells show reduced expression of this marker.
*Oct3/4 can both repress and activate the [[promoter (biology)|promoter]] of ''[[Rex1]]''. In cells that already express high level of Oct3/4, exogenously transfected Oct3/4 will lead to the repression of Rex1.<ref name=p758>{{cite journal | vauthors = Ben-Shushan E, Thompson JR, Gudas LJ, Bergman Y | title = Rex-1, a gene encoding a transcription factor expressed in the early embryo, is regulated via Oct-3/4 and Oct-6 binding to an octamer site and a novel protein, Rox-1, binding to an adjacent site | journal = Molecular and Cellular Biology | volume = 18 | issue = 4 | pages = 1866–78 | date = April 1998 | pmid = 9528758 | pmc = 121416 | doi = 10.1128/mcb.18.4.1866 }}</ref> However, in cells that are not actively expressing Oct3/4, exogenous transfection of Oct3/4 will lead to the activation of Rex1.<ref name=p758/> This implies a dual regulatory ability of Oct3/4 on Rex1. At low levels of the Oct3/4 protein, the Rex1 promoter is activated, while at high levels of the Oct3/4 protein, the Rex1 promoter is repressed.
*Oct4 contributes to the rapid cell cycle of ESCs by promoting progression through the [[G1 phase]], specifically through transcriptional inhibition of [[cyclin-dependent kinase]] [[cyclin-dependent kinase inhibitor|inhibitors]] such as [[p21]].<ref>{{cite journal | vauthors = Lee J, Go Y, Kang I, Han YM, Kim J | title = Oct-4 controls cell-cycle progression of embryonic stem cells | journal = The Biochemical Journal | volume = 426 | issue = 2 | pages = 171–81 | date = February 2010 | pmid = 19968627 | pmc = 2825734 | doi = 10.1042/BJ20091439 }}</ref>
*[[CRISPR-Cas9]] knockout of the gene in human embryonic stem cells demonstrated that Oct-4 is essential for the development after fertilisation.<ref>{{cite journal | vauthors = Fogarty NM, McCarthy A, Snijders KE, Powell BE, Kubikova N, Blakeley P, Lea R, Elder K, Wamaitha SE, Kim D, Maciulyte V, Kleinjung J, Kim JS, Wells D, Vallier L, Bertero A, Turner JM, Niakan KK | title = Genome editing reveals a role for OCT4 in human embryogenesis | journal = Nature | volume = 550 | issue = 7674 | pages = 67–73 | date = October 2017 | pmid = 28953884 | pmc = 5815497 | doi = 10.1038/nature24033 | bibcode = 2017Natur.550...67F }}</ref>
*Oct3/4 represses Suv39h1 expression through the activation of an antisense long non-coding RNA. Suv39h1 inhibition maintains low level of H3K9me3 in pluripotent cells limiting the formation of heterochromatin.<ref>{{cite journal | vauthors = Bernard LD, Dubois A, Heurtier V, Fischer V, Gonzalez I, Chervova A, Tachtsidi A, Gil N, Owens N, Bates LE, Vandormael-Pournin S, Silva JC, Ulitsky I, Cohen-Tannoudji M, Navarro P | title = OCT4 activates a Suv39h1-repressive antisense lncRNA to couple histone H3 Lysine 9 methylation to pluripotency | journal = Nucleic Acids Research | volume = 50 | issue = 13 | pages = 7367–7379 | date = July 2022 | pmid = 35762231 | pmc = 9303268 | doi = 10.1093/nar/gkac550 }}</ref>