
Oct‐4 : Gatekeeper in the Beginnings of Mammalian Development
Author(s) -
Pesce Maurizio,
Schöler Hans R.
Publication year - 2001
Publication title -
stem cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.159
H-Index - 229
eISSN - 1549-4918
pISSN - 1066-5099
DOI - 10.1634/stemcells.19-4-271
Subject(s) - biology , totipotent , epiblast , embryonic stem cell , stem cell , microbiology and biotechnology , inner cell mass , somatic cell , blastocyst , homeobox protein nanog , cellular differentiation , embryoid body , endoderm , gastrulation , embryo , adult stem cell , germ layer , primitive streak , induced pluripotent stem cell , genetics , embryogenesis , gene
The Oct‐4 POU transcription factor is expressed in mouse totipotent embryonic stem and germ cells. Differentiation of totipotent cells to somatic lineages occurs at the blastocyst stage and during gastrulation, simultaneously with Oct‐4 downregulation. Stem cell lines derived from the inner cell mass and the epiblast of the mouse embryo express Oct‐4 only if undifferentiated. When embryonic stem cells are triggered to differentiate, Oct‐4 is downregulated thus providing a model for the early events linked to somatic differentiation in the developing embryo. In vivo mutagenesis has shown that loss of Oct‐4 at the blastocyst stage causes the cells of the inner cell mass to differentiate into trophectoderm cells. Recent experiments indicate that an Oct‐4 expression level of roughly 50%‐150% of the endogenous amount in embryonic stem cells is permissive for self‐renewal and maintenance of totipotency. However, upregulation above these levels causes stem cells to express genes involved in the lineage differentiation of primitive endoderm. These novel advances along with latest findings on Oct‐4‐associated factors, target genes, and dimerization ability, provide new insights into the understanding of the early steps regulating mammalian embryogenesis.