The roles of FGF and MAP kinase signaling in the segregation of the epiblast and hypoblast cell lineages in bovine and human embryos
Kuijk, Ewart W; van Tol, Leni T A; Van de Velde, Hilde; Wubbolts, Richard; Welling, Maaike; Geijsen, Niels; Roelen, Bernard A J
(2012) Development (Cambridge, England), volume 139, issue 5, pp. 871 - 882
(Article)
Abstract
At the blastocyst stage of mammalian pre-implantation development, three distinct cell lineages have formed: trophectoderm, hypoblast (primitive endoderm) and epiblast. The inability to derive embryonic stem (ES) cell lines in a variety of species suggests divergence between species in the cell signaling pathways involved in early lineage specification. In mouse,
... read more
segregation of the primitive endoderm lineage from the pluripotent epiblast lineage depends on FGF/MAP kinase signaling, but it is unknown whether this is conserved between species. Here we examined segregation of the hypoblast and epiblast lineages in bovine and human embryos through modulation of FGF/MAP kinase signaling pathways in cultured embryos. Bovine embryos stimulated with FGF4 and heparin form inner cell masses (ICMs) composed entirely of hypoblast cells and no epiblast cells. Inhibition of MEK in bovine embryos results in ICMs with increased epiblast precursors and decreased hypoblast precursors. The hypoblast precursor population was not fully ablated upon MEK inhibition, indicating that other factors are involved in hypoblast differentiation. Surprisingly, inhibition of FGF signaling upstream of MEK had no effects on epiblast and hypoblast precursor numbers in bovine development, suggesting that GATA6 expression is not dependent on FGF signaling. By contrast, in human embryos, inhibition of MEK did not significantly alter epiblast or hypoblast precursor numbers despite the ability of the MEK inhibitor to potently inhibit ERK phosphorylation in human ES cells. These findings demonstrate intrinsic differences in early mammalian development in the role of the FGF/MAP kinase signaling pathways in governing hypoblast versus epiblast lineage choices.
show less
Download/Full Text
The full text of this publication is not available.
Keywords: Animals, Cattle, Cell Lineage, Embryo, Mammalian, Fibroblast Growth Factor 4, GATA4 Transcription Factor, GATA6 Transcription Factor, Germ Layers, Glycogen Synthase Kinase 3, Heparin, Homeodomain Proteins, Humans, MAP Kinase Signaling System, Mice, Mitogen-Activated Protein Kinases, Protein-Serine-Threonine Kinases, Proteoglycans, Receptors, Fibroblast Growth Factor, Receptors, Transforming Growth Factor beta
ISSN: 0950-1991
Publisher: Company of Biologists Ltd
(Peer reviewed)
See more statistics about this item