A membrane-associated β-catenin/Oct4 complex correlates with ground-state pluripotency in mouse embryonic stem cells

Abstract

The maintenance of pluripotency in mouse embryonic stem cells (mESCs) relies on the activity of a transcriptional network that is fuelled by the activity of three transcription factors (Nanog, Oct4 and Sox2) and balanced by the repressive activity of Tcf3. Extracellular signals modulate the activity of the network and regulate the differentiation capacity of the cells. Wnt/β-catenin signaling has emerged as a significant potentiator of pluripotency: increases in the levels of β-catenin regulate the activity of Oct4 and Nanog, and enhance pluripotency. A recent report shows that β-catenin achieves some of these effects by modulating the activity of Tcf3, and that this effect does not require its transcriptional activation domain. Here, we show that during self-renewal there is negligible transcriptional activity of β-catenin and that this is due to its tight association with membranes, where we find it in a complex with Oct4 and E-cadherin. Differentiation triggers a burst of Wnt/β-catenin transcriptional activity that coincides with the disassembly of the complex. Our results establish that β-catenin, but not its transcriptional activity, is central to pluripotency acting through a β-catenin/Oct4 complex.

Porcn-dependent Wnt signaling is not required prior to mouse gastrulation

“…Consistent with other recent studies (del Valle et al, 2013;Faunes et al, 2013;Rudloff and Kemler, 2012), however, our data do not preclude a non-transcriptional role for β-catenin in the maintenance of pluripotency in vitro.…”

“…Zygotic deletion of Porcn has been reported but not investigated in detail . Porcn functions in the preimplantation embryo are of particular interest, as canonical Wnt signaling and β-catenin have been implicated in the maintenance of pluripotent mouse embryonic stem cells (ESCs) (ten Berge et al, 2011;del Valle et al, 2013;Faunes et al, 2013;Habib et al, 2013), which are derived from the inner cell mass (ICM) of the mouse blastocyst.…”

Tankyrase inhibition promotes a stable human naïve pluripotent state with improved functionality

“…Distinct mechanisms of reinforcement of pluripotency by GSK3β inhibition include TCF repression (Wray et al, 2011) and direct targeting of NANOG, OCT4, KLF4, ESRRB and CBP (CREBBP) (Takao et al, 2007;Tam et al, 2008;Kelly et al, 2011;Evans et al, 2010;Martello et al, 2012). WNT activation was previously shown to be not only rate limiting for naïve reversion of mEpiSCs, but also facilitated mESC derivation from 'nonpermissive' mouse strains (Faunes et al, 2013). Additionally, both nuclear (transcriptional) and cytoplasmic (non-transcriptional) activities of β-catenin have been linked to stabilizing mouse naïve pluripotency via interactions with E-cadherin and cytoplasmic OCT4 and NANOG (Marucci et al, 2014).…”

Generation of Aggregates of Mouse Embryonic Stem Cells that Show Symmetry Breaking, Polarization and Emergent Collective Behaviour <em>In Vitro</em>

“…Please click here to view a larger version of this figure. 19,22,27,30,[36][37][38][39][40] have been characterized for the formation of aggregates and, although subtle differences between cell lines are expected and have been observed, all the above lines show similar dynamics in terms of elongation and morphology. In terms of gene expression, the expression pattern is specific to the gene expressed, but within each cell line, the expression pattern is generally consistent over a number of passages.…”