RT Journal Article
SR Electronic
T1 Endogenous fluctuations of OCT4 and SOX2 bias pluripotent cell fate decisions
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 299073
DO 10.1101/299073
A1 Daniel Strebinger
A1 Elias T. Friman
A1 Cédric Deluz
A1 Subashika Govindan
A1 Andrea B. Alber
A1 David M. Suter
YR 2018
UL http://biorxiv.org/content/early/2018/04/11/299073.abstract
AB The SOX2 and OCT4 transcription factors are key regulators of embryonic stem (ES) cell self-renewal and differentiation, but how temporal fluctuations in their endogenous expression levels bias lineage commitment is unknown. We generated knock-in reporter fusion ES cell lines allowing to measure endogenous SOX2 and OCT4 protein fluctuations and determine their impact on mesendodermal and neuroectodermal commitment. Surprisingly, small differences in endogenous SOX2 and OCT4 levels impacted cell fate commitment in G1 but not in S phase. While SOX2 fluctuations had a minor impact on neuroectodermal commitment, elevated OCT4 levels at the onset of differentiation strongly biased ES cell towards both neuroectoderm and mesendoderm at the expense of self-renewal and primitive endoderm. Genome-wide measurements of chromatin accessibility revealed OCT4 level-dependent priming of differentiation-associated enhancers. Finally, CRISPR-Cas9 knock-out of an OCT4 binding site in a key Eomes enhancer abolished the ability of OCT4 to promote mesendodermal differentiation. Our study demonstrates how small endogenous fluctuations of transcription factors prime cell fate decisions in a cell cycle-specific manner by modulating chromatin accessibility at regulatory regions, and thus represent a major source of heterogeneity in the ability of individual ES cells to respond to differentiation cues.