Auxin-degron system identifies immediate mechanisms of Oct4

Abstract

The pluripotency factor Oct4 is essential for the maintenance of naïve pluripotent stem cells in vitro and in vivo. However, the specific role of Oct4 in this process remains unknown. Here, we developed a rapid protein-level Oct4 depletion system that demonstrates that the immediate downstream response to loss of Oct4 is reduced expression of key pluripotency factors. Our data show a requirement for Oct4 for the efficient transcription of several key pluripotency factors, and suggest that expression of trophectoderm markers is a subsequent event. Additionally, we find that Nanog is competent to bind to the genome in the absence of Oct4, and this binding is in fact enhanced. Globally, however, active enhancer associated histone mark H3K27ac is depleted. Our work establishes that while Oct4 is required for the maintenance of the naïve transcription factor network, at a normal ESC level it antagonises this network through inhibition of Nanog binding.

OCT4 induces embryonic pluripotency via STAT3 signaling and metabolic mechanisms

“…This suggests that OCT4 indirectly provides sufficient acetyl-CoA to support an open chromatin state ( 71 ). These observations are consistent with recent analysis ( 72 ) showing that OCT4 is critical to maintain a permissive chromatin environment.…”

“…4 ) suggest that the response to the stress of loss of Oct4 is largely metabolic. We used a recently developed auxin degron system that can induce relatively rapid depletion of OCT4 protein in ESCs ( 72 ) to substantiate the role of OCT4 in metabolic processes ( Fig. 4 H and SI Appendix , Fig.…”

“…Indole-3-acetic acid (IAA, Sigma) inducible Oct4 deletable pluripotent stem cells have recently been described ( 72 ). For TFEB staining, expanded colonies were passaged in standard N2B27 + 2iL.…”