BMB Rep. 2016; 49(10): 527-528  
Oct4 resetting by Aurkb-PP1 cell cycle axis determines the identity of mouse embryonic stem cells
Jihoon Shin1 & Hong-Duk Youn1,2,*
1National Creative Research Center for Epigenome Reprogramming Network, Department of Biomedical Sciences, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, 2Department of Molecular Medicine & Biopharmaceutical Sciences, Graduate School of Convergence Science, Seoul National University, Seoul 03080, Korea
Correspondence to: E-mail:
Received: September 22, 2016; Published online: October 31, 2016.
© Korean Society for Biochemistry and Molecular Biology. All rights reserved.

In embryonic stem cells (ESCs), cell cycle regulation is deeply connected to pluripotency. Especially, core transcription factors (CTFs) which are essential to maintaining the pluripotency transcription programs should be reset during M/G1 transition. However, it remains unknown about how CTFs are governed during cell cycle progression. Here, we describe that the regulation of Oct4 by Aurora kinase b (Aurkb)/protein phosphatase 1 (PP1) axis during the cell cycle is important for resetting Oct4 to pluripotency and cell cycle related target genes in determining the identity of ESCs. Aurkb starts to phosphorylate Oct4(S229) at the onset of G2/M phase, inducing the dissociation of Oct4 from chromatin, whereas PP1 binds Oct4 and dephosphorylates Oct4(S229) during M/G1 transition, which resets Oct4-driven transcription for pluripotency and the cell cycle. Furthermore, Aurkb phosphormimetic and PP1 binding-deficient mutations in Oct4 disrupt the pluripotent cell cycle, lead to the loss of pluripotency in ESCs, and decrease the efficiency of somatic cell reprogramming. Based on our findings, we suggest that the cell cycle is directly linked to pluripotency programs in ESCs.
Keywords: Aurkb, Cell cycle, Embryonic stem cells, Oct4 resetting, PP1

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