Pluripotency-State-Dependent Role of Dax1 in Embryonic Stem Cells Self-Renewal.

Jianjun He ,Gaoke Liu,Jiali Wang,Ping He,Jiaxiang Xiong,Jiangjun Wang,Wei Wu,Yuda Cheng,He Huang,Binyu Zhao,Fengsheng Wang,Junlei Zhang,Yanping Tian,Lianlian Liu,Yue Zhang,Chen Zhang,Jiaqi Wang,Meng Yu,Rui Jian,Yan Ruan,Yi Yang,Yixiao Xu

doi:10.1155/2021/5522723

Abstract

Dax1(also known as Nr0b1) is regarded as an important component of the transcription factor network in mouse embryonic stem cells (ESCs). However, the role and the molecular mechanism of Dax1 in the maintenance of different pluripotency states are poorly understood. Here, we constructed a stable Dax1 knockout (KO) cell line using the CRISPR/Cas9 system to analyze the precise function of Dax1. We reported that 2i/LIF-ESCs had significantly lower Dax1 expression than LIF/serum-ESCs. Dax1KO ES cell lines could be established in 2i/LIF and their pluripotency was confirmed. In contrast, Dax1-null ESCs could not be continuously passaged in LIF/serum due to severe differentiation and apoptosis. In LIF/serum, the activities of the Core module and Myc module were significantly reduced, while the PRC2 module was activated after Dax1KO. The expression of most proapoptotic genes and lineage-commitment genes were drastically increased, while the downregulated expression of antiapoptotic genes and many pluripotency genes was observed. Our research on the pluripotent state-dependent role of Dax1 provides clues to understand the molecular regulation mechanism at different stages of early embryonic development.

Highlights

Dax1 (Dosage-sensitive sex reversal-adrenal hypoplasia congenital on the X-chromosome gene-1) has been suggested to play important roles in reproductive development, sex determination, steroidogenesis, and tumorigenesis
Dax1 is expressed at a high level in undifferentiated embryonic stem cells (ESCs), but not in epiblast stem cells (EpiSCs) and differentiated ESCs [13]
Dax1 appears to be critical for the core pluripotency circuitry of conventional ESCs [1, 2, 18], but the effect of the loss of function of Dax1 on the pluripotency-associated transcription factor network was not well analyzed

Summary

Introduction

Dax (Dosage-sensitive sex reversal-adrenal hypoplasia congenital on the X-chromosome gene-1) has been suggested to play important roles in reproductive development, sex determination, steroidogenesis, and tumorigenesis. Dax is identified as a core member of pluripotency gene regulatory network [1, 2]. Dax can inhibit extraembryonic endoderm differentiation by binding to the promoter of Gata and inhibiting its transcription and can inhibit trophectoderm differentiation either independently of or cooperatively with Oct4 [3]. It is proposed that Dax and Nanog act in parallel to maintain an optimal pluripotent state [3]. Two independent reports confirmed that Dax is necessary for pluripotency inducing [3, 8]. All the investigations concerning the role of Dax on pluripotency maintenance

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Conclusion