The dynamical organization of the core pluripotency transcription factors responds to differentiation cues in early S-phase

Camila Oses; Marcos Gabriel Francia; Paula Verneri; Camila Vazquez Echegaray; Alejandra Sonia Guberman; Valeria Levi

doi:10.3389/fcell.2023.1125015

The dynamical organization of the core pluripotency transcription factors responds to differentiation cues in early S-phase

Front Cell Dev Biol. 2023 May 4:11:1125015. doi: 10.3389/fcell.2023.1125015. eCollection 2023.

Authors

Camila Oses¹, Marcos Gabriel Francia¹, Paula Verneri¹, Camila Vazquez Echegaray¹, Alejandra Sonia Guberman^{1

2}, Valeria Levi^{1

3}

Affiliations

¹ Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina.
² Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
³ Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.

Abstract

DNA replication in stem cells is a major challenge for pluripotency preservation and cell fate decisions. This process involves massive changes in the chromatin architecture and the reorganization of many transcription-related molecules in different spatial and temporal scales. Pluripotency is controlled by the master transcription factors (TFs) OCT4, SOX2 and NANOG that partition into condensates in the nucleus of embryonic stem cells. These condensates are proposed to play relevant roles in the regulation of gene expression and the maintenance of pluripotency. Here, we asked whether the dynamical distribution of the pluripotency TFs changes during the cell cycle, particularly during DNA replication. Since the S phase is considered to be a window of opportunity for cell fate decisions, we explored if differentiation cues in G1 phase trigger changes in the distribution of these TFs during the subsequent S phase. Our results show a spatial redistribution of TFs condensates during DNA replication which was not directly related to chromatin compaction. Additionally, fluorescence fluctuation spectroscopy revealed TF-specific, subtle changes in the landscape of TF-chromatin interactions, consistent with their particularities as key players of the pluripotency network. Moreover, we found that differentiation stimuli in the preceding G1 phase triggered a relatively fast and massive reorganization of pluripotency TFs in early-S phase. Particularly, OCT4 and SOX2 condensates dissolved whereas the lifetimes of TF-chromatin interactions increased suggesting that the reorganization of condensates is accompanied with a change in the landscape of TF-chromatin interactions. Notably, NANOG showed impaired interactions with chromatin in stimulated early-S cells in line with its role as naïve pluripotency TF. Together, these findings provide new insights into the regulation of the core pluripotency TFs during DNA replication of embryonic stem cells and highlight their different roles at early differentiation stages.

Keywords: DNA replication; cell cycle; condensates; differentiation; embryonic stem cells; pluripotency transcription factors.

Grants and funding

This work was supported by Agencia Nacional de Promoción Científica y Tecnológica (PICT 2016-0828 to VL and AG, PICT 2018-01921 to VL, PICT 2018-01516 to AG), Universidad de Buenos Aires (UBACyT 20020190100101BA to VL and 20020190100154BA to AG).