Loss of Resf1 reduces the efficiency of embryonic stem cell self-renewal and germline entry

Matúš Vojtek,Ian Chambers

doi:10.26508/lsa.202101190

Abstract

Retroelement silencing factor 1 (RESF1) interacts with the key regulators of mouse embryonic stem cells (ESCs) OCT4 and NANOG, and its absence results in sterility of mice. However, the function of RESF1 in ESCs and germline specification is poorly understood. In this study, we used Resf1 knockout cell lines to determine the requirements of RESF1 for ESC self-renewal and for in vitro specification of ESCs into primordial germ cell-like cells (PGCLCs). We found that deletion of Resf1 in ESCs cultured in serum and LIF reduces self-renewal potential, whereas episomal expression of RESF1 has a modest positive effect on ESC self-renewal. In addition, RESF1 is not required for the capacity of NANOG and its downstream target ESRRB to drive self-renewal in the absence of LIF. However, Resf1 deletion reduces the efficiency of PGCLC differentiation in vitro. These results identify Resf1 as a novel player in the regulation of pluripotent stem cells and germ cell specification.

Highlights

Pluripotency is a feature of early embryonic epiblast and derivative cell lines (Martello & Smith, 2014)
A previous study showed that Resf1−/− embryonic stem cells (ESCs) could be maintained in serum/leukemia inhibitory factor (LIF) culture (Fukuda et al, 2018), suggesting that ESC selfrenewal continues after Resf1 deletion
We have extended these observations by showing that Resf1−/− ESCs cultured at low LIF concentrations show reduced self-renewal compared

Summary

Introduction

Pluripotency is a feature of early embryonic epiblast and derivative cell lines (Martello & Smith, 2014). Whereas Oct and Sox are uniformly expressed in all pluripotent states, Nanog expression is reduced at the peri-implantation formative state (Chambers et al, 2003; Osorno et al, 2012). Both the germline and the naıve epiblast show dependencies on NANOG: constitutive Nanog deletion prevents specification of the naıve epiblast (Mitsui et al, 2003; Silva et al, 2009), whereas germline-specific Nanog deletion reduces the number of primordial germ cells (PGCs) in mid-gestation mouse embryos (Chambers et al, 2007; Zhang et al, 2018a). Similarities between the GRN of ESCs and PGCs are highlighted by the capacity of the NANOG target gene, Esrrb, to maintain LIF-independent self-renewal in Nanog−/− ESCs and to restore wild-type PGC numbers in mouse embryos where Nanog was deleted from the germline (Zhang et al, 2018a)

Methods

Results

Conclusion