Germline development in amniotes: A paradigm shift in primordial germ cell specification

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 germ line specification is poorly understood. In this study, we used Resf1 knockout cell lines to determine the requirements of RESF1 for ESCs 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 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.

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Generation of Primordial Germ Cell-like Cells from iPSCs Derived from Turner Syndrome Patients

Cells ◽

10.3390/cells10113099 ◽

2021 ◽

Vol 10 (11) ◽

pp. 3099

Author(s):

Aline Fernanda de Souza ◽

Fabiana Fernandes Bressan ◽

Naira Caroline Godoy Pieri ◽

Ramon Cesar Botigelli ◽

Tamas Revay ◽

...

Keyword(s):

Germ Cell ◽

Turner Syndrome ◽

Genetic Disorder ◽

Primordial Germ Cells ◽

Primordial Germ Cell ◽

Cell Formation ◽

In Vitro Models ◽

Germline Development ◽

Germ Cell Specification

Turner syndrome (TS) is a genetic disorder in females with X Chromosome monosomy associated with highly variable clinical features, including premature primary gonadal failure leading to ovarian dysfunction and infertility. The mechanism of development of primordial germ cells (PGCs) and their connection with ovarian failure in TS is poorly understood. An in vitro model of PGCs from TS would be beneficial for investigating genetic and epigenetic factors that influence germ cell specification. Here we investigated the potential of reprogramming peripheral mononuclear blood cells from TS women (PBMCs-TS) into iPSCs following in vitro differentiation in hPGCLCs. All hiPSCs-TS lines demonstrated pluripotency state and were capable of differentiation into three embryonic layers (ectoderm, endoderm, and mesoderm). The PGCLCs-TS recapitulated the initial germline development period regarding transcripts and protein marks, including the epigenetic profile. Overall, our results highlighted the feasibility of producing in vitro models to help the understanding of the mechanisms associated with germ cell formation in TS.

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Nodal induces sequential restriction of germ cell factors during primordial germ cell specification

Development ◽

10.1242/dev.155663 ◽

2018 ◽

Vol 145 (2) ◽

pp. dev155663 ◽

Cited By ~ 5

Author(s):

Tara M. Fresques ◽

Gary M. Wessel

Keyword(s):

Germ Cell ◽

Primordial Germ Cell ◽

Cell Specification ◽

Germ Cell Specification ◽

Sequential Restriction

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Testing the role of SOX15 in human primordial germ cell fate

Wellcome Open Research ◽

10.12688/wellcomeopenres.15381.2 ◽

2019 ◽

Vol 4 ◽

pp. 122

Author(s):

Merrick Pierson Smela ◽

Anastasiya Sybirna ◽

Frederick C.K. Wong ◽

M. Azim Surani

Keyword(s):

Flow Cytometry ◽

Germ Cell ◽

Primordial Germ Cell ◽

Mechanistic Study ◽

Germline Development ◽

Cell Identity ◽

Protein Levels ◽

Germ Cell Specification ◽

The Impact ◽

Early Human

Background: Potentially novel regulators of early human germline development have been identified recently, including SOX15 and SOX17, both of which show specific expression in human primordial germ cells. SOX17 is now known to be a critical specifier of human germ cell identity. There have been suggestions, as yet without evidence, that SOX15 might also play a prominent role. The early human germline is inaccessible for direct study, but an in vitro model of human primordial germ cell-like cell (hPGCLC) specification from human embryonic stem cells (hESCs) has been developed. This enables mechanistic study of human germ cell specification using genetic tools to manipulate the levels of SOX15 and SOX17 proteins to explore their roles in hPGCLC specification. Methods: SOX15 and SOX17 proteins were depleted during hPGCLC specification from hESCs using the auxin-inducible degron system, combined with a fluorescent reporter for tracking protein levels. Additionally, SOX15 protein was overexpressed using the ProteoTuner system. Protein-level expression changes were confirmed by immunofluorescence. The impact on hPGCLC specification efficiency was determined by flow cytometry at various time points. qPCR experiments were performed to determine some transcriptional effects of SOX15 perturbations. Results: We observed specific SOX15 expression in hPGCLCs by using immunofluorescence and flow cytometry analysis. Depletion of SOX15 had no significant effect on hPGCLC specification efficiency on day 4 after induction, but there was a significant and progressive decrease in hPGCLCs on days 6 and 8. By contrast, depletion of SOX17 completely abrogated hPGCLC specification. Furthermore, SOX15 overexpression resulted in a significant increase in hPGCLC fraction on day 8. qPCR analysis revealed a possible role for the germ cell and pluripotency regulator PRDM14 in compensating for changes to SOX15 protein levels. Conclusions: SOX17 is essential for hPGCLC specification, yet SOX15 is dispensable. However, SOX15 may have a role in maintaining germ cell identity.

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