Germ cell nuclear factor regulates gametogenesis in developing gonads.

Davood Sabour,Hans R Schöler,Guangming Wu,Vittorio Sebastiano,Arthur C K Chung,Luca Gentile,Damien Le Menuet,Kinarm Ko,Boris Greber,Austin J Cooney,Xueping Xu,Karin Hübner,Natalia Tapia,Marcos J Araúzo-Bravo,Qiang Wu

doi:10.1371/journal.pone.0103985

Abstract

Expression of germ cell nuclear factor (GCNF; Nr6a1), an orphan member of the nuclear receptor gene family of transcription factors, during gastrulation and neurulation is critical for normal embryogenesis in mice. Gcnf represses the expression of the POU-domain transcription factor Oct4 (Pou5f1) during mouse post-implantation development. Although Gcnf expression is not critical for the embryonic segregation of the germ cell lineage, we found that sexually dimorphic expression of Gcnf in germ cells correlates with the expression of pluripotency-associated genes, such as Oct4, Sox2, and Nanog, as well as the early meiotic marker gene Stra8. To elucidate the role of Gcnf during mouse germ cell differentiation, we generated an ex vivo Gcnf-knockdown model in combination with a regulated CreLox mutation of Gcnf. Lack of Gcnf impairs normal spermatogenesis and oogenesis in vivo, as well as the derivation of germ cells from embryonic stem cells (ESCs) in vitro. Inactivation of the Gcnf gene in vivo leads to loss of repression of Oct4 expression in both male and female gonads.

Highlights

Germ Cell Nuclear Factor (GCNF), known as nuclear receptor subfamily 6, group A, member 1 (Nr6a1), is an orphan member of the nuclear receptor (NR) gene family of ligandactivated transcription factors [1]
Two outstanding questions in the analysis of the Gcnf-mutant embryo phenotype are whether segregation of the germline has been compromised and whether Gcnf is required for further primordial germ cells (PGCs) development
To directly address these questions, we crossed the Oct4-GFP(DPE) reporter mice—a transgenic line generated with a construct lacking the proximal enhancer (PE) element of the Oct4 promoter, which typically drives Oct4 expression in the epiblast, here driving the expression of green fluorescent protein (GFP)— with our Gcnf-knockout (KO) mice

Summary

Introduction

Germ Cell Nuclear Factor (GCNF), known as nuclear receptor subfamily 6, group A, member 1 (Nr6a1), is an orphan member of the nuclear receptor (NR) gene family of ligandactivated transcription factors [1]. Gcnf is expressed in the developing nervous system, placenta [8,9], embryonic gonads, and adult ovaries and testes [1,10,11]. As Oct is required for the survival of primordial germ cells (PGCs) [21], the question arises as to whether Gcnf plays a role in the segregation or maintenance of the PGC lineage. To address this question, we developed new mouse models and in vitro cell models to study the role of Gcnf in PGCs

Methods

Results

Conclusion