Loss of NEDD4 causes complete XY gonadal sex reversal in mice

Simon P Windley,Serge Nef,Natasha L Harvey,Alice E Mcgovern,Quenten Schwarz,Dagmar Wilhelm,Chloé Mayère,Sharad Kumar

doi:10.1038/s41419-022-04519-z

Abstract

Gonadogenesis is the process wherein two morphologically distinct organs, the testis and the ovary, arise from a common precursor. In mammals, maleness is driven by the expression of Sry. SRY subsequently upregulates the related family member Sox9 which is responsible for initiating testis differentiation while repressing factors critical to ovarian development such as FOXL2 and β-catenin. Here, we report a hitherto uncharacterised role for the ubiquitin-protein ligase NEDD4 in this process. XY Nedd4-deficient mice exhibit complete male-to-female gonadal sex reversal shown by the ectopic upregulation of Foxl2 expression at the time of gonadal sex determination as well as insufficient upregulation of Sox9. This sex reversal extends to germ cells with ectopic expression of SYCP3 in XY Nedd4-/- germ cells and significantly higher Sycp3 transcripts in XY and XX Nedd4-deficient mice when compared to both XY and XX controls. Further, Nedd4-/- mice exhibit reduced gonadal precursor cell formation and gonadal size as a result of reduced proliferation within the developing gonad as well as reduced Nr5a1 expression. Together, these results establish an essential role for NEDD4 in XY gonadal sex determination and development and suggest a potential role for NEDD4 in orchestrating these cell fate decisions through the suppression of the female pathway to ensure proper testis differentiation.

Highlights

Gonadogenesis is a unique process wherein two morphologically distinct organs, the testis and the ovary, arise from a common precursor
Homozygous deletion of Nedd4 causes complete male-tofemale gonadal sex reversal We have previously shown that NEDD4 is expressed in all cells of the developing testis at 15.5 dpc, with its transcript detectable in both somatic and germ cells from 12.5 to 15.5 dpc [26]
This was confirmed at the transcript level using quantitative RT-PCR (RT-qPCR), which showed that XY Nedd4-/- gonads had a complete loss of Nedd4 expression (Fig. 2J), a significant reduction in SRY-box containing gene 9 (Sox9) and Amh (Fig. 2K, L) and a significant increase in Foxl2 (Fig. 2M) relative to XY controls, consistent with ovarian development at this time

Summary

INTRODUCTION

Gonadogenesis is a unique process wherein two morphologically distinct organs, the testis and the ovary, arise from a common precursor. Established on the ventromedial side of the mesonephros, this shared anlage develops as a thickening of the epithelium, which proliferates to give rise to the bipotential genital ridges This process begins as early as 10.0 days post coitum (dpc) in mice with the expression of GATA4, which is quickly followed by expression of nuclear receptor subfamily 5 group A member 1, Nr5a1 Antagonism between testicular and ovarian promoting pathways exists and as such the testicular phenotype must be actively maintained in the XY gonad while simultaneously repressing proovarian pathways In this way, ectopic strengthening of the ovarian pathway in XY gonads can result in male-to-female sex reversal as seen in mice over-expressing the pro-ovarian transcription factors FOXL2 Our results reveal an uncharacterised role for NEDD4 in mouse development with Nedd4-deficient mice exhibiting complete male-to-female gonadal sex reversal

RESULTS

DISCUSSION

MATERIALS AND METHODS