HUWE1 is involved in Sertoli cell polarity establishment by ubiquitination mediated degradation of WT1.

HUWE1, a member of HECT E3 ubiquitin ligase family, is implicated in a variety of cellular processes. Recent studies find that HUWE1 also plays critical roles in germ cell development and inactivation of HUWE1 causes germ cell loss in both male and female mice. In this study, we found that Huwe1 was also highly expressed in testicular Sertoli cells. Inactivation of Huwe1 in Sertoli cells resulted in loss of cell polarity, which in turn caused germ cells loss and male infertility. Further study revealed that dysregulation in the expression of cytoskeletal and adhesion-related molecules, as well as a significant increase in EMT-related trans-factors SNAI1&2 in Huwe1-deficient Sertoli cells. Intriguingly, the protein level of WT1 was significantly increased in Huwe1-deficient Sertoli cells, and overexpression of Wt1 in Sertoli cells also caused the defects in spermatogenesis which was consistent with Huwe1 CKO mouse model. Furthermore, the defect of spermatogenesis in Huwe1 CKO mice was partially rescued by deleting one allele of Wt1 gene. Mechanistic studies revealed that WT1 interacts with HUWE1 protein and it could be ubiquitinated by HUWE1. Our study demonstrates that HUWE1 is involved in the establishment of Sertoli cell polarity mainly by regulating the protein level of WT1 gene.