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Updated: Oct 5, 2025
A Seminiferous Tubule Squash Technique for the Cytological Analysis of Spermatogenesis Using the Mouse Model
Published on: February 6, 2018
E3 ubiquitin ligase ASB17 is required for spermiation in mice
Cong Shen1, Jinfu Xu2, Qiao Zhou3
1State Key Laboratory of Reproductive Medicine, Center for Reproduction and Genetics, Suzhou Municipal Hospital, The Affiliated Suzhou Hospital of Nanjing Medical University, Gusu School, Nanjing Medical University, Suzhou, China.
Background:
A major goal of spermiation is to degrade the apical ectoplasmic specialization (ES) junction between Sertoli cells and elongating spermatids in preparation for the eventual disengagement of spermatids into the lumen. E3 ubiquitin ligases mediate the process of ubiquitination and the subsequent proteasomal degradation, but their specific role during spermiation remains largely unexplored.
Methods:
Ankyrin repeat and SOCS box protein 17 (Asb17)-knockout mice were generated via a CRISPR/Cas9 approach. Epididymal sperm parameters were assessed by a computer-assisted sperm analysis (CASA) system, and morphological analysis of testicular tissues were performed based on histological and immunostaining staining, and transmission electron microscopy (TEM). The interactions between ASB17 and Espin (ESPN) were predicted by HawkDock server and validated through protein pull-down and immunoprecipitation assays.
Results:
We report that ASB17, an E3 ligase, is required for the completion of spermiation and that mice lacking Asb17 are oligozoospermic owing to spermiation failure. ASB17-deficient mice are fertile; however, spermatids exhibit a disorganized ES junction, resulting in retention within the seminiferous epithelium. Mechanistically, ASB17 deficiency leads to excess accumulation of ESPN, an actin-binding essential structural component of the ES. We determined that ASB17 regulates the removal of the ES through ubiquitin mediated protein degradation of ESPN.
Conclusions:
In summary, our study describes a role for ASB17 in the regulation of cell-cell junctions between germ cells and somatic cells in the testis. These findings establish a novel mechanism for the regulatory role of E3 ligases during spermatogenesis.
