The origin and function of the posterior ring in mouse sperm head
7 affiliations
- 1Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, 510623 China
- 2Jiangsu Engineering Center for Precision Diagnosis and Treatment Research of Polygenic Diseases, Key Laboratory of Genetic Foundation and Clinical Application, Department of Genetics, Xuzhou Medical University, Xuzhou, 221004 China
- 3Department of Reproductive Medicine and Genetics Center, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, 530021 China
- 4The Key Laboratory of Organ Regeneration and Reconstruction, State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100049 China
- 5Dalian Medical University, Dalian, 116044 China
- 6Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510700 China
- 7Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 100049 China
Abstract
Background: Despite extensive characterization of sperm structures, certain specialized subcellular structures are still not well understood. Among these, the posterior ring has been recognized for over half a century; yet, its molecular composition and biological role remain unknown. This research aims to define the molecular components and functional roles of the sperm posterior ring.
Methods: 3D-rendered confocal microscopy was used to determine the localization and developmental dynamics of SPEM3 and TEX50 in mature spermatozoa and spermatids at different steps of spermiogenesis. Spem3 and Tex50 knockout mouse models were generated to explore their physiological functions. Sperm morphology and ultrastructure were investigated through immunofluorescence along with transmission and scanning electron microscopy, whereas sperm motility was evaluated using computer-assisted sperm analysis. Proteomics, coimmunoprecipitation, and immunoblotting were performed to identify SPEM3 and TEX50 as structurally interdependent interacting components of the posterior ring and to elucidate how their loss disrupts sperm architecture and fertility.
Results: We identified SPEM3 as a core component of the posterior ring located at the sperm head–tail linkage. The posterior ring arises from the marginal ring at the acroplaxome periphery during early spermiogenesis. Loss of Spem3 led to severe bending of the head–tail linkage, accompanied by a marked reduction in sperm motility, ultimately leading to male infertility. Furthermore, SPEM3 interacts and colocalizes with TEX50, and deficiency of either protein resulted in similar phenotypes, including disorganization of the posterior ring and postacrosomal region as well as impairment of the sperm connecting piece.
Conclusions: These findings establish SPEM3 and TEX50 as critical posterior ring components essential for maintaining postacrosomal integrity and anchoring the sperm head to the tail. By resolving the long unknown molecular composition of the posterior ring, this study provides new mechanistic insight into sperm head–tail integrity and the pathogenesis of certain forms of male infertility.
Graphical Abstract:
Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1186/s11658-026-00997-7.
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BibTeX
@article{wu2026origin,
title = {{The origin and function of the posterior ring in mouse sperm head}},
author = {Bingbing Wu and Chenghong Long and Jiayi Liu and Zuobin Zhu and Liling Liu and Qingling Ma and Yan Long and Liying Wang and Huafang Wei and Yanjie Ma and Jingwen Hou and Heying Li and Li Yuan and Wei Li and Chao Liu},
journal = {Cellular \& Molecular Biology Letters},
year = {2026},
month = jul,
doi = {10.1186/s11658-026-00997-7},
url = {https://doi.org/10.1186/s11658-026-00997-7},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - The origin and function of the posterior ring in mouse sperm head
AU - Bingbing Wu
AU - Chenghong Long
AU - Jiayi Liu
AU - Zuobin Zhu
AU - Liling Liu
AU - Qingling Ma
AU - Yan Long
AU - Liying Wang
AU - Huafang Wei
AU - Yanjie Ma
AU - Jingwen Hou
AU - Heying Li
AU - Li Yuan
AU - Wei Li
AU - Chao Liu
PY - 2026
DA - 2026/07/01
JO - Cellular & Molecular Biology Letters
DO - 10.1186/s11658-026-00997-7
UR - https://doi.org/10.1186/s11658-026-00997-7
AB - Background: Despite extensive characterization of sperm structures, certain specialized subcellular structures are still not well understood. Among these, the posterior ring has been recognized for over half a century; yet, its molecular composition and biological role remain unknown. This research aims to define the molecular components and functional roles of the sperm posterior ring. Methods: 3D-rendered confocal microscopy was used to determine the localization and developmental dynamics of SPEM3 and TEX50 in mature spermatozoa and spermatids at different steps of spermiogenesis. Spem3 and Tex50 knockout mouse models were generated to explore their physiological functions. Sperm morphology and ultrastructure were investigated through immunofluorescence along with transmission and scanning electron microscopy, whereas sperm motility was evaluated using computer-assisted sperm analysis. Proteomics, coimmunoprecipitation, and immunoblotting were performed to identify SPEM3 and TEX50 as structurally interdependent interacting components of the posterior ring and to elucidate how their loss disrupts sperm architecture and fertility. Results: We identified SPEM3 as a core component of the posterior ring located at the sperm head–tail linkage. The posterior ring arises from the marginal ring at the acroplaxome periphery during early spermiogenesis. Loss of Spem3 led to severe bending of the head–tail linkage, accompanied by a marked reduction in sperm motility, ultimately leading to male infertility. Furthermore, SPEM3 interacts and colocalizes with TEX50, and deficiency of either protein resulted in similar phenotypes, including disorganization of the posterior ring and postacrosomal region as well as impairment of the sperm connecting piece. Conclusions: These findings establish SPEM3 and TEX50 as critical posterior ring components essential for maintaining postacrosomal integrity and anchoring the sperm head to the tail. By resolving the long unknown molecular composition of the posterior ring, this study provides new mechanistic insight into sperm head–tail integrity and the pathogenesis of certain forms of male infertility. Graphical Abstract: Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1186/s11658-026-00997-7.
SN - 1425-8153
SN - 1689-1392
ER -