Characterization of a novel cell-surface protein expressed on human sperm

Ruey Bing Yang, Heng Kien Au, Chii Ruey Tzeng, Ming T. Tsai, Ping Wu, Yu Chih Wu, Thai Y. Ling, Yen H. Huang

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

BACKGROUND: Precise sperm-oocyte interaction is a critical event for successful fertilization. However, the identity of molecules involved in this process in humans remains largely unknown. This report describes the identification and characterization of a novel cell-surface protein and its potential role in human sperm-oocyte interaction. METHODS: AND RESULTSWe previously identified an orphan guanylyl cyclase receptor (mouse GC-G) highly enriched in mouse testis and involved in sperm activation. By using a comparative genomic approach, we found the homologue gene in human (hGC-G) composed of 21 exons, spanning a minimum of 48 kb on chromosome 10q25. Real-time RT-PCR analysis revealed hGC-G mRNA selectively expressed in testis but with low or no expression in all other tissues examined. Compared with mGC-G, the hGC-G transcript contains three 1-bp deletions and two in-frame termination codons, which results in a short putative receptor-like polypeptide. Western blot analysis with an anti-hGC-G-specific antibody confirmed the protein expression of hGC-G in human sperm lysate. Flow cytometry and confocal immunofluorescence analysis demonstrated the localization of hGC-G protein on the acrosome cap and equatorial segment of mature human sperm. In addition, an integrin-binding Arg-Gly-Asp (RGD) motif was found in the extracellular domain of hGC-G. Pre-incubation of the hGC-G RGD peptide with zona pellucida-free oocytes greatly decreased the binding of human sperm to hamster oocytes, which suggests a role for hGC-G role in sperm-oocyte interaction. CONCLUSION: ShGC-G is a novel surface protein on human sperm and potentially mediates sperm-oocyte interaction through its RGD-containing motif.

Original languageEnglish
Pages (from-to)42-51
Number of pages10
JournalHuman Reproduction
Volume25
Issue number1
DOIs
Publication statusPublished - Jan 2010

Keywords

  • Cell-surface protein
  • Gamete interaction
  • Human sperm
  • Integrin
  • RGD motif

ASJC Scopus subject areas

  • Obstetrics and Gynaecology
  • Rehabilitation
  • Reproductive Medicine

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