Behaviour of a sperm surface transmembrane glycoprotein basigin during epididymal maturation and its role in fertilization in mice

in Reproduction
Authors:
DK Saxena
Search for other papers by DK Saxena in
Current site
Google Scholar
PubMed
Close
,
T Oh-Oka
Search for other papers by T Oh-Oka in
Current site
Google Scholar
PubMed
Close
,
K Kadomatsu
Search for other papers by K Kadomatsu in
Current site
Google Scholar
PubMed
Close
,
T Muramatsu
Search for other papers by T Muramatsu in
Current site
Google Scholar
PubMed
Close
, and
K Toshimori
Search for other papers by K Toshimori in
Current site
Google Scholar
PubMed
Close
Free access

Sign up for journal news

Basigin (bsg) is a transmembrane glycoprotein belonging to an immunoglobulin superfamily and is localized on the surface of the sperm tail. The behaviour of bsg during epididymal maturation and its role in fertilization were examined using an anti-bsg antibody. Spermatozoa from caput, corpus and cauda epididymides were immunostained by indirect immunofluorescence (IIF). Immunostaining revealed that bsg is localized on the principal piece of caput spermatozoa and the molecule was found on the middle piece during transit in the corpus and cauda epididymides. Concomitantly, the molecular mass of bsg was reduced from 37 kDa (testis) to 26 kDa (cauda epididymidis). IVF experiments were designed to assess the effect of anti-bsg antibody on the fertilization events. Anti-bsg antibody significantly inhibited primary binding to the cumulus-invested oocytes with intact zonae pellucidae in a dose-dependent manner. Consequently, the fertilization rate of cumulus-invested oocytes with intact zonae pellucidae was also inhibited. The bsg molecule was also detected on the head of live capacitated spermatozoa by IIF under IVF conditions. These findings indicate that testicular bsg is a glycosylated protein that undergoes molecular processing and deglycosylation during its transit in the epididymis. The bsg molecule that was detected on the sperm head after capacitation may facilitate the primary binding or might be involved in distinct events required for primary binding of spermatozoa to the zona pellucida during capacitation and sperm-cumulus interaction.

 

  • Collapse
  • Expand