Role of egg sulfolipidimmobilizing protein 1 on mouse sperm-egg plasma membrane binding

Biol Reprod. 1999 Sep;61(3):749-56. doi: 10.1095/biolreprod61.3.749.

Abstract

We have shown that sperm sulfolipidimmobilizing protein 1 (SLIP1, molecular mass of 68 kDa), a sulfogalactosylglycerolipid (SGG)-binding protein, is significant in sperm-zona pellucida (ZP) interaction. The objective of this study was to localize SLIP1 on the egg and determine its role in gamete interaction. Immunofluorescence and immunoprotein A gold electron microscopy localized SLIP1 to the egg plasma membrane. In vitro gamete binding, using zona-free eggs preincubated with antiSLIP1 Fab before coincubation with sperm, showed a significant, dose-dependent decrease in sperm-egg plasma membrane binding. Similar results were obtained when affinity-purified antiSLIP1 IgG was used for egg pretreatment. The significance of egg SLIP1 in sperm-egg plasma membrane binding was further demonstrated by a decrease (36-52%) in in vitro fertilization when zona-intact eggs were pretreated with antiSLIP1 IgG. Since SLIP1 has been shown to bind SGG in vitro, we investigated the possibility that sperm SGG may participate in sperm-egg plasma membrane binding through egg SLIP1. Pretreatment of sperm with antiSGG Fab prior to coincubation with zona-free eggs resulted in a dose-dependent decrease in sperm-egg plasma membrane binding. Collectively, these findings strongly suggest a role for egg SLIP1 in sperm-egg plasma membrane interaction, which may be through its binding to sperm SGG.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / pharmacology
  • Carrier Proteins / analysis
  • Carrier Proteins / antagonists & inhibitors
  • Carrier Proteins / physiology*
  • Cell Membrane / chemistry
  • Cell Membrane / metabolism
  • Female
  • Fluorescent Antibody Technique, Direct
  • Immunoblotting
  • Male
  • Mice
  • Microscopy, Immunoelectron
  • Ovum / chemistry
  • Ovum / physiology
  • Ovum / ultrastructure
  • RNA-Binding Proteins
  • Sperm-Ovum Interactions*
  • Spermatozoa / physiology
  • Spermatozoa / ultrastructure

Substances

  • Antibodies
  • Carrier Proteins
  • RNA-Binding Proteins
  • Slip1 protein, mouse