Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Mech Dev. November 1, 2014; 134 80-95.

The need of MMP-2 on the sperm surface for Xenopus fertilization: its role in a fast electrical block to polyspermy.

Iwao Y , Shiga K , Shiroshita A , Yoshikawa T , Sakiie M , Ueno T , Ueno S , Ijiri TW , Sato K .

Monospermic fertilization in the frog, Xenopus laevis, is ensured by a fast-rising, positive fertilization potential to prevent polyspermy on the fertilized egg, followed by a slow block with the formation of a fertilization envelope over the egg surface. In this paper, we found that not only the enzymatic activity of sperm matrix metalloproteinase-2 (MMP-2) was necessary for a sperm to bind and/or pass through the extracellular coat of vitelline envelope, but also the hemopexin (HPX) domain of MMP-2 on the sperm surface was involved in binding and membrane fusion between the sperm and eggs. A peptide with a partial amino acid sequence of the HPX domain caused egg activation accompanied by an increase in [Ca(2+)]i in a voltage-dependent manner, similar to that in fertilization. The membrane microdomain (MD) of unfertilized eggs bound the HPX peptide, and this was inhibited by ganglioside GM1 distributed in the MD. The treatment of sperm with GM1 or anti-MMP-2 HPX antibody allows the sperm to fertilize an egg clamped at 0 mV, which untreated sperm cannot achieve. We propose a model accounting for the mechanism of voltage-dependent fertilization based on an interaction between the positively charged HPX domain in the sperm membrane and negatively-charged GM1 in the egg plasma membrane.

PubMed ID: 25296387
Article link: Mech Dev.

Genes referenced: cat.2 dnai1 fn1 hpx kit mmp2 mmp7 sgp spr upk3a

Antibodies referenced: Mmp2 Ab1 Mmp2 Ab2 Sperm Ab1

Article Images: [+] show captions

Xenbase: The Xenopus laevis and X. tropicalis resource.
Version: 4.8.0
Major funding for Xenbase is provided by the National Institute of Child Health and Human Development, grant P41 HD064556