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The immunoglobulin superfamily protein Izumo is required for sperm to fuse with eggs
Author(s) -
Inoue N,
Ikawa M,
Isotani A,
Okabe M
Publication year - 2006
Publication title -
american journal of reproductive immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.071
H-Index - 97
eISSN - 1600-0897
pISSN - 1046-7408
DOI - 10.1111/j.1600-0897.2006.00383_3.x
Subject(s) - sperm , zona pellucida , biology , antibody , human fertilization , monoclonal antibody , immunology , zona pellucida glycoprotein , semen , fusion protein , hamster , antigen , genetics , immunoglobulin superfamily , andrology , microbiology and biotechnology , gene , oocyte , embryo , medicine , recombinant dna
Representing the 60 trillion cells that build a human body, a sperm and an egg meet, recognize each other, and fuse to form a new generation of life. The factors involved in this important membrane fusion event, fertilization, have been sought for a long time. Recently, CD9 on the egg membrane was found to be essential for fusion, but sperm‐related fusion factors remain unknown. Here, by using a fusion‐inhibiting monoclonal antibody and gene cloning, we identify a mouse sperm fusion related antigen and show that the antigen is a novel immunoglobulin superfamily protein. We have termed the gene Izumo and produced a gene‐disrupted mouse line. Izumo ‐/‐ mice were healthy but males were sterile. They produced normal‐looking sperm that bound to and penetrated the zona pellucida but were incapable of fusing with eggs. Human sperm also contain Izumo and addition of the antibody against human Izumo left the sperm unable to fuse with zona‐free hamster eggs.