Researchers have, for the first time, identified a protein on sperm that is essential for fusion with eggs during fertilization (Nature; 10 March 2005; Vol. 434, No. 7030, pp 234-238). This and other molecules involved in fusion may suggest new methods of contraception and might be targeted with new clinical treatments for infertility.
Scientists are just starting to uncover the molecules needed in order for the cell membranes of sperm and eggs to fuse. Masaru Okabe and his team used a monoclonal antibody known to block fusion of mouse sperm, and searched for the protein on sperm that is bound by this antibody. They named the protein Izumo, after a Japanese shrine dedicated to marriage.
Mice genetically engineered to lack Izumo were healthy but sterile; they produced normal-looking sperm that were unable to fuse with eggs. Human sperm also contain Izumo, the researchers found, and the antibody blocked frozen human sperm from experimentally fusing with hamster eggs.
Masaru Okabe (Osaka University, Japan)
Tel: +81-6-6879 8374
Richard Schultz (University of Pennsylvania, Philadelphia, PA, USA.)
Tel: +1 215 898 7869
(C) Nature press release.
Message posted by: Trevor M. D'Souza