Sperm protein needed for fertilization found

Japanese scientists said on Wednesday they have discovered a protein on sperm that is essential to fertilize eggs.

The protein, which they named Izumo after a Japanese shrine dedicated to marriage, could lead to improvements in contraceptives and fertility techniques.

“The finding not only provides insight into the enigmatic fusion mechanism but also promises benefits in the clinical treatment of infertility and the potential development of new contraceptive strategies,” said Masaru Okabe of Osaka University in Japan in the science journal Nature.

Before sperm can fertilize a female egg it must pass through an outer layer of the egg, then interact with the inner coat surrounding it and bind to its plasma membrane.

The scientists bred genetically engineered mice which did not produce the protein and found the animals could not complete fertilization.

The mice were healthy and produced sperm but they were sterile.

For Subscribers

FOR SUBSCRIBERSCBP leaders cut out of Trump ad buy decision

FOR SUBSCRIBERSAmerican passenger drafted goodbye texts to her family as Flydubai plane plummeted

FOR SUBSCRIBERSCornell rape allegation pushes embattled New York prosecutor into national spotlight

FOR SUBSCRIBERSAbdul El-Sayed tries to woo MAHA voters as Democrats seek inroads with RFK’s supporters

FOR SUBSCRIBERSKratom-like substances are popping up in a typically benign supplement

FOR SUBSCRIBERSGOP super PAC increases its spending for Sen. Jon Husted in tough Ohio race

FOR SUBSCRIBERSRecords reveal tumultuous marriage between slain New York Times executive and wife

FOR SUBSCRIBERSFrom clean energy warrior to ‘wall of shame,’ James Talarico reverses on a fossil fuel money pledge

FOR SUBSCRIBERSCongressional staff planned official trip with luxury stops in Italy and France weeks before election

FOR SUBSCRIBERSA harrowing ordeal aboard an Israel-bound plane

FOR SUBSCRIBERSOpenAI CEO Sam Altman to skip congressional hearing on rogue AI agents

FOR SUBSCRIBERSKey DOJ lawyers departed Trump ‘grand conspiracy’ probe amid pressure to produce, source says

FOR SUBSCRIBERSTrump’s new AI chatbot often links to a site launched under Clinton 26 years ago

FOR SUBSCRIBERSAt MAHA summit, industry CEOs the movement once vilified take the stage

FOR SUBSCRIBERSThis Paralympian has two goals: Win medals and give away $500,000 to her teammates

Target for contraception
The search for Izumo began 18 years ago when the scientists found an antibody that recognized a molecule on sperm and inhibited fertilization.

For Subscribers

FOR SUBSCRIBERSCBP leaders cut out of Trump ad buy decision

FOR SUBSCRIBERSAmerican passenger drafted goodbye texts to her family as Flydubai plane plummeted

FOR SUBSCRIBERSCornell rape allegation pushes embattled New York prosecutor into national spotlight

FOR SUBSCRIBERSAbdul El-Sayed tries to woo MAHA voters as Democrats seek inroads with RFK’s supporters

FOR SUBSCRIBERSKratom-like substances are popping up in a typically benign supplement

FOR SUBSCRIBERSGOP super PAC increases its spending for Sen. Jon Husted in tough Ohio race

FOR SUBSCRIBERSRecords reveal tumultuous marriage between slain New York Times executive and wife

FOR SUBSCRIBERSFrom clean energy warrior to ‘wall of shame,’ James Talarico reverses on a fossil fuel money pledge

FOR SUBSCRIBERSCongressional staff planned official trip with luxury stops in Italy and France weeks before election

FOR SUBSCRIBERSA harrowing ordeal aboard an Israel-bound plane

FOR SUBSCRIBERSOpenAI CEO Sam Altman to skip congressional hearing on rogue AI agents

FOR SUBSCRIBERSKey DOJ lawyers departed Trump ‘grand conspiracy’ probe amid pressure to produce, source says

FOR SUBSCRIBERSTrump’s new AI chatbot often links to a site launched under Clinton 26 years ago

FOR SUBSCRIBERSAt MAHA summit, industry CEOs the movement once vilified take the stage

FOR SUBSCRIBERSThis Paralympian has two goals: Win medals and give away $500,000 to her teammates

Human sperm also contains a counterpart of Izumo. When the scientists used the antibody in laboratory experiments, they found that it blocked frozen human sperm from fusing with hamster eggs -- a test for male fertility.

Richard Schultz and Carmen Williams at the University of Pennsylvania in the United States described the research in a commentary as compelling.

“These findings raise the exciting possibility that, because Izumo is sperm-specific and extracellular, this protein and its interacting partners could be new targets for non-hormonal contraception,” they wrote.