Fig.3 (image) Osaka University Share Print E-Mail Caption Impaired zona pellucida binding of Nell2 knockout sperm Left, Wild-type sperm binds to zona pellucida, a specialized extracellular matrix surrounding the egg. Right, Nell2 knockout sperm cannot bind to zona pellucida. Credit Osaka University Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.