Fig. 2 (IMAGE) Osaka University Caption <b>Immunostaining of IZUMO1 in <i>Fimp KO</i> spermatozoa. </b>IZUMO1 is used as a marker of the acrosome reaction. The acrosome reaction occurred in <i>Fimp KO</i> (-1/-1) spermatozoa. Acrosome reaction is determined by IZUMO1 localization (acrosome-intact spermatozoa: acrosomal cap pattern [orange dashed squares], acrosome-reacted spermatozoa: entire head pattern [green dashed squares]). Acrosome-reacted spermatozoa are indicated by asterisks. Credit Original image from <i>PNAS</i> (Fujihara et al). Usage Restrictions None License Licensed content 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.