The sperm acrosome is essential for sperm-egg fusion and is often defective in men with nonobstructive infertility. Here we report that male mice with a null mutation in Hrb are infertile and display round-headed spermatozoa that lack an acrosome. In wild-type spermatids, Hrb, is associated with the cytosolic surface of proacrosomic transport vesicles that fuse to create a single large acrosomic vesicle at step 3 of spermiogenesis. Although proacrosomic vesicles form in spermatids that lack Hrb, the vesicles are unable to fuse, blocking acrosome development at step 2. We conclude that Hrb is required for docking and/or fusion of proacrosomic vesicles during acrosome biogenesis.
|Original language||English (US)|
|Number of pages||3|
|State||Published - Nov 16 2001|