Acrosome Biogenesis in the Hamster: DISCUSSION(2)
The human SP10 proteins have been demonstrated to associate with the outer and inner acrosomal membranes of the anterior acrosome and are also present within the equatorial segment . In the mouse, the SPlO-related polypeptides localize to the acrosome by immunofluorescence , but their incorporation into a stable acrosomal matrix assembly was not demonstrated. Our data on hamster spermatozoa demonstrate a more restricted intra-acro-somal distribution and membrane association of AM22 and AM29. These acrosomal proteins are not present in the equatorial segment, and they are associated with the outer acrosomal membrane of the apical and principal segments but not with the inner acrosomal membrane. We have noted an identical distribution pattern of related proteins in bovine spermatozoa , suggesting that this may represent the general acrosomal distribution pattern of SPlO-related proteins in nonhuman spermatozoa. buy ortho tri-cyclen online
A surprising finding was that the major structural proteins of the ml and m2 domains represent a related polypeptide family. Since both the monoclonal antibody and the polyclonal antibody used in the present study recognized both AM22 and AM29, it remains unknown whether the individual polypeptides are restricted to separate matrix domains or whether they co-localize to both the ml and m2 domains. In the apical segment of guinea pig spermatozoa, homopolymeric complexes of nonrelated structural proteins form the basis for the distinct matrix assemblies . Whether AM29 and AM22 assemble into higher-order complexes remains to be determined, but it is possible that homopolymeric complexes of AM22 and of AM29 represent the basis for the distinct structural appearance of ml and m2 matrix domains in the hamster acrosome.