Region-specific localization of IMDS-60 protein in mouse epididymis and its relationship with sperm maturation

Spermatozoa acquire forward motility and fertilizing cap- acity during their transit through the epididymis. This maturation process involves modifications of the sperm surface by different proteins secreted by a series of specia- lized regions in the epididymal epithelium. Previously, our lab has reported IMDS-60 gene, which is highly expressed in mouse corpus and cauda epididymidis. Here, to perform further characterization of IMDS-60 protein, the specific polyclonal antisera were raised to the C-terminal peptide of the IMDS-60 protein. Western blot and immu- nohistochemistry assay revealed that IMDS-60 protein was specifically localized in the corpus and cauda regions of epididymidis. IMDS-60 could be transported from epi- didymal epithelium to the surface of epididymal spermato- zoa. Finally, the results of the antibody block experiments suggested that IMDS-60 might play important roles in sperm maturation in the epididymis.