Sperm Acrosome Associated Protein 5 (SPACA5)

By searching for genes duplicated on the X chromosome, Chen et al. (2006) identified SPACA5, which they called LOC389852. The deduced protein contains 159 amino acids. Quantitative RT-PCR detected strong expression in testis and moderate expression in brain, colon, kidney, pancreas, and prostate.By sequence analysis, Chen et al. (2006) determined that there are 2 direct repeats of the SPACA5 gene on chromosome Xp11.23.

The acrosome is an organelle that develops over the anterior half of the head in the spermatozoa (sperm cell) of many animals. It is a cap-like structure derived from the Golgi apparatus. Acrosome formation is completed during testicular maturation. In Eutherian mammals the acrosome contains digestive enzymes (including hyaluronidase and acrosin).