Epididymal biology: spermatic maturation and gene expression

Abstract

The mammalian epididymis consists of a single coiled duct that connects the efferent ducts to the different duct. Anatomically,four segments are distinguished in this organ: the caput, the corpus and the cauda epididymidis. This classification is basedin the epithelium height, in the diameter of the duct and in the cell types present in each segment. During their transit through theepididymis, the sperm, produced in the testis, acquire progressive motility and become able to fertilize the oocyte, a process called spermmaturation. During this transit, the epididymis fluid changes its osmolarity, energetic reserves and proteins, in a way to promote spermmaturation.The programmed and differential gene expression along the epididymis provides the appropriate environment to spermmaturation. Although different studies have identified many epididymis-enriched and specific genes that are important to understandthe transcriptome of this organ, many aspects of epididymis gene expression is still to be shown, such as what proteins are produced bythe genes described so far, what are the functions of these proteins and where they act.