Proteomics of the Spermatozoon

The study of the sperm proteins is crucial for understanding its normal function and alterations in infertile patients. The sperm is a highly specialized cell with a very large flagella, with little cytoplasm and a highly condensed nucleus. The most abundant proteins in the nucleus of mammalian sperm are the protamines. The main functions of the protamines are the condensation of the DNA, possibly contributing to the generation of a more hydrodynamic sperm head and to the protection of the genetic message. However, in addition to protamines, about 5.0-15.0% of the paternal genome is also complexed with histones and histone variants. It has also demonstrated a differential distribution of genes in regions associated with histone and protamine-associated regions, suggesting a potential epigenetic relevance in embryonic development. More recently, detailed lists of proteins have been described corresponding to the different compartments of the sperm cell thanks to the application of recent proteomic techniques based on mass spectrometry (MS). Differential proteomics is also being applied to identify the presence of protein abnormalities found in infertile patients.