The lack of protamine 2 (P2) in boar and bull spermatozoa is due to mutations within the P2 gene

• Published in: Nucleic acids research 1990-03, Vol.18 (5), p.1249-1254
• Main Authors: MAIER, W.-M, NUSSBAUM, G, DOMENJOUD, L, KLEMM, U, ENGEL, W
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Base Sequence; Biological and medical sciences; Blotting, Northern; Cattle - genetics; DNA - genetics; DNA - isolation & purification; Fundamental and applied biological sciences. Psychology; Gene Expression; Genes; Holoproteins; Humans; Male; Molecular Sequence Data; Mutation; Nuclear proteins; Nucleic Acid Hybridization; Protamines - analysis; Protamines - genetics; Protein Biosynthesis; Proteins; Sequence Homology, Nucleic Acid; Spermatozoa - analysis; Spermatozoa - metabolism; Swine - genetics
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/18.5.1249

The nuclei of spermatozoa in all mammals examined so far contain P1 protamine. A second protamine variant, protamine P2, has to date been isolated only from human and murine spermatozoa where it represents the major fraction of basic nuclear protein. In order to elucidate the reason for this unusual distribution of the protamine variants among mammals we have investigated the expression of protamine P2 in boar and bull. It can be shown that also in these species protamine 2 is transcribed and translated on low levels. Various mutational events though have altered the primary structure of the protein: In boar, a deletion of 8 aminoacids has removed a sequence motif from the amino-terminus of the molecule, which highly probable is of functional relevance. The bovine sequence, as a consequence of numerous point mutations has accumulated neutral and hydrophobic aminoacids which reduce the affinity of the protamine 2 to DNA.