Human protamines and male infertility

Sperm protamine 1/protamine 2 ratios are related to in vitro fertilization pregnancy rates and predictive of fertilization ability

“…In mice, protamine haploinsufficiency causes severe male infertility and results in abnormal embryo development (14,15). Previous studies in human beings have noted that aberrant P1/P2 stoichiometry also may relate to male infertility (5)(6)(7)(8)(9)(10)(11)(12). Indeed, patients with aberrant P1/P2 ratios typically present with diminished semen quality.…”

“…Although the ratio of P1 to P2 (P1/P2) varies among species, within human beings it is regulated strictly in a one-to-one fashion (4). Studies elsewhere have shown that aberrations in the P1/P2 ratio are related to human male infertility (5)(6)(7)(8)(9)(10)(11)(12). In particular, men with abnormal expression of either of the protamines present with diminished semen quality parameters, such as sperm count, motility, and head morphology (5,6,12,13).…”

Global sperm deoxyribonucleic acid methylation is unaffected in protamine-deficient infertile males

“…Protamines are critical for proper sperm DNA integrity and chromatin structure, exemplified by a recent report documenting increased DNA fragmentation in infertile men with protamine deficiency (7). Protamine-deficient men also present with diminished semen quality and compromised sperm functional ability, highlighting the importance of the protamines for proper spermatogenesis (14,15). The data suggesting that global methylation patterns are unaffected in these patients are consistent with previous reports show- ing little relationship between global methylation patterns and semen quality or sperm DNA fragmentation (22)(23)(24).…”

Semen Analysis at the Turn of the Century: An Evaluation of Potential Uses of New Sperm Function Assays

“…First, acidic aniline blue can be used in a relatively simple staining procedure to qualitatively evaluate the degree of protamine replacement of the histones [17]. Second, nuclear proteins can be isolated by purification techniques, then identified and quantified by electrophoresis [35]. Following electrophoresis, the ratio of protamine 1/ protamine 2 (P1/P2) can be calculated.…”