Deficiency in major high molecular-weight seminal proteins in men producing poorly coagulating and alkaline liquid ejaculates

Gel electrophoresis of human sperm: a simple method for evaluating sperm protein quality

Background

The limitations of conventional sperm analyses have highlighted the need for additional means of evaluating sperm quality.

Methods

In a study of a cohort of 245 men with known conventional sperm parameters, one-dimensional PAGE was used to monitor protein content and quality in samples from individual ejaculates.

Results

The sperm protein content varied markedly from sample to another, especially in the high-molecular-weight range. The intensity of the 80–110 kDa bands was correlated with progressive motility (r = 0.15, p = 0.015) and was significantly higher (p = 0.0367) in the group of men with conventional parameters above the World Health Organization’s 2010 reference values than in the group with at least one subnormal parameter (i.e. semen volume, sperm concentration, sperm count per ejaculate, progressive motility, proportion of normal forms or multiple anomaly index below the lower reference value). Using mass spectrometry, the 80–110 kDa bands were found to correspond primarily to three proteins from the flagellum’s fibrous sheath: A-kinase anchor protein 4, A-kinase anchor protein 3, and spermatogenic cell-specific type 1 hexokinase.

Conclusion

One-dimensional PAGE constitutes a simple, rapid, reliable, inexpensive method for analyzing proteins associated with sperm motility in individual human ejaculates.

Unaltered protein pattern/genital tract secretion marker levels in seminal plasma of highly viscous human ejaculates

SDS-PAGE (12.5%) analysis and neutral alpha-glucosidase, fructose, and zinc level assessment were carried out in seminal plasma of 20 patients with highly viscous ejaculates and of 20 control subjects, with the aim to investigate the relations between high consistency of semen and epididymal, vesicular, and prostatic secretions. Very low sperm motility was observed in all the patients' ejaculates, both normo- and oligozoospermics. Protein patterns obtained in control and highly viscous semina showed similar protein bands, in the range of 10-100 kD. Furthermore, unaltered seminal neutral alpha-glucosidase, zinc, and fructose level were measured in the same specimens. These results indicated no impairment of epididymal, vesicular, and prostatic function in patients with hyperviscous semina, while their normal electrophoretic seminal protein profile suggested unaltered genital fluid interactions during the semen coagulation-liquefaction process.

Androgen induction of the SVS family related protein MSVSP99: identification of a functional androgen response element

The gene encoding MSVSP99 (mouse seminal vesicle secretory protein of 99 amino acids) is specifically expressed in the mouse seminal vesicle under androgenic control. To study hormonal regulation, fragments of the 5'-flanking region, extending from -2365 to +16 were linked to the chloramphenicol acetyl transferase (CAT) gene and cotransfected with an androgen receptor expression vector into CV-1 cells. A minimal region (-387 to +16) was sufficient for full androgen induction. Further deletion, up to nt-261, almost completely abolished androgen inducibility. DNase I footprinting and band-shift assays, using the DNA binding domain of the androgen receptor (AR-DBD), revealed three AR binding sites: two putative androgen response elements (AREs) occurring at positions -361 (AREd) and -208 (AREp), and an androgen receptor binding region (ARBR) located between positions -317 and -293. Transient transfection assays revealed that site-directed mutation in AREp abolished androgen induced expression, whereas mutation in AREd or in ARBR had no effect. The results demonstrate that AREp is a functional sequence that must cooperate with additional cis-acting elements, located between -387 and -261, for androgen induction of the MSVSP99 gene.

First report on purification of the predominant acidic coagulum protein of human semen prior to liquefaction

The predominant acidic coagulum protein of freshly ejaculated human semen under reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was purified for the first time from washed seminal coagulum keeping urea throughout the entire procedure. Washed seminal coagulum was isolated from fresh semen sample in acetate buffer at pH 4.5 at 0 degrees C, solubilized rapidly in deionized 4 M urea followed by reduction and carboxymethylation of disulfide bonds. By CM-Sephadex and Sephacryl S-300 high-resolution chromatography in presence of urea at room temperature, the predominant acidic coagulum protein was highly purified (99.1%) with a yield of 2.7% of the coagulum protein. The molecular weight of the purified protein in reducing SDS-PAGE was 162 kD.

Collective isolation of two major, close molecular weight coagulum proteins occurring in human semen before liquefaction

Two major, close molecular weight basic coagulum proteins of freshly ejaculated human semen identifiable on reducing SDS-PAGE, have been isolated together from washed seminal coagulum. The latter was solubilized in urea, followed by reduction and carboxymethylation of disulphide bonds. By high-resolution chromatography on carboxymethy-Sephadex and Sephacryl S-300 using 8 M urea in 0.1M Tris-HCl (pH 7.4) as eluate these proteins were isolated together (purity 99%) with a yield of 10.5%. The molecular weights of the isolated proteins on SDS-PAGE were 75 and 79 kD.