[Reproduction-related proteins differentially expressed in the testes of the mice with kidney-yang or kidney-yin deficiency].

OBJECTIVE: To compare the differentially expressed proteins in mice with kidney-yang deficiency and those with kidney-yin deficiency induced by hydrocortisone, and explore the similar and different material bases of male infertility caused by the two types of kidney deficiency. METHODS: Thirty Kunming mice were equally randomized into a normal control, a kidney-yang deficiency and a kidney-yin deficiency group. The animals of the normal control group were injected intraperitoneally with normal saline at 0.2 ml qd for 7 days, while those of the latter two groups with hydrocortisone at 25 mg/kg/d for 10 days and 50 mg/kg/d for 7 days, respectively, for establishment of kidney-yang deficiency and kidney-yin deficiency models. Then the pathological changes in the testicular tissue of the mice were observed by HE staining and the differentially expressed proteins were compared among different groups using isobaric tags for relative and absolute quantitation (iTRAQ) and the bioinformatics method. RESULTS: Sod1 was found to be a reproduction-related node protein differentially expressed in the testis tissues of the two types of kidney-deficiency mice, more highly expressed in the kidney-yin than in the kidney-yang deficiency group (P < 0.05). Five reproduction-associated node proteins were co-expressed in the testes of the two groups of kidney-deficiency mice, with significantly up-regulated expression of Rps28 and down-regulated expressions of Rpl11, Rplp2, Svs2 and Svs3a (P < 0.01). CONCLUSIONS: Sod1 may be one of the key material bases for the differentiation of male infertility caused by kidney-yang deficiency from that induced by kidney-yin deficiency, while Rps28, Rpl11, Rplp2, Svs2 and Svs3a may be the common material bases of male infertility caused by the two types of kidney deficiency.

Milk caseins decrease the binding of the major bovine seminal plasma proteins to sperm and prevent lipid loss from the sperm membrane during sperm storage.

Milk is used as a medium for sperm preservation. Caseins, the major proteins of milk, appear to be responsible for the protective effect of milk on sperm. Recently, we have shown that egg yolk, which is also widely used to preserve semen, protects sperm functions by preventing the binding to sperm of the major proteins of bull seminal plasma (BSP proteins), thereby preventing BSP protein-mediated stimulation of lipid loss from the sperm membrane. In the present study, we investigated whether milk caseins protect sperm in the same manner as egg yolk. Bovine ejaculates were diluted with skimmed milk permeate (skimmed milk devoid of caseins) or permeate that was supplemented with caseins and stored at 4 degrees C for 4 h. In the semen diluted with permeate, sperm viability and motility decreased in a time-dependent manner. However, in semen diluted with milk or permeate supplemented with caseins, sperm functions were maintained. In addition, lower amounts of the BSP proteins were associated with sperm in semen diluted with milk or permeate supplemented with caseins, as compared to semen diluted with permeate. No milk proteins were detected in the sperm protein extracts. Furthermore, sperm diluted with milk or permeate supplemented with caseins showed 3-fold lower losses of cholesterol and choline phospholipids than sperm diluted with permeate during storage. Thus, milk caseins decreased the binding of BSP proteins to sperm and reduced sperm lipid loss, while maintaining sperm motility and viability during storage. These results support our view that milk caseins prevent the detrimental effects of BSP proteins on the sperm membrane during sperm preservation.

Androgen-dependent expression, gene structure, and molecular evolution of guinea pig caltrin II, a WAP-motif protein.

We determined the cDNA and gene structures of guinea pig caltrin II, a unique member of the calcium transporter inhibitors containing a whey acidic protein (WAP) motif, and we established that it is a secretory protein with a potential 21-amino acid signal peptide in its N-terminus. Northern blot analysis and in situ hybridization histochemistry indicated that the expression of caltrin II is restricted to luminal epithelial cells in the seminal vesicles. Its message levels markedly decreased either after castration (and were restored by simultaneous administration of testosterone) or after treatment of the animals with estradiol, suggesting that the expression of caltrin II is androgen-dependent. Recombinant caltrin II had an elastase-inhibitor activity. Comparison of sequence between the caltrin II and related genes and their molecular evolutionary analyses revealed that caltrin II and seminal vesicle secretory proteins (SVPs) appear to be evolved from a common ancestor gene that is made by the fusion of semenogelin and trappin genes. Caltrin II and SVPs lost the transglutaminase substrate domain and the WAP motif, respectively, within a single exon, resulting in the exertion of different functions.

Molecular cloning of complementary DNA encoding mouse seminal vesicle-secreted protein SVS I and demonstration of homology with copper amine oxidases.

The primary structure of mouse SVS I was determined by peptide sequencing and nucleotide sequencing of cloned cDNA. The precursor molecule consists of 820 amino acid residues, including a signal peptide of 24 residues, and the mature polypeptide chain of 91 kDa has one site for potential N-linked glycosylation. The SVS I is homologous with amiloride-binding protein 1 (ABP1), a diamine oxidase. However, it probably lacks enzymatic activity, because the cDNA codes for His instead of Tyr at the position of the active-site topaquinon. The SVS I monomer probably binds one molecule of copper, because the His residues coordinated by Cu(II) are conserved. The SVS I gene consists of five exons and is situated on mouse chromosome 6,B2.3. It is located in a region of 100 kilobases (kb) containing several genes with homology to SVS I, including the gene of ABP1 and two other proteins with homology to diamine oxidase. The locus is conserved on rat chromosome 4q24, but the homologous region on human chromosome 7q34-q36 solely contains ABP1. The other genes with homology to diamine oxidase were probably present in a progenitor of primates and rodents but were lost in the evolutionary lineage leading to humans-presumably during recombination between chromosomes. The estimated molecular mass of rat SVS I is 102 kDa (excluding glycosylation). The species difference in size of SVS I is caused by tandem repeats of 18 amino acid residues in the central part of the molecule: The mouse has seven repeats, and the rat has 12 repeats.