Iqcg is essential for sperm flagellum formation in mice

Mammalian spermatogenesis comprises three successive phases: mitosis phase, meiosis phase, and spermiogenesis. During spermiogenesis, round spermatid undergoes dramatic morphogenesis to give rise to mature spermatozoon, including the condensation and elongation of nucleus, development of acrosome, formation of flagellum, and removal of excessive cytoplasm. Although these transformations are well defined at the morphological level, the mechanisms underlying these intricate processes are largely unknown. Here, we report that Iqcg, which was previously characterized to be involved in a chromosome translocation of human leukemia, is highly expressed in the spermatogenesis of mice and localized to the manchette in developing spermatids. Iqcg knockout causes male infertility, due to severe defects of spermiogenesis and resultant total immobility of spermatozoa. The axoneme in the Iqcg knockout sperm flagellum is disorganized and hardly any typical (“9+2”) pattern of microtubule arrangement could be found in Iqcg knockout spermatids. Iqcg interacts with calmodulin in a calcium dependent manner in the testis, suggesting that Iqcg may play a role through calcium signaling. Furthermore, cilia structures in the trachea and oviduct, as well as histological appearances of other major tissues, remain unchanged in the Iqcg knockout mice, suggesting that Iqcg is specifically required for spermiogenesis in mammals. These results might also provide new insights into the genetic causes of human infertility.

Altered protein prenylation in Sertoli cells is associated with adult infertility resulting from childhood mumps infection

Loss of GGPPS from childhood mumps infection or deletion in mice results in constitutively activated MAPK and NF-kB signaling that induces spermatogonium apoptosis, macrophage invasion into seminiferous tubules, and sterility.

Mumps commonly affects children 5–9 yr of age, and can lead to permanent adult sterility in certain cases. However, the etiology of this long-term effect remains unclear. Mumps infection results in progressive degeneration of the seminiferous epithelium and, occasionally, Sertoli cell–only syndrome. Thus, the remaining Sertoli cells may be critical to spermatogenesis recovery after orchitis healing. Here, we report that the protein farnesylation/geranylgeranylation balance is critical for patients’ fertility. The expression of geranylgeranyl diphosphate synthase 1 (GGPPS) was decreased due to elevated promoter methylation in the testes of infertile patients with mumps infection history. When we deleted GGPPS in mouse Sertoli cells, these cells remained intact, whereas the adjacent spermatogonia significantly decreased after the fifth postnatal day. The proinflammatory MAPK and NF-κB signaling pathways were constitutively activated in GGPPS^−/− Sertoli cells due to the enhanced farnesylation of H-Ras. GGPPS^−/− Sertoli cells secreted an array of cytokines to stimulate spermatogonia apoptosis, and chemokines to induce macrophage invasion into the seminiferous tubules. Invaded macrophages further blocked spermatogonia development, resulting in a long-term effect through to adulthood. Notably, this defect could be rescued by GGPP administration in EMCV-challenged mice. Our results suggest a novel mechanism by which mumps infection during childhood results in adult sterility.

Integrity of the blood-testis barrier in healthy men after suppression of spermatogenesis with testosterone and levonorgestrel

STUDY QUESTION

Do exogenous male hormonal contraceptives that suppress intratesticular testosterone and spermatogenesis interfere with the blood-testis barrier integrity in men?

SUMMARY ANSWER

When spermatogenesis was suppressed by testosterone alone or combined with levonorgestrel (LNG) treatment in men, the structural appearance of Sertoli cell tight junctions remained intact in the human testis.

WHAT IS ALREADY KNOWN

Testosterone promotes the integrity of the blood-testis barrier. Intratesticular androgen deprivation induced by exogenous testosterone plus a progestin to suppress spermatogenesis in a contraceptive regimen may disturb the structural and functional integrity of the blood-testis barrier.

STUDY DESIGN, SIZE AND DURATION

Testicular biopsies were obtained from a sub-study of a randomized clinical trial of 36 healthy Chinese men who were treated for 18 weeks and followed for at least a 12-week recovery period.

PARTICIPANTS/MATERIAL, SETTING, METHODS

Healthy Chinese male volunteers (27-48 years) were randomized to two treatment groups (n = 18/group) for 18 weeks: (1) testosterone undecanoate (TU) 1000 mg i.m. injection followed by a 500 mg injection every 6 weeks and (2) TU + LNG 250 μg orally daily. Blood samples were obtained from all participants before and during treatment and at the end of the recovery phase. Open testicular biopsies for this study were obtained from four men before treatment and from four men in each of the TU and TU + LNG groups at 2 and 9 weeks of treatment. The presence of antisperm antibodies was checked in the archived serum samples of the subjects at baseline, during treatment and at the end of the recovery period. Stored testicular biopsy samples from cynomolgus monkeys treated with either sub-cutaneous testosterone or placebo for 12 weeks were used for additional protein expression studies.

MAIN RESULTS AND ROLE OF THE CHANCE

Expression of blood-testis barrier associated proteins quantified by immunohistochemistry (claudin 3, claudin 11, junctional adhesion molecule-A, zonula occludens-1) remained unchanged despite a significant decrease in the numbers of pachytene spermatocytes and round spermatids in the seminiferous tubules at 9 weeks in the TU + LNG group. This was confirmed by immunoblots showing a lack of quantitative change in these tight junction proteins in monkeys after testosterone treatment. There were no increases in serum antisperm antibodies in the volunteers during the study.

LIMITATIONS/REASONS FOR CAUTION

The duration of the study was short and the long-term effects of male hormonal contraceptive treatments on the integrity of the blood-testis barrier remain to be determined.

WIDER IMPLICATIONS OF THE FINDINGS

This study supports the safety of male hormonal contraceptive treatment and does not corroborate the previous findings of disturbed immunological integrity of the blood-testis barrier from animal studies such as androgen receptor knockout mice and exogenous hormonal treatment in rats.

STUDY FUNDING/COMPETING INTEREST

The study was supported by grants from the Contraceptive Research and Development Program and the Mellon Foundation (MFG-02-64, MFG-03-67), Endocrine, Metabolism and Nutrition Training Grant (T32 DK007571), the Clinical and Translational Science Institute at Los Angeles Biomedical and Harbor-UCLA Medical Center (UL1RR033176 and UL1TR000124) and the Los Angeles Biomedical Research Institute Summer High School Student Program.

[Location of Dctn1 in the mouse testis and sperm and its role in spermiogenesis]

OBJECTIVE

To investigate the role of dynactin 1 (Dctn1) in the process of mouse spermiogenesis.

METHODS

Western blot and indirect immunofluorescence were used to analyze the expression and location of Dctn1 in the mouse testis and spermatozoa. The highest efficiency of small interference RNA (siRNA) was verified by GC2-spd cell line in vitro and in vivo studies, respectively. Dctn1 siRNA mixed with the indicator (0.4% trypan blue) was injected into the seminiferous tubules of 3-week-old ICR mice through rete testis microinjection, and negative control siRNA injected into the control testes. The normal group included 3-week-old ICR mice that did not receive any treatment. Spermatozoa were collected from the cauda epididymis 3 weeks after siRNA injection for morphological analysis.

RESULTS

Dctn1 was mainly localized in the tail of spermatozoa. After interference, the sperm tail abnormality in the Dctn1 siRNA group was (23.57 +/- 0.55)%, significantly higher than (12.35 +/- 2.29)% in the control (P < 0.01, n = 3), and it was (3.37 +/- 0.69)% in the normal group.

CONCLUSION

Dctn1 plays an important role in mouse spermiogenesis, and mainly affects the formation of the tail of spermatozoa.

Effects of di-n-butyl phthalate on male rat reproduction following pubertal exposure

Di-n-butyl phthalate (DBP) is an endocrine-disrupting chemical that has the potential to affect male reproduction. However, the reproductive effects of low-dose DBP are still not well known, especially at the molecular level. In the present study, pubertal male Sprague-Dawley rats were orally administered DBP at a wide range of doses (0.1, 1.0, 10, 100 and 500 mg kg⁻¹ day⁻¹) for 30 days. The selected end points included reproductive organ weights, testicular histopathology and serum hormonal levels. Additionally, proteomic analysis was performed to identify proteins that are differentially expressed as a result of exposure to DBP at low doses (0.1, 1.0 and 10 mg kg⁻¹ day⁻¹). Toxic effects were observed in the high-dose groups, including anomalous development of testes and epididymides, severe atrophy of seminiferous tubules, loss of spermatogenesis and abnormal levels of serum hormones. Treatment with low doses of DBP seemed to exert a 'stimulative effect' on the serum hormones. Proteomics analysis of rat testes showed 20 differentially expressed proteins. Among these proteins, alterations in the expression of HnRNPA2/B1, vimentin and superoxide dismutase 1 (SOD1) were further confirmed by Western blot and immunohistochemistry. Taken together, we conclude that high doses of DBP led to testicular toxicity, and low doses of DBP led to changes in the expression of proteins involved in spermatogenesis as well as changes in the number and function of Sertoli and Leydig cells, although no obvious morphological changes appeared. The identification of these differentially expressed proteins provides important information about the mechanisms underlying the effects of DBP on male rat reproduction.

[Expression of annexin A7 in spermatogonial stem cells]

OBJECTIVE

To study the expression of Annexin A7 in the mouse testis, especially in different types of spermatogonia.

METHODS

We prepared Annexin A7 recombinant protein using prokaryotic expression, adsorbed the Annexin A7 antibody with it after identified by mass spectrometry, and detected the expression of Annexin A7 by Western-blot and immunohistochemistry.

RESULTS

Annexin A7 was expressed in a development-dependent manner in the spermatogonia of the prepubertal mice and in the type-A single (As) and type-A paired (Apr) spermatogonia of adult mice. These results were confirmed by the co-localization of Annexin A7 and Stra8, a known determinant of differentiated spermatogonial stem cells (SSCs).

CONCLUSION

Annexin A7 is the internal factor of As and Apr spermatogonia, which might be involved in the biological functions of SSCs.

Caveolae-dependent endocytosis is required for class A macrophage scavenger receptor-mediated apoptosis in macrophages

SR-A (class A macrophage scavenger receptor) is a transmembrane receptor that can bind many different ligands, including modified lipoproteins that are relevant to the development of vascular diseases. However, the precise endocytic pathways of SR-A/mediated ligands internalization are not fully characterized. In this study, we show that the SR-A/ligand complex can be endocytosed by both clathrin- and caveolae-dependent pathways. Internalizations of SR-A-lipoprotein (such as acLDL) complexes primarily go through clathrin-dependent endocytosis. In contrast, macrophage apoptosis triggered by SR-A-fucoidan internalization requires caveolae-dependent endocytosis. The caveolae-dependent process activates p38 kinase and JNK signaling, whereas the clathrin-mediated endocytosis elicits ERK signaling. Our results suggest that different SR-A endocytic pathways have distinct functional consequences due to the activation of different signaling cascades in macrophages.

Proteomics of spermatogenesis: from protein lists to understanding the regulation of male fertility and infertility

Proteomic technologies have undergone significant development in recent years, which has led to extensive advances in protein research. Currently, proteomic approaches have been applied to many scientific areas, including basic research, various disease and malignant tumour diagnostics, biomarker discovery and other therapeutic applications. In addition, proteomics-driven research articles examining reproductive biology and medicine are becoming increasingly common. The key challenge for this field is to move from lists of identified proteins to obtaining biological information regarding protein function. The present article reviews the available scientific literature related to spermatogenesis. In addition, this study uses two-dimensional electrophoresis mass spectrometry (2DE-MS) and liquid chromatography (LC)-MS to construct a series of proteome profiles describing spermatogenesis. This large-scale identification of proteins provides a rich resource for elucidating the mechanisms underlying male fertility and infertility.

[Expression of carbonic anhydrase II in human testes and spermatozoa and its clinical significance]

OBJECTIVE

To investigate the expression of carbonic anhydrase II (CA2) in human testes and spermatozoa, and to compare the expressions of CA2 in ejaculated spermatozoa between normozoospermic and asthenozoospermic men.

METHODS

The localization of CA2 in human testes was observed by immunohistochemistry, and that in human sperm by immunofluorescence. Western blot was used to detect the expression of CA2 in the semen samples obtained from 16 normozoospermic and 16 asthenozoospermic volunteers.

RESULTS

The CA2 protein was shown to be localized in the tail of elongating spermatids by immunohistochemistry and in the flagellum of human sperm by immunofluorescence. Western blot revealed an obviously increased expression of CA2 in the spermatozoa of asthenozoospermic patients, with statistically significant difference from the normozoospermic group (1.84 +/- 0.32 vs 1.41 +/- 0.26, P < 0.05).

CONCLUSION

The CA2 protein is expressed in the spermatogenic stage of elongating spermatids in human testes and localized in the sperm tail. The expression of CA2 is significantly increased in the spermatozoa of asthenozoospermic men, which might be responsible for low sperm motility.

The role of ezrin-associated protein network in human sperm capacitation

Membrane modifications in sperm cells represent a key step in sperm capacitation; however, the molecular basis of these modifications is not fully understood. Ezrin is the best-studied member of the ezrin/radixin/merlin family. As a cross-linker between the cortical cytoskeleton and plasma membrane proteins, ezrin contributes to remodeling of the membrane surface structure. Furthermore, activated ezrin and the Rho dissociation inhibitor, RhoGDI, promote the formation of cortical cytoskeleton-polymerized actin through Rho activation. Thus, ezrin, actin, RhoGDI, Rho and plasma membrane proteins form a complicated network in vivo, which contributes to the assembly of the structure of the membrane surface. Previously, we showed that ezrin and RhoGDI1 are expressed in human testes. Thus, we sought to determine whether the ezrin-RhoGDI1-actin-membrane protein network has a role in human sperm capacitation. Our results by Western blot indicate that ezrin is activated by phosphorylation of the threonine567 residue during capacitation. Co-immunoprecipitation studies revealed that, during sperm capacitation, the interaction between ezrin and RhoGDI1 increases, and phosphostaining of two dimensional electrophoresis gels showed that RhoGDI1 is phosphorylated, suggesting that RhoGDI1 dissociates from RhoA and leads to actin polymerization on the sperm head. We speculate that activated ezrin interacts with polymerized actin and the glycosylated membrane protein cd44 after capacitation. Blocking sperm capacitation using ezrin- or actin-specific monoclonal antibodies decreases their acrosome reaction (AR) rate, but has no effect on the AR alone. Taken together, our results show that a network consisting of ezrin, RhoGDI1, RhoA, F-actin and membrane proteins functions to influence the modifications that occur on the membrane of the sperm head during human sperm capacitation.

AF-2364 is a prospective spermicide candidate

AbstractInhibition of sperm motility has recently become a promising target for male contraceptive development. AF-2364, an analogue of Lonidamine (LND), had a contraceptive effect when orally administered to adult Sprague-Dawley rats. LND can also target mitochondria to inhibit oxygen consumption and block energy metabolism in tumour cells. However, there are no reports of the effects of AF-2364 on human sperm function. Herein we describe the action of AF-2364 on human sperm in vitro, as well as the mechanisms involved. AF-2364 specifically blocked human sperm motility in vitro. Further experiments revealed that AF-2364 can target sperm mitochondrial permeability transition (MPT) pores to induce the loss of sperm mitochondrial membrane potential (DeltaPsim) and decrease ATP generation; however, no significant changes in the cytoskeletal network or the human sperm proteome were detected after exposure to AF-2364. Incubation of AF-2364 with other human or mouse cell lines indicated that the spermicidal effect at the lower concentration was specific. In summary, the spermicidal effect of AF-2364 involves direct action on sperm MPT pores, and this compound should be further investigated as a new spermicide candidate.

NYD-SP27, a novel intrinsic decapacitation factor in sperm

Prior to fertilization sperm has to undergo an activation process known as capaciation, leading to the acrosome reaction. Till now, little is known about the mechanism for preventing premature capacitation in sperm although decapacitation factors from various sources have been thought to be involved. In this study, we report that NYD-SP27, an isoform of phospholipase C Zeta 1 (PLCZ1), is localized to the sperm acrosome in mouse and human spermatozoa by immunofluorescence using a specific antibody. Western blot and double staining analyses show NYD-SP27 becomes detached from sperm, as they undergo capacitation and acrosome reaction. The absence of HCO3-, a key factor in activating capacitation, from the capacitation-inducing medium prevents the loss of NYD-SP27 from sperm. The anti-NYD-SP27 antibody also prevents the loss of NYD-SP27 from sperm, reduced the number of capacitated sperm, inhibited the acrosome reaction induced by ATP and progesterone, and inhibited agonist-induced PLC-coupled Ca2+ mobilization in sperm, which can be mimicked by the PLC inhibitor, U73122. These data strongly suggest that NYD-SP27 is a physiological inhibitor of PLC that acts as an intrinsic decapacitation factor in sperm to prevent premature capacitation and acrosome reaction.

The association of CaM and Hsp70 regulates S-phase arrest and apoptosis in a spatially and temporally dependent manner in human cells

The cell cycle is controlled by regulators functioning at the right time and at the right place. We have found that calmodulin (CaM) has specific distribution patterns during different cell-cycle stages. Here, we identify cell-cycle-specific binding proteins of CaM and examine their function during cell-cycle progression. We first applied immunoprecipitation methods to isolate CaM-binding proteins from cell lysates obtained at different cell-cycle phases and then identified these proteins using mass spectrometry methods. A total of 41 proteins were identified including zinc finger proteins, ribosomal proteins, and heat shock proteins operating in a Ca(2+)-dependent or independent manner. Fifteen proteins were shown to interact with CaM in a cell-phase-specific manner. The association of the selected proteins and CaM were confirmed with in vitro immunoprecipitation and immunostaining methods. One of the identified proteins, heat shock protein 70 (Hsp70), was further studied with respect to its cell-cycle-related function. In vivo fluorescence resonance energy transfer (FRET) analysis showed that the interaction of CaM and Hsp70 was found in the nucleus during the S phase. Overexpression of Hsp70 is shown to arrest cells at S phase and, thus, induce cell apoptosis. When we disrupted the CaM-Hsp70 association with HSP70 truncation without the CaM-binding domain, we found that S-phase arrest and apoptosis could be rescued. The results suggest that the spatial and temporal association of CaM and Hsp70 can regulate cell-cycle progression and cell apoptosis.

Role of translation by mitochondrial-type ribosomes during sperm capacitation: an analysis based on a proteomic approach

Mammalian spermatozoa contain a complex population of mRNAs, some of which have been demonstrated to be translated de novo by mitochondrial-type ribosomes using D-chloramphenicol (CP), a specific inhibitor of mitochondrial translation. However, little is known about the functions of these mRNAs in mature sperm. In the present study, differential proteomic approaches were applied to study sperm protein profiles translated by mitochondrial-type ribosomes using the inhibitor CP and 44 proteins were identified with lower expression in CP-treated sperm in comparison to capacitated sperm (ratio >or= 1.5, p<0.05). Results of Western blot and real-time PCR suggest that four proteins were translated by mitochondrial-type ribosomes. Bioinformatics analysis indicated that 26 of 44 proteins were involved in some critical processes correlated to sperm-egg interaction event. In addition, Mups, whose functions in reproduction have never been studied, were chosen for further study. Our results showed that Mups proteins were localized to the acrosome and flagellum of precapacitated sperm, and were also expressed in the equatorial segment of capacitated sperm. The depletion of Mups using neutralizing antibodies significantly inhibited capacitation in a dose-dependent manner, subsequently inhibited acrosome reaction and sperm-egg fusion. In summary, mitochondrial translation during capacitation can store proteins beneficial for sperm-egg interaction.

Levonorgestrel enhances spermatogenesis suppression by testosterone with greater alteration in testicular gene expression in men

Prior studies have demonstrated that combined treatment of testosterone with a progestin induces a more rapid and greater suppression of spermatogenesis than testosterone treatment alone. We hypothesized that the suppressive effects of the combination of testosterone undecanoate (TU) injections plus oral levonorgestrel (LNG) on spermatogenesis may be mediated through a greater perturbation of testicular gene expression than TU alone. To test this hypothesis, we performed open testicular biopsy on 12 different adult healthy subjects: 1) four healthy men as controls; 2) four men 2 wk after TU treatment; and 3) four men 2 wk after TU + LNG administration. RNA isolated from biopsies was used for DNA microarray using the Affymetrix Human Genome U133 Plus 2.0 oligonucleotide microarrays. Gene expression with >or=2-fold changes (P < 0.05) compared with control was analyzed using the National Institutes of Health Database for Annotation, Visualization, and Integrated Discovery 2008 resource. The TU treatment altered the gene expression in 109 transcripts, whereas TU + LNG altered the gene expression in 207 transcripts compared with control. Both TU and TU + LNG administration suppressed gene expression of insulin-like 3; cytochrome P450, family 17, subfamily A1 in Leydig cells; and inhibin alpha in Sertoli cells; they increased proapoptotic transcripts BCL2-like 14, insulin-like growth factor-binding protein 3; and they decreased X-linked inhibitor of apoptosis protein. In comparison with TU treatment alone, TU + LNG treatment upregulated insulin-like 6 and relaxin 1, and downregulated RNA-binding protein transcripts. We conclude that TU + LNG administration induces more changes in testicular gene expression than TU alone. This exploratory study provided a novel and valuable database to study the mechanisms of action of hormonal regulation of spermatogenesis in men and identified testicular-specific molecules that may serve as potential targets for male contraceptive development.

Characterization of Spindlin1 isoform2 in mouse testis

AIM

To investigate the expression of Spindlin 1 (Spin 1) isoform2 and assess its function in mouse testis.

METHODS

First, reverse-transcription polymerase chain reaction (RT-PCR) was used to determine whether Spin1 isoform2 is present in mouse testis. Then the expression patterns of the isoform between newborn and adult mice testes were compared by immunoblot analysis. Finally, the diversity of its localization in mice testes at different ages (days 0, 7, 14, 21, 28 and 60) was observed by immunohistochemistry. The localization of the protein in mouse sperm was also investigated by immunofluorescence.

RESULTS

The RT-PCR results show that Spin1 isoform2 is present in mouse testis. As shown by immunoblot analysis, the isoform was more highly expressed in adult testes compared with newborn testes. Interestingly, Spin1 isoform2 did not show up in the cytoplasm of primary spermatocytes until day 14. Also, the protein exists at the tail of the mouse sperm.

CONCLUSION

Spin1 isoform2 is a protein expressed highly in adult testis, which might be involved in spermatogenesis and could be necessary for normal sperm motility.

Construction of a proteome profile and functional analysis of the proteins involved in the initiation of mouse spermatogenesis

Spermatogenesis is a complex process of terminal differentiation wherein mature sperm are produced. In the first wave of mouse spermatogenesis, different spermatogenic cells appear at specific time points, and their appearance is expected to be accompanied by changes in specific protein expression patterns. In this study, we used 2D-PAGE and MALDI-TOF/TOF technology to construct a comparative proteome profile for mouse testis at specific time points (days 0, 7, 14, 21, 28, and 60 postpartum). We identified 362 differential protein spots corresponding to 257 different proteins. Further cluster analysis revealed 6 expression patterns, and bioinformatics analysis revealed that each pattern was related to many specific cell processes. Among them, 28 novel proteins with unknown functions neither in somatic cells nor germ cells were identified, 8 of which were found to be uniquely or highly expressed in mouse testes via comparison with the GNF SymAtlas database. Further, we randomly selected 7 protein spots and the above 8 novel proteins to verify the expression pattern via Western blotting and RT-PCR, and 6 proteins with little information in testis were further investigated to explore their cellular localization during spermatogenesis by performing immunohistochemistry for the mouse testis tissue. Taken together, the above results reveal an important proteome profile that is functional during the first wave of mouse spermatogenesis, and they provide a strong basis for further research.

transient scrotal hyperthermia and levonorgestrel enhance testosterone-induced spermatogenesis suppression in men through increased germ cell apoptosis

CONTEXT

In rodents and monkeys, a combination of hormonal and physical agents accelerates germ cell death.

OBJECTIVE

A "proof of concept" study was performed to investigate whether addition of heat exposure or a progestin to an androgen induces germ cell death and more complete and rapid spermatogenesis suppression.

DESIGN AND SETTINGS

A randomized clinical trial was performed at academic medical centers.

PARTICIPANTS

We treated four groups of healthy male volunteers (18 per group) for 18 wk: 1) testosterone undecanoate (TU) 1000 mg im (first dose), followed by 500 mg im every 6 wk; 2) submersion of scrota at 43 C in water for 30 min/d for 6 consecutive days; 3) TU plus heat; and 4) TU plus oral levonorgestrel (LNG) 250 microg/d.

MAIN OUTCOME MEASURES

Semen parameters, testicular histology, and germ cell apoptosis were the main outcome measures.

RESULTS

Heat alone and TU plus heat suppressed sperm counts more than TU alone by wk 6. By wk 9, recovery began in the heat only group, whereas spermatogenesis remained suppressed in the TU plus heat group. Oral LNG plus TU suppressed spermatogenesis earlier and more severely than TU alone. At wk 2, significantly greater germ cell apoptosis occurred in heat and heat plus TU subjects, but not in subjects without heat treatment, compared with pretreatment subjects. By 9 wk, markedly smaller seminiferous tubule diameters and fewer spermatocytes and spermatids were noted in all 12 biopsies from men receiving TU, TU plus LNG, with most dramatic differences for the TU plus heat group, whereas no differences from pretreatment biopsies were observed in men who received heat treatment only.

CONCLUSIONS

Heat causes a rapid and transient suppression of spermatogenesis. TU plus heat resulted in low-sperm output that was maintained by continuous treatment with TU. Addition of an oral progestin accelerated spermatogenesis suppression by TU alone. Increased germ cell apoptosis contributed to suppression of spermatogenesis.

Rapid evolution, genetic variations, and functional association of the human spermatogenesis-related gene NYD-SP12

NYD-SP12 is a recently identified spermatogenesis-related gene with a pivotal role in human testis development. In this study, we analyzed between-species divergence and within-species variation of NYD-SP12 in seven representative primate species, four worldwide human populations, and 124 human clinical subjects. Our results indicate that NYD-SP12 evolves rapidly in both the human and the chimpanzee lineages, which is likely caused by Darwinian positive selection and/or sexual selection. We observed significant interpopulation divergence among human populations, which might be due to the varied demographic histories. In the association analysis, we demonstrated significant frequency discrepancy of a synonymous sequence polymorphism among the clinical groups with different sperm traits.

Identification of several proteins involved in regulation of sperm motility by proteomic analysis

Proteomic technology was used to compare sperm protein expression profiles in asthenozoospermic patients with that of normozoospermic donors and 10 differentially expressed proteins were identified. These proteins may play roles in the regulation of sperm motility, and their characterization could merit further investigation on sperm motility-related male factor infertility.

Cloning and characterization of a novel sperm tail protein, NYD-SP28

In this study, a gene coding a novel human sperm tail protein named NYD-SP28 was cloned and characterized using a complementary DNA (cDNA) microarray. Its expression was 3.5 times higher in human testis than in fetal testis, and very high in human spermatozoa. The full length of NYD-SP28 cDNA was 1798 bp and encoded a 484-amino-acid protein. Motif analysis revealed that the protein contained a cluster of phosphorylation sites, N-glycosylation sites and N-myristoylation sites. Immunohistochemical analysis of normal human testes showed that NYD-SP28 was expressed in the cytoplasm of spermatogenic cells but not in interstitial cells. The EGFP-NYD-SP28 fusion protein was also localized in the cytoplasm of transfected 7721 cells. In human spermatozoa, NYD-SP28 immunoreactivity was detected in entire sperm tail. Using the two-dimensional (2-D) gel electrophoresis and immunoblotting technique, NYD-SP28 was found to be post-translationally modified during sperm capacitation. In conclusion, these results suggest that NYD-SP28 is a new human sperm tail protein and might play an important role during sperm capacitation.

Proteomic Analysis of Effect of Hyperthermia on Spermatogenesis in Adult Male Mice

We characterized cellular and molecular mechanisms involved in spermatogenesis following short-term heat exposure of murine testis. For these studies, we utilized a proteomic approach with two-dimensional gel electrophoresis (2DE) analyses and mass spectroscopic identification of proteins with altered expression in mouse testes at different times after heat shock. We established a proteome reference map from 7-wk-old mouse testis linked to a federated proteome database. We used these tools to analyze quantitative variations in the tissue over a time course of 0.5, 2, 6, and 12 h following heat exposure. We separated 108 protein spots expressed differentially between the heat shock tissues and the control mouse testes. Of these spots, we identified 36 by comparing with the control reference map. We then focused on the heterogeneous nuclear ribonucleoproteins (hnRNPs) and the chaperonins containing t-complex polypeptide-1 (CCT). Further analysis in this heat-shocked model suggests numerous potential mechanisms for heat shock-induced spermatogenic disorder.

Gene functional research using polyethylenimine-mediated in vivo gene transfection into mouse spermatogenic cells

AIM

To study polyethylenimine (PEI)-mediated in vivo gene transfection into testis cells and preliminary functional research of spermatogenic cell-specific gene NYD-SP12 using this method.

METHODS

PEI/DNA complexes were introduced into the seminiferous tubules of mouse testes using intratesticular injection. Transfection efficiency and speciality were analyzed on the third day of transfection with fluorescent microscopy and hematoxylin staining. The long-lasting expression of the GFP-NYD-SP12 fusion protein and its subcellular localization in spermatogenic cells at different stages were analyzed with fluorescent microscopy and propidium iodide staining.

RESULTS

With the mediation of PEI, the GFP-NYD-SP12 fusion gene was efficiently transferred and expressed in the germ cells (especially in primary spermatocytes). Transfection into Sertoli cells was not observed. The subcellular localization of the GFP-NYD-SP2 fusion protein showed dynamic shifts in spermatogenic cells at different stages during spermatogenesis.

CONCLUSION

PEI can efficiently mediate gene transfer into spermatocytes. Thus, it might be useful for the functional research of spermatogenic-cell specific genes such as the NYD-SP12 gene. In our study, the NYD-SP12 protein was visualized and was involved in the formation of acrosome during spermatogenesis. Our research will continue into the detailed function of NYD-SP12 in spermatocytes.

Expression of a novel beta adaptin subunit mRNA splice variant in human testes

AIM

To identify a novel isoform of adaptin 2 beta subunit (named Ap2beta-NY) and to investigate its relationship with testicular development and spermatogenesis.

METHODS

Using a human testis cDNA microarray, a clone (Ap2beta-NY), which was strongly expressed in adult testes but weakly expressed in embryo testes, was sequenced and analyzed. Using polymerase chain reaction (PCR), the tissue distribution and expression time pattern of Ap2beta-NY were determined.

RESULTS

Ap2beta-NY was identified and has been deposited in the GenBank (AY341427). The expression level of Ap2beta-NY in the adult testis was about 3-fold higher than that in the embryo testis. PCR analysis using multi-tissue cDNA indicated that Ap2beta-NY was highly expressed in the testis, spleen, thymus, prostate, ovary, blood leukocyte and brain, but not in the heart, placenta, lung, liver, skeletal muscle, kidney and pancreas. In addition, Ap2beta-NY was variably expressed in the testes of patients with spermatogenesis-disturbance and spermatogenesis-arrest but not expressed in those of Sertoli-cell-only syndrome, which implied that, in the testis, Ap2beta-NY was restrictively expressed in germ cells.

CONCLUSION

Ap2beta-NY is an isoform of Ap2beta and may be involved in regulating the process of spermatogenesis and testis development.

Expression of a novel alternative transcript of the novel retinal pigment epithelial cell gene NORPEG in human testes

AIM

To identify a novel alternative transcript of the novel retinal pigment epithelial cell gene (NORPEG) expressed in the human testis.

METHODS

A human testis cDNA microarray was established and hybridized with cDNA probes from human fetal testes, adult testes and human spermatozoa. Differentially expressed clones were sequenced and analyzed. One of these clones was a short transcript of NORPEG which we proceeded to analyze by RT-PCR.

RESULTS

The novel short alternative transcript of NORPEG was isolated and named sNORPEG. It was 3486 bp in length and contained a 2952-bp open reading frame, encoding a 110.4-kDa protein of 983 amino acids. Amino acid sequence analysis showed that the sNORPEG protein contains six ankyrin repeats and two coiled-coil domains. It shares a high homology with the NORPEG and ankycorbin proteins in both its sequence and motifs. Blasting the human genome database localized sNORPEG to human chromosome 5p13.2-13.3. Expression profiles showed that sNORPEG was expressed in human fetal testes, adult testes and spermatozoa. Moreover, sNORPEG was found to be ubiquitously expressed in human tissues.

CONCLUSION

sNORPEG is expressed in different developmental stages of the testis and encodes a protein that may have roles in human testis development and spermatogenesis.

Expression of a novel dipeptidyl peptidase 8 (DPP8) transcript variant, DPP8-v3, in human testis

AIM

To investigate the role of a novel dipeptidyl peptidase 8 transcript variant (DPP8-v3) gene in testis development and/or spermatogenesis.

METHODS

A human testis cDNA microarray was hybridized with mRNA of human adult and fetal testes. Differentially expressed clones were sequenced and characterized and their expression was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR) and Southern-blot analysis.

RESULTS

A new transcript variant of the human dipeptidyl peptidase (DPP8), exhibiting a 5-fold higher expression level in human adult than that in fetal testes, was cloned and was named DPP8 variant 3 (DPP8-v3). The full-length sequence of DPP8-v3 was 3,030 bp, encoding a protein of 898 amino acids.

CONCLUSION

DPP8-v3 is a novel human DPP8 transcript variant highly expressed in the adult testis. Similar to DPPIV, DPP8-v3 may play a key role in the immunoregulation of testes and accordingly may influence spermatogenesis and male fertility.

Pregnancies and births resulting from in vitro matured oocytes fertilized with testicular spermatozoa

PURPOSE

In vitro maturation (IVM) of immature human oocytes is an attractive option for the treatment of infertility. Similarly, intracytoplasmic sperm injection (ICSI) followed by testicular fine needle aspiration (TEFNA) is an important treatment for primarily male-factor infertility. This report highlights the combination of these two advanced assisted reproduction techniques, namely IVM and fertilization with TEFNA-retrieved spermatozoa by ICSI to overcome both of male and female infertility problems.

METHODS

Before immature oocyte retrieval (IOR), gonadotropin stimulation was given for 3 or 5 days. Following IVM, and mature oocytes were inseminated by ICSI followed by TEFNA.

RESULTS

Four couples with five completed treatment cycles were performed, and total of 36 immature oocytes were retrieved. Following 36 to 48 h of culture, 32 (88.89%, 32/36) oocytes became mature. The mature oocytes were inseminated with TEFNA-retrieved sperm, and 18 (56.25%, 18/32) oocytes were fertilized normally following ICSI. Eleven embryos were transferred in five cycles and two pregnancies and two singleton births were achieved in two patients.

CONCLUSIONS

This result demonstrates that the successful pregnancies and live births can be established from embryos produced from in vitro matured oocytes that fertilized with testicular sperm.

A two-dimensional electrophoresis reference map of human ovary

The ovary plays a central role in oogenesis and gonadal hormone secretion. Proteomic analysis is a valuable approach for gaining an increased understanding of the molecular nature of the ovary. In this work, two-dimensional electrophoresis for protein separation followed by matrix-assisted laser desorption/ionization mass spectrometry and database searches, identified 231 protein spots corresponding to 138 individual proteins that were found in gels representing both the follicular and luteal phases. The data were used to construct a database online (http://reprod.njmu.edu.cn/2d). The identified proteins were functionally classified into seven groups: (1) cell signaling/communication, (2) cell division, (3) gene/protein expression, (4) metabolism, (5) cell structure and motility, (6) cell/organism defense, and (7) unclassified. Among the proteins identified, 47% had not been previously reported in the human ovary. In addition, a number of disease-related proteins were identified in this protein map, including some cancer- and polycystic ovarian syndrome-related proteins. Two proteins with phosphorylation were verified by Western blot analysis. Comparison of protein abundance between follicular and luteal stages produced seven protein spots that had been identified in our database. This study provides a preliminary reference map of normal human ovary that will form a basis for comparative studies on normal and pathological conditions of the human ovary and may serve as a potential tool for clinical diagnosis, therapeutics, and prognosis.

Identification and characterization of the BGR-like gene with a potential role in human testicular development/spermatogenesis

AIM

To investigate the roles of the BGR-like gene in testicular development/spermatogenesis.

METHODS

A human testis cDNA microarray was hybridized with probes from human adult testes and embryo testes. The differentially expressed clones were sequenced and analyzed. Expression of the BGR-like gene was analyzed by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

A new gene exhibiting 50-fold difference in expression level between adult and fetal human testes was cloned and named the BGR-like gene. The cDNA consisted of 2500 nucleotides and had an open reading frame of 1437 nucleotides encoding a putative protein of 497 amino acid residues. Homologous comparison showed that the BGR-like gene was a new alternative splicing variant of the BGR gene and had sequence homology with the bubblegum gene of human, mouse, rat and Drosophila. Protein motif analysis of the BGR-like gene revealed that it contained a conserved adenosine monophosphate (AMP)-binding domain and a fatty acyl-CoA synthetase signature motif which existed in all acyl-CoA synthetases. The BGR-like gene transcript was imperceptibly expressed in human fetal testes, highly in human adult testes and moderately in elderly testes and human Leydig cells. RT-PCR-based tissue distribution experiments showed that the BGR-like gene was exclusively expressed in testes and was a testes-specific isoform of the BGR gene. A BGR-like gene transcript was not detected in some azoospermic testes.

CONCLUSION

The BGR-like gene may play an important role in spermatogenesis/testicular development and may be correlated with male infertility.

Identification and characterization of cul-3b, a novel hominine CUL-3 transcript variant

AIM

To identify genes related to the human testis development by substrate hybridization technique.

METHODS

A human testis cDNA microarray was constructed and hybridized with probes prepared from human adult and fetal testes and spermatozoa mRNAs by reverse transcription reactions. The differentially expressed genes were sequenced. And a newly identified cullin-3 (CUL-3) transcript variant (designated cul-3b) was bio-informatically analyzed with an online GenBank database. Multi-tissue reverse transcription polymerase chain reaction (RT-PCR) was used to determine the tissue expression profile of cul-3b.

RESULTS

Cul-3b, a novel CUL-3 transcript variant, was identified. The expression level of cul-3b in adult testes was 3.79-fold higher than that in fetal ones. Cul-3b differed from cul-3 (including NM_003590 and AY337761) in the opening reading frame and had three internal ribosomal entry sites IRESes in the 5'-UTR. These led to a 24 amino acid (aa) truncation at N-terminus of CUL-3b as compared with CUL-3 and a more motivated expression pattern of cul-3b under some strict circumstances. Additionally, cul-3b expressed ubiquitously in human tissues according to multi-tissue RT-PCR.

CONCLUSION

Cul-3b is a novel transcript variant of CUL-3, which may be important not only for the development of human testis but also for that of other organs.

Identification of a novel testis-specific gene and its potential roles in testis development/spermatogenesis

AIM

To identify and characterize a novel gene with potential roles in testis development and spermatogenesis.

METHODS

A cDNA microarray was constructed from a human testis large insert cDNA library and hybridized with probes of human or mouse adult and fetal testes. Differentially expressed genes were isolated and sequenced. RT-PCR was used to test the tissue distribution of the genes of interest and in situ hybridization was performed to localize the gene expression in the mouse testis. A range of bioinformatical programs including Gene Runner, SMART, NCBI Blast and Emboss CpGPlot were used to characterize the new gene's feature.

RESULTS

A novel testis-specific gene, NYD-SP5, was differentially expressed in fetal and adult testes. The deduced protein structure of NYD-SP5 was found to contain an IQ motif (a short calmodulin-binding motif containing conserved Ile and Gln residues), a Carbamate kinase-like domain, a Zn-dependent exopeptidase domain and a lactate dehydrogenase (LDH) C-terminal-like domain. RT-PCR analysis revealed that NYD-SP5 was predominantly expressed in the testis but not in other 15 tissues examined. In situ hybridization and RT-PCR examinations revealed that the expression of NYD-SP5 was confined in the male germ cell but not present in the somatic cell in the testes.

CONCLUSION

NYD-SP5 is a newly found testis-specific gene with potential roles in testis development and spermatogenesis through a calmodulin-activated enzyme.

Fertilization of in vitro matured human oocytes by intracytoplasmic sperm injection (ICSI) using ejaculated and testicular spermatozoa

AIM

To evaluate the fertilization competence of spermatozoa from ejaculates and testicle when the oocytes were matured in vitro following intracytoplasmic sperm injection (ICSI).

METHODS

Fifty-six completed cycles in 46 women with polycystic ovarian syndrome were grouped according to the semen parameters of their male partners. Group 1 was 47 cycles that presented motile and normal morphology spermatozoa in ejaculates and Group 2 was the other nine cycles where male partners were diagnosed as obstructive azoospermia and spermatozoa could only be found in testicular tissue fragment. All female patients received minimal stimulation with gonadotropin. Immature oocytes were matured in vitro and inseminated by ICSI. The spermatozoa from testes were retrieved by testicular fine needle aspiration.

RESULTS

A total of 449 and 78 immature oocytes were collected and cultured for 48 hours, 75.5 % (339/449) and 84.6 % (66/78) oocytes were matured in Groups 1 and 2, respectively. The percentage of oocytes achieving normal fertilization was significantly higher in Group 1 than that in Group 2 (72.9 % vs. 54.5 %, P 0.05). There were no significant differences in the rates of oocytes cleavage and clinical pregnancies in these two groups [87.4 % (216/247) vs. 88.9 % (32/36); 21.3 % (10/47) vs. 44.4 % (4/9)]. A total of 15 babies in the two groups were healthy delivered at term.

CONCLUSION

It appears that IVM combined with ICSI using testicular spermatozoa can produce healthy infants, while the normal fertilization rate of in vitro matured oocytes after ICSI using testicular spermatozoa was significantly lower than using the ejaculated spermatozoa.

Molecular cloning and expression of a novel alternative splice variant of BRDT gene

In this study, a human adult testis cDNA microarray was constructed and hybridized with (33)P-labeled human adult testis, embryo testis and sperm cDNA probes, respectively. A novel alternative splice variant of BRDT gene, named BRDT-NY, presumably involved in testicular function was cloned. It was expressed 3.96-fold more in human adult than embryo testis and also expressed in human spermatozoa. Similarly, RT-PCR revealed a differential expression pattern of this gene in human adult testes and fetal testes. The full length of BRDT-NY was 3438 bp and contained a 2883 bp open reading frame, encoding a 960-amino-acid protein. Sequence analysis showed that it has two bromodomains in N-terminal of the protein. Multiple tissue RT-PCR results showed that BRDT-NY was exclusively expressed in testis. mRNA expression of BRDT-NY gene was deleted in some azoospermic patients' testes. These experiments suggested that BRDT-NY gene may have an important role in the process of spermatogenesis and may be correlated with male infertility.

Molecular cloning and characterization of a novel splicing variant of PIASx

AIM

To investigate molecular mechanism of testis development and spermatogenesis.

METHODS

A human testis cDNA microarray was hybridized with probes from human adult testis, embryo testis and human sperm, and the differential expressed clones were sequenced and analyzed. Expression of PIAS-NY gene was analyzed by RT-PCR.

RESULT

A new isoform of PIAS family, named PIAS-NY, was isolated from human testis cDNA library. It was strongly expressed in adult testis and weakly expressed in both embryo testis and human sperm. Analysis of the open reading frame of PIAS-NY indicated that PIAS-NY was a polypeptide of 405 amino acid residues, and the sequence from the 15th amino acid to the end of PIAS-NY protein was the same as the N-terminal amino acids of PIASx-alpha and PIASx-beta protein. PIAS-NY protein contained two conserved putative LXXLL signature motifs and a zinc binding motif. Tissue distribution analysis revealed that PIAS-NY was predominantly expressed in testis, weakly in the pancreas, and almost imperceptibly in the other organs.

CONCLUSION

PIAS-NY may play important role in testis development and/or spermatogenesis.

Expression of a novel pyridoxal kinase mRNA splice variant, PKH-T, in human testis

AIM

To identify the genes specifically expressed in human adult and fetal testes and spermatozoa.

METHODS

A human testis cDNA microarray was established. Then mRNAs of human adult and fetal testis and spermatozoa were purified and probes were prepared by a reverse transcription reaction with mRNA as the template. The microarray was hybridized with probes of adult and fetal testes and spermatozoa. The nucleic acid sequences of differentially expressed genes were determined and homologies were searched in the databases of GenBank.

RESULTS

A novel human testis-specific gene, PKH-T, was identified by hybridizing adult and fetal testis and spermatozoa probes with a human testis cDNA microarray. The cDNA of PKH-T was 1 069 bp in length. The cDNA sequence of this clone was deposited in the Genbank (AY303972) and PKH-T was also determined as Interim GenSymbol (Unigene, HS.38041). PKH-T contained most PKH conserved motif. The 239 amino acid sequences deduced from the 719 bp open reading frame (ORF) had a homology with the gene PKH (U89606). PKH-T was specifically and strongly expressed in the testis. Comparison of the differential expressions of PKH and PKH-T in testes of different developmental stages indicated that PKH-T was expressed in the adult testis and spermatozoa, while PKH, in the adult, fetal and aged testes. PKH-T had no expression in the testis of Sertoli cell only and partially spermatogenic arrest patients.

CONCLUSION

PKH-T is a gene highly expressed in adult human testis and spermatozoa. It may play an important role in spermatogenesis and could be related to male infertility.

Differential expression of glucose-regulated protein 78 during spermatogenesis

The aim of the present study was to isolate and identify proteins involved in the process of spermatogenesis. To achieve this goal we used the technique of proteomic analysis. Comparison of testis protein patterns obtained by high-resolution two-dimensional gel electrophoresis from 1-week- and 7-week-old mice showed significant differences in protein spot intensities. Subsequently several of these variant protein spots were identified by mass spectrometry. Glucose-regulated protein (GRP) 78 (Bip) was one of them. GRP78, expressed at a lower level in 1-week-old mouse testes compared to 7-week-old mouse testes, is a member of the heat shock 70 protein family. It has recently been shown to be important for protecting cells from apoptosis in somatic cells, especially in progressively growing tumor cells. Further, immunohistochemical (IHC) analyses of mouse and human testes sections were performed to determine the cellular distribution of this protein. A strong GRP78 staining was seen beginning with pachytene spermatocytes. These findings suggested that GRP78 might perform an important function in the process of spermatogenesis.

Identification and characteristics of a novel E1 like gene nUBE1L in human testis

A gene, presumably involved in spermatogenesis, was identified and characterized by using cDNA microarray. Hybridization intensity was 2.13 fold higher in adult testis than that in fetal testis. The full length of this gene was 4288 bp and it encoded a 578 amino acid protein. Conserved structure and amino acid sequence analysis revealed that the protein contained 1 Thif-domain, 2 UBACT-domains, and a functional active site cysteine lay upstream of UBACT domain, all of them also existed in ubiquitin-activating enzyme E1 and E1 like proteins. So we named this gene as a novel ubiquitin-activating enzyme E1 like gene (nUBE1L). Expression profile showed that nUBE1L was predominantly expressed in testis. Comparison of the expression of nUBE1L in different developmental stages of testis indicated that it was highly expressed in adult testis. In conclusion, nUBE1L is a novel human E1 like gene highly expressed in adult testis, which plays key role in ubiquitin system, and accordingly influences spermatogenesis and male fertility.

Expression of a novel bHLH-Zip gene in human testis

AIM

To identify specifically expressed genes in the adult and fetal testes.

METHODS

A human testis cDNA microarray was established. Then the mRNA of adult and fetal testis was purified and probes were prepared by a reverse transcription reaction with the testis mRNA as template. The microarray was hybridized with probes of adult and fetal testes. The nucleic sequences of differentially expressed genes were determined and homologies were searched in the databases of the GenBank.

RESULTS

When hybridized with adult or fetal testis probes, the positive clones were 96.8 % and 95.4 %, respectively. Among these genes, one was a new testis-specific gene, which was named TSP1. TSP1 was highly expressed in human adult testis. The cDNA of TSP1 was 1,484 bp in length. The cDNA sequence of this clone was deposited in the Genbank (AF333098). TSP1 was also determined as Interim Gen Symbol (Unigene, No. Hs.98266). Protein analysis showed that TSP1 contained two functional domains: an N-terminal basic helix-loop-helix (bHLH) and a C-terminal leucine zipper (Zip). Homologous analysis showed that the 430 amino acid sequences deduced from the 1293 bp open reading frame (ORF) had a homology with the human gene FLJ2509 (AK098575). TSP1 had also a sequence homology with Spz 1 protein of mouse. Expression profiles showed that TSP1 was specifically and strongly expressed in the testis.

CONCLUSION

TSP1 is a gene highly expressed in adult testis. It may play an important role in spermatogenesis in the humans.

[Application of two-dimensional electrophoresis and mass spectrometry in the research of testicular proteins]

OBJECTIVES

To evaluate the application of two-dimensional electrophoresis and mass spectrometry in the research of proteins expressed in testis.

METHODS

Protein from adult ICR mouse testes was extracted by two-dimensional electrophoresis. Two protein spots were cut from the gel, then the proteins were digested in-gel by enzyme and the generated peptides were measured by matrix assisted laser desorption/ionization-time of flight mass spectrometry. The proteins were identified through database searching.

RESULTS

Two spots in Commasie Brilliant Blue-stained gel were identified as serum albumin and protein disulfide isomerase by database searching.

CONCLUSIONS

This rapid high resolution and efficient method is a very powerful way to analyze testicular proteins.

[Study on the relationship of balanced translocation t(1;12) with spermatogenesis]

OBJECTIVES

To investigate the relationship between chromosome balanced translocation t(1;12) (q24;q24) and spermatogenesis in infertile twin brothers.

METHODS

For twin brothers, karotype were determined. The levels of testosterone, FSH and LH were detected. YRRM1, DAZ and DYS240 were analyzed. In younger brother a biopsy was taken from testis.

RESULTS

Chromosome analysis for both twin brothers revealed a karotype of 46, XY, t(1;12) (q24;q24). Sperm count was less than 1.0 x 10(6)/ml. There was no deletion for YRRM1, DAZ and DYS240 gene on Y chromosome. Photomicrograph of seminiferous tubules showed the arrest of spermatogenesis.

CONCLUSIONS

Chromosome balanced translocation t(1;12) (q24;q24) may be the cause of the spermatogenesis arrest in infertile twin brothers. Gene in the point of translocation may be related to spermatogenesis.

[Effect of MPA and MPA + TU on the rat spermatogenesis and sexual hormones]

OBJECTIVES

To investigate the effect of administration of MPA with/without TU on serum sexual hormones and spermatogenesis of male rats.

METHODS

Twenty rats had been classified into four groups. Each group received injection of saline(group A) or MPA(37.5 or 75 mg/kg) (group B or group C, respectively) or MPA (75 mg/kg) + TU (25 mg/kg) (group D) every month during three months. Data from serum sexual hormones (FSH, LH, T), sperm counting and motility had been collected and analysed.

RESULTS

Spermatogenesis of rats undergoing administration of MPA with or without TU had been suppressed. Serum FSH and LH of group B, C, D declined, and so did serum T of group D. Testis of rats of group D atrophied and sperm counting of group D decreased remarkably compared with group B and C. But there was no statistics difference of the sexual hormone level among group B, C and D.

CONCLUSIONS

Administration of MPA alone could suppress the levels of FSH and LH and block the spermatogenesis of male rats. MPA combined with TU could offer stronger suppression on spermatogenesis. Mechanism of the suppression on spermatogenesis of MPA + TU is not only limited in the feed-back of gonadotropin, but there maybe exist a direct suppression on testis.

Cloning and characterization of a novel isoform of calpastatin in human adult testis

AIM

To clone a new gene related to human spermatogenesis.

METHODS

cDNA probes of embryo and adult testis were used to hybridize the cDNA microarray of adult testis, and the clones of differential hybridization were sequenced and analyzed.

RESULTS

A novel isoform of calpastatin exclusively and highly expressed in human adult testis was found.

CONCLUSION

A novel isoform of calpastatin expresses in human testis and it is related to spermatogenesis.

Expression of a novel reticulon-like gene in human testis

Identification of genes that are specifically expressed in the adult testis or the fetal testis is important for the study of genes related to the development of the testis. In this study, a human testis cDNA microarray was established. PCR products of 9216 clones from a human testis cDNA library were dotted on a nylon membrane; mRNA from adult and fetal testes were purified and probes were prepared by a reverse transcription reaction with testis mRNA as template. The microarray was hybridized with probes of adult and fetal testes, and 96.8 and 95.4% of clones were positive, respectively. In total, 731 clones were differentially expressed: 592 were highly expressed in adult testis and 139 were highly expressed in fetal testis. Among these genes, a new reticulon (Rtn)-like gene was detected and named Rtn-T. Rtn-T was highly expressed in adult human testis. The cDNA of Rtn-T contains 3491 bp and the putative protein had 968 amino acids. This protein is homologous to the six known members of the Rtn family (KIAA0886, Rtn xL, reticulon 4a, Nogo-A, Nogo-A short form, and brain my043) but was different at the 5' end. All homologues originate from one gene, and result from both different promotor regions and different splicing. Rtn-T lacks the first exon and contains a second exon that is lacking in the other homologues. Rtn-T is shorter than KIAA0886, Rtn xL, reticulon 4a and Nogo-A, but longer than the Nogo-A short form and brain my043. Sequence analysis showed that Rtn-T protein has two hydrophobic regions that may be membrane-spanning domains. Expression profiles showed that Rtn-T is specifically and strongly expressed in testis. The results of the present study indicate that the Rtn-T gene is differentially expressed in adult and fetal testes and encodes a membrane protein that may have a function in testis development.

Localisation and regulation of 17beta-hydroxysteroid dehydrogenase type 3 mRNA during development in the mouse testis

The final step in the biosynthesis of testosterone is the reduction of androstenedione to testosterone catalysed by the enzyme 17beta-hydroxysteroid dehydrogenase (17betaHSD). Five isoforms of the enzyme have been identified in the mouse and the type 3 isoform has been shown to be the predominant reductive form present in the adult human and mouse testis. In this study the regulation of 17betaHSD type 3 isoform mRNA levels and the cellular localisation of the enzyme mRNA have been studied in the mouse testis. To examine regulation of 17betaHSD type 3 mRNA expression in the testis, mRNA levels were measured during development in normal mice and in mice lacking circulating gonadotrophins (hpg) or functional androgen receptors (Tfm). In these mutants testicular descent does not occur at the normal time (25 days) and control animals were, therefore, rendered cryptorchid at 19 days. In neonatal mice, it has been shown a peak of type 3 expression occurs around day 5 and this was found to be normal in all groups in the current study. In normal animals there was a marked increase in type 3 isoform expression between 25 and 30 days and this continued into adulthood. In cryptorchid animals the increase in type 3 mRNA levels after 25 days was less marked than in untreated controls and by 90 days was about 15% of normal animals. In Tfm mice, levels of 17betaHSD type 3 mRNA failed to show any increase around puberty (25 days) and in adult Tfm mice, levels were less than 1% of cryptorchid controls. In hpg mice, levels of type 3 mRNA increased slowly after puberty and were about 30% of cryptorchid controls by 90 days. Studies using in situ hybridisation showed that the type 3 isoform was expressed only in the interstitial tissue of the adult normal mouse testis. No specific hybridisation could be determined in adult hpg or Tfm testes. Results show that 17betaHSD type 3 is an interstitial enzyme in the testis and is, probably, localised in the Leydig cells. During neonatal development expression of 17betaHSD type 3 is independent of gonadotrophin action while the increase in type 3 expression at puberty is primarily dependent upon androgen action although testicular descent and gonadotrophins are also required.