Mammalian testis exhibits remarkably high transcriptome complexity, and spermatogenesis undergoes two periods of transcriptional cessation. These make the RNA-binding proteins (RBPs) the utmost importance during male germ cell development. Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a large family of RBPs implicated in many steps of RNA processing; however, their roles in spermatogenesis are largely unknown. Here, we investigated the expression pattern of 12 hnRNP family members in mouse testes and found that most detected members are highly expressed in the testis. Furthermore, we found that most of the detected hnRNP proteins (hnRNPD, hnRNPK, hnRNPQ, hnRNPU, and hnRNPUL1) display the highest signals in the nuclei of pachytene spermatocytes, round spermatids, and Sertoli cells, whereas hnRNPE1 exclusively concentrates in the manchette of elongating spermatids. The expression of these hnRNP proteins showed both similarities and specificity, suggesting their diverse roles in spermatogenesis.
Mice ; Male ; Animals ; Heterogeneous-Nuclear Ribonucleoproteins/metabolism* ; Spermatogenesis/genetics* ; Testis/metabolism* ; Spermatids/metabolism* ; Sertoli Cells ; Spermatocytes/metabolism* ; RNA-Binding Proteins/metabolism* ; Mammals

RNA binding proteins (RBPs) regulate the function of cells by interacting with nascent transcripts and therefore are receiving increasing attention from researchers for their roles in tissue development and homeostasis. The polypyrimidine tract binding (PTB) protein family of RBPs are important posttranscriptional regulators of gene expression. Further investigations on the post-transcriptional regulation mechanisms and isoforms of PTB proteins in the spermatogenesis show that PTB protein 1 (Ptbp1) is a predominant isoform in mitotic cells (spermatogonia), while Ptbp2 predominates in meiotic spermatocytes and postmeiotic spermatids and binds to the specific 3' untranslated region (3' UTR) of the phosphoglycerate kinase 2 (Pgk-2) mRNA, which helps to stabilize Pgk-2 mRNA in male mouse germ cells. In case of Ptbp2 inactivation in the testis, the differentiation of germ cells arrests in the stage of round spermatids, with proliferation of multinucleated cells in the seminiferous tubule, increased apoptosis of spermatocytes, atrophy of seminiferous tubules, and lack of elongating spermatids, which consequently affects male fertility. This article presents an overview on the structure of the PTB protein and its role in regulating mammalian spermatogenesis.
Animals ; Atrophy ; Gene Expression Regulation ; physiology ; Heterogeneous-Nuclear Ribonucleoproteins ; metabolism ; physiology ; Homeostasis ; Isoenzymes ; metabolism ; Male ; Mice ; Nerve Tissue Proteins ; metabolism ; physiology ; Phosphoglycerate Kinase ; metabolism ; Polypyrimidine Tract-Binding Protein ; metabolism ; physiology ; RNA, Messenger ; metabolism ; RNA-Binding Proteins ; Seminiferous Tubules ; pathology ; Spermatids ; metabolism ; Spermatocytes ; metabolism ; Spermatogenesis ; physiology ; Spermatogonia ; metabolism ; Testis ; metabolism

OBJECTIVETo prepare a specific polyclonal antibody against full-length SUN5 for detecting the expression of SUN5 in human germ cells.

METHODSBioinformatic methods were used to compare the full-length SUN5 and its variant SUN5β, and a short peptide was designed based on the differential region to prepare SUN5 antibody. The prepared antibody was used to detect the expression of SUN5 in Ntera-2 cells and in human germ cells by Western blotting and immunofluorescence assay.

RESULTSThe short peptide was correctly synthesized and SUN5 antibody was obtained and purified. Western blotting showed that the prepared antibody was capable of recognizing full-length SUN5 in Ntera-2 cells, and SUN5 expression was localized on the nuclear membrane and in the cytoplasm as shown by immunofluorescence assay. Using this antibody, we detected SUN5 expression in the spermatocytes, round spermatids and sperms in human germ cells.

CONCLUSIONWe successfully prepared SUN5-specific antibody. SUN5 is expressed in the spermatocytes, round spermatids and sperms in human germ cells, suggesting its important role in spermatogenesis.

Antibodies ; chemistry ; Blotting, Western ; Cytoplasm ; metabolism ; Fluorescent Antibody Technique ; Humans ; Male ; Nuclear Envelope ; metabolism ; Proteins ; immunology ; metabolism ; Spermatids ; metabolism ; Spermatocytes ; metabolism ; Spermatogenesis ; Spermatozoa ; metabolism

The dynamic polar polymers actin filaments and microtubules are usually employed to provide the structural basis for establishing cell polarity in most eukaryotic cells. Radially round and immotile spermatids from nematodes contain almost no actin or tubulin, but still have the ability to break symmetry to extend a pseudopod and initiate the acquisition of motility powered by the dynamics of cytoskeleton composed of major sperm protein (MSP) during spermiogenesis (sperm activation). However, the signal transduction mechanism of nematode sperm activation and motility acquisition remains poorly understood. Here we show that Ca(2+) oscillations induced by the Ca(2+) release from intracellular Ca(2+) store through inositol (1,4,5)-trisphosphate receptor are required for Ascaris suum sperm activation. The chelation of cytosolic Ca(2+) suppresses the generation of a functional pseudopod, and this suppression can be relieved by introducing exogenous Ca(2+) into sperm cells. Ca(2+) promotes MSP-based sperm motility by increasing mitochondrial membrane potential and thus the energy supply required for MSP cytoskeleton assembly. On the other hand, Ca(2+) promotes MSP disassembly by activating Ca(2+)/calmodulin-dependent serine/threonine protein phosphatase calcineurin. In addition, Ca(2+)/camodulin activity is required for the fusion of sperm-specifi c membranous organelle with the plasma membrane, a regulated exocytosis required for sperm motility. Thus, Ca(2+) plays multifunctional roles during sperm activation in Ascaris suum.
Animals ; Ascaris suum ; metabolism ; Calcineurin ; metabolism ; Calcium ; metabolism ; Calmodulin ; metabolism ; Cytoskeleton ; metabolism ; Cytosol ; metabolism ; Egtazic Acid ; analogs & derivatives ; pharmacology ; Helminth Proteins ; metabolism ; Inositol 1,4,5-Trisphosphate Receptors ; metabolism ; Male ; Membrane Potential, Mitochondrial ; physiology ; Mitochondria ; metabolism ; Pseudopodia ; metabolism ; Signal Transduction ; Sperm Motility ; Spermatids ; drug effects ; physiology ; Spermatogenesis ; Type C Phospholipases ; metabolism

OBJECTIVE: To investigate distribution specificity of human fucosyltransferase 5 (FUT5) as well as its expression and localization in spermatids. METHODS: Human semen, vaginal swab, saliva and venous blood from healthy individuals were collected. The spermatids were isolated and the spermatid membrane protein was then extracted. Expression levels of FUT5 from human spermatid membrane, seminal plasma, vaginal fluid, saliva and serum were detected by immunoblotting technique. The expression and localization of FUT5 in spermatids were analyzed by immunofluorescent method. RESULTS: Immunoblotting technique showed that FUT5 was expressed on spermatid membranes and in serum, but not in seminal plasma, vaginal fluid and saliva. The expressed FUT5 on spermatids was mostly localized on head of spermatids by fluorescent microscopy, suggesting that there was certain amount of FUT5 on human spermatid membrane, and the spermatids might be isolated from mixed stains with vaginal fluid by antigen-antibody reaction. CONCLUSION Human FUT5 shows a characteristic distribution specificity, and this feature may be used for identification of mixed stain involved in criminal sexual offence in future forensic practice.
Cell Membrane/metabolism* ; Female ; Fluorescent Antibody Technique/methods* ; Forensic Genetics/methods* ; Fucosyltransferases/metabolism* ; Humans ; Immunoblotting ; Male ; Saliva/metabolism* ; Semen/metabolism* ; Spermatids/metabolism* ; Vagina/metabolism*

OBJECTIVETo observe the apoptosis of spermatogenic cells and the expressions of Bcl-2 and Bax proteins after burying the testis in the inguinal pocket, and to investigate their relationship.

METHODSWe randomly divided 36 healthy male New Zealand white rabbits into an experimental group (n = 18) and a control group (n = 18). Models were established by burying testes in the inguinal pocket in the experimental group, while the controls were left untreated. At the end of the 8th week after surgery, 6 animals were randomly taken from each group for measurement of the testis surface temperature and testicular biopsy. The apoptosis of spermatogenic cells in the testis tissues was detected by TUNEL assay, and the expressions of Bcl-2 and Bax proteins determined by immunohistochemistry and imaging analysis.

RESULTSAt 8 weeks after burying the testis in the inguinal pocket, the testicular surface temperature was significantly higher in the experimental group than in the control ([ 38.02 +/- 0.36] degrees C vs [36.15 +/- 0.64 ] degrees C, P < 0.05), and so was the apoptosis index (AI) of spermatogenic cells ([89.69 +/- 3.76] % vs [7.73 +/- 4.95 ] %, P < 0.05). The expression of the Bax protein in the testis was significantly increased, while that of the Bcl-2 protein remarkably decreased in the experimental group as compared with the control group (P < 0.05). The apoptotic cells were mostly primary spermatocytes and round spermatids.

CONCLUSIONElevated local temperature of the testis buried in the inguinal pocket increases the apoptosis of spermatogenic cells, and the spermatogenic cell apoptosis is highly correlated with the decreased expression of Bcl-2 and increased expression of Bax. The changes in the expressions of Bcl-2 and Bax proteins were a main mechanism behind the temperature elevation-induced apoptosis of spermatogenic cells.

Animals ; Apoptosis ; Groin ; Male ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rabbits ; Spermatids ; metabolism ; Temperature ; Testis ; metabolism ; pathology ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo explore the temperature change at the testis surface, apoptosis of spermatogenous cells and the expression of the heat shock protein 70 (HSP70) after scrotal reconstruction with the skin flap.

METHODSWe included 36 healthy New Zealand white rabbits, 24 males and 12 females, in this study, and equally randomized the males into an experimental and a control group. The scrotal of the experimental rabbits were excised and reconstructed with the hypogastric flap, while the controls were left untreated. At the end of the 8th week after surgery, 6 animals were randomly taken from each of the two groups for measurement of the testis surface temperature and testicular biopsy. The apoptosis of spermatogenous cells in the testis tissues was detected by HE staining, and the expression of HSP70 determined by immunohistochemistry and imaging analysis. The other 6 animals exempt from testicular biopsy in each of the experimental and control groups were mated with the female rabbits, and observed for fertility.

RESULTSAt the end of the 8th week after scrotal reconstruction, the testicular surface temperature was (38.1 +/- 0.6) degrees C in the experimental group, significantly higher than (36.0 +/- 0.30) degrees C before surgery (P < 0.05), and the apoptosis index (AI) of the spermatogenous cells was (71.85 +/- 2.7) %, as compared with (7.73 +/- 4.95) % in the control group (P < 0.05). The expression of HSP70 was found mainly in the spermatogenous cells of the experimental group and in the spermatoblasts of the control. A total of 6.0 +/- 1.3 baby rabbits were born in the control group, but none in the experimental group (P < 0.05).

CONCLUSIONThe testicular surface temperature rises after scrotal reconstruction with the hypogastric flap, which increases the apoptosis of spermatogenic cells and causes infertility. HSP70 is involved in protecting spermatogenic cells from apoptosis after scrotal reconstruction.

Animals ; Apoptosis ; Female ; HSP70 Heat-Shock Proteins ; metabolism ; Male ; Rabbits ; Scrotum ; surgery ; Spermatids ; cytology ; metabolism ; Surgical Flaps

OBJECTIVES: Bisphenol A diglycidyl ether (BADGE) is a liquid compound obtained by condensation of two molecules of epichlorohydrin with one molecule of bisphenol A. General and reproductive toxicity with BADGE has been reported higher than 1000 mg/kg/day. This study was performed to show the effects of acute exposure to BADGE below 1000 mg/kg/day on the testis in adult male rats. METHODS: BADGE was administered by gastric lavage in a single dose of 500, 750, 1000, and 2000 mg/kg/day in 8-week old male SPF Sprague-Dawley rats. The right testis was processed for light microscopic analysis. The left testis was homogenized and spermatids were counted to determine the daily sperm production and daily abnormal sperm production. The sperm count, sperm motility, and incidence of abnormal sperm were estimated in the epididymis. In testicular sections, the seminiferous tubules were observed for qualitative changes. The progression of spermatogenesis was arbitrarily classified as full-matured, maturing, and immature. The specimen slide was observed at 3 points and 10 seminiferous tubules were evaluated at each point. RESULTS: The male rats exposed to single oral dose of BADGE at 750, 1000, and 2000 mg/kg/day were significantly increased the number of immature and maturing sperm on the testis. There were no significant differences with respect to sperm head count, sperm motility, and sperm abnormality in the BADGE treatment groups. CONCLUSIONS: These results suggest that single oral exposure of BADGE 750 mg/kg/day can affect adult male testis development.
Animals ; Dose-Response Relationship, Drug ; Epoxy Compounds/*toxicity ; Male ; Rats ; Rats, Sprague-Dawley ; Semen Analysis ; Spermatids/drug effects ; Spermatogenesis/drug effects ; Testis/*drug effects/metabolism

AIMTo study the expression pattern of the retinoic acid metabolizing enzymes RALDH2 and CYP26b1 during mouse postnatal testis development at both mRNA and protein levels.

METHODSReal-time polymerase chain reaction and Western blot analysis were performed to determine the relative quantity of RALDH2 and CYP26b1 at both mRNA and protein levels at postnatal day 1, 5, 10, 20, and in adult mice (70 days testes). Testicular localization of RALDH2 and CYP26b1 during mouse postnatal development was examined using immunohistochemistry assay.

RESULTSAldh1a2 transcripts and its protein RALDH2 began to increase at postnatal day 10, and remained at a high level through postnatal day 20 to adulthood. Cyp26b1 transcripts and CYP26b1 protein did not change significantly during mouse postnatal testis development. RALDH2 was undetectable in the postnatal 1, 5 and 10 day testes using immunohistochemistry assay. At postnatal day 20 it was detected in pachytene spermatocytes. Robust expression of RALDH2 was restricted in round spermatids in the adult mouse testis. In the developing and adult testis, CYP26b1 protein was confined to the peritubular myoepithelial cells.

CONCLUSIONOur results indicate that following birth, the level of retinoic acid in the seminiferous tubules might begin to increase at postnatal day 10, and maintain a high level through postnatal day 20 to adulthood.

Aldehyde Oxidoreductases ; genetics ; metabolism ; Animals ; Cytochrome P-450 Enzyme System ; genetics ; metabolism ; Gene Expression Regulation, Developmental ; Male ; Mice ; Mice, Inbred BALB C ; RNA, Messenger ; metabolism ; Rabbits ; Retinoic Acid 4-Hydroxylase ; Seminiferous Epithelium ; cytology ; metabolism ; Sensitivity and Specificity ; Spermatids ; cytology ; metabolism ; Testis ; cytology ; growth & development ; metabolism

AIMTo show whether molecular motor dynein on a microtubule track, molecular motor myosin Va, motor recruiter myosin Va, VIIa-Rab27a/b interacting protein (MyRIP), and vesicle receptor Rab27b on an F-actin track were present during human and monkey spermiogenesis involving intramanchette transport (IMT).

METHODSSpermiogenic cells were obtained from three men with obstructive azoospermia and normal adult cynomolgus monkey (Macaca fascicularis). Immunocytochemical detection and reverse transcription-polymerase chain reaction (RT-PCR) analysis of the proteins were carried out. Samples were analyzed by light microscope.

RESULTSUsing RT-PCR, we found that dynein, myosin Va, MyRIP and Rab27b were expressed in monkey testis. These proteins were localized to the manchette, as shown by immunofluorescence, particularly during human and monkey spermiogenesis.

CONCLUSIONWe speculate that during primate spermiogenesis, those proteins that compose microtubule-based and actin-based vesicle transport systems are actually present in the manchette and might possibly be involved in intramanchette transport.

Actins ; metabolism ; Adult ; Animals ; Biological Transport ; physiology ; Dyneins ; metabolism ; Humans ; Macaca fascicularis ; Male ; Microtubules ; metabolism ; Myosin Heavy Chains ; metabolism ; Myosin Type V ; metabolism ; Myosins ; metabolism ; Spermatids ; cytology ; metabolism ; Spermatogenesis ; physiology ; Testis ; cytology ; metabolism ; Transport Vesicles ; physiology ; Vesicular Transport Proteins ; metabolism ; rab GTP-Binding Proteins ; metabolism