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Sex-specific proteins in normal chick embryo gonads and testis feminized by oestrogen treatment: a two-dimensional gel electrophoresis investigation.

Gonads dissected from 17-day-old normal chick embryos, as well as testes feminized by oestrogen treatment, were labelled in vitro with [35S]methionine and [14C]leucine. The patterns of cytosolic protein synthesis by the gonads were analysed using two-dimensional (2-D) polyacrylamide gel electrophoresis. In the feminized testis, two female-specific proteins appeared, the rate of synthesis of four testis-specific proteins was decreased, and quantitative variations of other synthesized proteins in relation to sex were detected. This altered protein synthesis indicates that the protein synthesis of the testis feminized by oestrogen treatment has in part become similar to that of a normal ovary. The synthesis of female-specific proteins in the feminized testis raises the question of their role in normal ovarian differentiation.

Animals↗

Purification and properties of steroid 17 alpha-hydroxylase from calf testis.

Steroid 17 alpha-hydroxylase has emerged as a key enzyme in steroidogenic cells: (i) it represents the branch point between the 17-deoxy (mineralo) and the 17-hydroxy (gluco) corticosteroid pathways in the adrenal cortex; (ii) the corresponding specific cytochrome (P-450(17 alpha] is highly dependent upon hormonal regulation; and (iii) the enzyme also catalyzes the steroid 17-20 lyase reaction, leading to the major androgens in the testis. As a prerequisite to the study of its regulation in intact cell, 17 alpha-hydroxylase was purified from calf testis microsomal preparations. Following five chromatographic steps, the enzyme was obtained as an apparently homogeneous protein of Mr = 57 kDa upon gel electrophoresis. The procedure yielded a recovery of about 10% as judged by cytochrome P-450 assay. Whereas 17 alpha-hydroxylase specific activity was about 30-fold enriched during the purification, that of the C17-20 lyase was increased by about 6-fold, strongly suggesting that its organelle environment may modulate the enzymatic activity. The purified enzyme yielded a 20 N-terminal amino-acid sequence showing a complete homology with that of its adrenal counterpart and a polyclonal antibody raised against our preparation revealed a 57 kDa protein band in bovine adrenocortical microsomal extracts, upon immunoblotting experiments. It was thus concluded that bovine 17 alpha-hydroxylase activity is supported by highly similar if not identical enzymatic proteins in both testis and adrenal cortex tissues. The purified P-450(17 alpha) preparation is now being used in reconstitution experiments which suggest that microsomal components may contribute to a different expression of the enzyme specificity in its native testis or adrenocortical intracellular environment, respectively.

Amino Acid Sequence↗

Sertoli-germ cells interactions in the human testis.

In previous histoimmunochemical studies we reported that transferrin (TF) and insulin-like growth factor I (IGF-I) are present in the cytoplasm of the Sertoli cells of the adult human testis. Receptors for TF were found mainly in adluminal germ cells and type I receptors for IGF-I both in Sertoli and germ cells. Using electron microscopy, evidence of transfer of both TF and IGF-I from the Sertoli to the germ cells through a receptor-mediated endocytosis mechanism was also found. In this paper we report the results of the histoimmunochemical localization of alpha inhibin in the human fetal, prepubertal and adult testis. In 8- to 14-week-old fetal testes a positive immunostaining was found mainly in the interstitial cells, whereas no staining was found in the germ cords. In the prepubertal testis the immunostaining was present in the Sertoli cells but not in the interstitial cells. In the adult human testis the immunostaining was present not only in the Sertoli cells but also in the spermatocytes and in several Leydig cells. Using electron microscopy and immunogold labeling the presence of alpha inhibin immunoreactivity was found in the rough endoplasmic reticulum and in the Golgi cisternae of both Sertoli and Leydig cells. Moreover we found evidence of transfer of alpha inhibin from the Sertoli to the germ cells through receptor-mediated endocytosis.

Adult↗

Effects of endocrine-disrupting chemicals on expression of ubiquitin C-terminal hydrolase mRNA in testis and brain of the Japanese common goby.

We investigated the effects of endocrine-disrupting chemicals (EDCs) on the expression of ubiquitin C-terminal hydrolase (UCH) mRNA in the testis and brain of the Japanese common goby, Acanthogobius flavimanus. The cDNA sequence of goby UCH contained an open reading frame encoding 220 amino acid residues (M(r)=24,223) with 51.3% overall sequence identity with human and mouse UCHL1. A competitive PCR assay was used to quantify the levels of UCH mRNA in the testis and brain of male gobies after exposure to bisphenol A, nonylphenol, or estradiol-17beta for 3 weeks. Exposure to estradiol-17beta at a nominal concentration of 100 ng/L induced significant increase in UCH mRNA levels in both testis and brain (P<0.05), whereas exposure to nonylphenol induced a significant decrease in UCH mRNA levels in the testis (P<0.01). These results suggest that EDCs can either positively or negatively regulate UCH mRNA levels.

Amino Acid Sequence↗

Vitamin K deficiency reduces testosterone production in the testis through down-regulation of the Cyp11a a cholesterol side chain cleavage enzyme in rats.

Vitamin K (K) is an essential factor for the posttranslational modification of blood coagulation factors as well as proteins in the bone matrix (Gla proteins). It is known that K is not only distributed in the liver and bones but also abundantly distributed in the brain, kidney, and gonadal tissues. However, the role of K in these tissues is not well clarified. In this study, we used DNA microarray and identified the genes whose expression was affected in the testis under the K-deficient (K-def) state. The expression of genes involved in the biosynthesis of cholesterol and steroid hormones was decreased in the K-def group. The mRNA levels of Cyp11a - a rate-limiting enzyme in testosterone synthesis - positively correlated with the menaquinone-4 (MK-4) concentration in the testis. Moreover, as compared to the control (Cont) and K-supplemented (K-sup) groups, the K-def group had decreased testosterone concentrations in the plasma and testis. These results suggested that K is involved in steroid production in the testis through the regulation of Cyp11a.

Alkyl and Aryl Transferases↗

Cloning of a full-length cDNA of human testis-specific spermatogenic cell apoptosis inhibitor TSARG2 as a candidate oncogene.

A novel human gene full-length cDNA sequence-TSARG2 was identified from a human testis cDNA library using the SRG2 gene (GenBank Accession No. ), which was significantly up-regulated in cryptorchidism, as an electronic probe. TSARG2 was 1223 bp in length. The putative protein encoded by this gene was 305 amino acids with a theoretical molecular weight of 34,751 and isoelectric point of 9.85. The sequence shared no significant homology with any known protein in databases except SRG2. Northern blot analysis revealed that 1.7 kb TSARG2 transcript was detected selectively in human testis. Furthermore, results of in situ hybridization assay confirmed that TSARG2 was expressed in seminiferous tubules, more precisely in spermatogonia and spermatocyte. No mutation was found by PCR-SSCP in 122 cases of azoospermia, severe oligzoospermia, and cryptorchidism. The green fluorescence produced by pEGFP-C1/TSARG2 was detected on the nucleus of COS7 cells after 24h post-transfection. The pcDNA3.1(-)/TSARG2 plasmid was constructed and introduced into MCF7 cells by liposome transfection. TSARG2 can accelerate MCF7 cells to traverse the S-phase and enter the G2-phase compared with the control without transfection of TSARG2, which suggested that this gene plays an important role in the development of cryptorchid testis and is a testis-specific apoptosis candidate oncogene.

Amino Acid Sequence↗

Identification of a novel testis-specific gene mtLR1, which is expressed at specific stages of mouse spermatogenesis.

A novel testis-specific gene termed mtLR1 was identified by digital differential display. Sequence analyses revealed that mtLR1 protein contains an amino terminus leucine-rich repeat domain and shows 33% similarities to PIDD which functions in p53-mediated apoptosis. Northern blot analysis showed that mtLR1 mRNA was specifically expressed in adult mouse testis, and RT-PCR results also showed that mtLR1 was exclusively expressed in adult testis and not in spermatogonial cells. The expression of mtLR1 mRNA was developmentally upregulated in the testes during sexual maturation and was, conversely, downregulated by experimental cryptorchidism in vivo. We also showed that the expression of mtLR1 mRNA was relatively highly sensitive to heat stress in vitro. The green fluorescent protein produced by pEGFP-C3/mtLR1 was only detected in the cytoplasm of spermatogonia cell line GC-1 after 24 h posttransfection. Immunohistochemical analysis revealed that the protein is most abundant in the cytoplasm of spermatocytes and round spermatids within seminiferous tubules of the adult testis. The time-dependent expression pattern of mtLR1 in postnatal mouse testes suggested that mtLR1 gene might be involved in the regulation of spermatogenesis and sperm maturation.

Aging↗

Stage dependent and androgen inductive expression of orphan receptor TR4 in rat testis.

In this study, we investigated the expression of TR4 in different stages of seminiferous tubules and the relationship between TR4 and androgen in rat testis. We found that TR4 was stage-dependently expressed in rat seminiferous tubules, T withdrawal induced by high doses of testosterone undecanoate and ethane dimethane sulfonate inhibit TR4 expression in rat testis, and testosterone induced TR4 expression in co-cultured primary germ/Sertoli cells. Furthermore, we demonstrated that androgen receptor could enhance TR4-mediated transactivation activity in testis cells in the presence of testosterone. Together, these data indicate that the expression of TR4 in rat testis is stage dependent and androgen inductive, and suggest the important role of orphan receptor TR4 in spermatogenesis.

Androgens↗

Identification and characterization of a novel splice variant of beta3 subunit of GABA(A) receptor in rat testis and spermatozoa.

Gamma-aminobutyric acid type A (GABA(A)) receptors are the major sites of inhibitory action of fast synaptic neurotransmission in the brain. Their receptors are also widely distributed in peripheral and endocrine tissues. A full-length cDNA encoding a novel splice variant of beta3 subunit of GABA(A) receptor, designated as beta3t, was identified in rat testis. This isoform contains a segment, having identical amino acid sequence as the beta3 subunit of neuronal GABA(A) receptors except for a section composed of 25 different amino acid sequence in the N-terminus. Northern blot shows that this isoform is found in rat testis. The beta3t isoform mRNA was detected in germ cells in the late step of spermatogenesis by in situ hybridization assay. Results of immunohistochemical and immunocytochemical assays indicate that the beta3t isoform is expressed in rat testis and spermatozoa. To determine a possible function of the N-terminal 25 amino acid segment, a recombinant plasmid of beta3t-EGFPC was constructed by fusing green fluorescent protein to the C-terminus of the beta3t isoform. The chimera product failed to be translocated unto the cell surface when expressed in HEK 293 cells; whereas, the beta3 subunit of rat brain is incorporated into the plasma membrane. In conclusion, the present results show that one variant of beta3 subunit of GABA(A) receptor, designated as beta3t, is found in germ cells of rat testis and sperm. The inability of the beta3t variant to target into the plasma membrane maybe a consequence of the unique 25 amino acid segment in the N-terminus.

Alternative Splicing↗

Multiple PolK (POLK) transcripts in mammalian testis.

The Y-family of DNA polymerases are capable of translesion synthesis both in vitro and in vivo. The mouse/human gene (Polkappa/POLK) that encodes the Y-family member Polk is highly expressed in mouse/human testis. Using RT-PCR to amplify the coding sequence of the PolK gene, 11 forms of mouse PolK and 5 forms of human POLK transcripts were identified from testis. This phenomenon is apparently specific to PolK since several other specialized DNA polymerases capable of TLS do not express functional alternative transcripts in the testis. The multiple mouse/human (PolK/POLK) transcripts may encode multiple Polkappa isoforms in testis.

Alternative Splicing↗

Genomic structure and expression analysis of the mouse testis-specific ribbon protein (Trib) gene.

During our analyses of genes required for the development and function of the mouse gonads, we identified a novel testis-specific mRNA, transcribed from a gene that we have named testis-specific ribbon protein (Trib). In the mouse, Trib is located on chromosome 15, overlapping with and transcribed in the opposite orientation of the meiosis specific gene Smc1beta. The deduced amino acid sequence of testis ribbon (TRIB) protein is highly conserved between human, mouse, and rat and contains the ribbon motifs found in the largely uncharacterized microtubule ribbon protein ribbon43a (RIB43A). We show by Northern blot analyses and reverse transcription-polymerase chain reaction (RT-PCR) that Trib mRNA is specifically expressed in the adult testis. In situ hybridization indicates that Trib is expressed solely in germ cells during the leptotene-pachytene stages of spermatogenesis. The high level of evolutionary conservation and the cellular and temporal expression suggest that Trib may be required for mouse spermatogenesis and male fertility. Here, we describe the genomic structure and expression profile of mouse Trib and compare its homology with other ribbon proteins.

Amino Acid Sequence↗

Exposure to bisphenol A during embryonic/fetal life and infancy increases oxidative injury and causes underdevelopment of the brain and testis in mice.

We investigated the modifications in endogenous antioxidant capacity and oxidative damage in the brain, liver, kidney and testis in mice exposed to bisphenol A (BPA), an environmental endocrine disrupter. Mice were exposed to BPA throughout embryonic/fetal life and during lactation by feeding their pregnant/lactating mothers BPA at 5 or 10 microg per milliliter of drinking water. At the age of four weeks, male mice were sacrificed. Exposure to BPA increased the activity of catalase and glutathione peroxidase in the liver and kidney, respectively. It also increased thiobarbituric acid-reactive substances in the brain, kidney and testis, and decreased the wet weight of the brain, kidney and testis. Our results suggest that exposure to BPA throughout embryonic/fetal life and during infancy induces tissue oxidative stress and peroxidation, ultimately leading to underdevelopment of the brain, kidney and testis.

Administration, Oral↗

Identification of unique, differentiation stage-specific patterns of expression of the bromodomain-containing genes Brd2, Brd3, Brd4, and Brdt in the mouse testis.

The bromodomain, an evolutionarily conserved motif that binds acetyl-lysine on histones, is found in many chromatin-associated proteins, transcription factors, and in nearly all known histone acetyltransferases. The BET subclass of bromodomain-containing proteins contains two bromodomains and one ET domain and consists of at least four members in mouse and human, Brd2, Brd3, Brd4, and Brdt. We isolated mouse cDNAs for these genes and studied their expression patterns with particular focus on the testis. Northern hybridization revealed that Brd3 is most abundant in testis, ovary, placenta, uterus, and brain; that Brd4 is rather ubiquitously expressed but is most abundant in mid-gestation embryo, testis, ovary, and brain; and that Brdt is specifically expressed in testis. In situ hybridization and immunostaining on histological sections of mouse testes revealed a strikingly specific and dynamic change of cellular specificity in the germ line during the progression of spermatogenesis. Brd4 is expressed in spermatogonia, Brdt is only expressed in mid- to late-spermatocytes, Brd2 is expressed in diplotene spermatocytes and round spermatids and at low levels in spermatogonia, and Brd3 is expressed in round spermatids. This unique expression pattern suggests that genes in this subclass are not simply redundant. Rather, their expression is tightly regulated in the male germ cell lineage, suggesting that they likely have specific roles in different developmental stages and/or cell types.

Animals↗

CD55 in rat male reproductive tissue: differential expression in testis and expression of a unique truncated isoform on spermatozoa.

CD55 is a key regulator of complement activation, expressed on most tissues and cells in man and other mammals. In the rat, alternative splicing in the gene encoding CD55 yields GPI-anchored (GPI-CD55) and transmembrane (TM-CD55) forms. Published Northern blot analysis indicated that while GPI-CD55 was broadly expressed, TM-CD55 was primarily expressed in the testis, although the precise site of expression was not identified. To clarify the distribution of CD55 isoforms in rat reproductive tissues, we first performed immunohistochemistry and Western blot analysis with an anti-rat CD55 mAb that recognized all reported CD55 isoforms, and a polyclonal immunoglobulin specific for TM-CD55. CD55 was absent in testis prior to puberty. Post-puberty, CD55 was expressed at high levels on all spermiogenic cells from step 6 spermatid onward, and on mature spermatozoa focussed on the acrosome, but was absent from support cells and early progenitors. Enzymatic digestion revealed that GPI-CD55 was predominant in testis and spermatozoa. Staining for TM-CD55 with specific immunoglobulin confirmed its absence from mature sperm and expression on spermatids only between steps 11 and 14 of development. GPI-CD55 on spermatozoa was of lower molecular weight than that in testis and other tissues; sequencing from spermatozoal mRNA identified a unique isoform of GPI-CD55 missing short consensus repeat 4. The predominant acrosome expression and presence of a unique, truncated isoform of CD55 on spermatozoa provides further support for the hypothesis that the acrosome is a highly specialized region in which closely regulated complement activation may contribute to reproductive function.

Acrosome↗

Gonadins, a novel family of glutamyl-tripeptide amides present in the testis with activity in the hypophyseal-gonadal axis.

Here we present a new family of endogenous peptides identified in rat testis with structure of glutamyl-tripeptide amides which are also present in plasma. These peptides have different activities in the hypophyseal-gonadal axis. Evidences showing the endocrine activities of some of the peptides are presented. In this communication we demonstrate the presence of peptides with a common structure Glu-X-Pro amide, where X can be one of the following amino acids: glutamic acid, glutamine, aspartic acid, asparagine, phenylalanine or tyrosine. These peptides have been identified by a series of chromatographies and by mass spectrometry. Some of the peptides where tested for its biological activity observing that subcutaneous administration of the peptides Glu-Glu-Pro amide, Glu-Gln-Pro amide and Glu-Phe-Pro amide were able to reduce plasma levels of testosterone and luteinizing hormone (LH) without modification of the levels of follicle stimulating hormone (FSH). The peptide Glu-Asp-Pro amide, however, produced an increase in the levels of testosterone without modifying LH or FSH levels. It is proposed that the glutamyl-tripeptide amides that reduce the levels of testosterone and LH are released from the testis and act in the pituitary via circulation in an endocrine manner. The specific inhibition of LH release is similar to that produced by inhibin on FSH release. On the other hand the peptide that increases the levels of testosterone is produced in the testis and seems to act directly in the testis in a paracrine or autocrine manner. It is proposed here a new mechanism of regulation of hypophyseal-gonadal axis, a negative feedback exerted by the glutamyl-tripeptide amides in the pituitary. Also it is proposed the generic name of gonadins for the novel family of glutamyl-tripeptide amides. We suggest that gonadins could be used in the future as drugs for treatment of different endocrine disorders, hormone-dependent cancer and as contraceptives.

Amides↗

Gene expression profiling in liver and testis of rats to characterize the toxicity of triazole fungicides.

Four triazole fungicides were studied using toxicogenomic techniques to identify potential mechanisms of action. Adult male Sprague-Dawley rats were dosed for 14 days by gavage with fluconazole, myclobutanil, propiconazole, or triadimefon. Following exposure, serum was collected for hormone measurements, and liver and testes were collected for histology, enzyme biochemistry, or gene expression profiling. Body and testis weights were unaffected, but liver weights were significantly increased by all four triazoles, and hepatocytes exhibited centrilobular hypertrophy. Myclobutanil exposure increased serum testosterone and decreased sperm motility, but no treatment-related testis histopathology was observed. We hypothesized that gene expression profiles would identify potential mechanisms of toxicity and used DNA microarrays and quantitative real-time PCR (qPCR) to generate profiles. Triazole fungicides are designed to inhibit fungal cytochrome P450 (CYP) 51 enzyme but can also modulate the expression and function of mammalian CYP genes and enzymes. Triazoles affected the expression of numerous CYP genes in rat liver and testis, including multiple Cyp2c and Cyp3a isoforms as well as other xenobiotic metabolizing enzyme (XME) and transporter genes. For some genes, such as Ces2 and Udpgtr2, all four triazoles had similar effects on expression, suggesting possible common mechanisms of action. Many of these CYP, XME and transporter genes are regulated by xeno-sensing nuclear receptors, and hierarchical clustering of CAR/PXR-regulated genes demonstrated the similarities of toxicogenomic responses in liver between all four triazoles and in testis between myclobutanil and triadimefon. Triazoles also affected expression of multiple genes involved in steroid hormone metabolism in the two tissues. Thus, gene expression profiles helped identify possible toxicological mechanisms of the triazole fungicides.

Animals↗

Missed testis on laparoscopy despite blind-ending vessels and closed processus vaginalis.

Laparoscopy has become a preferred technique to evaluate a nonpalpable testis. It gives excellent visualization of the anatomy to differentiate a viable or absent testis. We present a case of an intra-abdominal testis that was missed on diagnostic laparoscopy. Despite a closed processus vaginalis, an absent vas deferens, and blind-ending vessels above the internal ring, the testis was missed.

Cryptorchidism↗

Stem cell and niche development in the postnatal rat testis.

Adult tissue stem cells self-renew and differentiate in a way that exactly meets the biological demand of the dependent tissue. We evaluated spermatogonial stem cell (SSC) activity in the developing rat testis and the quality and accessibility of the stem cell niche in wild type, and two busulfan-treated models of rat pup recipient testes using an SSC transplantation technique as a functional assay. While our results revealed a 69-fold increase in stem cell activity during rat testis development from neonate to adult, only moderate changes in SSC concentration were observed, and stem cells from neonate, pup, and adult donor testes produce spermatogenic colonies of similar size. Analysis of the stem cell niche in recipient rat testes demonstrated that pup testes support high levels of donor stem cell engraftment when endogenous germ cells are removed or compromised by busulfan treatment. Fertility was established when rat pup donor testis cells were transplanted into fetal- or pup-busulfan-treated recipient rat pup testes, and the donor genotype was transmitted to subsequent generations. These results provide insight into stem cell/niche interactions in the rat testis and demonstrate that techniques originally developed in mice can be extended to other species for regenerative medicine and germline modification.

Animals↗