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PubMed1992

Immortalization of germ cells and somatic testicular cells using the SV40 large T antigen.

We report the immortalization, using the SV40 large T antigen, of all the cell types contributing to a developing seminiferous tubule in the mouse testis. Sixteen peritubular, 22 Leydig, 8 Sertoli, and 1 germ cell line have been established and cultured successfully for 90 generations in a period of 2.5 years. Immortalized peritubular cells were identified by their spindle-like appearance, their high expression of alkaline phosphatase, and their expression of the intermediary filament desmin. They also produce high amounts of collagen. Immortalized Leydig cells are easily identifiable by the accumulation of lipid droplets in their cytoplasm and the production of the enzyme 3-beta-hydroxysteroid dehydrogenase. Some Leydig cell lines also express LH receptors. The immortalized Sertoli cells are able to adopt their typical in vivo columnar appearance when cultured at high density. They exhibit a typical indented nucleus and cytoplasmic phagosomes. Some Sertoli cell lines also express FSH receptors. A germ cell line (GC-1spg) was established that corresponds to a stage between spermatogonia type B and primary spermatocyte, based on its characteristics in phase contrast and electron microscopy. This cell line expresses the testicular cytochrome ct and lactate dehydrogenase-C4 isozyme. These four immortalized cell types, when plated together, are able to reaggregate and form structures resembling two-dimensional spermatogenic tubules in vitro. When only the immortalized somatic cells are cocultured, the peritubular and Sertoli cells form cord-like structures in the presence of Leydig cells. Fresh pachytene spermatocytes cocultured with the immortalized somatic cells integrate within the cords and are able to survive for at least 7 days. The ability to perform coculture experiments with immortalized testicular cell lines represents an important advancement in our ability to study the nature of cell-cell and cell-matrix interactions during spermatogenesis and testis morphogenesis.

Animals↗
PubMed1993

Structure and regulated expression of angiotensin-converting enzyme and the receptor for angiotensin II.

The renin-angiotensin system maintains a homeostasis of blood pressure and blood volume. One component of this system is angiotensin-converting enzyme (ACE). There are two isozymes of ACE. The protein produced by vascular endothelium is termed "somatic ACE" and is regulated as a function of the growth state of these cells in vitro. The second isozyme, "testis ACE," is only produced by developing spermatozoa. The two ACE isozymes are the result of two distinct promoter regions within the ACE gene. Angiotensin II binds to specific receptors on the surface of cells. We have isolated cDNA encoding the AT1 subtype of receptor. This subtype is responsible for the hemodynamic consequences of angiotensin.

Animals↗
PubMed1996

Hormonal modulation of riboflavin carrier protein secretion by immature rat Sertoli cells in culture.

We report here that a protein species with biochemical and immunological similarity with chicken egg riboflavin carrier protein (RCP) is synthesized and secreted by immature rat Sertoli cells in culture. When quantitated by a specific heterologous radioimmunoassay, optimal concentrations of FSH (25 ng/ml) brought about 3-fold stimulation of RCP secretion. FSH, in the presence of testosterone (10(-6) M) brought about 6-fold stimulation of secretion of RCP over the control cultures which were maintained in the absence of these two factors. The aromatase inhibitor (1,4,6-androstatrien-3,17-dione) curtailed 85% of the enhanced secretion of RCP, suggesting that the hormonal stimulation is mediated through in situ synthesized estrogen and this could be confirmed with exogenous estradiol-17 beta which brought about 3-fold enhancement of secretion of RCP at a concentration of 10(-6) M. When tamoxifen (10 microM) was added along with FSH and testosterone, there was 75% decrease in the enhanced secretion of RCP. Addition of this anti-estrogen together with exogenous estradiol resulted in 55% decrease in elevated levels of RCP. Cholera toxin (1 microgram/ml) and 8-bromo-cyclic AMP (0.5 mM) mimicked the action of FSH on the secretion of RCP thus suggesting that FSH stimulation of RCP production may be mediated through cyclic AMP. These findings suggest that estrogen mediates RCP induction in hormonally stimulated Sertoli cells presumably to function as the carrier of riboflavin to the developing germ cells through blood-testis barrier in rodents.

Animals↗
PubMed1981

Malignant mesothelioma of the testicular tunic.

Mesotheliomas are neoplasms arising from the serous membranes lining the body cavities. One such cavity, the tunica vaginalis propria testis, is a common site for development of the benign mesothelioma, the adenomatoid tumor. However, the malignant mesothelioma is a rare neoplasm in this region. We report a case of a malignant mesothelioma of the testicular tunic. We review briefly the history of malignant mesothelioma, compare it with the adenomatoid tumor and discuss the possible embryologic histogenesis of these tumors.

Humans↗
PubMed1998

The role of anti-Müllerian hormone in gonadal development.

Anti-Müllerian (AMH), a member of the transforming growth factor beta produced by immature Sertoli cells and, to a lesser degree, by granulosa cells from birth to the end of reproductive life, does not affect gonadal determination but has a negative effect upon gonadal development in both sexes. It blocks meiosis in fetal ovaries, leading to loss of germ cells and subsequent fibrous degeneration, and inhibits the transcription of aromatase and LH receptor. AMH also affects the development and function of the adult testis by blocking the differentiation of mesenchymal into Leydig cells and by independently decreasing the expression of steroidogenic enzymes.

Animals↗
PubMed1999

Regulation and expression of gonadotropin-releasing hormone in salmon embryo and gonad.

This study examines whether gonadotropin-releasing hormone (GnRH) expression in gonads differs from that in brain as to use of alternative promoters and time of expression in early development and reproductive maturation. Within ovary, testis, and embryos, the transcripts from sGnRH gene 1 or gene 2 were expressed using either a conventional or upstream start site and conventional and alternative splicing. In immature sockeye salmon gonads, sGnRH mRNA was expressed briefly during the first 2 years, but in precociously mature fish was expressed for 2 months in the second year. Also, a cDNA encoding another form of GnRH (chicken GnRH-II) was isolated from the gonads. We conclude that differential regulation of GnRH occurs in embryos, ovary and testis compared to brain in salmonids and that more than one form of GnRH is expressed in the salmonid gonad.

Age Factors↗
PubMed1995

Structural predictions for the ligand-binding region of glycoprotein hormone receptors and the nature of hormone-receptor interactions.

BACKGROUND: Glycoprotein hormones influence the development and function of the ovary, testis and thyroid by binding to specific high-affinity receptors. The extracellular domains of these receptors are members of the leucine-rich repeat (LRR) protein superfamily and are responsible for the high-affinity binding. The crystal structure of a glycoprotein hormone, namely human choriogonadotropin (hCG), is known, but neither the receptor structure, mode of hormone binding, nor mechanism for activation, have been established. RESULTS: Despite very low sequence similarity between exon-demarcated LRRs in the receptors and the LRRs of porcine ribonuclease inhibitor (RI), the secondary structures for the two repeat sets are found to be alike Constraints on curvature and beta-barrel geometry from the sequence pattern for repeated beta alpha units suggest that the receptors contain three-dimensional structures similar to that of RI. With the RI crystal structure as a template, models were constructed for exons 2-8 of the receptors. The model for this portion of the choriogonadotropin receptor is complementary in shape and electrostatic characteristics to the surface of hCG at an identified focus of hormone-receptor interaction. CONCLUSIONS: The predicted models for the structures and mode of hormone binding of the glycoprotein hormone receptors are to a large extent consistent with currently available biochemical and mutational data. Repeated sequences in beta-barrel proteins are shown to have general implications for constraints on structure. Averaging techniques used here to recognize the structural motif in these receptors should also apply to other proteins with repeated sequences.

Amino Acid Sequence↗
PubMed2004

Murine bubblegum orthologue is a microsomal very long-chain acyl-CoA synthetase.

It has been suggested that a gene termed bubblegum (Bgm), encoding an acyl-CoA synthetase, could be involved in the pathogenesis of the inherited neurodegenerative disorder X-ALD (X-linked adrenoleukodystrophy). The precise function of the ALDP (ALD protein) still remains unclear. Aldp deficiency in mammals and Bgm deficiency in Drosophila led to accumulation of VLCFAs (very long-chain fatty acids). As a first step towards studying this interaction in wild-type versus Aldp-deficient mice, we analysed the expression pattern of the murine orthologue of the Bgm gene. In contrast with the ubiquitously expressed Ald gene, Bgm expression is restricted to the tissues that are affected by X-ALD such as brain, testis and adrenals. During mouse brain development, Bgm mRNA was first detected by Northern-blot analysis on embryonic day 18 and increased steadily towards adulthood, whereas the highest level of Ald mRNA was found on embryonic day 12 and decreased gradually during differentiation. Protein fractionation and confocal laser imaging of Bgm-green fluorescent protein fusion proteins revealed a microsomal localization that was different from peroxisomes (where Aldp is detected), endoplasmic reticulum and Golgi. Mouse Bgm showed acyl-CoA synthetase activity towards a VLCFA substrate in addition to LCFAs, and this activity was enriched in the microsomal compartment. Speculating that Bgm expression could be regulated by Ald deficiency, we compared the abundance of Bgm mRNA in wild-type and Ald knockout mice but observed no difference. Although mouse Bgm is capable of activating VLCFA, we conclude that a direct interaction between the mouse Bgm and the Aldp seems unlikely.

ATP-Binding Cassette Transporters↗
PubMed2000

Identification of tudor repeat associator with PCTAIRE 2 (Trap). A novel protein that interacts with the N-terminal domain of PCTAIRE 2 in rat brain.

PCTAIRE 2 is a Cdc2-related kinase that is predominantly expressed in the terminally differentiated neuron. To elucidate the function of PCTAIRE 2, proteins that associate with PCTAIRE 2 were screened by the yeast two-hybrid system. A positive clone was found to encode a novel protein that could bind to PCTAIRE 2 in vitro as well as in vivo, and was designated as Trap (tudor repeat associator with PCTAIRE 2). The overall structure of Trap shows no significant homology to any proteins, but contains five repeated domains (the tudor-like domain), conserved in Drosophila tudor protein. Trap associates with the N-terminal domain of PCTAIRE 2 through its C-terminal domain, which contains two tudor-like domains. PCTAIRE 1, but not PCTAIRE 3, can also associate with Trap. Trap is predominantly expressed in brain and testis, and gradually increases during brain development throughout life, consistent with the expression pattern of PCTAIRE 2. Immunoreactivities for PCTAIRE 2 and Trap were colocalized to the mitochondria in COS 7 cells. Immunohistochemical analyses showed that PCTAIRE 2 and Trap were distributed in the same cell layer of the cerebral cortex and cerebellum. These findings suggest that Trap is a physiological partner of PCTAIRE 2 in terminally differentiated neurons.

Amino Acid Sequence↗
PubMed2002

Laparoscopic Palomo varicocelectomy in the adolescent is safe after previous ipsilateral inguinal surgery.

OBJECTIVE: To evaluate the outcome of laparoscopic Palomo varicocelectomy (LPV) in young boys who had undergone previous ipsilateral inguinal surgery (in whom potentially the arterial supply to the testicles may be compromised) in an attempt to assess its safety for the collateral vascular supply in such cases. PATIENTS AND METHODS: Over a 5-year period (1995-2000) 44 patients underwent LPV, where both the spermatic artery and vein were ligated high above the internal ring. Thirteen patients had undergone previous ipsilateral inguinal surgery, which included inguinal hernia repairs in five, orchidopexy in two, communicating hydrocele repair in three and previous varicocele repair in three. All patients were followed clinically at 3 months and 1 year after surgery. RESULTS: There were no complications related to laparoscopy or varicocele ligation. No patient developed ipsilateral testicular atrophy; moreover the testis size remained stable or was associated with compensatory growth in all patients. CONCLUSION: Previous inguinal surgery involving the ipsilateral testicle does not appear to affect the collateral blood circulation to the affected testis in boys who undergo LPV mass ligation of the internal spermatic vein and artery. LPV for varicocele is safe in boys who have undergone previous inguinal surgery, suggesting that an adequate collateral blood supply is present.

Adolescent↗
PubMed1978

Acetylated histone H4 is preferentially associated with template-active chromatin.

Chromatin from trout testis at an early stage of development was digested with DNase II (deoxyribonucleate 3'-oligonucleotidohydrolase; EC 3.1.4.6), and the solubilized products were fractionated into Mg2+-soluble and -insoluble components. An examination of the histones from these fractions by one- and two-dimensional polyacrylamide gels showed that the highly acetylated species of histone H4 (di-, tri-, and tetra-acetylated) were associated mainly with the Mg2+-soluble material. Digestion of this chromatin fraction with pancreatic ribonuclease converted more than half of it to an insoluble state, and the acetylated H4 remained associated with the precipitated fraction. No changes in the other histones were noted, but two other basic proteins were also found to be associated with the Mg2+-soluble fraction. Since this fraction is enriched in transcribing gene sequences, it is concluded that the histone H4 of active genes is present in a highly acetylated state.

Acetylation↗
PubMed2001

Lung Krüppel-like factor contains an autoinhibitory domain that regulates its transcriptional activation by binding WWP1, an E3 ubiquitin ligase.

Lung Krüppel-like factor (LKLF/Krüppel-like factor 2), a member of the Krüppel-like factor family of transcription factors, is expressed predominantly in the lungs, with low levels of expression in other organs such as heart, spleen, skeletal muscle, and testis. LKLF is essential during pulmonary development and single-positive T-cell development and is indispensable during mouse embryogenesis. In this study, we performed a series of experiments to define the activation domain of LKLF as a means to further advance the understanding of the molecular mechanisms underlying transcriptional regulation by this transcription factor. Using deletion analysis, it is shown that LKLF contains a transcriptional activation domain as well as a strong autoinhibitory subdomain. The inhibitory subdomain is able to independently suppress transcriptional activation of other strong activators such as viral protein 16, VP16. This occurs either when the inhibitory domain is fused directly to VP16 or when the inhibitory domain is independently bound to DNA by GAL4 DNA-binding domain independent of the VP16 activator. Overexpression of the LKLF autoinhibitory domain alone potentiates transactivation by wild type LKLF, suggesting that the inhibitory domain binds a cofactor that prevents LKLF from transactivating. A yeast-two hybrid screen identified WWP1, an E3 ubiquitin ligase that binds specifically to the LKLF inhibitory domain but not to other transcription factors. In mammalian cells, WWP1 functions as a cofactor by binding LKLF and suppressing transactivation. These data demonstrate that LKLF contains multiple domains that either potentiate or inhibit the ability of this factor to function as an activator of transcription; moreover, regulation of LKLF transactivation is attenuated by an E3 ubiquitin ligase, WWP1.

Animals↗
PubMed2002

Characterization and expression of mammalian cyclin b3, a prepachytene meiotic cyclin.

We report the identification and expression pattern of a full-length human cDNA and a partial mouse cDNA encoding cyclin B3. Cyclin B3 (CCNB3) is conserved from Caenorhabditis elegans to Homo sapiens and has an undefined meiotic function in female, but not male Drosophila melanogaster. We show that H. sapiens cyclin B3 interacts with cdk2, is localized to the nucleus, and is degraded during anaphase entry after the degradation of cyclin B1. Degradation is dependent on sequences conserved in a destruction box motif. Overexpression of nondegradable cyclin B3 blocks the mitotic cell cycle in late anaphase, and at higher doses it can interfere with progression through G(1) and entry into S phase. H. sapiens cyclin B3 mRNA and protein are detected readily in developing germ cells in the human testis and not in any other tissue. The mouse cDNA has allowed us to further localize cyclin B3 mRNA to leptotene and zygotene spermatocytes. The expression pattern of mammalian cyclin B3 suggests that it may be important for events occurring in early meiotic prophase I.

Animals↗
PubMed2003

A Novel voltage-dependent chloride current activated by extracellular acidic pH in cultured rat Sertoli cells.

Sertoli cells from mammalian testis are key cells involved in development and maintenance of stem cell spermatogonia as well as secretion of a chloride- and potassium-rich fluid into the lumen of seminiferous tubules. Using whole-cell patch clamp experiments, a novel chloride current was identified. It is activated only in the presence of an extracellular acidic pH, with an estimated half-maximal activation at pH 5.5. The current is strongly outwardly rectifying, activated with a fast time-dependent onset of activation but a slow time-dependent kinetic at depolarization pulses. The pH-activated chloride current was not detected at physiological or basic pH and is not sensitive to intracellular or extracellular Ca2+ variation. Diphenylamine-2-carboxylic acid and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid blocked the induced currents, and its anionic selectivity sequence was Cl- > Br- > I-> gluconate. We have performed a reverse transcription-PCR analysis to search for voltage-dependent chloride rClC channels in cultured rat Sertoli cells. Among the nine members of the family only rClC-2, rClC-3, rClC-6, and rClC-7 have been identified. The inwardly rectifying rClC-2 chloride current was activated by hyperpolarization but not by pH variation. A different depolarization-activated outwardly rectifying chloride current was activated only by hypotonic challenge and may correspond either to rClC-3 or rClC-6. Immunolocalization experiments demonstrate that rClC-7 resides in the intracellular compartment of Sertoli cells. This study provides the first functional identification of a native acid-activated chloride current. Based on our molecular analysis of rClC proteins, this new chloride current does not correspond to rClC-2, rClC-3, rClC-6, or rClC-7 channels. The potential physiological role of this native current in an epithelial cell from the reproductive system is discussed.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

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