PubMed Health⌕ Search

Biomedical subjects

R Pierantoni

Publications and source records attributed to R Pierantoni.

At least 19 recordsLinked to original sources
PubMed2005

Structure of msj-1 gene: a comparative analysis.

Msj-1 gene encodes a DnaJ protein highly expressed in spermatids and spermatozoa of both rodents and amphibians. We isolated and characterized the msj-1 gene in mice. A bioinformatic approach was then used to predict the putative promoter region, chromosomal localization, and its presence in the human genome. The analysis of msj-1 genomic sequence revealed that msj-1 is an intronless gene. Interestingly, two regions (A and B, separated by 10,682 bp) on human chromosome 2 having respectively 78% and 77% nucleotide identity with the murine msj-1 coding region were identified. This suggests the existence of an msj-1-like gene also in humans.

Animals↗
PubMed2004

Jun localization in cytosolic and nuclear compartments in brain-pituitary system of the frog, Rana esculenta: an analysis carried out in parallel with GnRH molecular forms during the annual reproductive cycle.

The presence of c-jun like mRNA was assessed in the brain of the frog, Rana esculenta, during the annual sexual cycle. In parallel, Jun protein and GnRH molecular form (mammalian and chicken II also indicated as GnRH1 and GnRH2, respectively) activity was studied in order to establish possible relationships. Northern blot analysis of total RNA reveals the presence of a 2.7 kb c-jun-like mRNA. Western blots, carried out on cytoplasmic and nuclear protein extracts, show the presence of Jun immunoreactive band of 39 kDa in brain and pituitary. Fluctuations of c-jun-like mRNA and Jun immunoreactive protein (cytoplasmic and nuclear) levels in brains during the year indicate relationships among transcription, translation, and nuclear activity. In particular, mRNA levels increase gradually from September until November when Jun protein concentration peaks in cytosolic extracts. Conversely, the nuclear protein reaches highest concentration in July when the cytosolic level shows low values. Immunocytochemical studies confirm the presence of Jun immunoreactivity in both cytoplasmic and nuclear compartments of several brain areas, including those primarily involved in gonadotropin discharge (e.g., anterior preoptic area and preoptic nucleus). GnRH molecular forms and Jun are colocalized in anterior preoptic area and preoptic nucleus. Moreover, during the period characterized by GnRH release, Jun levels strongly decrease in nuclei. Finally, we show that treatments with a GnRH analog (buserelin, Hoechst, Frankfurt) increase Jun levels in brain nuclear extracts.

Animals↗
PubMed2002

Early defect in the expression of mouse sperm DNAJ 1, a member of the DNAJ/heat shock protein 40 chaperone protein family, in the spinal cord of the wobbler mouse, a murine model of motoneuronal degeneration.

Prevention of protein misfolding is ensured by chaperone proteins, including the heat shock proteins (HSP) of the DNAJ/HSP40 family. Detection of abnormal protein aggregates in various neurodegenerative diseases has led to the proposal that altered chaperone activity contributes to neurodegeneration. Msj-1, a DNAJ/HSP40 protein located around the spermatozoa acrosome, was recently found to be down-regulated in the testis of wobbler mutant mice. Wobbler is an unidentified recessive mutation which triggers progressive motoneuron degeneration with abnormal intracellular protein accumulations, and defective spermatozoa maturation. Here, we examined Msj-1 expression in the spinal cord of the mutants and their controls. Msj-1 transcripts were amplified by reverse transcription-polymerase chain reaction from mutant and wild-type spinal cord RNA. Sequencing of Msj-1 coding region revealed no change in the mutant. In contrast, decreased Msj-1 mRNA levels were observed in five to six-week-old wobbler mice spinal cord, when motoneuron degeneration is at its apex, as compared to controls. A similar decrease was observed in two-week-old wobbler spinal cord, when the number of motoneurons is still unaltered, indicating that the decreased mRNA content is intrinsic to the mutant and not simply related to the loss of cells expressing Msj-1. Assays of Msj-1 protein levels yielded similar results. Immunofluorescent labeling revealed numerous Msj-1-ir motoneurons in five-week-old control spinal cord while no signal was observed in age-matched wobbler. Our results show, therefore, that Msj-1 expression is down-regulated in both organs affected by the wobbler mutation, the CNS and the testis, and that this defect precedes the first histological signs of motoneuron degeneration. These results provide the first example of an association between transcriptional repression of a chaperone protein and a neurodegenerative process.

Animals↗
PubMed2002

The amphibian testis as model to study germ cell progression during spermatogenesis.

Testicular morphology of vertebrate testis indicates requirement of local control. In urodeles, the testis is organized in lobes of increasing maturity throughout the cephalocaudal axis. The anuran testis is organized in tubules. Spermatogenesis occurs in cysts composed by Sertoli cells enveloping germ cells at synchronous stages. Moreover, in numerous species germ cell progression lasts a year which defines the sexual cycle. Due to the above quoted features, research on factors regulating germ cell progression in amphibians may reach greater insight as compared with mammalian animal models. In particular, studies on endocrine and paracrine/autocrine factors involved in the regulation of germ cell functions reveal that fos activation and a J protein, previously specifically found in mouse testis, exert an important role in spermatogonial proliferation and maturation of post-meiotic stages, respectively.

Acrosome Reaction↗
PubMed2000

Effects of multiple injections of ethane 1,2-dimethane sulphonate (EDS) on the frog, Rana esculenta, testicular activity.

Ethane 1,2-dimethane sulphonate (EDS) is an alkylating agent, which has a selective cytotoxic effect on Leydig cells in some mammalian species. Similarly, in the frog, Rana esculenta, Leydig cells are destroyed after a single EDS injection and regenerate after 28 days. Regeneration of Leydig cells in frogs appears to be independent of the pituitary. The present experiments in R. esculenta were carried out: a) to investigate Leydig cell responsiveness to gonadotropin stimulation during 58 days after a single EDS injection; and b) to assess whether four consecutive EDS injections induce additional effects on the testicular cell population. Our results show that androgen stimulation after gonadotropin injections is restored after 44 days from a single EDS injection. Since the interstitial compartment appears to be normal at least 28 days after EDS treatment, it is likely that new Leydig cells lack gonadotropin receptors. With respect to multiple-EDS injections, Leydig cells completely disappear in several areas and the adjacent germinal compartment is disorganised. In some cases damaged germinal compartment is still surrounded by intact Leydig cells. Surprisingly, testicular and plasma androgens strongly increase in EDS-treated animals. Therefore, Sertoli cells may produce substances inhibiting androgen production in Leydig cells. J. Exp. Zool. 287:384-393, 2000.

Animals↗
PubMed1999

Fos localization in cytosolic and nuclear compartments in neurones of the frog, Rana esculenta, brain: an analysis carried out in parallel with GnRH molecular forms.

C-fos activity was determined in the brain of the frog, Rana esculenta, during the annual sexual cycle. The localization of GnRH molecular forms (mammalian- and chicken-GnRHII) was also carried out to determine whether or not the proto-oncogene and the peptides showed a functional relationship. Northern blot analysis of total RNA revealed the presence of a single strong signal of c-fos like mRNA of 1.9 Kb during February and April. This was followed by expression of c-Fos protein (Fos) in several brain areas during March and July shown by immunocytochemistry. In particular, the olfactory region, the lateral and medial pallium, the nucleus lateralis septi, the ventral striatum, the caudal region of the anterior preoptic area, the suprachiasmatic nucleus, the ventral thalamus, tori semicircularis and ependymal layers of the tectum were immunostained. There was no overlap between Fos immunoreactive perikarya and GnRH immunoreactive perikarya (e.g. gonadotrophin-releasing hormone (GnRH) in the rostral part and Fos in the caudal region of the anterior preoptic area). Interestingly, a cytoplasmic localization of Fos was also observed by immunocytochemistry and gel retardation experiments supported this observation. Cytoplasmic extracts from September-October animals bound the AP1 oligonucleotide. The complex was not available in the nuclear extracts from the same preparation, suggesting that, besides Fos, Jun products were also present. Conversely, nuclear but not cytosolic binding was detected in the brain of animals collected in July. In conclusion, we show that Fos and GnRH activity does not correlate in the frog brain and, for the first time in a vertebrate species, we give evidence of a cytoplasmic AP1 complex in neuronal cells.

Animals↗
PubMed1999

c-fos activity in Rana esculenta testis: seasonal and estradiol-induced changes.

Estradiol-17beta (E2) is suspected to exert a role in the regulation of testicular activity. Using a nonmammalian vertebrate model (the frog, Rana esculenta), we have investigated whether c-fos activity is detectable in the testis during the annual sexual cycle and whether E2 exerts a regulatory role on spermatogenesis through fos activity. FOS protein is available in testicular nuclear extracts (about 60 kDa) and, surprisingly, also in cytosolic extracts (about 60, 80, and 100 kDa). Estradiol induces primary spermatogonia (ISPG) proliferation [this effect is counteracted by antiestrogens (Tamoxifen and ICI 182-780)] and FOS appearance in testicular cytosolic extracts as well as c-fos transcription. Also, this effect is counteracted by ICI 182-780. Interestingly, the number of FOS immunopositive nuclei of ISPG strongly increases after E2 treatment, whereas a great increase of immunopositivity in the cytoplasm of ISPG is observed with the contemporaneous treatment with antiestrogens. In conclusion, our results demonstrate that E2 induces ISPG multiplication in the frog, R. esculenta, and, for the first time in a vertebrate species, that it triggers c-fos activity in the testis. Moreover, E2 may be involved in mechanisms related to FOS transport in the nucleus of ISPG to induce the mitotic activity.

Animals↗
PubMed1997

17 beta-estradiol effects on mast cell number and spermatogonial mitotic index in the testis of the frog, Rana esculenta.

Estrogen affects mast cell activity and cellular proliferation in several vertebrate tissues. Due to the presence of mast cells in the interstitial tissue of the testis and due to the annual changes of spermatogonial proliferation and estradiol level in the frog, Rana esculenta, we have studied the possible regulation of mast cell number (MCN) and primary spermatogonial mitosis exerted by 17 beta-estradiol (E2). MCN changed in the testis during the annual reproductive cycle, showing peaks in December and in May. Administration of E2 elicited an increase of MCN both in intact and hypophysectomized frogs, and this effect was counteracted by tamoxifen. In vitro experiments indicated that E2 induced an increase of both MCN and the primary spermatogonial mitotic index. Moreover, a significant decrease of intratesticular androgen content was measured in E2-treated testes. All the in vitro effects induced by E2 were counteracted by tamoxifen. In conclusion, our data indicate that in Rana esculenta testis E2 increase MCN and primary spermatogonial mitotic index via intratesticular mechanisms. A possible involvement of the decrease of androgen levels exerted by E2 in the mechanism underlying the increase of MCN is also considered.

Animals↗
PubMed1997

c-fos- and c-jun-like mRNA expression in frog (Rana esculenta) testis during the annual reproductive cycle.

The expression of c-fos and c-jun mRNA has been examined in the testis of a seasonal breeder (the frog, Rana esculenta) during the annual reproductive cycle, using Northern blot analysis along with measurements of plasma levels of estradiol-17 beta and androgens (testosterone + 5 alpha-dihydrotestosterone). A c-fos-like transcript of 1.9 kb was revealed using a 1.1-kb v-fos probe, while three different transcripts of 3.7, 3.4, and 2.7 kb were seen using 1.0-kb human (h)-c-jun fragment. The proto-oncogene-like mRNAs appear during the period of the year associated with the new wave of spermatogenic activity. The levels of fos-like mRNA were highest after the estradiol-17 beta peak, while low levels were concomitant with high androgen concentrations. It is concluded that there is a close correlation between c-fos- and c-jun-like expression and testicular activity in R. esculenta.

Analysis of Variance↗
PubMed1997

Proto-oncogene activity in the testis of the lizard, Podarcis s. sicula, during the annual reproductive cycle.

Since proto-oncogenes play a central role in the regulation of cellular growth and differentiation, localization of MYC, FOS, and JUN proteins has been studied in the testis of the lizard, Podarcis s. sicula, during the annual reproductive cycle by immunocytochemistry using antisera against c-myc, c-fos, and c-jun products. MYC was localized in the nuclei of spermatogonia (SPG), I and II spermatocytes (SPC), and spermatids (SPT). Strong immunoreactivity was detected in Sertoli cells just prior to the onset of the early spring spermatogenic wave coinciding with the androgen peak. FOS protein was present in the nuclei of SPG and SPC. In SPG an exclusive nuclear localization was seen during the active spermatogenic period (February-March and September). A perinuclear localization was observed during other months. Immunoreactivity in Sertoli cells was also observed during the periods of active spermatogenesis. JUN protein was localized in the cytoplasm of SPG as well as in I and II SPC and was detected in the nuclei of I and II SPC during April and October when spermatogenic waves occur. These data suggest that proto-oncogene activities have regulatory roles in the spermatogenesis of the lizard.

Amino Acid Sequence↗
PubMed1997

Detection of GnRH molecular forms in brains and gonads of the crested newt, Triturus carnifex.

Gonadotrophin-releasing hormone (GnRH) immunoreactivity is detectable in the brain, ovary, and testis of the newt, Triturus carnifex, collected during February (reproductive phase), May, and July (nonreproductive phase). In the brain of May animals, chicken GnRH-II positive cell bodies are located within the terminal nerve, the anterior preoptic area, and the preoptic nucleus, which appears to be devoid of immunoreactive mammalian GnRH cell bodies. During February and July, both chicken GnRH-II and mammalian GnRH are detected only within the terminal nerve and anterior preoptic area. Generally, in the reproductive as well as the nonreproductive periods, chicken GnRH-II fibers are widely distributed in the brain; however, the distribution of fibers of both molecular forms suggests that they exert hypophysiotropic activity. High-pressure liquid chromatography (HPLC) coupled with radioimmunoassay indicates the presence of an early-eluting GnRH peak in brains and gonads but not in plasma. Using chicken GnRH-II antiserum, immunoreactivity is observed in spermatocytes, spermatozoa, and the external theca layer. Seasonal changes of the GnRH-like material are observed in both sexes, and its high concentration detectable during February is in good correlation with the timing of reproduction.

Animals↗
PubMed1996

Localization of GnRH molecular forms in the brain, pituitary, and testis of the frog, Rana esculenta.

In the amphibian brain four molecular forms of GnRH have been identified so far: mammalian GnRH (m- and hydroxyproline9m-), chicken II GnRH (cII), and a salmon (s) GnRH-like peptide. In Rana esculenta, cII- and s-GnRH-like molecules have been partially characterized in the brain extracts using HPLC combined with radioimmunoassay. Moreover, since cII-GnRH-like material has been detected in Rana esculenta testis, the present study describes the localization of the above peptides in the brain and testis of the frog. Immunoreactive cII-GnRH and m-GnRH neurons and fibers were identified in the anterior preoptic area (APOA) and in the median septal area (MSA). A population of cells located on the dorsal side of the caudal preoptic region was also stained. Immunopositive fibers were seen to overlap the median eminence before ending within the pars nervosa. Moreover, densely packed fibers made close contact with the vascular complex in the median eminence. Conversely, immunoreactive s-GnRH-like material was absent in APOA and MSA, but weakly scattered elements were detected by the anti-s-GnRH serum in the dorsal side of the caudal preoptic region. Using m-GnRH antiserum, a strong immunopositivity was observed in the median eminence but not within the pars nervosa, indicating that, besides cII-GnRH and s-GnRH-like material, also m-GnRH-like material is present in Rana esculenta brain. In the testis, cells of the interstitial and germinal compartment were detected by anti-cII-GnRH during different periods of the annual cycle. In particular, in October and February interstitial tissue was intensely stained, coinciding with periods of increased androgen production and the onset of the new spermatogenic wave, respectively.

Animals↗
PubMed1996

Induction of S-phase entry by a gonadotropin releasing hormone agonist (buserelin) in the frog, Rana esculenta, primary spermatogonia.

In the testis of the frog, Rana esculenta, mitotic activity of primary spermatogonia is regulated by gonadotropins and synergistically by testosterone. In addition GnRH-like material directly stimulates gonadal activity. Intact animals were treated with a GnRH agonist (GnRHa, buserelin, Hoechst) and/or a GnRH antagonist giving injections intraperitoneally on alternate days for 15 days. Moreover, testes were treated in vitro for 24 hr with GnRHa. 3H-thymidine and colchicine were used to assess the labelling and the mitotic index (LI and MI) of primary spermatogonia. Both LI and MI were increased by the treatment with GnRHa but the rate of cells measured by LI was significantly higher than that of cells measured by MI. Therefore, our results confirm the role of GnRH-like material as local regulator of the testicular activity in vertebrates and show its involvement in promoting the G1-S transition of spermatogonial cell cycle in the frog, Rana esculenta.

Animals↗
PubMed1995

Localization and characterization of gonadotropin-releasing hormones in the brain, gonads, and plasma of a dipnoi (lungfish, Protopterus annectens).

Two molecular forms of GnRH (chicken GnRH II and a second variant) are present in the brains of species from all the major vertebrate groups. Their differential distribution in the brain and temporal expression during development suggests that have different functional roles. We investigated the nature of GnRH molecular forms in the brain, plasma, testis, and ovary of adult and juvenile lungfish (Protopterus annectens), using high performance liquid chromatography and radioimmunoassay with specific GnRH antisera. In the brain of adult and juvenile lungfish, two peptides with identical chromatographic and immunologic properties to mammalian GnRH and chicken GnRH II were detected. Chicken GnRH II predominated in both the adult and juvenile brain, and the percentage of chicken GnRH II relative to mammalian GnRH was greater in the juvenile brain. In the plasma, only mammalian GnRH was present. Immunoreactive GnRH was not detected in the testis and ovary. Chicken GnRH II and mammalian GnRH were found in the cells of the preoptic nucleus and in the ganglion of the nervus terminalis. Fibers were seen in the ventral hypothalamus, and chicken GnRH II immunoreactivity was detected within the neural lobe of the pituitary. The finding of chicken GnRH II in a sarcopterygian fish adds further support to our hypothesis that this ubiquitous structural variant is highly conserved and likely to have an important functional role. Mammalian GnRH, previously described in several early-evolved actinopterygian fish, also has a fairly widespread distribution and early evolutionary origin. The immunocytochemical distribution of mammalian GnRH and chicken GnRH II fibers in the lungfish brain suggests that both forms are hypophysiotropic. In addition, the presence of mammalian GnRH in the plasma of the lungfish suggests that this molecular form of GnRH has a hypophysiotropic function reaching target organs (pituitary and gonads) via the general circulation.

Animals↗
PubMed1995

Detection of c-mos related products in the dogfish (Scyliorhinus canicula) testis.

The objective of the present paper was to do a comparative study to assess somatic versus germ cell localization of c-mos products in the testis. In mouse and amphibian oocytes, c-mos activity is necessary for meiotic maturation. Lack of c-mos expression has been reported in somatic cells of male and female gonads while transcripts have been found in germ cells of testis and ovary. Using a v-mos probe, we report here the detection of a c-mos related transcript (1.7 kb) in the dogfish Scyliorhinus canicula testis. Western blot analysis detects two proteins of 106 and 32 kDa. A specific immunostaining was exclusively localized in the interstitial tissue while the germinal compartment was completely negative. In conclusion, our results indicate for the first time the presence of c-mos products in an elasmobranch species and, moreover, their presence in somatic testicular cells rather than germ cells. Therefore, this finding in an ancient vertebrate indicates that c-mos activity does not have a direct universal role in the regulation of spermatogenesis.

Animals↗
PubMed1995

Ethane 1,2-dimethane sulfonate effects on the testis of the lizard, Podarcis s. sicula Raf: morphological and hormonal changes.

Ethane 1,2-dimethane sulfonate (EDS) destroys Leydig cells in the testis of some rodents (mice excluded), disrupts interstitial and germinal compartments in the frog, Rana esculenta, while it stimulates testicular activity in the teleost, Gobius paganellus. In the Japanese quail the toxin removes mature spermatozoa. There is no information on EDS effects in reptiles. The present study examines the effect of EDS treatment in the lizard Podarcis s. sicula Raf during two different periods of the testicular cycle (winter stasis and breeding season). Animals received a single EDS injection (100 mg/kg body wt) and were sacrificed at 0 and 24 hr and 3, 5, 7, 11, and 28 days after injection. Androgens were measured in plasma and right testes, while left testes were examined histologically. Plasma androgen levels decreased 5-7 days after EDS injection, alongside interstitial tissue destruction and mast cell appearance, with slight but significant increases on Days 11 and 28. Testicular androgen levels did not change. On Day 11 metaphases were present in the interstitial tissue which regenerated on Day 28. Between Days 5 and 7 some pycnotic nuclei of spermatocytes appeared, mitotic activity of spermatogonia was normal, but germ cell stages were disorganized and empty spaces appeared at the boundary of the tubule. These data show that a single EDS injection results in destruction and repopulation of the interstitial cells in a reptile. Moreover, the effects of EDS in the lizard suggest that P. s. sicula Raf testis responds to the toxin in a similar fashion to the rat testis.

Androgens↗