1-Methyladenine: a starfish oocyte maturation-inducing substance

Zygote ◽  
1999 ◽  
Vol 8 (S1) ◽  
pp. S9-S11 ◽  
Author(s):  
Masatoshi Mita
Keyword(s):  
Oocyte Maturation ◽  
Hormone Receptor ◽  
Ovarian Follicle ◽  
Germinal Vesicle ◽  
Follicle Cells ◽  
Glycoprotein Hormone ◽  
Late Prophase ◽  
Immature Oocytes ◽  
Extracellular Region ◽  
Glycoprotein Hormone Receptor

1-Methyladenine (1-MeAde) in starfish was the first compound to be identified as an oocyte maturation-inducing substance (MIS) among invertebrates in 1969 by Kanatani and co-workers. In starfish, the ripe ovary contains a huge number of fully grown oocytes of almost equal size. Each oocyte possesses a large nucleus (germinal vesicle, GV), which is arrested in late prophase of the first maturation division. The oocyte is surrounded by a single follicle layer. Such immature oocytes are not fertilisable. Resumption of meiosis in immature oocytes can be induced by 1-MeAde, and the mature oocytes thus become fertilisable (Kanatani et al., 1969; Kanatani, 1985). 1-MeAde is produced by ovarian follicle cells upon stimulation with a gonad-stimulating substance (GSS) released from the radial nerves (Fig. 1).It has been demonstrated that GSS is a peptide hormone (Kanatani et al., 1971). The action of GSS on 1-MeAde production in follicle cells appears to be mediated by its receptor, G-proteins and adenylyl cyclase (Mita & Nagahama, 1991). These findings suggest that a G-protein coupled (seven transmembrane type) receptor is involved in GSS signal transduction, similarly to the pituitary-gonadal axis in vertebrates.Thus, using degenerate probes derived from consensus sequences of the mammalian glycoprotein hormone (GTH and TSH) receptors, cDNA was cloned from mRNA of ovaries of Asterina pectinifera. The cDNA showed striking structural homology with members of the glycoprotein hormone receptor family in the transmembrane region, and contained a very large extracellular region. Expression was observed in isolated ovarian follicle cells. Thus, it seems likely that the glycoprotein hormone receptor (GTHR) family gene is related to GSS receptor in ovarian follicle cells. The phylogenic relatedness of the starfish GTHR was also assessed in relation to other vertebrate GTHRs. The analysis showed that the starfish gene diverged before differentiation of the gonadotropin (LH and FSH) and TSH receptors in vertebrates.

Structures of full-length glycoprotein hormone receptor signalling complexes

Nature ◽  
2021 ◽  
Author(s):  
Jia Duan ◽  
Peiyu Xu ◽  
Xi Cheng ◽  
Chunyou Mao ◽  
Tristan Croll ◽  
...  
Keyword(s):  
Hormone Receptor ◽  
Full Length ◽  
Glycoprotein Hormone ◽  
Receptor Signalling ◽  
Glycoprotein Hormone Receptor

scholarly journals A sea lamprey glycoprotein hormone receptor similar with gnathostome thyrotropin hormone receptor

2008 ◽  
Vol 41 (4) ◽  
pp. 219-228 ◽  
Author(s):  
Mihael Freamat ◽  
Stacia A Sower
Keyword(s):  
Hormone Receptor ◽  
Hormone Receptors ◽  
Functional Divergence ◽  
Sea Lamprey ◽  
Glycoprotein Hormone ◽  
Receptor System ◽  
Glycoprotein Hormone Receptors ◽  
Molecular Phylogenetic ◽  
Synthetic Ligand ◽  
Glycoprotein Hormone Receptor

The specificity of the vertebrate hypothalamic–pituitary–gonadal and hypothalamic–pituitary–thyroid axes is explained by the evolutionary refinement of the specificity of expression and selectivity of interaction between the glycoprotein hormones GpH (FSH, LH, and TSH) and their cognate receptors GpH-R (FSH-R, LH-R, and TSH-R). These two finely tuned signaling pathways evolved by gene duplication and functional divergence from an ancestral GpH/GpH-R pair. Comparative analysis of the protochordate and gnathostome endocrine systems suggests that this process took place prior or concomitantly with the emergence of the gnathostome lineage. Here, we report identification and characterization of a novel glycoprotein hormone receptor (lGpH-R II) in the Agnathan sea lamprey. This 781 residue protein was found ∼43% identical with mammalian TSH-R and FSH-R representative sequences, and similarly with these two classes of mammalian receptors it is assembled from ten exons. A synthetic ligand containing the lamprey glycoprotein hormone β-chain tethered upstream of a mammalian α-chain activated the lGpH-R II expressed in COS-7 cells but in a lesser extent than lGpH-R I. Molecular phylogenetic analysis of vertebrate GpH-R protein sequences suggests a closer relationship between lGpH-R II and gnathostome thyrotropin receptors. Overall, the presence and characteristics of the lamprey glycoprotein hormone receptors suggest existence of a primitive functionally overlapping glycoprotein hormone/glycoprotein hormone receptor system in this animal.

Involvement of catecholamines in the regulation of oocyte maturation in frogs

Zygote ◽  
2002 ◽  
Vol 10 (3) ◽  
pp. 271-281 ◽  
Author(s):  
Inés Ramos ◽  
Susana Cisint ◽  
Claudia A. Crespo ◽  
Marcela F. Medina ◽  
Silvia N. Fernández
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Significant Inhibition ◽  
Follicle Cells ◽  
Germinal Vesicle Breakdown ◽  
Nuclear Maturation ◽  
Dose Dependent ◽  
Metabolic Behaviour

The present study investigates the role of catecholamines in the regulation of Bufo arenarum oocyte maturation. The metabolic changes in the oxidation of carbohydrates and the meiotic resumption evinced by the germinal vesicle breakdown were used as indicators of cytoplasmic and nuclear maturation, respectively. The results obtained suggest that noradrenaline (norepinephrine) could be one of the factors responsible for the metabolic behaviour that characterises cytoplasmically immature oocytes. The use of adrenaline (epinephrine), on the other hand, induced a metabolic change which made oocytes cytoplasmically mature. The effect of both catecholamines, which was dose-dependent, was observed in ovarian oocytes (surrounded by follicle cells) as well as in coelomic oocytes (free from follicle cells), suggesting the presence of adrenergic receptors in the gamete. The results obtained using adrenergic agonists and antagonists suggest that the effect of adrenaline would be due to an interaction with β2-receptors. Although catecholamines have an influence on the determination of the stage of cytoplasmic maturation of the oocytes, they do not affect nuclear maturation by themselves. Nevertheless, pretreatment of follicles with adrenaline caused a significant inhibition in progesterone-induced nuclear maturation even though this effect was markedly weaker when using noradrenaline.

The potential roles of c-Jun N-terminal kinase (JNK) during the maturation and aging of oocytes produced by a marine protostome worm

Zygote ◽  
2017 ◽  
Vol 25 (6) ◽  
pp. 686-696 ◽  
Author(s):  
Stephen A. Stricker ◽  
Niharika Ravichandran
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Germinal Vesicle Breakdown ◽  
Specific Antibodies ◽  
Immature Oocytes ◽  
Jnk Inhibitors ◽  
Jnk Activation ◽  
Mode Of Death ◽  
Maturation Promoting Factor

SummaryPrevious investigations have indicated that c-Jun N-terminal kinase (JNK) regulates the maturation and aging of oocytes produced by deuterostome animals. In order to assess the roles of this kinase in a protostome, oocytes of the marine nemertean worm Cerebratulus were stimulated to mature and subsequently aged before being probed with phospho-specific antibodies against active forms of JNK and maturation-promoting factor (MPF). Based on blots of maturing oocytes, a 40-kD putative JNK is normally activated during germinal vesicle breakdown (GVBD), which begins at 30 min post-stimulation with seawater, whereas treating immature oocytes with JNK inhibitors downregulates both the 40-kD JNK signal and GVBD, collectively suggesting a 40-kD JNK may facilitate oocyte maturation. Along with this JNK activity, mature oocytes also exhibit high levels of MPF at 2 h post-stimulation. However, by ~6–8 h post-GVBD, mature oocytes lose the 40-kD JNK signal, and at ~20–30 h of aging, an ~48-kD phospho-JNK band arises as oocytes deactivate MPF and begin to lyse during a necroptotic-like mode of death. Accordingly, JNK inhibitors reduce the aging-related 48-kD JNK phosphorylation while maintaining MPF activity and retarding oocyte degradation. Such findings suggest that a 48-kD JNK may help deactivate MPF and trigger death. Possible mechanisms by which JNK activation either together with, or independently of, protein neosynthesis might stimulate oocyte degradation are discussed.

scholarly journals GRIS: Glycoprotein-Hormone Receptor Information System

2006 ◽  
Vol 20 (9) ◽  
pp. 2247-2255 ◽  
Author(s):  
Joost Van Durme ◽  
Florence Horn ◽  
Sabine Costagliola ◽  
Gert Vriend ◽  
Gilbert Vassart
Keyword(s):  
Information System ◽  
Hormone Receptor ◽  
Glycoprotein Hormone ◽  
Glycoprotein Hormone Receptor

scholarly journals Involvement of Cyclic Adenosine 3′,5′-Monophosphate in the Differential Regulation of Activin βA and βB Expression by Gonadotropin in the Zebrafish Ovarian Follicle Cells

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 491-499 ◽  
Author(s):  
Yajun Wang ◽  
Wei Ge
Keyword(s):  
Oocyte Maturation ◽  
Ovarian Follicle ◽  
Mrna Level ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
Differential Regulation ◽  
Follicle Cells ◽  
Intracellular Camp ◽  
Dependent Manner

Activin is a dimeric protein consisting of two similar but distinct β-subunits, βA and βB. In our previous studies, both activin A (βAβA) and activin B (βBβB) have been demonstrated to stimulate oocyte maturation and promote oocyte maturational competence in the zebrafish. Follistatin, a specific activin-binding protein, can block both activin- and gonadotropin-induced final oocyte maturation in vitro, suggesting that activin is likely a downstream mediator of gonadotropin actions in the zebrafish ovary. In the present study, a full-length cDNA encoding zebrafish ovarian activin βA was cloned and sequenced. The precursor of zebrafish activin βA consists of 395 amino acids and its mature region exhibits about 78% homology with that of mammals. Using an in vitro primary culture of the ovarian follicle cells and semiquantitative RT-PCR assays, we examined the regulation of activin βA and βB expression by human chorionic gonadotropin (hCG) and its intracellular signal transduction mechanisms. hCG (15 IU/ml) increased the mRNA level of activin βA-subunit; however, it significantly down-regulated the steady-state expression level of activin βB in a time- and dose-dependent manner. The differential regulation of the two β-subunits by hCG could be mimicked by 3-isobutyl-1-methylxanthine, forskolin, and dibutyryl-cAMP, suggesting involvement of the intracellular cAMP pathway. Interestingly, H89 (a specific inhibitor of protein kinase A, PKA) could effectively block hCG- and forskolin-stimulated activin βA expression at 10 μm, but it was unable to reverse the inhibitory effects of hCG and forskolin on βB expression. This suggests that the hCG-stimulated activin βA expression is dependent on the activation of the cAMP-PKA pathway, whereas the inhibitory effect of hCG on activin βB expression is likely mediated by PKA-independent pathway(s).

scholarly journals Membrane estrogen receptor (GPER) and follicle-stimulating hormone receptor heteromeric complexes promote human ovarian follicle survival

2020 ◽  
Author(s):  
Livio Casarini ◽  
Clara Lazzaretti ◽  
Elia Paradiso ◽  
Silvia Limoncella ◽  
Laura Riccetti ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Cell Viability ◽  
Oocyte Maturation ◽  
Granulosa Cells ◽  
Hormone Receptor ◽  
Ovarian Follicle ◽  
Follicle Stimulating Hormone ◽  
Oocyte Growth ◽  
Expression Levels ◽  
Stimulating Hormone

AbstractClassically, follicle stimulating hormone receptor (FSHR) driven cAMP-mediated signaling boosts human ovarian follicle growth and would be essential for oocyte maturation. However, contradicting in vitro suggest a different view on physiological and clinical significance of FSHR-mediated cAMP signaling. We found that the G protein coupled estrogen receptor (GPER) heteromerizes with FSHR, reprogramming cAMP/death signals into proliferative stimuli fundamental for sustaining oocyte survival. In human granulosa cells, survival signals are effectively delivered upon equal expression levels of both receptors, while they are missing at high FSHR:GPER ratio, which negatively impacts follicle maturation and strongly correlates with FSH responsiveness of patients undergoing controlled ovarian stimulation. Consistent with high FSHR expression levels during follicular selection, cell viability is dramatically reduced in FSHR overexpressing cells due to preferential coupling to the Gαs protein/cAMP pathway. In contrast, FSHR/GPER heteromer formation resulted in FSH-triggered anti-apoptotic/proliferative signaling delivered via the Gβγ dimer while heteromer impairment or GPER-associated Gαs inhibitory protein complexes resulted in cell death. GPER-depleted granulosa cells have an amplified FSH-dependent decrease in cell viability and steroidogenesis, consistent with the requirement of estrogen signaling for successful oocyte growth. Therefore, our findings indicate how oocyte maturation depends on the capability of GPER to shape FSHR selective signals, indicating hormone receptor heteromers may be a marker of cell proliferation.One Sentence SummaryFSHR/GPER heteromers block cAMP-dependent selection of ovarian follicles and target tumor growth and poor FSH-response in women.

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