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The Journal of Experimental Zoology Oct 1991Vitellogenin (VTG) synthesis has been described as an ideal system to study the hormonal regulation of gene expression. In Xenopus the molecular aspects of this control...
Vitellogenin (VTG) synthesis has been described as an ideal system to study the hormonal regulation of gene expression. In Xenopus the molecular aspects of this control have been analyzed; however, in other non-mammalian species such as reptiles, very few studies approaching this level have been undertaken. We report on the induction by estradiol-17 beta of VTG-like proteins in liver explants from adult males and immature male and female lizards (A. pulchellus). A concentration of 10(-7) M was optimum for adult males while a higher concentration (10(-6) M) is required for the immature animals. No differences were observed in the hormonal induction in male and female immature animals, suggesting that there are no sexual distinctions in the liver at this stage. The effect of the hormone in male liver appears to be primarily on mRNA synthesis, since increases in 3H-uridine incorporation in total RNA were prevented by addition of 1 microgram/ml of the RNA polymerase II inhibitor alpha-Amanitin; however, rRNA synthesis was also increased as observed by agarose gel analysis. A 48 hr lag period was required for the detection of the intracellular as well as the secreted VTG-like protein. Electrophoretical analysis of the secretory products revealed the induction of a group of phosphoproteins immunologically related to yolk lipovitellin whose molecular weights range from 116,000 to 200,000.
Topics: Amanitins; Animals; Culture Techniques; Egg Proteins; Egg Proteins, Dietary; Electrophoresis, Agar Gel; Estradiol; Estrogen Antagonists; Female; Gene Expression Regulation; Liver; Lizards; Male; Molecular Weight; Precipitin Tests; RNA, Messenger; Vitellogenesis
PubMed: 1791422
DOI: 10.1002/jez.1402600107 -
Development (Cambridge, England) Sep 2020Vitellogenin (Vg) is a prerequisite for egg production and embryonic development after ovipositioning in oviparous animals. In many insects, juvenile hormone (JH)...
Vitellogenin (Vg) is a prerequisite for egg production and embryonic development after ovipositioning in oviparous animals. In many insects, juvenile hormone (JH) promotes fat body cell polyploidization for the massive Vg synthesis required for the maturation of multiple oocytes, but the underlying mechanisms remain poorly understood. Using the migratory locust as a model system, we report here that JH induces the dephosphorylation of Forkhead box O transcription factor (FoxO) through a signaling cascade including leucine carboxyl methyltransferase 1 (LCMT1) and protein phosphatase 2A (PP2A). JH promotes PP2A activity via LCMT1-mediated methylation, consequently triggering FoxO dephosphorylation. Dephosphorylated FoxO binds to the upstream region of two endocycle-related genes, () and (), and activates their transcription. Depletion of , or results in blocked polyploidization of fat body cells, accompanied by markedly reduced Vg expression, impaired oocyte maturation and arrested ovarian development. The results suggest that JH acts via LCMT1-PP2A-FoxO to regulate and expression, and to enhance ploidy of fat body cells in preparation for the large-scale Vg synthesis required for synchronous maturation of multiple eggs.
Topics: Animals; Fat Body; Female; Grasshoppers; Insect Proteins; Juvenile Hormones; Locusta migratoria; Oocytes; Polyploidy; Signal Transduction; Transcription Factors; Transcription, Genetic; Vitellogenesis; Vitellogenins
PubMed: 32907849
DOI: 10.1242/dev.188813 -
Journal of Agricultural and Food... Jan 2023The insulin receptor substrate (IRS), as the core cytoplasmic adapter protein in the insulin/insulin-like signaling (IIS) pathway, is an important mediator of cellular...
The insulin receptor substrate (IRS), as the core cytoplasmic adapter protein in the insulin/insulin-like signaling (IIS) pathway, is an important mediator of cellular signaling. However, it is still unknown how IRS crosstalk with hormone signaling regulates insect growth, development, and reproduction. In this study, we demonstrated that knockdown of significantly inhibited oogenesis, vitellogenesis, and the development of nurse cells and follicular epithelial cells. In addition, qRT-PCR results showed that transcription factors significantly responded to silencing of the gene. However, silencing had no significant effect on the expression of juvenile hormone/20-hydroxyecdysone (JH/20E)-signaling genes, JH synthesis, and degradation enzyme-related genes and the JH/20E titers. Our results suggested that the IIS pathway regulated ovarian development and production through , independent of JH and 20E signaling pathways. This study revealed the reproductive regulation mechanism in , which provides a theoretical basis for large-scale expansion of as an environment-friendly biological control strategy.
Topics: Animals; Vitellogenesis; Transcription Factors; Insulin Receptor Substrate Proteins; Oogenesis; Signal Transduction; Juvenile Hormones; Coleoptera; Insulins; Insect Proteins
PubMed: 36538395
DOI: 10.1021/acs.jafc.2c07433 -
Acta Biochimica Polonica 1996A comparison between vitellogenesis in virgin and mated females of Tenebrio molitor showed significant differences at each investigated developmental stage. Yolk protein... (Comparative Study)
Comparative Study
A comparison between vitellogenesis in virgin and mated females of Tenebrio molitor showed significant differences at each investigated developmental stage. Yolk protein deposition in oocytes, measured as an increase in their size parameters (length, width, and volume), proceeded much faster and was more efficient in mated females as compared to virgins. In fertilized females the gonadotropic cycle showed a cyclicity with an eight-day period while virgin females finish their vitellogenic stage after the first cycle. These differences were reflected in changes in the rate of protein synthesis in the fat body of females completing vitellogenesis or entering the next oogenetic cycle. In the haemolymph, in addition to a large (158 kDa) and two small (56 kDa and 45 kDa) subunits of vitellogenin, there was an abundance of proteins of 80 kDa and 60 kDa.
Topics: Animals; Breeding; Electrophoresis, Polyacrylamide Gel; Female; Hemolymph; Male; Oocytes; Tenebrio; Vitellogenesis
PubMed: 9104498
DOI: No ID Found -
General and Comparative Endocrinology Jan 2019In shrimp aquaculture, eyestalk ablation is the only technique that is widely used to accelerate ovarian development. Alternative methods for producing improved ovarian...
In shrimp aquaculture, eyestalk ablation is the only technique that is widely used to accelerate ovarian development. Alternative methods for producing improved ovarian development in broodstock are currently being investigated. Several factors involved in the regulation of ovarian development in shrimp have been investigated. Among these factors, growth factors in the transforming growth factor beta (TGF-β) superfamily have been implicated as playing potential roles in the regulation of gonad development. In this work, a member of the TGF-β superfamily known as glass bottom boat (GBB), an ortholog of bone morphogenetic protein (BMP), was investigated to uncover its role in ovarian development in the banana shrimp Fenneropenaeus merguiensis. Full-length cDNA of FmGBB was obtained from transcriptome data. Phylogenetic analysis indicated that the sequence of FmGBB from banana shrimp was similar to those of other arthropods and vertebrate BMP 5/6/7, but was different from those of decapentaplegic proteins and vertebrate BMP 2/4. The FmGBB transcript was found to be widely expressed in shrimp tissues, and its expression in the ovary was dramatically increased in early and late vitellogenic stages during ovarian development and decreased in the mature stage, suggesting its role in vitellogenesis. To study the effects of FmGBB, a soluble recombinant mature FmGBB peptide (His-TF-rgbb) containing both monomers and homodimers was successfully expressed in Escherichia coli. The His-TF-rgbb peptide triggered oocyte proliferation in both cultured ovarian explants and in previtellogenic shrimp upon injection. Interestingly, the injection of His-TF-rgbb into previtellogenic female shrimp stimulated an increase in Vg expression in their ovaries while suppressing production of 20-hydroxyecdysone. Our results suggest the potential role of FmGBB in oocyte proliferation and vitellogenesis; this novel finding can be utilized to stimulate ovarian development in cultured shrimp.
Topics: Animals; Bone Morphogenetic Proteins; Female; Penaeidae; Vitellogenesis
PubMed: 30315758
DOI: 10.1016/j.ygcen.2018.10.005 -
Journal of Peptide Science : An... Dec 2023The insulin superfamily comprises a group of peptides with diverse physiological functions and is conserved across the animal kingdom. Insulin-like peptides (ILPs) of...
The insulin superfamily comprises a group of peptides with diverse physiological functions and is conserved across the animal kingdom. Insulin-like peptides (ILPs) of crustaceans are classified into four major types: insulin, relaxin, gonadulin, and androgenic gland hormone (AGH)/insulin-like androgenic gland factor (IAG). Of these, the physiological functions of AGH/IAG have been clarified to be the regulation of male sex differentiation, but those of the other types have not been uncovered. In this study, we chemically synthesized Maj-ILP1, an ILP identified in the ovary of the kuruma prawn Marsupenaeus japonicus, using a combination of solid-phase peptide synthesis and regioselective disulfide bond formation reactions. As the circular dichroism spectral pattern of synthetic Maj-ILP1 is typical of other ILPs reported thus far, the synthetic peptide likely possessed the proper conformation. Functional analysis using ex vivo tissue incubation revealed that Maj-ILP1 significantly increased the expression of the yolk protein genes Maj-Vg1 and Maj-Vg2 in the hepatopancreas and Maj-Vg1 in the ovary of adolescent prawns. This is the first report on the synthesis of a crustacean ILP other than IAGs and also shows the positive relationship between the reproductive process and female-dominant ILP.
Topics: Animals; Female; Male; Insulin; Vitellogenesis; Peptides; Androgens
PubMed: 37403818
DOI: 10.1002/psc.3529 -
Parasitology Research Aug 2005Vitellogenesis in two spathebothriidean tapeworms, dixenous adult Cyathocephalus truncatus and monoxenous progenetic Diplocotyle olrikii, has been examined using...
Vitellogenesis in two spathebothriidean tapeworms, dixenous adult Cyathocephalus truncatus and monoxenous progenetic Diplocotyle olrikii, has been examined using transmission electron microscopy and cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate for glycogen. Each vitelline follicle consists of vitellocytes at various stages of development and one irregularly shaped interstitial cell. Projections of the interstitial cell enclose the vitellocytes and extend as a cytoplasmic sheath on the follicular periphery. An outer thin fibrous layer (= extracellular lamina) covers the cytoplasmic sheath in C. truncatus, but lacks in D. olrikii. Maturing and mature vitellocytes contain vitelline material in the form of single small shell globules that gradually fuse and give rise to the large shell globule clusters. Morphology of shell globule clusters differs slightly in both species. In addition, single "lamellar" granules are present in the cytoplasm of vitellocytes of C. truncatus, but not in D. olrikii. Both electron lucent and electron dense lipid droplets are present in the vitellocytes of C. truncatus, whereas only electron dense lipids occur in D. olrikii. A single lipid droplet turns up occasionally in the nuclei of some of the vitellocytes of C. truncatus. The ultrastructural features of vitellogenesis in spathebothriideans resemble those reported previously in "lower" cestodes, especially in pseudophyllideans.
Topics: Animals; Cestoda; Glycogen; Microscopy, Electron, Transmission; Oocytes; Periodic Acid-Schiff Reaction; Vitellogenesis
PubMed: 15940521
DOI: 10.1007/s00436-005-1378-7 -
Animal : An International Journal of... Jun 2020In teleosts, vitellogenin (Vtg) is a phospholipoglycoprotein synthesized by the liver, released into the blood circulation and incorporated into the oocytes via...
In teleosts, vitellogenin (Vtg) is a phospholipoglycoprotein synthesized by the liver, released into the blood circulation and incorporated into the oocytes via endocytosis mediated by the Vtg receptor (VTGR) to form the yolk granules. The VTGR is crucial for oocyte growth in egg-laying animals but is also present in non-oviparous vertebrates, such as human. The VTGR belongs to the low-density lipoprotein receptor superfamily (LDLR) and is also named very-low-density lipoprotein receptor (VLDLR). In this study, we identified and phylogenetically positioned the VTGR of a basal teleost, the European eel, Anguilla anguilla. We developed quantitative real-time PCR (qRT-PCR) and investigated the tissue distribution of vtgr transcripts. We compared by qRT-PCR the ovarian expression levels of vtgr in juvenile yellow eels and pre-pubertal silver eels. We also analyzed the regulation of ovarian vtgr expression throughout vitellogenesis in experimentally matured eels. The Vtg plasma level was measured by homologous ELISA experimental maturation. Our in silico search and phylogenetical analysis revealed a single vtgr in the European eel, orthologous to other vertebrate vtgr. The qRT-PCR studies revealed that vtgr is mainly expressed in the ovary and also detected in various other tissues such as brain, pituitary, gill, fat, heart, and testis, suggesting some extra-ovarian functions of VTGR. We showed that vtgr is expressed in ovaries of juvenile yellow eels with no higher expression in pre-pubertal silver eels nor in experimentally matured eels. This suggests that vtgr transcription already occurs during early pre-vitellogenesis of immature eels and is not further activated in vitellogenic oocytes. European eel Vtg plasma level increased throughout experimental maturation in agreement with previous studies. Taken together, these results suggest that vtgr transcript levels may not be a limiting step for the uptake of Vtg by the oocyte in the European eel.
Topics: Anguilla; Animals; Egg Proteins; Female; Gene Expression Regulation; Liver; Oocytes; Ovary; Pituitary Gland; Receptors, Cell Surface; Receptors, LDL; Sexual Maturation; Vitellogenesis; Vitellogenins
PubMed: 31971122
DOI: 10.1017/S1751731119003355 -
Folia Parasitologica Mar 2007The vitellogenesis of Paraechinophallus japonicus (Yamaguti, 1934), the first pseudophyllidean tapeworm of the family Echinophallidae studied using transmission electron...
The vitellogenesis of Paraechinophallus japonicus (Yamaguti, 1934), the first pseudophyllidean tapeworm of the family Echinophallidae studied using transmission electron microscope, is described on the basis of ultrastructural observations of specimens from the benthopelagic fish Psenopsis anomala (Temminck et Schlegel, 1844) (Perciformes: Centrolophidae). The process of vitellogenesis in P. japonicus follows the same general pattern observed in other tapeworms. Five stages of vitellocyte development have been distinguished. The first stage corresponds to immature cells containing ribosomes and mitochondria. The second stage of development is characterized by the appearance of granular endoplasmic reticulum and Golgi complexes, formation of shell globules and lipid droplets at the periphery of the cell cytoplasm. Vitellocyte of the third stage presents accumulation of shell globules and lipid droplets. During the fourth stage, shell globule clusters are formed, and lipid droplets and rosettes of alpha-glycogen are accumulated. Mature vitelline cells are characterized by a great number of lipid droplets with glycogen in the centre of the cytoplasm, whereas shell globule clusters are situated more peripherally. The interstitial tissue of vitelline follicles of P. japonicus is syncytial with long cytoplasmic projections extending between vitelline cells. The presence of a large amount of lipid droplets in the vitelline cytoplasm within the eggs of P. japonicus may be related to egg accumulation in the uterine sac.
Topics: Animals; Cestoda; Cestode Infections; Female; Fish Diseases; Glycogen; Histocytochemistry; Lipids; Microscopy, Electron, Transmission; Ovum; Perciformes; Vitelline Membrane; Vitellogenesis
PubMed: 17441436
DOI: 10.14411/fp.2007.006 -
Comparative Biochemistry and... Mar 2010This study investigated the effects of different doses of 17-beta-estradiol (E(2)) in Rhamdia quelen. Groups of males exposed to different doses of E(2) (0.1 mg...
This study investigated the effects of different doses of 17-beta-estradiol (E(2)) in Rhamdia quelen. Groups of males exposed to different doses of E(2) (0.1 mg kg(-)(1), 1 mg kg(-)(1) and 10 mg kg(-)(1)) were compared with non-exposed male and female fish groups. Among the considered biomarkers, no significant differences were observed for micronuclei test, reduced glutathione concentration and lipid peroxidation. All E(2)-treated individuals had decreased glutathione S-transferase activity. Increased catalase and superoxide dismutase activities, increased vitellogenin expression and decreased metallothionein concentration were observed in males treated with the highest dose. Liver of all test groups showed necrotic areas, but cytoplasm vacuolization was again found only in the individuals exposed to highest dose. E(2) causes deleterious hepatic effects to R. quelen, and vitellogenin expression, catalase and superoxide dismutase activity and metallothionein concentration represent appropriate biomarkers for studying E(2) effects. Additionally, the response of some biomarkers was similar in males exposed to E(2) and unexposed females, and therefore exposure to endocrine disruptors may cause consequences for fish populations.
Topics: Animals; Blotting, Western; Catalase; Catfishes; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Estradiol; Estrogens; Female; Fresh Water; Glutathione; Glutathione Peroxidase; Glutathione Transferase; Lipid Peroxidation; Liver; Male; Metallothionein; Micronucleus Tests; Necrosis; Superoxide Dismutase; Vitellogenesis; Vitellogenins; Water Pollutants, Chemical
PubMed: 19897053
DOI: 10.1016/j.cbpc.2009.11.002