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Makoto Asashima - One of the best experts on this subject based on the ideXlab platform.
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Growing kidney in the frog.
Nephron. Experimental nephrology, 2006Co-Authors: Techuan Chan, Makoto AsashimaAbstract:An understanding of the regulation of kidney development has increased dramatically in the past decade. The Pronephros, mesonephros, and metanephros represent three distinct renal organs that function, in succession, as the vertebrate excretory system during development of the kidney. These three organ systems are derived from the intermediate mesoderm and develop in a well-defined temporal and spatial sequence. The Pronephros, which consists of a tubule, duct and glomus, is established first and is the simplest of the excretory organs in vertebrates. Xenopus Pronephros serves as an ideal model for investigating organogenesis and development of renal function in vertebrates. In this article, we highlight the advantages of Xenopus for analyzing kidney organogenesis and the latest research in Pronephros development.
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Structure and sequential gene expression of in vitro-induced Pronephros (kidney) in the amphibian development
Kidney International, 2005Co-Authors: Makoto AsashimaAbstract:We have successfully induced the formation of 20 different organs in vitro from animal caps (undifferentiated or multipotent cells) of Xenopus blastulae and six different tissues from mice embryonic stem cells. For the Xenopus embryo, we subsequently have attempted to transplant these in vitro-generated organs into embryos to determine their functional capacity. In the experiment we induced the Pronephros (nephron) consisting of renal tubule, glomerulus, and renal duct from animal caps treated with activin and retinoic acid. Then we transplanted these cell mass treated with activin and retinoic acid into an embryo in which the renal rudiment had been removed. We found that the transplant developed into Pronephros normally and function in vivo. Using this system, we have cloned and analyzed the Pronephros-specific genes in Xenopus development. Sequential gene expressions of Pronephros in vivo and in vitro resemble the mesonephros formation in mammals. In the screening for genes expressed in pronephroi, we isolated a novel gene, named dullard. Dullard protein contains the C-terminal conserved domain of nuclear LIM interactor-interacting factor (NLI-IF), a protein whose function is unknown. The spatial expression was in neural regions at neurula stages, and localized to neural tissues, branchial arches, and pronephroi. The translational knockdown of dullard resulted in failure of neural tube development and structural deformation of the pronephric tubules, and the embryos consequently showed a reduction of head development. In the same screening method for the Pronephros-specific genes, we isolated the XTRAP-gamma gene that codes translucent-associated protein, one of the subunit of the translocon-associated protein complex. XTRAP is one of the proteins proposed to aid in the translocation of nascent polypeptides into the lumen of the endothelium reticulum. XTRAP-gamma is expressed in Pronephros tubules during Pronephros development. The translational knockdown of XTRAP-gamma caused the suppression of tubulogenesis, the increase of Xlim-1 expression, and the decrease of Xpax-2 and Xwnt-4 expression. This translational knockdown of XTRAP-gamma also inhibited differentiation of the Pronephros in animal caps by the treatment with activin and retinoic acid. These results showed that XTRAP-gamma plays an important role in the pronephric development. As another approach to clarify the molecular mechanisms of renal development, we investigated the role of Xenopus frizzled-8 ( Xfz8 ) in Pronephros development to study the relation between Wnt signaling and nephric development. Translational inhibition of Xfz8 caused reduction in the staining of a duct-specific antibody and defects in pronephric tubule branching, while there was no effect on the expression of early pronephric maker genes in the duct region. Histologic analysis showed that the Xfz8-inhibited cells failed to form a normal epithelial structure. These results suggest that Xfz8 is involved in the formation of epithelium in the developing pronephric duct and tubules.
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Identification and characterization of Xenopus NDRG1.
Biochemical and biophysical research communications, 2003Co-Authors: Jun-ichi Kyuno, Akimasa Fukui, Tatsuo Michiue, Makoto AsashimaAbstract:NDRG1 is a member of the N-myc downstream-regulated gene (NDRG) family and is involved in cellular differentiation, activation of p53, cell cycle arrest, metastasis, and hypoxia. Expression of NDRG1 is repressed by the proto-oncogene, N-myc during mouse development, although the exact functional role of NDRG1 in development remains unknown. Here, we report the characterization of Xenopus laevis NDRG1 (xNDRG1) during X. laevis development. Expression of xNDRG1 transcript was first detected at stage 15, and was localized to the presumptive pronephric anlagen at stage 26 and to Pronephros, eye, branchial arches, and tail-bud at stage 32. Overexpression of xNDRG1 results in a reduced Pronephros and disorganized somites. Depletion of xNDRG1, using morpholinos, causes failure of Pronephros development. These results suggest that xNDRG1 is required for Pronephros development in X. laevis.
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The isolation and characterization of XC3H-3b: a CCCH zinc-finger protein required for Pronephros development
Biochemical and biophysical research communications, 2003Co-Authors: Tomoyo Kaneko, Techuan Chan, Reiko Satow, Toshiro Fujita, Makoto AsashimaAbstract:We describe the isolation and characterization of the RNA-binding protein XC3H-3b that is expressed during Pronephros development. XC3H-3b is a member of the TTP/TIS family of CCCH tandem zinc-finger proteins, which are physiological stimulators of instability for the mRNA encoding tumor necrosis factor-α in certain cell types. XC3H-3b is localized primarily to the mesodermal tissues around the Pronephros. Overexpression of XC3H-3b markedly and specifically inhibits kidney development. Morpholino-mediated knockdown of XC3H-3b also results in defects in nephrogenesis. In both cases, the expression of numerous pronephric marker genes, such as Xlim-1, Xpax-2, Xpax-8, Xwnt-4, and XWT1, is decreased and morphological development of the pronephric tubules is abrogated. We conclude that XC3H-3b plays an important role in the regulation of Pronephros differentiation. This is the first report of a gene localized around the Pronephros that regulates Pronephros development.
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in vitro induction of the pronephric duct in xenopus explants
Development Growth & Differentiation, 2002Co-Authors: Kenji Osafune, Shinji Komazaki, Ryuichi Nishinakamura, Makoto AsashimaAbstract:The earliest form of embryonic kidney, the Pronephros, consists of three components: glomus, tubule and duct. Treatment of the undifferentiated animal pole ectoderm of Xenopus laevis with activin A and retinoic acid (RA) induces formation of the pronephric tubule and glomus. In this study, the rate of induction of the pronephric duct, the third component of the Pronephros, was investigated in animal caps treated with activin A and RA. Immunohistochemistry using pronephric duct-specific antibody 4A6 revealed that a high proportion of the treated explants contained 4A6-positive tubular structures. Electron microscopy showed that the tubules in the explants were similar to the pronephric ducts of normal larvae, and they also expressed Gremlin and c-ret, molecular markers for pronephric ducts. These results suggest that the treatment of Xenopus ectoderm with activin A and RA induces a high rate of differentiation of pronephric ducts, in addition to the differentiation of the pronephric tubule and glomus, and that this in vitro system can serve as a simple and effective model for analysis of the mechanism of Pronephros differentiation.
Ryuichi Nishinakamura - One of the best experts on this subject based on the ideXlab platform.
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Kidney development conserved over species: essential roles of Sall1.
Seminars in cell & developmental biology, 2003Co-Authors: Ryuichi NishinakamuraAbstract:The kidney develops in three stages: Pronephros, mesonephros, and metanephros. Molecular mechanisms underlying these three steps are similar, and we can thus examine genetic cascades occurring during development. The induction system for Pronephros in vitro has been established in Xenopus. Using this system, we isolated Sall1 that is essential for the initial step in metanephros formation. The potential mechanisms involved and future directions regarding kidney development are discussed.
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in vitro induction of the pronephric duct in xenopus explants
Development Growth & Differentiation, 2002Co-Authors: Kenji Osafune, Shinji Komazaki, Ryuichi Nishinakamura, Makoto AsashimaAbstract:The earliest form of embryonic kidney, the Pronephros, consists of three components: glomus, tubule and duct. Treatment of the undifferentiated animal pole ectoderm of Xenopus laevis with activin A and retinoic acid (RA) induces formation of the pronephric tubule and glomus. In this study, the rate of induction of the pronephric duct, the third component of the Pronephros, was investigated in animal caps treated with activin A and RA. Immunohistochemistry using pronephric duct-specific antibody 4A6 revealed that a high proportion of the treated explants contained 4A6-positive tubular structures. Electron microscopy showed that the tubules in the explants were similar to the pronephric ducts of normal larvae, and they also expressed Gremlin and c-ret, molecular markers for pronephric ducts. These results suggest that the treatment of Xenopus ectoderm with activin A and RA induces a high rate of differentiation of pronephric ducts, in addition to the differentiation of the pronephric tubule and glomus, and that this in vitro system can serve as a simple and effective model for analysis of the mechanism of Pronephros differentiation.
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Cloning and expression pattern of a Xenopus Pronephros-specific gene, XSMP-30.
Mechanisms of development, 2000Co-Authors: Akira Sato, Makoto Asashima, Takashi Yokota, Ryuichi NishinakamuraAbstract:The first step in kidney development is the formation of the Pronephros which is derived from mesoderm. Xenopus is an appropriate model to study this process since the Pronephros can be efficiently induced in animal cap explants by treatment with activin and retinoic acid (RA). Using this in vitro system, we isolated a Xenopus homologue of SMP-30 (Senescence marker protein-30), which is a Ca(2+)-binding protein that is highly conserved in vertebrates. This gene, termed XSMP-30, was found to be selectively expressed in pronephric tubules from the late tadpole stage, by whole mount in situ hybridization. Furthermore XSMP-30 was expressed in animal caps treated with both activin and RA, a condition in which the Pronephros is formed in vitro. These data indicate that XSMP-30 is a specific marker for the Pronephros.
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Gene expression pattern Cloning and expression pattern of a Xenopus Pronephros-specific gene, XSMP-30
2000Co-Authors: Akira Sato, Makoto Asashima, Takashi Yokota, Ryuichi NishinakamuraAbstract:The first step in kidney development is the formation of the Pronephros which is derived from mesoderm. Xenopus is an appropriate model to study this process since the Pronephros can be efficiently induced in animal cap explants by treatment with activin and retinoic acid (RA). Using this in vitro system, we isolated a Xenopus homologue of SMP-30 (Senescence marker protein-30), which is a Ca 21 -binding protein that is highly conserved in vertebrates. This gene, termed XSMP-30, was found to be selectively expressed in pronephric tubules from the late tadpole stage, by whole mount in situ hybridization. Furthermore XSMP-30 was expressed in animal caps treated with both activin and RA, a condition in which the Pronephros is formed in vitro. These data indicate that XSMP-30 is a specific marker for the Pronephros. q 2000 Elsevier Science Ireland Ltd. All rights reserved.
Minoru Uchiyama - One of the best experts on this subject based on the ideXlab platform.
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Ontogeny of ENaC expression in the gills and the kidneys of the Japanese black salamander (Hynobius nigrescens Stejneger).
Journal of Experimental Zoology, 2010Co-Authors: Minoru Uchiyama, Tomoko Kumano, Norifumi Konno, Hideki Yoshizawa, Kouhei MatsudaAbstract:A full-length cDNA cloning and tissue distribution of epithelial sodium channel (ENaC) protein were studied during ontogeny by immunohistochemistry in the external gills, and the kidney, Pronephros and mesonephros, of the Japanese black salamander, Hynobius nigrescens (Family Hynobiidae; a primitive caudate species). The amino acid sequence of Hynobius ENaCα is 64 and 63% identical to Bufo ENaCα and Rat ENaCα, respectively. In aquatic larva salamander at the digit differentiation stage, Hynobius ENaCα mRNA was expressed in the external gills and Pronephros. In the adult, the mRNA was expressed in the skin and the mesonephros. In the larvae, juvenile, and adult specimens, Hynobius ENaCα immunoreactivity was observed at the apical cell membrane of the external gills, late parts of the distal tubules, and mesonephric duct in the kidney. Colocalization of the apical Hynobius ENaCα and the basolateral Na+,K+-ATPase was observed in the tubular cells of Pronephros and mesonephros. These results suggest that Hynobius ENaCα plays an important role in the regulation of sodium transport in the external gills and Pronephros of aquatic larvae, and in the skin and mesonephros of terrestrial adult. This is the first study to indicate ENaC expression during ontogeny in amphibians. Since no orthologs or paralogs for ENaC have been found, so far, in databases of the genomes of teleosts, it is assumed that ENaC might have played a role in terrestriality during the evolution of early tetrapods, the origin of lissamphibians. J. Exp. Zool. (Mol. Dev. Evol.) 316:135–145, 2011. © 2010 Wiley-Liss, Inc.
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Ontogeny of ENaC expression in the gills and the kidneys of the Japanese black salamander (Hynobius nigrescens Stejneger).
Journal of experimental zoology. Part B Molecular and developmental evolution, 2010Co-Authors: Minoru Uchiyama, Tomoko Kumano, Norifumi Konno, Hideki Yoshizawa, Kouhei MatsudaAbstract:A full-length cDNA cloning and tissue distribution of epithelial sodium channel (ENaC) protein were studied during ontogeny by immunohistochemistry in the external gills, and the kidney, Pronephros and mesonephros, of the Japanese black salamander, Hynobius nigrescens (Family Hynobiidae; a primitive caudate species). The amino acid sequence of Hynobius ENaCα is 64 and 63% identical to Bufo ENaCα and Rat ENaCα, respectively. In aquatic larva salamander at the digit differentiation stage, Hynobius ENaCα mRNA was expressed in the external gills and Pronephros. In the adult, the mRNA was expressed in the skin and the mesonephros. In the larvae, juvenile, and adult specimens, Hynobius ENaCα immunoreactivity was observed at the apical cell membrane of the external gills, late parts of the distal tubules, and mesonephric duct in the kidney. Colocalization of the apical Hynobius ENaCα and the basolateral Na(+) ,K(+) -ATPase was observed in the tubular cells of Pronephros and mesonephros. These results suggest that Hynobius ENaCα plays an important role in the regulation of sodium transport in the external gills and Pronephros of aquatic larvae, and in the skin and mesonephros of terrestrial adult. This is the first study to indicate ENaC expression during ontogeny in amphibians. Since no orthologs or paralogs for ENaC have been found, so far, in databases of the genomes of teleosts, it is assumed that ENaC might have played a role in terrestriality during the evolution of early tetrapods, the origin of lissamphibians.
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Cellular localization of a putative Na^+/H^+ exchanger 3 during ontogeny in the Pronephros and mesonephros of the Japanese black salamander (Hynobius nigrescens Stejneger)
Cell and Tissue Research, 2008Co-Authors: Tomoko Kumano, Norifumi Konno, Tatsuya Wakasugi, Kouhei Matsuda, Hideki Yoshizawa, Minoru UchiyamaAbstract:The cloning of cDNA and an examination of the tissue distribution of Na^+/H^+ exchanger 3 (NHE3) were carried out in the Japanese black salamander, Hynobius nigrescens . The cellular localization of Hynobius NHE3 was examined by in situ hybridization and immunohistochemistry during ontogeny in the nephron of the Pronephros and mesonephros of the salamander. The partial amino acid sequence of Hynobius NHE3 was 81% and 72% identical to rat NHE3 and stingray NHE3, respectively. Hynobius NHE3 mRNA and protein were exclusively expressed along the late portion of the distal tubule to the anterior part of the pronephric duct of premetamorphic larvae (IY stages 43–50). NHE3 mRNA was expressed in the Pronephros but not in the external gills in the larvae at the digit differentiation stage (IY stage 50). In the adult, mRNA was strongly expressed in the mesonephros but not in the ventral and dorsal skin. In juvenile and adult specimens, NHE3 immunoreactivity was observed at the apical membrane of the initial parts of the distal tubules of the mesonephric kidney. Immunohistochemical and in situ hybridization studies suggested that Na^+ absorption coupled with H^+ secretion via NHE3 occurred in the distal nephron of the Pronephros and mesonephros. This is the first study to indicate NHE3 expression during ontogeny in amphibians.
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cellular localization of a putative na h exchanger 3 during ontogeny in the Pronephros and mesonephros of the japanese black salamander hynobius nigrescens stejneger
Cell and Tissue Research, 2008Co-Authors: Tomoko Kumano, Norifumi Konno, Tatsuya Wakasugi, Kouhei Matsuda, Hideki Yoshizawa, Minoru UchiyamaAbstract:The cloning of cDNA and an examination of the tissue distribution of Na+/H+ exchanger 3 (NHE3) were carried out in the Japanese black salamander, Hynobius nigrescens. The cellular localization of Hynobius NHE3 was examined by in situ hybridization and immunohistochemistry during ontogeny in the nephron of the Pronephros and mesonephros of the salamander. The partial amino acid sequence of Hynobius NHE3 was 81% and 72% identical to rat NHE3 and stingray NHE3, respectively. Hynobius NHE3 mRNA and protein were exclusively expressed along the late portion of the distal tubule to the anterior part of the pronephric duct of premetamorphic larvae (IY stages 43–50). NHE3 mRNA was expressed in the Pronephros but not in the external gills in the larvae at the digit differentiation stage (IY stage 50). In the adult, mRNA was strongly expressed in the mesonephros but not in the ventral and dorsal skin. In juvenile and adult specimens, NHE3 immunoreactivity was observed at the apical membrane of the initial parts of the distal tubules of the mesonephric kidney. Immunohistochemical and in situ hybridization studies suggested that Na+ absorption coupled with H+ secretion via NHE3 occurred in the distal nephron of the Pronephros and mesonephros. This is the first study to indicate NHE3 expression during ontogeny in amphibians.
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Cellular localization of a putative Na(+)/H (+) exchanger 3 during ontogeny in the Pronephros and mesonephros of the Japanese black salamander (Hynobius nigrescens Stejneger).
Cell and tissue research, 2007Co-Authors: Tomoko Kumano, Norifumi Konno, Tatsuya Wakasugi, Kouhei Matsuda, Hideki Yoshizawa, Minoru UchiyamaAbstract:The cloning of cDNA and an examination of the tissue distribution of Na+/H+ exchanger 3 (NHE3) were carried out in the Japanese black salamander, Hynobius nigrescens. The cellular localization of Hynobius NHE3 was examined by in situ hybridization and immunohistochemistry during ontogeny in the nephron of the Pronephros and mesonephros of the salamander. The partial amino acid sequence of Hynobius NHE3 was 81% and 72% identical to rat NHE3 and stingray NHE3, respectively. Hynobius NHE3 mRNA and protein were exclusively expressed along the late portion of the distal tubule to the anterior part of the pronephric duct of premetamorphic larvae (IY stages 43–50). NHE3 mRNA was expressed in the Pronephros but not in the external gills in the larvae at the digit differentiation stage (IY stage 50). In the adult, mRNA was strongly expressed in the mesonephros but not in the ventral and dorsal skin. In juvenile and adult specimens, NHE3 immunoreactivity was observed at the apical membrane of the initial parts of the distal tubules of the mesonephric kidney. Immunohistochemical and in situ hybridization studies suggested that Na+ absorption coupled with H+ secretion via NHE3 occurred in the distal nephron of the Pronephros and mesonephros. This is the first study to indicate NHE3 expression during ontogeny in amphibians.
Muriel Umbhauer - One of the best experts on this subject based on the ideXlab platform.
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pax8 and pax2 are specifically required at different steps of xenopus Pronephros development
Developmental Biology, 2015Co-Authors: Isabelle Buisson, Ronan Le Bouffant, Melinee Futel, Jean -françois Riou, Muriel UmbhauerAbstract:Abstract The respective role of Pax2 and Pax8 in early kidney development in vertebrates is poorly understood. In this report, we have studied the roles of Pax8 and Pax2 in Xenopus Pronephros development using a loss-of-function approach. Our results highlight a differential requirement of these two transcription factors for proper Pronephros formation. Pax8 is necessary for the earliest steps of pronephric development and its depletion leads to a complete absence of pronephric tubule. Pax2 is required after the establishment of the tubule pronephric anlage, for the expression of several terminal differentiation markers of the pronephric tubule. Neither Pax2 nor Pax8 is essential to glomus development. We further show that Pax8 controls hnf1b, but not lhx1 and Osr2, expression in the kidney field as soon as the mid-neurula stage. Pax8 is also required for cell proliferation of pronephric precursors in the kidney field. It may exert its action through the wnt/beta-catenin pathway since activation of this pathway can rescue MoPax8 induced proliferation defect and Pax8 regulates expression of the wnt pathway components, dvl1 and sfrp3. Finally, we observed that loss of Pronephros in Pax8 morphants correlates with an expanded vascular/blood gene expression domain indicating that Pax8 function is important to delimit the blood/endothelial genes expression domain in the anterior part of the dorso-lateral plate.
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Mix.1/2-dependent control of FGF availability during gastrulation is essential for Pronephros development in Xenopus
Developmental biology, 2008Co-Authors: Alexandre Colas, Isabelle Buisson, Muriel Umbhauer, Jérôme Cartry, James C. Smith, Jean -françois RiouAbstract:Although FGFs are known to affect mesoderm patterning, their influence on intermediate mesoderm specification during gastrulation is ignored. Here, we show that Pronephros precursors are exposed to FGF, but a strict control of FGF signals is necessary to allow Pronephros development. We provide evidence that this control is mediated by the paired-like homeobox genes Mix.1 and Mix.2. Morpholino-based Mix.1/2 knockdown, or repression of Mix.1 target genes with an enRMix.1 construct, causes an expansion of FGF4 and FGF8 expression in the lateral marginal zone at gastrula stage, together with an inhibition of Pronephros development at neurula and tailbud stages. Expression of the nephrogenic mesoderm markers Xlim-1 and XPax-8 can be rescued in Mix.1/2 morphants by intrablastocoelic injections of the FGFR inhibitor SU5402 at mid-gastrula stage, showing that inhibition of Pronephros development results from an increase of FGF signalling. We further show that Mix.1 overexpression results in the down-regulation of FGF3, 4, 8 and XmyoD, in addition to Xbra. However, cells overexpressing Mix.1 can normally populate somites, indicating that Mix.1 does not affect their fate cell autonomously. These data support the idea that Mix.1/2 regulates levels and/or duration of FGF signals to which Pronephros precursors are exposed during gastrulation.
Kouhei Matsuda - One of the best experts on this subject based on the ideXlab platform.
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Ontogeny of ENaC expression in the gills and the kidneys of the Japanese black salamander (Hynobius nigrescens Stejneger).
Journal of Experimental Zoology, 2010Co-Authors: Minoru Uchiyama, Tomoko Kumano, Norifumi Konno, Hideki Yoshizawa, Kouhei MatsudaAbstract:A full-length cDNA cloning and tissue distribution of epithelial sodium channel (ENaC) protein were studied during ontogeny by immunohistochemistry in the external gills, and the kidney, Pronephros and mesonephros, of the Japanese black salamander, Hynobius nigrescens (Family Hynobiidae; a primitive caudate species). The amino acid sequence of Hynobius ENaCα is 64 and 63% identical to Bufo ENaCα and Rat ENaCα, respectively. In aquatic larva salamander at the digit differentiation stage, Hynobius ENaCα mRNA was expressed in the external gills and Pronephros. In the adult, the mRNA was expressed in the skin and the mesonephros. In the larvae, juvenile, and adult specimens, Hynobius ENaCα immunoreactivity was observed at the apical cell membrane of the external gills, late parts of the distal tubules, and mesonephric duct in the kidney. Colocalization of the apical Hynobius ENaCα and the basolateral Na+,K+-ATPase was observed in the tubular cells of Pronephros and mesonephros. These results suggest that Hynobius ENaCα plays an important role in the regulation of sodium transport in the external gills and Pronephros of aquatic larvae, and in the skin and mesonephros of terrestrial adult. This is the first study to indicate ENaC expression during ontogeny in amphibians. Since no orthologs or paralogs for ENaC have been found, so far, in databases of the genomes of teleosts, it is assumed that ENaC might have played a role in terrestriality during the evolution of early tetrapods, the origin of lissamphibians. J. Exp. Zool. (Mol. Dev. Evol.) 316:135–145, 2011. © 2010 Wiley-Liss, Inc.
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Ontogeny of ENaC expression in the gills and the kidneys of the Japanese black salamander (Hynobius nigrescens Stejneger).
Journal of experimental zoology. Part B Molecular and developmental evolution, 2010Co-Authors: Minoru Uchiyama, Tomoko Kumano, Norifumi Konno, Hideki Yoshizawa, Kouhei MatsudaAbstract:A full-length cDNA cloning and tissue distribution of epithelial sodium channel (ENaC) protein were studied during ontogeny by immunohistochemistry in the external gills, and the kidney, Pronephros and mesonephros, of the Japanese black salamander, Hynobius nigrescens (Family Hynobiidae; a primitive caudate species). The amino acid sequence of Hynobius ENaCα is 64 and 63% identical to Bufo ENaCα and Rat ENaCα, respectively. In aquatic larva salamander at the digit differentiation stage, Hynobius ENaCα mRNA was expressed in the external gills and Pronephros. In the adult, the mRNA was expressed in the skin and the mesonephros. In the larvae, juvenile, and adult specimens, Hynobius ENaCα immunoreactivity was observed at the apical cell membrane of the external gills, late parts of the distal tubules, and mesonephric duct in the kidney. Colocalization of the apical Hynobius ENaCα and the basolateral Na(+) ,K(+) -ATPase was observed in the tubular cells of Pronephros and mesonephros. These results suggest that Hynobius ENaCα plays an important role in the regulation of sodium transport in the external gills and Pronephros of aquatic larvae, and in the skin and mesonephros of terrestrial adult. This is the first study to indicate ENaC expression during ontogeny in amphibians. Since no orthologs or paralogs for ENaC have been found, so far, in databases of the genomes of teleosts, it is assumed that ENaC might have played a role in terrestriality during the evolution of early tetrapods, the origin of lissamphibians.
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Cellular localization of a putative Na^+/H^+ exchanger 3 during ontogeny in the Pronephros and mesonephros of the Japanese black salamander (Hynobius nigrescens Stejneger)
Cell and Tissue Research, 2008Co-Authors: Tomoko Kumano, Norifumi Konno, Tatsuya Wakasugi, Kouhei Matsuda, Hideki Yoshizawa, Minoru UchiyamaAbstract:The cloning of cDNA and an examination of the tissue distribution of Na^+/H^+ exchanger 3 (NHE3) were carried out in the Japanese black salamander, Hynobius nigrescens . The cellular localization of Hynobius NHE3 was examined by in situ hybridization and immunohistochemistry during ontogeny in the nephron of the Pronephros and mesonephros of the salamander. The partial amino acid sequence of Hynobius NHE3 was 81% and 72% identical to rat NHE3 and stingray NHE3, respectively. Hynobius NHE3 mRNA and protein were exclusively expressed along the late portion of the distal tubule to the anterior part of the pronephric duct of premetamorphic larvae (IY stages 43–50). NHE3 mRNA was expressed in the Pronephros but not in the external gills in the larvae at the digit differentiation stage (IY stage 50). In the adult, mRNA was strongly expressed in the mesonephros but not in the ventral and dorsal skin. In juvenile and adult specimens, NHE3 immunoreactivity was observed at the apical membrane of the initial parts of the distal tubules of the mesonephric kidney. Immunohistochemical and in situ hybridization studies suggested that Na^+ absorption coupled with H^+ secretion via NHE3 occurred in the distal nephron of the Pronephros and mesonephros. This is the first study to indicate NHE3 expression during ontogeny in amphibians.
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cellular localization of a putative na h exchanger 3 during ontogeny in the Pronephros and mesonephros of the japanese black salamander hynobius nigrescens stejneger
Cell and Tissue Research, 2008Co-Authors: Tomoko Kumano, Norifumi Konno, Tatsuya Wakasugi, Kouhei Matsuda, Hideki Yoshizawa, Minoru UchiyamaAbstract:The cloning of cDNA and an examination of the tissue distribution of Na+/H+ exchanger 3 (NHE3) were carried out in the Japanese black salamander, Hynobius nigrescens. The cellular localization of Hynobius NHE3 was examined by in situ hybridization and immunohistochemistry during ontogeny in the nephron of the Pronephros and mesonephros of the salamander. The partial amino acid sequence of Hynobius NHE3 was 81% and 72% identical to rat NHE3 and stingray NHE3, respectively. Hynobius NHE3 mRNA and protein were exclusively expressed along the late portion of the distal tubule to the anterior part of the pronephric duct of premetamorphic larvae (IY stages 43–50). NHE3 mRNA was expressed in the Pronephros but not in the external gills in the larvae at the digit differentiation stage (IY stage 50). In the adult, mRNA was strongly expressed in the mesonephros but not in the ventral and dorsal skin. In juvenile and adult specimens, NHE3 immunoreactivity was observed at the apical membrane of the initial parts of the distal tubules of the mesonephric kidney. Immunohistochemical and in situ hybridization studies suggested that Na+ absorption coupled with H+ secretion via NHE3 occurred in the distal nephron of the Pronephros and mesonephros. This is the first study to indicate NHE3 expression during ontogeny in amphibians.
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Cellular localization of a putative Na(+)/H (+) exchanger 3 during ontogeny in the Pronephros and mesonephros of the Japanese black salamander (Hynobius nigrescens Stejneger).
Cell and tissue research, 2007Co-Authors: Tomoko Kumano, Norifumi Konno, Tatsuya Wakasugi, Kouhei Matsuda, Hideki Yoshizawa, Minoru UchiyamaAbstract:The cloning of cDNA and an examination of the tissue distribution of Na+/H+ exchanger 3 (NHE3) were carried out in the Japanese black salamander, Hynobius nigrescens. The cellular localization of Hynobius NHE3 was examined by in situ hybridization and immunohistochemistry during ontogeny in the nephron of the Pronephros and mesonephros of the salamander. The partial amino acid sequence of Hynobius NHE3 was 81% and 72% identical to rat NHE3 and stingray NHE3, respectively. Hynobius NHE3 mRNA and protein were exclusively expressed along the late portion of the distal tubule to the anterior part of the pronephric duct of premetamorphic larvae (IY stages 43–50). NHE3 mRNA was expressed in the Pronephros but not in the external gills in the larvae at the digit differentiation stage (IY stage 50). In the adult, mRNA was strongly expressed in the mesonephros but not in the ventral and dorsal skin. In juvenile and adult specimens, NHE3 immunoreactivity was observed at the apical membrane of the initial parts of the distal tubules of the mesonephric kidney. Immunohistochemical and in situ hybridization studies suggested that Na+ absorption coupled with H+ secretion via NHE3 occurred in the distal nephron of the Pronephros and mesonephros. This is the first study to indicate NHE3 expression during ontogeny in amphibians.
