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Developmental Biology Nov 1999We have used monoclonal antibodies that recognize the pronephric tubules or pronephric duct to explore the induction of the embryonic kidney in developing Xenopus...
We have used monoclonal antibodies that recognize the pronephric tubules or pronephric duct to explore the induction of the embryonic kidney in developing Xenopus embryos. Morphogenesis of the pronephros was examined in UV-ventralized and lithium-dorsalized embryos. We find that the pronephric tubules are present in all but the strongest UV-induced phenotypes, but absent from relatively moderate lithium phenotypes. Interestingly the pronephric duct, which develops from the ventroposterior portion of the pronephric anlage, is missing from more of the mild UV phenotypes than are pronephric tubules. The loss of the capacity to form pronephroi in UV-ventralized embryos is caused by the loss of tissues capable of inducing the pronephric mesoderm, as marginal zone explants from ventralized embryos are still competent to respond to pronephric-inductive signals. Explant recombination experiments indicate that the tissue responsible for both the loss of pronephroi in UV-ventralized embryos and the induction of pronephroi during normal development is the anterior somites. The absence of pronephroi in relatively mild lithium phenotypes has a developmental basis different from that of the UV phenotype, as explants from lithium-treated embryos are effective inducers of pronephroi in recombinants with competent mesoderm, even though they themselves do not form pronephroi in isolation. Together these data indicate that dorsal tissues, especially the anterior somites, are responsible for the establishment of the intermediate mesoderm and the induction of the embryonic kidneys and that even mild dorsalization destroys the capacity to form cells competent to receive this signal.
Topics: Animals; Female; Lithium; Mesoderm; Nephrons; Phenotype; Ultraviolet Rays; Xenopus
PubMed: 10545233
DOI: 10.1006/dbio.1999.9476 -
Pediatric Nephrology (Berlin, Germany) Apr 2014The main functions of the kidney are to excrete metabolic waste products and actively reabsorb essential molecules such as amino acids, ions, glucose and water. In... (Review)
Review
The main functions of the kidney are to excrete metabolic waste products and actively reabsorb essential molecules such as amino acids, ions, glucose and water. In humans, a wide range of genetic disorders exist characterized by wasting of metabolically important compounds. At the cellular level, more than 20 highly specialized renal epithelial cell types located in different segments of the nephron contribute to the reabsorption process. In particular, proximal tubular cells play a crucial role and are uniquely adapted to maximize reabsorption efficiency. They accommodate high numbers of transporters and channels by increasing the apical surface area in contact with the primary filtrate by forming a brush border as well as undergoing hypertrophy and hyperplasia. This adaptation is evolutionarily conserved and is detected in the primitive pronephric kidney of fish and amphibians as well as the metanephric kidney of higher vertebrates. Surprisingly, signaling pathways regulating these three processes have remained largely unknown. Here we summarize recent studies that highlight the early phases of kidney development as a critical juncture in establishing proximal tubule size.
Topics: Animals; Humans; Nephrons
PubMed: 23974984
DOI: 10.1007/s00467-013-2581-x -
Scientific Reports Oct 2023CLIC5 belongs to a family of ion channels with six members reported so far. In vertebrates, the CLIC5 gene encodes two different isoforms, CLIC5A and CLIC5B. In addition...
CLIC5 belongs to a family of ion channels with six members reported so far. In vertebrates, the CLIC5 gene encodes two different isoforms, CLIC5A and CLIC5B. In addition to its ion channel activity, there is evidence for further functions of CLIC5A, such as the remodeling of the actin cytoskeleton during the formation of a functional glomerulus in the vertebrate kidney. However, its specific role is still incompletely understood and a specific functional role for CLIC5B has not been described yet. Here we report our findings on the differential expression and functions of Clic5a and Clic5b during zebrafish kidney development. Whole-mount in situ hybridization studies revealed specific expression of clic5a in the eye and pronephric glomerulus, and clic5b is expressed in the gut, liver and the pronephric tubules. Clic5 immunostainings revealed that Clic5b is localized in the cilia. Whereas knockdown of Clic5a resulted in leakiness of the glomerular filtration barrier, Clic5b deficient embryos displayed defective ciliogenesis, leading to ciliopathy-associated phenotypes such as ventral body curvature, otolith deposition defects, altered left-right asymmetry and formation of hydrocephalus and pronephric cysts. In addition, Clic5 deficiency resulted in dysregulation of cilia-dependent Wnt signalling pathway components. Mechanistically, we identified a Clic5-dependent activation of the membrane-cytoskeletal linker proteins Ezrin/Radixin/Moesin (ERM) in the pronephric tubules of zebrafish. In conclusion, our in vivo data demonstrates a novel role for Clic5 in regulating essential ciliary functions and identified Clic5 as a positive regulator of ERM phosphorylation.
Topics: Animals; Actin Cytoskeleton; Chloride Channels; Chlorides; Cilia; Kidney Glomerulus; Microfilament Proteins; Zebrafish
PubMed: 37848494
DOI: 10.1038/s41598-023-44235-y -
Gene Expression Patterns : GEP 2011In recent years the zebrafish has become a popular model system to study organ development and disease. To facilitate these studies, genetic tools are required which...
In recent years the zebrafish has become a popular model system to study organ development and disease. To facilitate these studies, genetic tools are required which allow to modify and manipulate gene expression in organs of interest. Here we describe a zebrafish 2kb glutamyl aminopeptidase (enpep) promoter fragment, and show that it can drive gene expression specifically in the kidney during early and late development. We established a stable transgenic line using this promoter fragment that has specific GFP expression in pronephric ducts and tubules starting at 20h post-fertilization.
Topics: Animals; Animals, Genetically Modified; Embryo, Nonmammalian; Glutamyl Aminopeptidase; Kidney; Kidney Tubules; Promoter Regions, Genetic; Zebrafish
PubMed: 20969977
DOI: 10.1016/j.gep.2010.10.002 -
Cells Sep 2015The nephron is the basic structural and functional unit of the vertebrate kidney. To ensure kidney functions, the nephrons possess a highly segmental organization where... (Review)
Review
The nephron is the basic structural and functional unit of the vertebrate kidney. To ensure kidney functions, the nephrons possess a highly segmental organization where each segment is specialized for the secretion and reabsorption of particular solutes. During embryogenesis, nephron progenitors undergo a mesenchymal-to-epithelial transition (MET) and acquire different segment-specific cell fates along the proximo-distal axis of the nephron. Even if the morphological changes occurring during nephrogenesis are characterized, the regulatory networks driving nephron segmentation are still poorly understood. Interestingly, several studies have shown that the pronephric nephrons in Xenopus and zebrafish are segmented in a similar fashion as the mouse metanephric nephrons. Here we review functional and molecular aspects of nephron segmentation with a particular interest on the signaling molecules and transcription factors recently implicated in kidney development in these three different vertebrate model organisms. A complete understanding of the mechanisms underlying nephrogenesis in different model organisms will provide novel insights on the etiology of several human renal diseases.
PubMed: 26378582
DOI: 10.3390/cells4030483 -
Developmental Biology Sep 2006The pronephros is a transient embryonic kidney that is essential for the survival of aquatic larvae. It is also absolutely critical for adult kidney development, as the...
The pronephros is a transient embryonic kidney that is essential for the survival of aquatic larvae. It is also absolutely critical for adult kidney development, as the pronephric derivative the wolffian duct forms the ductal system of the adult kidney and also triggers the condensation of metanephric mesenchyme into the adult nephrons. While exploring Xenopus pronephric patterning, we observed that epidermally delivered hedgehog completely suppresses pronephric kidney tubule development but does not effect development of the pronephric glomus, the equivalent of the mammalian glomerulus or corpuscle. This effect is not mediated by apoptosis. Microarray analysis of microdissected primordia identified FGF8 as one of the potential mediators of hedgehog action. Further investigation demonstrated that SU5402-sensitive FGF signaling plays a critical role in the very earliest stages of pronephric tubule development. Modulation of FGF8 activity using a morpholino has a later effect that blocks condensation of pronephric mesenchyme into the pronephric tubule. Together, these data show that FGF signaling plays a critical role at two stages of embryonic kidney development, one in the condensation of the pronephric primordium from the intermediate mesoderm and a second in the later epithelialization of this mesenchyme into the pronephric nephron. The data also show that in Xenopus, development of the glomus/glomerulus can be uncoupled from nephron formation via ectopic hedgehog expression and provides an experimental avenue for investigating glomerulogenesis in the complete absence of tubules.
Topics: Animals; Body Patterning; Embryo, Nonmammalian; Embryonic Induction; Epithelial Cells; Fibroblast Growth Factor 8; Fibroblast Growth Factors; Gene Expression Regulation, Developmental; Hedgehog Proteins; Kidney; Mesoderm; Nephrons; Oligonucleotide Array Sequence Analysis; Pyrroles; Signal Transduction; Trans-Activators; Xenopus Proteins; Xenopus laevis
PubMed: 16872594
DOI: 10.1016/j.ydbio.2006.04.469 -
Gene Expression Patterns : GEP Apr 2008Collectrin/tmem27 encodes a transmembrane protein that plays a critical role in amino-acid transport. Originally described as being expressed only in collecting ducts,...
Collectrin/tmem27 encodes a transmembrane protein that plays a critical role in amino-acid transport. Originally described as being expressed only in collecting ducts, it has subsequently also been shown to also be expressed in the S1 segment of the proximal tubule of mammalian metanephric nephrons. In this report we describe the expression of collectrin in the simple embryonic kidney of amphibians, the pronephros. Each pronephros contains a single large nephron with a proximo-distal segmentation very similar to that of mammalian metanephric nephrons. Analysis of collectrin expression in pronephroi at a variety of embryonic stages indicates that this gene is expressed at very high levels throughout the pronephric system, including proximal and distal segments and the Wolffian duct. Expression in the pronephros commences at Xenopus embryonic stage 28 which corresponds to when epithelialization begins within the pronephric mesenchyme. Like the Na+K+ATPase/atp1a1, another highly expressed pronephric marker, collectrin is also expressed in the cloaca but not in the cloacal derived posterior segment of the Wolffian duct, the rectal diverticulum. Unlike the Na+K+ATPase, which is expressed at lower levels in proximal portions of the pronephric nephron, expression of collectrin is even throughout all of the pronephric epithelia. This expression domain extends far beyond that shown to express amino-acid transporters and indicates collectrin may function in facilitating additional transport processes. Its high level of expression and broad distribution make it an excellent marker with which to examine pronephric kidney development.
Topics: Amino Acid Sequence; Animals; Gene Expression; Humans; In Situ Hybridization; Membrane Glycoproteins; Membrane Proteins; Molecular Sequence Data; Nephrons; RNA, Messenger; Sequence Alignment; Wolffian Ducts; Xenopus; Xenopus Proteins
PubMed: 18226983
DOI: 10.1016/j.gep.2007.12.002 -
Development (Cambridge, England) Feb 2012The Homeobox (Hox) and Paired box (Pax) gene families are key determinants of animal body plans and organ structure. In particular, they function within regulatory...
The Homeobox (Hox) and Paired box (Pax) gene families are key determinants of animal body plans and organ structure. In particular, they function within regulatory networks that control organogenesis. How these conserved genes elicit differences in organ form and function in response to evolutionary pressures is incompletely understood. We molecularly and functionally characterized one member of an evolutionarily dynamic gene family, plac8 onzin related protein 1 (ponzr1), in the zebrafish. ponzr1 mRNA is expressed early in the developing kidney and pharyngeal arches. Using ponzr1-targeting morpholinos, we show that ponzr1 is required for formation of the glomerulus. Loss of ponzr1 results in a nonfunctional glomerulus but retention of a functional pronephros, an arrangement similar to the aglomerular kidneys found in a subset of marine fish. ponzr1 is integrated into the pax2a pathway, with ponzr1 expression requiring pax2a gene function, and proper pax2a expression requiring normal ponzr1 expression. In addition to pronephric function, ponzr1 is required for pharyngeal arch formation. We functionally demonstrate that ponzr1 can act as a transcription factor or co-factor, providing the first molecular mode of action for this newly described gene family. Together, this work provides experimental evidence of an additional mechanism that incorporates evolutionarily dynamic, lineage-specific gene families into conserved regulatory gene networks to create functional organ diversity.
Topics: Animals; Animals, Genetically Modified; Biological Evolution; Biomarkers; Branchial Region; Embryo, Nonmammalian; Gene Expression Regulation, Developmental; Gene Knockdown Techniques; Kidney; Morphogenesis; PAX2 Transcription Factor; Phenotype; Pronephros; Transcription Factors; Zebrafish; Zebrafish Proteins
PubMed: 22274699
DOI: 10.1242/dev.071720 -
Kidney & Blood Pressure Research 2016Vitamin C is an antioxidant and acts as a cofactor for several key enzymatic catalytic reactions in animals. Amphibians produce vitamin C in their kidneys, as opposed to...
BACKGROUNDS/AIMS
Vitamin C is an antioxidant and acts as a cofactor for several key enzymatic catalytic reactions in animals. Amphibians produce vitamin C in their kidneys, as opposed to mammals that produce vitamin C in their liver. Gulo serves as a crucial enzyme for vitamin C synthesis in mammals, but the characteristics and localization of its homologous genes during kidney development in Xenopus laevis, an amphibian, remains unknown.
METHODS
We aligned amino acid sequences of Gulo across different species by using bioinformatics methods and detected patterns of expression for Gulo during kidney development by using RT-PCR and in situ hybridization.
RESULTS
We identified a new site on the X. laevis genome, LOC495407. Sequence alignment analysis indicated this fragment is highly conserved and homologous to gulo genes in mammals. RT-PCR and in situ hybridization results reveal that X. laevis gulo is maternally expressed during the early stages of embryonic development, particularly, in the tubules of the pronephros from the middle tail-bud stage and onward in embryos.
CONCLUSION
Gulo is a novel specific marker for pronephros tubules in X. laevis, and may be used as a potential marker for kidney development studies and disease diagnosis in mammals.
Topics: Animals; Biomarkers; Female; Kidney Tubules; L-Gulonolactone Oxidase; Mammals; Pronephros; Sequence Alignment; Xenopus laevis
PubMed: 27832650
DOI: 10.1159/000450561 -
Development, Growth & Differentiation May 2009Ca(2+) is a highly versatile intra- and intercellular signal that has been reported to regulate a variety of different pattern-forming processes during early...
Inhibition of stored Ca2+ release disrupts convergence-related cell movements in the lateral intermediate mesoderm resulting in abnormal positioning and morphology of the pronephric anlagen in intact zebrafish embryos.
Ca(2+) is a highly versatile intra- and intercellular signal that has been reported to regulate a variety of different pattern-forming processes during early development. To investigate the potential role of Ca(2+) signaling in regulating convergence-related cell movements, and the positioning and morphology of the pronephric anlagen, we treated zebrafish embryos from 11.5 h postfertilization (hpf; i.e. just before the pronephric anlagen are morphologically distinguishable in the lateral intermediate mesoderm; LIM) to 16 hpf, with a variety of membrane permeable pharmacological reagents known to modulate [Ca(2+)](i). The effect of these treatments on pronephric anlagen positioning and morphology was determined in both fixed and live embryos via in situ hybridization using the pronephic-specific probes, cdh17, pax2.1 and sim1, and confocal imaging of BODIPY FL C(5)-ceramide-labeled embryos, respectively. We report that Ca(2+) released from intracellular stores via inositol 1,4,5-trisphosphate receptors plays a significant role in the positioning and morphology of the pronephric anlagen, but does not affect the fate determination of the LIM cells that form these primordia. Our data suggest that when Ca(2+) release is inhibited, the resulting effects on the pronephric anlagen are a consequence of the disruption of normal convergence-related movements of LIM cells toward the embryonic midline.
Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Calcium; Calcium Channel Blockers; Cell Movement; Dantrolene; Estrenes; In Situ Hybridization; Mesoderm; PAX2 Transcription Factor; Pyrrolidinones; Repressor Proteins; Thapsigargin; Zebrafish; Zebrafish Proteins
PubMed: 19382938
DOI: 10.1111/j.1440-169X.2009.01106.x