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structural and biochemical characterization of an rna/dna binding motif in the n-terminal domain of recq4 helicases.the recq4 helicase belongs to the ubiquitous recq family but its exact role in the cell is not completely understood. in addition to the helicase domain, recq4 has a unique n-terminal part that is essential for viability and is constituted by a region homologous to the yeast sld2 replication initiation factor, followed by a cysteine-rich region, predicted to fold as a zn knuckle. we carried out a structural and biochemical analysis of both the human and xenopus laevis recq4 cysteine-rich regions ...201626888063
oshkt1;4-mediated na(+) transport in stems contributes to na(+) exclusion from leaf blades of rice at the reproductive growth stage upon salt stress.na(+) exclusion from leaf blades is one of the key mechanisms for glycophytes to cope with salinity stress. certain class i transporters of the high-affinity k(+) transporter (hkt) family have been demonstrated to mediate leaf blade-na(+) exclusion upon salinity stress via na(+)-selective transport. multiple hkt1 transporters are known to function in rice (oryza sativa). however, the ion transport function of oshkt1;4 and its contribution to the na(+) exclusion mechanism in rice remain to be elu ...201626786707
oshkt2;2/1-mediated na(+) influx over k(+) uptake in roots potentially increases toxic na(+) accumulation in a salt-tolerant landrace of rice nona bokra upon salinity stress.hkt transporters are na(+)-permeable membrane proteins, which mediate na(+) and k(+) homeostasis in k(+)-depleted and saline environments in plants. class ii hkt transporters, a distinct subgroup found predominantly in monocots, are known to mediate na(+)-k(+) co-transport in principle. here we report features of ion transport functions of no-oshkt2;2/1, a class ii transporter identified in a salt tolerant landrace of indica rice, nona bokra. we profiled no-oshkt2;2/1 expression in organs of non ...201626578190
proteome-wide dataset supporting the study of ancient metazoan macromolecular complexes.our analysis examines the conservation of multiprotein complexes among metazoa through use of high resolution biochemical fractionation and precision mass spectrometry applied to soluble cell extracts from 5 representative model organisms caenorhabditis elegans, drosophila melanogaster, mus musculus, strongylocentrotus purpuratus, and homo sapiens. the interaction network obtained from the data was validated globally in 4 distant species (xenopus laevis, nematostella vectensis, dictyostelium dis ...201626870755
frog virus 3 dissemination in the brain of tadpoles, but not in adult xenopus, involves blood brain barrier dysfunction.while increasing evidence points to a key role of monocytes in amphibian host defenses, monocytes are also thought to be important in the dissemination and persistent infection caused by ranavirus. however, little is known about the fate of infected macrophages or if ranavirus exploits immune privileged organs, such as the brain, in order to establish a reservoir. the amphibian xenopus laevis and frog virus 3 (fv3) were established as an experimental platform for investigating in vivo whether ra ...201626931458
xenopus laevis and emerging amphibian pathogens in chile.amphibians face an extinction crisis with no precedence. two emerging infectious diseases, ranaviral disease caused by viruses within the genus ranavirus and chytridiomycosis due to batrachochytrium dendrobatidis (bd), have been linked with amphibian mass mortalities and population declines in many regions of the globe. the african clawed frog (xenopus laevis) has been indicated as a vector for the spread of these pathogens. since the 1970s, this species has been invasive in central chile. we co ...201627682604
[xenopus laevis peroxiredoxins: gene expression during development and characterization of the enzymes].reactive oxygen species (ros) are produced via catabolic and anabolic processes during normal embryonic development, and ros content in the cell is maintained at a certain level. peroxiredoxins are a family of selenium-independent peroxidases and play a key role in maintaining redox homeostasis of the cell. in addition to regulating the ros level, peroxiredoxins are involved in intracellular and intercellular signaling, cell differentiation, and tissue development. the time course of peroxiredox ...201627239855
identification and characterization of a novel intelectin in the digestive tract of xenopus laevis.the intelectin (intl) family is a group of secretory lectins in chordates that serve multiple functions, including innate immunity, through ca(2+)-dependent recognition of carbohydrate chains. although six intl family lectins have so far been reported in xenopus laevis, none have been identified in the intestine. using a monoclonal antibody to the xenopus embryonic epidermal lectin (xeel or intl-1), i identified cross-reactive proteins in the intestines. the proteins were purified by affinity ch ...201626855011
differential effects of the recombinant toxin pntx4(5-5) from the spider phoneutria nigriventer on mammalian and insect sodium channels.the toxin pntx4(5-5) from the spider phoneutria nigriventer is extremely toxic/lethal to insects but has no macroscopic behavioral effects observed in mice after intracerebral injection. nevertheless, it was demonstrated that it inhibits the n-methyl-d-aspartate (nmda) - subtype of glutamate receptors of cultured rat hippocampal neurons. pntx4(5-5) has 63% identity to pntx4(6-1), another insecticidal toxin from p. nigriventer, which can slow down the sodium current inactivation in insect central ...201626747232
recombinant expression and characterization of α-conotoxin lvia in escherichia coli.α-conotoxin lvia is derived from conus lividus, native to hainan, and is the most selective inhibitor of α3β2 nicotinic acetylcholine receptors (nachrs) known to date. in this study, an efficient approach for the production of recombinant α-conotoxin lvia is described. tandem repeats of a lvia gene fragment were constructed and fused with a ksi gene and a his₆ tag in a escherichia coli (e. coli) expression vector pet-31b(+). the recombinant plasmids were transformed into e. coli and were found t ...201626742048
investigations of the synergistic enhancement of antimicrobial activity in mixtures of magainin 2 and pgla.magainins are antimicrobial peptides isolated from the african clawed frog xenopus laevis. they interact with bacterial membranes where they cause channel formation and membrane disruption. when added as a cocktail magainin 2 and pgla are considerably more efficient when compared to the corresponding amounts of individual components. in order to investigate this synergistic interaction of pgla and magainin a number of magainin variants have been prepared and investigated in biological and biophy ...201626099623
inter- and intra-subunit butanol/isoflurane sites of action in the human glycine receptor.glycine receptors (glyrs) mediate inhibitory neurotransmission and are targets for alcohols and anesthetics in brain. glyr transmembrane (tm) domains contain critical residues for alcohol/anesthetic action: amino acid a288 in tm3 forms crosslinks with tm1 (i229) in the adjacent subunit as well as tm2 (s267) and tm4 (y406, w407, i409, y410) in the same subunit. we hypothesized that these residues may participate in intra-subunit and inter-subunit sites of alcohol/anesthetic action. the following ...201627378846
the cholinomimetic morantel as an open channel blocker of the ascaris suum acr-16 nachr.nematode parasite infections pose a significant threat in human and veterinary medicine. at least a third of the world's population is at risk from nematode parasite infections. these infections not only cause health problems, but also cause loss of livestock production and hence, economic losses. anthelmintic drugs are the mainstay by which control of nematode parasite infections is achieved. many of the currently available anthelmintics act on nicotinic acetylcholine receptors (nachrs). howeve ...201627995347
[follicular cells of the amphibian ovary: origin, structure, and functions].formation of the follicular envelopes surrounding oocytes in the developing ovary and their subsequent morphological differentiation go hand-in-hand with succession of the steroidogenesis stages, arrest of meiosis and its maintenance, establishment of the conditions necessary for vitellogenesis, oocyte growth, and maturation. metabolites are exchanged via gap junctions and receptor-mediated transport through the perioocytic space. the ion transport in follicular cells (fcs) regulates the plasma ...201625434201
xenopus lap2β protein knockdown affects location of lamin b and nucleoporins and has effect on assembly of cell nucleus and cell viability.xenopus lap2β protein is the single isoform expressed in xtc cells. the protein localizes on heterochromatin clusters both at the nuclear envelope and inside a cell nucleus. the majority of xlap2β fraction neither colocalizes with tpx2 protein during interphase nor can be immunoprecipitated with xlap2β antibody. knockdown of the xlap2β protein expression in xtc cells by synthetic sirna and plasmid encoded sirna resulted in nuclear abnormalities including changes in shape of nuclei, abnormal chro ...201626209045
regulation of growth rate and developmental timing by xenopus thyroid hormone receptor α.thyroid hormone (th) is critical for vertebrate postembryonic development, a period around birth in mammals when plasma th levels are high. interestingly, th receptors (trs), especially trα, are expressed prior to the synthesis and secretion of zygotic th, suggesting the existence of unliganded tr during development. however, the role of unliganded tr during mammalian development has been difficult to study, in part due to the relatively weak phenotype of tr knockout mice. amphibian metamorphosi ...201626219216
identification of genes expressed in the migrating primitive myeloid lineage of xenopus laevis.during primitive hematopoiesis in xenopus, cebpa and spib expressing myeloid cells emerge from the anterior ventral blood island. primitive myeloid cells migrate throughout the embryo and are critical for immunity, healing, and development. although definitive hematopoiesis has been studied extensively, molecular mechanisms leading to the migration of primitive myelocytes remain poorly understood. we hypothesized these cells have specific extracellular matrix modifying and cell motility gene exp ...201626264370
pre-meiotic transformation of germplasm-related structures during male gamete differentiation in xenopus laevis.to highlight the ultrastructural features of transformation occurring with germplasm-related structures (gprs), the spermatogenic cells of xenopus laevis were studied by transmission electron microscopy and quantitative analysis. it was determined that in spermatogonia and spermatocytes, the compact germinal granules underwent fragmentation into particles comparable with inter-mitochondrial cement (imc). fragments of imc agglutinated some cell mitochondria and resulted in the creation of mitocho ...201625511532
impact of the whole-cell patch-clamp configuration on the pharmacological assessment of the herg channel: trazodone as a case example.voltage- and state-dependent blocks are important mechanisms by which drugs affect voltage-gated ionic channels. however, spontaneous (i.e. drug-free) time-dependent changes in the activation and inactivation of herg and na(+) channels have been reported when using conventional whole-cell patch-clamp in hek-293 cells.201624412489
biometric data assessment on xenopus laeis tadpoles. 201630701053
structural heterogeneity of cnga1 channels revealed by electrophysiology and single-molecule force spectroscopy.the determination at atomic resolution of the three-dimensional molecular structure of membrane proteins such as receptors and several ion channels has been a major breakthrough in structural biology. the molecular structure of several members of the superfamily of voltage-gated ionic channels such as k+ and na+ is now available. however, despite several attempts, the molecular structure at atomic resolution of the full cyclic nucleotide-gated (cng) ion channel, although a member of the same sup ...201631457189
a matter of the heart: the african clawed frog xenopus as a model for studying vertebrate cardiogenesis and congenital heart defects.the african clawed frog, xenopus, is a valuable non-mammalian model organism to investigate vertebrate heart development and to explore the underlying molecular mechanisms of human congenital heart defects (chds). in this review, we outline the similarities between xenopus and mammalian cardiogenesis, and provide an overview of well-studied cardiac genes in xenopus, which have been associated with congenital heart conditions. additionally, we highlight advantages of modeling candidate genes deri ...201629367567
evaluating the teratogenicity of ritodrine and nifedipine using a frog embryo teratogenesis assay (fetax).the frog embryo teratogenesis assay-xenopus (fetax) was used to assess the teratogenic potential of two tocolytics. embryos of the south african clawed frog, xenopus laevis, were exposed to ritodrine or nifedipine. exposure media were changed and monitored at 24-hour intervals. the 96-hour lc50 (lethal concentration), the 96-hour ec50 (malformation), and the no observable adverse effect concentrations (noaec) and the lowest observable adverse effect concentration (loaec) for mortality, malformat ...201525156158
a hydrophobic area of the gaba ρ₁ receptor containing phenylalanine 124 influences both receptor activation and deactivation.experimental evidence suggests that gaba ρ1 receptors are potential therapeutic targets for the treatment of a range of neurological conditions, including anxiety and sleep disorders. homology modelling of the gaba ρ1 extracellular n-terminal domain has revealed a novel hydrophobic area that extends beyond, but not including the gaba-binding site. phenylalanine 124 (f124) is predicted to be involved in maintaining the structural integrity of the orthosteric-binding site. we have assessed the act ...201524816654
a di-arginine er retention signal regulates trafficking of hcn1 channels from the early secretory pathway to the plasma membrane.hyperpolarization-activated cyclic nucleotide-gated 1 (hcn1) channels carry ih, which contributes to neuronal excitability and signal transmission in the nervous system. controlling the trafficking of hcn1 is an important aspect of its regulation, yet the details of this process are poorly understood. here, we investigated how the c-terminus of hcn1 regulates trafficking by testing for its ability to redirect the localization of a non-targeted reporter in transgenic xenopus laevis photoreceptors ...201525142030
aberrant connexin26 hemichannels underlying keratitis-ichthyosis-deafness syndrome are potently inhibited by mefloquine.keratitis-ichthyosis-deafness (kid) syndrome is an ectodermal dysplasia caused by dominant mutations of connexin26 (cx26). loss of cx26 function causes nonsyndromic sensorineural deafness, without consequence in the epidermis. functional analyses have revealed that a majority of kid-causing mutations confer a novel expansion of hemichannel activity, mediated by connexin channels in a nonjunctional configuration. inappropriate cx26 hemichannel opening is hypothesized to compromise keratinocyte in ...201525229253
erythropoietin protects red blood cells from trail1-induced cell death during red blood cell transition in xenopus laevis.in anuran amphibians, larval red blood cells (rbcs) are replaced by adult-type rbcs during metamorphosis. we previously showed that tumor necrosis factor-related apoptosis-inducing ligand 1 (trail1) induces apoptosis in larval-, but not adult-type rbcs in xenopus laevis. we also found that protein kinase c (pkc) activation is involved in establishing resistance to trail1-induced apoptosis in adult-type rbcs. here, we investigated whether erythropoietin (epo), which induces pkc activation in mamm ...201525200139
effects of low dose endosulfan exposure on brain neurotransmitter levels in the african clawed frog xenopus laevis.understanding the impact of pesticides in amphibians is of growing concern to assess the causes of their decline. among pesticides, endosulfan belongs to one of the potential sources of danger because of its wide use and known effects, particularly neurotoxic, on a variety of organisms. however, the effect of endosulfan was not yet evaluated on amphibians at levels encompassing simultaneously brain neurotransmitters and behavioural endpoints. in this context, tadpoles of the african clawed frog ...201525192837
aromatase, estrogen receptors and brain development in fish and amphibians.estrogens affect brain development of vertebrates, not only by impacting activity and morphology of existing circuits, but also by modulating embryonic and adult neurogenesis. the issue is complex as estrogens can not only originate from peripheral tissues, but also be locally produced within the brain itself due to local aromatization of androgens. in this respect, teleost fishes are quite unique because aromatase is expressed exclusively in radial glial cells, which represent pluripotent cells ...201525038582
evaluation of developmental toxicity and teratogenicity of diclofenac using xenopus embryos.diclofenac is a non-steroidal anti-inflammatory drug (nsaid) with analgesic and anti-pyretic properties. this compound is therefore used to treat pain, inflammatory disorders, and dysmenorrhea. due to its multimodal mechanism of action and ability to penetrate placenta, diclofenac is known to have undesirable side effects including teratogenicity. however, limited data exist on its teratogenicity, and a detailed investigation regarding harmful effects of this drug during embryogenesis is warrant ...201524992311
sensitisation of trpv4 by par2 is independent of intracellular calcium signalling and can be mediated by the biased agonist neutrophil elastase.proteolytic activation of protease-activated receptor 2 (par2) may represent a major mechanism of regulating the transient receptor potential vanilloid 4 (trpv4) non-selective cation channel in pathophysiological conditions associated with protease activation (e.g. during inflammation). to provide electrophysiological evidence for par2-mediated trpv4 regulation, we characterised the properties of human trpv4 heterologously expressed in xenopus laevis oocytes in the presence and absence of co-exp ...201524906497
ntpdase2 and the p2y1 receptor are not required for mammalian eye formation.eye formation in vertebrates is controlled by a conserved pattern of molecular networks. homeobox transcription factors are crucially involved in the establishment and maintenance of the retina. a previous study of massé et al. (nature, 449: 1058-62, 2007) using morpholino knockdown identified the ectonucleotidase ntpdase2 and the p2y1 receptor as essential elements for eye formation in embryos of the clawed frog xenopus laevis. in order to investigate whether a similarly essential mechanism wou ...201525504514
kcnip1 a ca²⁺-dependent transcriptional repressor regulates the size of the neural plate in xenopus.in amphibian embryos, our previous work has demonstrated that calcium transients occurring in the dorsal ectoderm at the onset of gastrulation are necessary and sufficient to engage the ectodermal cells into a neural fate by inducing neural specific genes. some of these genes are direct targets of calcium. here we search for a direct transcriptional mechanism by which calcium signals are acting. the only known mechanism responsible for a direct action of calcium on gene transcription involves an ...201525499267
the small heat shock protein, hsp30, is associated with aggresome-like inclusion bodies in proteasomal inhibitor-, arsenite-, and cadmium-treated xenopus kidney cells.in the present study, treatment of xenopus laevis a6 kidney epithelial cells with the proteasomal inhibitor, mg132, or the environmental toxicants, sodium arsenite or cadmium chloride, induced the accumulation of the small heat shock protein, hsp30, in total and in both soluble and insoluble protein fractions. immunocytochemical analysis revealed the presence of relatively large hsp30 structures primarily in the perinuclear region of the cytoplasm. all three of the stressors promoted the formati ...201526260897
fluorescent ratiometric ph indicator sypher2: applications in neuroscience and regenerative biology.sypher is a genetically encoded fluorescent ph-indicator with a ratiometric readout, suitable for measuring fast intracellular ph shifts. however, the relatively low brightness of the indicator limits its use.201526259819
direct nkx2-5 transcriptional repression of isl1 controls cardiomyocyte subtype identity.during cardiogenesis, most myocytes arise from cardiac progenitors expressing the transcription factors isl1 and nkx2-5. here, we show that a direct repression of isl1 by nkx2-5 is necessary for proper development of the ventricular myocardial lineage. overexpression of nkx2-5 in mouse embryonic stem cells (escs) delayed specification of cardiac progenitors and inhibited expression of isl1 and its downstream targets in isl1(+) precursors. embryos deficient for nkx2-5 in the isl1(+) lineage faile ...201525524439
evidence for multiple, distinct adar-containing complexes in xenopus laevis.adar (adenosine deaminase acting on rna) is an rna-editing enzyme present in most metazoans that converts adenosines in double-stranded rna targets into inosines. although the rna targets of adar-mediated editing have been extensively cataloged, our understanding of the cellular function of such editing remains incomplete. we report that long, double-stranded rna added to xenopus laevis egg extract is incorporated into an adar-containing complex whose protein components resemble those of stress ...201525519486
brain-derived neurotrophic factor (bdnf) expression in normal and regenerating olfactory epithelium of xenopus laevis.olfactory epithelium has the capability to continuously regenerate olfactory receptor neurons throughout life. adult neurogenesis results from proliferation and differentiation of neural stem cells, and consequently, olfactory neuroepithelium offers an excellent opportunity to study neural regeneration and the factors involved in the maintenance and regeneration of all their cell types. we analyzed the expression of bdnf in the olfactory system under normal physiological conditions as well as du ...201525488259
distinct action of the α-glucosidase inhibitor miglitol on sglt3, enteroendocrine cells, and glp1 secretion.oral ingestion of carbohydrate triggers glucagon-like peptide 1 (glp1) secretion, but the molecular mechanism remains elusive. by measuring glp1 concentrations in murine portal vein, we found that the atp-sensitive k(+) (katp) channel is not essential for glucose-induced glp1 secretion from enteroendocrine l cells, while the sodium-glucose co-transporter 1 (sglt1) is required, at least in the early phase (5 min) of secretion. by contrast, co-administration of the α-glucosidase inhibitor (α-gi) m ...201525486965
nuclear size scaling during xenopus early development contributes to midblastula transition timing.early xenopus laevis embryogenesis is a robust system for investigating mechanisms of developmental timing. after a series of rapid cell divisions with concomitant reductions in cell size, the first major developmental transition is the midblastula transition (mbt), when zygotic transcription begins and cell cycles elongate. whereas the maintenance of a constant nuclear-to-cytoplasmic (n/c) volume ratio is a conserved cellular property, it has long been recognized that the n/c volume ratio chang ...201525484296
aminolevulinate synthase 2 mediates erythrocyte differentiation by regulating larval globin expression during xenopus primary hematopoiesis.hemoglobin synthesis by erythrocytes continues throughout a vertebrate's lifetime. the mechanism of mammalian heme synthesis has been studied for many years; aminolevulinate synthase 2 (alas2), a heme synthetase, is associated with x-linked dominant protoporphyria in humans. amphibian and mammalian blood cells differ, but little is known about amphibian embryonic hemoglobin synthesis. we investigated the function of the xenopus alas2 gene (xalas2) in primitive amphibian erythrocytes and found th ...201525482442
validation of the sperm chromatin dispersion (scd) test in the amphibian xenopus laevis using in situ nick translation and comet assay.the integrity of sperm dna is becoming increasingly recognised as an important parameter of semen quality, but there are no published reports of this procedure for any amphibian. the primary aim of this study was to apply a modified sperm chromatin dispersion (scd) test (halomax) to an amphibian sperm model (african clawed frog; xenopus laevis) and to validate the assay against in situ nick translation (isnt) and the double-comet assay procedure. inactivated spermatozoa were collected from fresh ...201525482041
essential amino acid transporter lat4 (slc43a2) is required for mouse development.amino acid (aa) uniporter lat4 (slc43a2) mediates facilitated diffusion of branched-chain aas, methionine and phenylalanine, although its physiological role and subcellular localization are not known. we report that slc43a2 knockout mice were born at expected mendelian frequency but displayed an ∼10% intrauterine growth retardation and low amniotic fluid aas, suggesting defective transplacental transport. postnatal growth was strongly reduced, with premature death occurring within 9 days such th ...201525480797
atp4 and ciliation in the neuroectoderm and endoderm of xenopus embryos and tadpoles.during gastrulation and neurulation, foxj1 expression requires atp4a-dependent wnt/β-catenin signaling for ciliation of the gastrocoel roof plate (walentek et al. cell rep. 1 (2012) 516-527.) and the mucociliary epidermis (walentek et al. dev. biol. (2015)) of xenopus laevis embryos. these data suggested that atp4a and wnt/β-catenin signaling regulate foxj1 throughout xenopus development. here we analyzed whether foxj1 expression was also atp4a-dependent in other ciliated tissues of the developi ...201526217756
coexistence of y, w, and z sex chromosomes in xenopus tropicalis.homomorphic sex chromosomes and rapid turnover of sex-determining genes can complicate establishing the sex chromosome system operating in a given species. this difficulty exists in xenopus tropicalis, an anuran quickly becoming a relevant model for genetic, genomic, biochemical, and ecotoxicological research. despite the recent interest attracted by this species, little is known about its sex chromosome system. direct evidence that females are the heterogametic sex, as in the related species xe ...201526216983
how does the xenopus laevis embryonic cell cycle avoid spatial chaos?theoretical studies have shown that a deterministic biochemical oscillator can become chaotic when operating over a sufficiently large volume and have suggested that the xenopus laevis cell cycle oscillator operates close to such a chaotic regime. to experimentally test this hypothesis, we decreased the speed of the post-fertilization calcium wave, which had been predicted to generate chaos. however, cell divisions were found to develop normally, and eggs developed into normal tadpoles. motivate ...201526212326
characterization of tweety gene (ttyh1-3) expression in xenopus laevis during embryonic development.the tweety family of genes encodes large-conductance chloride channels and has been implicated in a wide array of cellular processes including cell division, cell adhesion, regulation of calcium activity, and tumorigenesis, particularly in neuronal cells. however, their expression patterns during early development remain largely unknown. here, we describe the spatial and temporal patterning of ttyh1, ttyh2, and ttyh3 in xenopus laevis during early embryonic development. ttyh1 and ttyh3 are initi ...201525541457
human intestine luminal ace2 and amino acid transporter expression increased by ace-inhibitors.sodium-dependent neutral amino acid transporter b(0)at1 (slc6a19) and imino acid (proline) transporter sit1 (slc6a20) are expressed at the luminal membrane of small intestine enterocytes and proximal tubule kidney cells where they exert key functions for amino acid (re)absorption as documented by their role in hartnup disorder and iminoglycinuria, respectively. expression of b(0)at1 was shown in rodent intestine to depend on the presence of the carboxypeptidase angiotensin-converting enzyme 2 (a ...201525534429
the effect of 900 and 1800 mhz gsm-like radiofrequency irradiation and nicotine sulfate administration on the embryonic development of xenopus laevis.the aim of this study was to investigate the effects of gsm-like radiofrequency electromagnetic radiation (rf emr) and nicotine sulfate (ns) exposure on xenopus embryonic development.the developmental effects of gsm-like rf-emr (900-1800 mhz, at a sar value of 1w/kg and ns on xenopus laevis embryos were investigated). following the application of radiofrequency radiation and/or ns administration, the embryos were closely examined in order to determine their possible teratogenic effects. xenopus ...201525531835
notch is a direct negative regulator of the dna-damage response.the dna-damage response (ddr) ensures genome stability and proper inheritance of genetic information, both of which are essential to survival. it is presently unclear to what extent other signaling pathways modulate ddr function. here we show that notch receptor binds and inactivates atm kinase and that this mechanism is evolutionarily conserved in caenorhabditis elegans, xenopus laevis and humans. in c. elegans, the notch pathway impairs ddr signaling in gonad germ cells. in mammalian cells, ac ...201525895060
identification and expression of an atypical isoform of metallothionein in the african clawed frog xenopus laevis.exploiting the annotation of the western clawed frog silurana tropicalis genome, we identified a new metallothionein (mt) gene, exhibiting all the features to be considered an active gene, but with an atypical coding region, showing only 17 cysteine residues instead of the canonical 20 cysteines of vertebrate metallothioneins and two anomalous cysteine triplets. however, the presence of a gene in the genome does not ensure its effective expression. by using conventional and real-time pcr analyse ...201525882350
impact of maternal n-3 polyunsaturated fatty acid deficiency on dendritic arbor morphology and connectivity of developing xenopus laevis central neurons in vivo.docosahexaenoic acid (dha, 22:6n-3) is an essential component of the nervous system, and maternal n-3 polyunsaturated fatty acids (pufas) are an important source for brain development. here, the impact of dha on developing central neurons was examined using an accessible in vivo model. xenopus laevis embryos from adult female frogs fed n-3 pufa-adequate or deficient diets were analyzed every 10 weeks for up to 60 weeks, when frogs were then switched to a fish oil-supplemented diet. lipid analysi ...201525878281
neutrophil elastase activates protease-activated receptor-2 (par2) and transient receptor potential vanilloid 4 (trpv4) to cause inflammation and pain.proteases that cleave protease-activated receptor-2 (par(2)) at arg(36)↓ser(37) reveal a tethered ligand that binds to the cleaved receptor. par(2) activates transient receptor potential (trp) channels of nociceptive neurons to induce neurogenic inflammation and pain. although proteases that cleave par(2) at non-canonical sites can trigger distinct signaling cascades, the functional importance of the par(2)-biased agonism is uncertain. we investigated whether neutrophil elastase, a biased agonis ...201525878251
a new nomenclature of xenopus laevis chromosomes based on the phylogenetic relationship to silurana/xenopus tropicalis.xenopus laevis (xla) is an allotetraploid species which appears to have undergone whole-genome duplication after the interspecific hybridization of 2 diploid species closely related to silurana/xenopus tropicalis (xtr). previous cdna fluorescence in situ hybridization (fish) experiments have identified 9 sets of homoeologous chromosomes in x. laevis, in which 8 sets correspond to chromosomes 1-8 of x. tropicalis (xtr1-xtr8), and the last set corresponds to a fusion of xtr9 and xtr10. in addition ...201525871511
identification of a novel dehydration responsive gene, drp10, from the african clawed frog, xenopus laevis.during periods of environmental stress a number of different anuran species employ adaptive strategies to promote survival. our study found that in response to dehydration (i.e., loss of total body water content), the african clawed frog (xenopus laevis) increased the expression of a novel gene (drp10) that encodes a structural homolog of the freeze-responsive fr10 protein found in wood frogs. similar to fr10, the drp10 protein was found to also contain a highly conserved n-terminal cleavable si ...201525866033
germ layer formation during xenopus embryogenesis: the balance between pluripotency and differentiation.the african clawed frog, xenopus laevis, has long been a model animal for the studies in the fields of animal cloning, developmental biology, biochemistry, cell biology, and physiology. with the aid of xenopus, major molecular mechanisms that are involved in embryonic development have been understood. germ layer formation is the first event of embryonic cellular differentiation, which is induced by a few key maternal factors and subsequently by zygotic signals. meanwhile, another type of signals ...201525862657
toxic mechanisms of copper oxide nanoparticles in epithelial kidney cells.cuo nps have previously been reported as toxic to a range of cell cultures including kidney epithelial cells from the frog, xenopus laevis (a6). here we examine the molecular mechanisms affecting toxicity of cu in different forms and particle sizes. a6 cells were exposed to ionic cu (cu2+) or cuo particles of three different sizes: cuo nps of 6 nm (np6), larger poly-dispersed cuo nps of <100 nm (poly) and cuo micro particles of <5 μm (micro), at 200 μm, equal to 12.7 mg cu/l. poly was significan ...201525862124
a requirement for hedgehog signaling in thyroid hormone-induced postembryonic intestinal remodeling.intestinal remodeling during amphibian metamorphosis has long been studied as a model for the formation of the adult organs in vertebrates, especially the formation of adult organ-specific stem cells. like all other processes during metamorphosis, this process is controlled by thyroid hormone (t3), which affects cell fate and behavior through transcriptional regulation of target genes by binding to t3 receptors (trs). earlier studies have shown that sonic hedgehog (shh) is induced by t3 in the d ...201525859319
functional characterization of the human facilitative glucose transporter 12 (glut12) by electrophysiological methods.glut12 is a member of the facilitative family of glucose transporters. the goal of this study was to characterize the functional properties of glut12, expressed in xenopus laevis oocytes, using radiotracer and electrophysiological methods. our results showed that glut12 is a facilitative sugar transporter with substrate selectivity: d-glucose ≥ α-methyl-d-glucopyranoside (α-mg) > 2-deoxy-d-glucose(2-dog) > d-fructose = d-galactose. α-mg is a characteristic substrate of the na(+)/glucose (sglt) f ...201525855082
atp4a is required for development and function of the xenopus mucociliary epidermis - a potential model to study proton pump inhibitor-associated pneumonia.proton pump inhibitors (ppis), which target gastric h(+)/k(+)atpase (atp4), are among the most commonly prescribed drugs. ppis are used to treat ulcers and as a preventative measure against gastroesophageal reflux disease in hospitalized patients. ppi treatment correlates with an increased risk for airway infections, i.e. community- and hospital-acquired pneumonia. the cause for this correlation, however, remains elusive. the xenopus embryonic epidermis is increasingly being used as a model to s ...201525848696
light sensitivity in a vertebrate mechanoreceptor?using immunohistochemistry and western blot analysis, we demonstrate that melanopsin is localised in cells around the central pore of lateral line neuromasts in the african clawed frog, xenopus laevis. since melanopsin is a known photoreceptor pigment with diverse functions in vertebrates, we suggest that the lateral line of xenopus laevis, which is primarily a mechanoreceptor, might also be light sensitive. potential functions of such photosensitivity are discussed, including its role in mediat ...201526206352
concentration-response relationship of the α7 nicotinic acetylcholine receptor agonist frm-17874 across multiple in vitro and in vivo assays.pharmacological activation of α7 nicotinic acetylcholine receptors (α7 nachrs) may improve cognition in schizophrenia and alzheimer's disease. the present studies describe an integrated pharmacological analysis of the effects of frm-17874, an analogue of encenicline, on α7 nachrs in vitro and in behavioral and neurophysiological assays relevant to cognitive function. frm-17874 demonstrated high affinity binding to human α7 nachrs, displacing [(3)h]-methyllacaconitine (ki=4.3nm). in xenopus laevi ...201526206187
the n-methyl-d-aspartate receptor's neglected subunit - glun1 matters under normal and hyperbaric conditions.professional deep-water divers exposed to hyperbaric pressure (hp) above 1.1 mpa develop high-pressure neurological syndrome, which is associated with central nervous system hyperexcitability. it was previously reported that hp augments n-methyl-d-aspartate receptor (nmdar) synaptic responses, increases neuronal excitability, and potentially causes irreversible neuronal damage. in addition, we have reported that hp (10.1 mpa) differentially affects ionic currents, measured by the two-electrode v ...201526202884
kruppel-like factor family genes are expressed during xenopus embryogenesis and involved in germ layer formation and body axis patterning.kruppel-like factors (klfs) are a family of transcription factors consisting of 17 members in mammals, klf1-klf17, which are involved in fundamental cellular physiological procedures, such as cell proliferation, differentiation, and apoptosis. however, their functions in embryonic development have been poorly understood. our previous study has demonstrated that the pluripotency factor klf4 participates in germ layer formation and axis patterning of xenopus embryos by means of the regulation of k ...201526198170
selective depolarization of transmembrane potential alters muscle patterning and muscle cell localization in xenopus laevis embryos.the correct anatomical placement and precise determination of specific cell types is required for the establishment of normal embryonic patterning. understanding these processes is also important for progress in regenerative medicine and cancer biology. transmembrane voltage gradients across embryonic tissues can mediate cellular communication to regulate the processes of proliferation, migration, and differentiation. our past work showed that selective depolarization of an endogenous instructor ...201526198143
local and long-range endogenous resting potential gradients antagonistically regulate apoptosis and proliferation in the embryonic cns.bioelectric signals, particularly transmembrane voltage potentials (vmem), play an important role in large-scale patterning during embryonic development. endogenous bioelectric gradients across tissues function as instructive factors during eye, brain, and other morphogenetic processes. an important and still poorly-understood aspect is the control of cell behaviors by the voltage states of distant cell groups. here, experimental alteration of endogenous vmem was induced in xenopus laevis embryo ...201526198142
functional integration of mrna translational control programs.regulated mrna translation plays a key role in control of cell cycle progression in a variety of physiological and pathological processes, including in the self-renewal and survival of stem cells and cancer stem cells. while targeting mrna translation presents an attractive strategy for control of aberrant cell cycle progression, mrna translation is an underdeveloped therapeutic target. regulated mrnas are typically controlled through interaction with multiple rna binding proteins (rbps) but the ...201526197342
flexible subunit stoichiometry of functional human p2x2/3 heteromeric receptors.the aim of the present work was to clarify whether heterotrimeric p2x2/3 receptors have a fixed subunit stoichiometry consisting of one p2x2 and two p2x3 subunits as previously suggested, or a flexible stoichiometry containing also the inverse subunit composition. for this purpose we transfected hek293 cells with p2x2 and p2x3 encoding cdna at the ratios of 1:2 and 4:1, and analysed the biophysical and pharmacological properties of the generated receptors by means of the whole-cell patch-clamp t ...201526184350
annexin a3 regulates early blood vessel formation.annexins are a large family of calcium binding proteins that associate with cell membrane phospholipids and are involved in various cellular processes including endocytosis, exocytosis and membrane-cytoskeletal organization. despite studies on numerous annexin proteins, the function of annexin a3 (anxa3) is largely unknown. our studies identify anxa3 as a unique marker of the endothelial and myeloid cell lineages of xenopus laevis during development. anxa3 transcripts are also detected in endoth ...201526182056
the mutation p.t613a in the pore helix of the kv 11.1 potassium channel is associated with long qt syndrome.loss-of-function mutations in the voltage gated potassium channel kv 11.1 have been associated with the long qt syndrome (lqts) type 2. we identified the p.t613a mutation in kv 11.1 in a family with lqts. t613a is located in the outer part of the pore helix, a structure that is involved in c-type inactivation. here we characterize the effect of p.t613a on the functional properties of kv 11.1.201526173150
retention of duplicated itam-containing transmembrane signaling subunits in the tetraploid amphibian species xenopus laevis.the itam-bearing transmembrane signaling subunits (tss) are indispensable components of activating leukocyte receptor complexes. the tss-encoding genes map to paralogous chromosomal regions, which are thought to arise from ancient genome tetraploidization(s). to assess a possible role of tetraploidization in the tss evolution, we studied tss and other functionally linked genes in the amphibian species xenopus laevis whose genome was duplicated about 40 myr ago. we found that x. laevis has retain ...201526170006
dehydration triggers differential microrna expression in xenopus laevis brain.african clawed frogs, xenopus laevis, although primarily aquatic, have a high tolerance for dehydration, being capable of withstanding the loss of up to 32-35% of total water body water. recent studies have shown that micrornas play a role in the response to dehydration by the liver, kidney and ventral skin of x. laevis. micrornas act by modulating the expression of mrna transcripts, thereby affecting diverse biochemical pathways. in this study, 43 micrornas were assessed in frog brains comparin ...201526169019
deconstructing cartilage shape and size into contributions from embryogenesis, metamorphosis, and tadpole and frog growth.understanding skeletal diversification involves knowing not only how skeletal rudiments are shaped embryonically, but also how skeletal shape changes throughout life. the pharyngeal arch (pa) skeleton of metamorphosing amphibians persists largely as cartilage and undergoes two phases of development (embryogenesis and metamorphosis) and two phases of growth (larval and post-metamorphic). though embryogenesis and metamorphosis produce species-specific features of pa cartilage shape, the extents to ...201525913729
urotensin ii upregulates migration and cytokine gene expression in leukocytes of the african clawed frog, xenopus laevis.urotensin ii (uii) exhibits diverse physiological actions including vasoconstriction, locomotor activity, osmoregulation, and immune response via the uii receptor (utr) in mammals. however, in amphibians the function of the uii-utr system remains unknown. in the present study, we investigated the potential immune function of uii using leukocytes isolated from the african clawed frog, xenopus laevis. stimulation of male frogs with lipopolysaccharide increased mrna expression of uii and utr in leu ...201525907658
transport function of rice amino acid permeases (aaps).the transport function of four rice (oryza sativa) amino acid permeases (aaps), osaap1 (os07g04180), osaap3 (os06g36180), osaap7 (os05g34980) and osaap16 (os12g08090), was analyzed by expression in xenopus laevis oocytes and electrophysiology. osaap1, osaap7 and osaap16 functioned, similarly to arabidopsis aaps, as general amino acid permeases. osaap3 had a distinct substrate specificity compared with other rice or arabidopsis aaps. osaap3 transported the basic amino acids lysine and arginine we ...201525907566
influence of hydrophobic residues on the activity of the antimicrobial peptide magainin 2 and its synergy with pgla.magainin 2 (mag2) and pgla are two related antimicrobial peptides found in the skin of the african frog xenopus laevis with a pronounced synergistic activity, which act by permeabilizing bacterial membranes. to probe the influence of hydrophobic peptide-lipid and peptide-peptide interactions on the antimicrobial activity and on synergy, the sequence of mag2 was modified by replacing single amino acids either with a small alanine or with the stiff and bulky hydrophobic 3-(trifluoromethyl)-l-bicyc ...201525898805
the influence of artificially introduced n-glycosylation sites on the in vitro activity of xenopus laevis erythropoietin.erythropoietin (epo), the primary regulator of erythropoiesis, is a heavily glycosylated protein found in humans and several other mammals. intriguingly, we have previously found that epo in xenopus laevis (xlepo) has no n-glycosylation sites, and cross-reacts with the human epo (huepo) receptor despite low homology with huepo. in this study, we introduced n-glycosylation sites into wild-type xlepo at the positions homologous to those in huepo, and tested whether the glycosylated mutein retained ...201525898205
targeted gene disruption in xenopus laevis using crispr/cas9. 201525897376
glutamylation of nap1 modulates histone h1 dynamics and chromosome condensation in xenopus.linker histone h1 is required for mitotic chromosome architecture in xenopus laevis egg extracts and, unlike core histones, exhibits rapid turnover on chromatin. mechanisms regulating the recruitment, deposition, and dynamics of linker histones in mitosis are largely unknown. we found that the cytoplasmic histone chaperone nucleosome assembly protein 1 (nap1) associates with the embryonic isoform of linker histone h1 (h1m) in egg extracts. immunodepletion of nap1 decreased h1m binding to mitotic ...201525897082
dissecting microtubule structures by laser ablation.here, we describe a detailed protocol, based on laser ablation and fluorescence optical microscopy, to measure the microtubule organization in spindles, including microtubule length distribution, polarity, and plus and minus end densities. the method uses the asymmetry in microtubule depolymerization after a cut, where the newly created microtubule plus ends depolymerize all the way to the minus ends, whereas the newly created minus ends remain stable. the protocol described in this chapter is o ...201525640424
expression of a novel serine/threonine kinase gene, ulk4, in neural progenitors during xenopus laevis forebrain development.we have analyzed the expression pattern of a novel serine/threonine kinase gene ulk4 during forebrain development in xenopus laevis. to this aim, we firstly cloned a ulk4 cdna fragment from x.laevis and generated a rna probe that was used for its detection by in situ hybridization. throughout development xulk4 expression was detected along the ventricular (vz) and subventricular zones (svz) of all forebrain regions, with the exception of the vz of the striatum. in the adult, xulk4 was also mainl ...201525637795
distinct patterns of endosulfatase gene expression during xenopus laevis limb development and regeneration.the heparan sulfate 6-o-endosulfatases sulf1 and sulf2 regulate multiple cellular processes and organ development. sulfs modulate a range of heparan-sulfate-dependent extracellular pathways, including the fibroblast growth factor, bone morphogenetic protein, and wingless/wnt signaling pathways. known patterns of sulf transcript expression together with functional experiments have implicated the sulfs in chondrogenesis and muscle regeneration in mammals. here, we describe the expression patterns ...201527499864
the effects of simazine, a chlorotriazine herbicide, on the expression of genes in developing male xenopus laevis.simazine was investigated for gene expression concurrent with simazine-induced phenotype changes during development of male xenopus laevis. x. laevis tadpoles (nieuwkoop-faber stage 46) were exposed to 0.1, 1.2, 11.0 and 100.9 μg/l simazine for 100 days. the results showed that an increased mortality of x. laevis, decreased gonad weight and altered gonadosomatic index of males significantly (p<0.05) when exposed to simazine at 11.0 and 100.9 µg/l. significant degeneration in testicular tissues w ...201525634327
acute toxic effects of the herbicide formulation and the active ingredient used in cycloxydim-tolerant maize cultivation on embryos and larvae of the african clawed frog, xenopus laevis.most genetically engineered herbicide-tolerant crops are still awaiting approval in europe. there is, however, a recent trend for the cultivation of cycloxydim-tolerant maize hybrids for use in maize production. we studied the acute toxic effects of the complementary herbicide focus(®) ultra and its active ingredient cycloxydim on embryos and early-stage larvae of the african clawed frog (xenopus laevis). the results indicate that the herbicide formulation is significantly more toxic than the ac ...201525634323
α- and β-subunit composition of voltage-gated sodium channels investigated with μ-conotoxins and the recently discovered μo§-conotoxin gviij.we investigated the identities of the isoforms of the α (nav1)- and β (navβ)-subunits of voltage-gated sodium channels, including those responsible for action potentials in rodent sciatic nerves. to examine α-subunits, we used seven μ-conotoxins, which target site 1 of the channel. with the use of exogenously expressed channels, we show that two of the μ-conotoxins, μ-buiiib and μ-sxiiia, are 50-fold more potent in blocking nav1.6 from mouse than that from rat. furthermore, we observed that μ-bu ...201525632083
hydrogen sulfide decreases β-adrenergic agonist-stimulated lung liquid clearance by inhibiting enac-mediated transepithelial sodium absorption.in pulmonary epithelia, β-adrenergic agonists regulate the membrane abundance of the epithelial sodium channel (enac) and, thereby, control the rate of transepithelial electrolyte absorption. this is a crucial regulatory mechanism for lung liquid clearance at birth and thereafter. this study investigated the influence of the gaseous signaling molecule hydrogen sulfide (h2s) on β-adrenergic agonist-regulated pulmonary sodium and liquid absorption. application of the h2s-liberating molecule na2s ( ...201525632025
small-molecule high-throughput screening utilizing xenopus egg extract.screens for small-molecule modulators of biological pathways typically utilize cultured cell lines, purified proteins, or, recently, model organisms (e.g., zebrafish, drosophila, c. elegans). herein, we describe a method for using xenopus laevis egg extract, a biologically active and highly tractable cell-free system that recapitulates a legion of complex chemical reactions found in intact cells. specifically, we focus on the use of a luciferase-based fusion system to identify small-molecule mod ...201525618336
the wnt receptor frizzled-4 modulates adam13 metalloprotease activity.cranial neural crest (cnc) cells are a transient population of stem cells that originate at the border of the neural plate and the epidermis, and migrate ventrally to contribute to most of the facial structures including bones, cartilage, muscles and ganglia. adam13 is a cell surface metalloprotease that is essential for cnc cell migration. here, we show in xenopus laevis embryos that the wnt receptor fz4 binds to the cysteine-rich domain of adam13 and negatively regulates its proteolytic activi ...201525616895
temporal and spatial expression analysis of peripheral myelin protein 22 (pmp22) in developing xenopus.peripheral myelin protein 22 (pmp22), a member of the junction protein family claudin/emp/pmp22, contributes to the formation and maintenance of myelin sheaths in the peripheral nervous system. apart from the establishment and maintenance of peripheral nerves, pmp22 and its family member have also participated in a broad range of more general processes including cell cycle regulation and apoptosis during development. pmp22 has been identified from several vertebrate species including mouse, huma ...201525616247
discovery of a novel general anesthetic chemotype using high-throughput screening.the development of novel anesthetics has historically been a process of combined serendipity and empiricism, with most recent new anesthetics developed via modification of existing anesthetic structures.201525603205
highly efficient gene knockout by injection of talen mrnas into oocytes and host transfer in xenopus laevis.zinc-finger nucleases, transcription activator-like effector nucleases (talens) and the crispr/cas (clustered regularly interspaced short palindromic repeats/crispr-associated proteins) system are potentially powerful tools for producing tailor-made knockout animals. however, their mutagenic activity is not high enough to induce mutations at all loci of a target gene throughout an entire tadpole. in this study, we present a highly efficient method for introducing gene modifications at almost all ...201525596277
structural analysis of dopamine- and amphetamine-induced depolarization currents in the human dopamine transporter.amphetamine (amph) induces depolarizing currents through the human dopamine transporter (hdat). recently we discovered that the s(+) enantiomer of amph induces a current through hdat that persists long after its removal from the external milieu. the persistent current is less prominent for r(-)amph and essentially absent for dopamine (da)-induced currents. related agents such as methamphetamine also exhibit persistent currents, which are present in both frog oocyte and mammalian hek expression s ...201525594379
trpp2-dependent ca2+ signaling in dorso-lateral mesoderm is required for kidney field establishment in xenopus.in xenopus laevis embryos, kidney field specification is dependent on retinoic acid (ra) and coincides with a dramatic increase of ca(2+) transients, but the role of ca(2+) signaling in the kidney field is unknown. here, we identify trpp2, a member of the transient receptor potential (trp) superfamily of channel proteins encoded by the pkd2 gene, as a central component of ca(2+) signaling in the kidney field. trpp2 is strongly expressed at the plasma membrane where it might regulate extracellula ...201525588842
pan-african phylogeography of a model organism, the african clawed frog 'xenopus laevis'.the african clawed frog xenopus laevis has a large native distribution over much of sub-saharan africa and is a model organism for research, a proposed disease vector, and an invasive species. despite its prominent role in research and abundance in nature, surprisingly little is known about the phylogeography and evolutionary history of this group. here, we report an analysis of molecular variation of this clade based on 17 loci (one mitochondrial, 16 nuclear) in up to 159 individuals sampled th ...201525583226
interactive effects of ultraviolet-b radiation and pesticide exposure on dna photo-adduct accumulation and expression of dna damage and repair genes in xenopus laevis embryos.pesticide use and ultraviolet-b (uvb) radiation have both been suggested to adversely affect amphibians; however, little is known about their interactive effects. one potential adverse interaction could involve pesticide-induced dysregulation of dna repair pathways, resulting in greater numbers of dna photo-adducts from uvb exposure. in the present study, we investigated the interactive effects of uvb radiation and two common pesticides (endosulfan and α-cypermethrin) on induction of dna photo-a ...201525569846
effects on channel properties and induction of cell death induced by c-terminal truncations of pannexin1 depend on domain length.pannexin1 (panx1) is an integral membrane protein and known to form multifunctional hexameric channels. recently, panx1 was identified to be responsible for the release of atp and utp from apoptotic cells after site-specific proteolysis by caspases 3/7. cleavage at the carboxy-terminal (ct) position aa 376-379 irreversibly opens human panx1 channels and leads to the release of the respective nucleotides resulting in recruitment of macrophages and in subsequent activation of the immunologic respo ...201525567359
effect of allyl isothiocyanate on developmental toxicity in exposed xenopus laevis embryos.the pungent natural compound allyl isothiocyanate isolated from the seeds of cruciferous (brassica) plants such as mustard is reported to exhibit numerous beneficial health-promoting antimicrobial, antifungal, anticarcinogenic, cardioprotective, and neuroprotective properties. because it is also reported to damage dna and is toxic to aquatic organisms, the objective of the present study was to determine whether it possesses teratogenic properties. the frog embryo teratogenesis assay-xenopus (fet ...201528962355
distinct patterns of compartmentalization and proteolytic stability of pde6c mutants linked to achromatopsia.phosphodiesterase-6 (pde6) is an essential effector enzyme in vertebrate photoreceptor cells. mutations in rod and cone pde6 cause recessive retinitis pigmentosa and achromatopsia, respectively. the mechanisms of missense pde6 mutations underlying severe visual disorders are poorly understood. to probe these mechanisms, we expressed seven known missense mutants of cone pde6c in rods of transgenic xenopus laevis and examined their stability and compartmentalization. pde6c proteins with mutations ...201525461672
protocadherin-9 involvement in retinal development in xenopus laevis.biological roles of most protocadherins (pcdhs) are a largely unsolved problem. therefore, we cloned cdna for xenopus laevis protocadherin-9 and characterized its properties to elucidate the role. the deduced amino acid sequence was highly homologous to those of mammalian protocadherin-9 s. x. laevis protocadherin-9 expressed from the cdna in l cells showed basic properties similar to those of mammalian pcdhs. expression of x. laevis protocadherin-9 was first detected in stage-31 embryos and inc ...201525414271
a novel method for inducing nerve growth via modulation of host resting potential: gap junction-mediated and serotonergic signaling mechanisms.a major goal of regenerative medicine is to restore the function of damaged or missing organs through the implantation of bioengineered or donor-derived components. it is necessary to understand the signals and cues necessary for implanted structures to innervate the host, as organs devoid of neural connections provide little benefit to the patient. while developmental studies have identified neuronal pathfinding molecules required for proper patterning during embryogenesis, strategies to initia ...201525449797
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