Publications

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high-efficiency non-mosaic crispr-mediated knock-in and indel mutation in f0 xenopus.the revolution in crispr-mediated genome editing has enabled the mutation and insertion of virtually any dna sequence, particularly in cell culture where selection can be used to recover relatively rare homologous recombination events. the efficient use of this technology in animal models still presents a number of challenges, including the time to establish mutant lines, mosaic gene editing in founder animals, and low homologous recombination rates. here we report a method for crispr-mediated g ...201728694259
a functional approach to understanding the role of nckx5 in xenopus pigmentation.nckx5 is an ion exchanger expressed mostly in pigment cells; however, the functional role for this protein in melanogenesis is not clear. a variant allele of slc24a5, the gene encoding nckx5, has been shown to correlate with lighter skin pigmentation in humans, indicating a key role for slc24a5 in determining human skin colour. slc24a5 expression has been found to be elevated in melanoma. knockdown analyses have shown slc24a5 to be important for pigmentation, but to date the function of this ion ...201728692664
the c-terminal kinesin motor kifc1 may participate in nuclear reshaping and flagellum formation during spermiogenesis of larimichthys crocea.spermatogenesis is a highly ordered process in the differentiation of male germ cells. nuclear morphogenesis is one of the most fundamental cellular transformations to take place during spermatogenesis. these striking transformations from spermatogonia to spermatozoa are a result of phase-specific adaption of the cytoskeleton and its association with molecular motor proteins. kifc1 is a c-terminal kinesin motor protein that plays an essential role in acrosome formation and nuclear reshaping duri ...201728534180
are invasive populations characterized by a broader diet than native populations?invasive species are among the most significant threats to biodiversity. the diet of invasive animal populations is a crucial factor that must be considered in the context of biological invasions. a broad dietary spectrum is a frequently cited characteristic of invasive species, allowing them to thrive in a wide range of environments. therefore, empirical studies comparing diet in invasive and native populations are necessary to understand dietary requirements, dietary flexibility, and the assoc ...201728533950
coordinating heart morphogenesis: a novel role for hyperpolarization-activated cyclic nucleotide-gated (hcn) channels during cardiogenesis in xenopus laevis.hyperpolarization-activated cyclic-nucleotide gated channel (hcn) proteins are important regulators of both neuronal and cardiac excitability. among the 4 hcn isoforms, hcn4 is known as a pacemaker channel, because it helps control the periodicity of contractions in vertebrate hearts. although the physiological role of hcn4 channel has been studied in adult mammalian hearts, an earlier role during embryogenesis has not been clearly established. here, we probe the embryonic roles of hcn4 channels ...201728702127
charged antimicrobial peptides can translocate across membranes without forming channel-like pores.how can highly charged, cationic antimicrobial peptides (amps) translocate across hydrophobic lipid bilayers despite the prohibitive energetic penalty to do so? a common explanation has been the formation of peptide-lined channels. however, for most amps, no structures of membrane pores have been found despite clear evidence of membrane leakage and antimicrobial activity. the study here suggests an alternative and simple reason: for the amp pgla from xenopus laevis (charge +5), such pores are no ...201728700927
chk1 inhibition of the replication factor drf1 guarantees cell-cycle elongation at the xenopus laevis mid-blastula transition.the early cell divisions of many metazoan embryos are rapid and occur in the near absence of transcription. at the mid-blastula transition (mbt), the cell cycle elongates and several processes become established including the onset of bulk transcription and cell-cycle checkpoints. how these events are timed and coordinated is poorly understood. here we show in xenopus laevis that developmental activation of the checkpoint kinase chk1 at the mbt results in the scfβ-trcp-dependent degradation of a ...201728697335
measurement of surface topography and stiffness distribution on cross-section of xenopus laevis tailbud for estimation of mechanical environment in embryo.the stress distribution inside a xenopus laevis tailbud embryo was estimated to examine the cause of the straightening and elongation. the embryos were cut in the middle, yielding a cross-section perpendicular to the body axis. the section was not flat, owing to the residual stress relief. the stress needed to restore the flatness corresponded to the stress inside the embryo and was calculated using the surface topography and young's-moduli in the section. we found the areas of the notochord (nc ...201728627765
xenopus-fv3 host-pathogen interactions and immune evasion.we first review fundamental insights into anti-ranavirus immunity learned with the xenopus laevis/ranavirus fv3 model that are generally applicable to ectothermic vertebrates. we then further investigate fv3 genes involved in immune evasion. focusing on fv3 knockout (ko) mutants defective for a putative viral caspase activation and recruitment domain-containing (card)-like protein (δ64r-fv3), a β-hydroxysteroid dehydrogenase homolog (δ52l-fv3), and an immediate-early18kda protein (fv3-δ18k), we ...201728625407
fluorescence correlation spectroscopy experiments to quantify free diffusion coefficients in reaction-diffusion systems: the case of ca^{2+} and its dyes.many cell signaling pathways involve the diffusion of messengers that bind and unbind to and from intracellular components. quantifying their net transport rate under different conditions then requires having separate estimates of their free diffusion coefficient and binding or unbinding rates. in this paper, we show how performing sets of fluorescence correlation spectroscopy (fcs) experiments under different conditions, it is possible to quantify free diffusion coefficients and on and off rate ...201728709293
regulation of the insulin-akt signaling pathway and glycolysis during dehydration stress in the african clawed frog xenopus laevis.estivation is an adaptive stress response utilized by some amphibians during periods of drought in the summer season. in this study, we examine the regulation of the insulin signaling cascade and glycolysis pathway in the african clawed frog xenopus laevis during the dehydration stress induced state of estivation. we show that in the brain and heart of x. laevis, dehydration reduces the phosphorylation of the insulin growth factor-1 receptor (igf-1r), and this is followed by similar reductions i ...201728708941
an analysis of myod-dependent transcription using crispr/cas9 gene targeting in xenopus tropicalis embryos.myogenic regulatory factors (mrfs) are known to have essential roles in both the establishment and differentiation of the skeletal muscle cell lineage. myod is expressed early in the xenopus mesoderm where it is present and active several hours before the activation of muscle differentiation genes. previous studies in cultured cells and in xenopus laevis have identified sets of genes that require myod prior to differentiation of skeletal muscle. here we report results from experiments using cris ...201728536000
family of ricinus communis monosaccharide transporters and rcstp1 in promoting the uptake of a glucose-fipronil conjugate.enhancing the systemic distribution of a bioactive compound by exploiting the vascular transport system of a plant presents a means of reducing both the volume and frequency of pesticide/fungicide application. the foliar uptake of the glucose-fipronil conjugate n-[3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1h-pyrazol-5-yl]-1-(β-d-glucopyranosyl)-1h-1,2,3-triazole-4-methanamine (gtf) achieved in castor bean (ricinus communis) and its transport via the phloem ...201728692262
the cannabinoid receptor interacting proteins 1 of zebrafish are not required for morphological development, viability or fertility.the cannabinoid receptor interacting protein 1 (cnrip1) was discovered as an interactor with the intracellular region of cannabinoid receptor 1 (cb1r, also known as cnr1 or cb1). functional assays in mouse show cannabinoid sensitivity changes and cnrip1 has recently been suggested to control eye development in xenopus laevis. two cnrip1 genes are described in zebrafish, cnrip1a and cnrip1b. in situ mrna hybridisation revealed accumulation of mrna encoding each gene primarily in brain and spinal ...201728687732
digital dissection of the model organism xenopus laevis using contrast-enhanced computed tomography.the african clawed frog, xenopus laevis, is one of the most widely used model organisms in biological research. however, the most recent anatomical description of x. laevis was produced nearly a century ago. compared with other anurans, pipid frogs - including x. laevis - exhibit numerous unusual morphological features; thus, anatomical descriptions of more 'typical' frogs do not detail many aspects of x. laevis skeletal and soft-tissue morphology. the relatively new method of using iodine-based ...201728547827
a magnesium transporter osmgt1 plays a critical role in salt tolerance in rice.salt stress is one of the major factors limiting rice (oryza sativa) production globally. although several transporters involved in salt tolerance have been identified in rice, the mechanisms regulating their transport activity are still poorly understood. here, we show evidence that a rice mg transporter osmgt1 is required for salt tolerance probably by regulating transport activity of oshkt1;5, a key transporter for the removal of na+ from the xylem sap at the root mature zone. knockout of osm ...201728487477
functional assessment of the nmda receptor variant glun2a r586k.background: the n-methyl-d-aspartate receptor (nmdar) is an ionotropic glutamate receptor that has important roles in synaptogenesis, synaptic transmission, and synaptic plasticity. recently, a large number of rare genetic variants have been found in nmdar subunits in people with neurodevelopmental disorders, and also in healthy individuals. one such is the glun2ar586k variant, found in a person with intellectual disability. identifying the functional consequences, if any, of such variants allow ...201728459106
editorial: the xenopus laevis genome. 201728457863
leptin induces mitosis and activates the canonical wnt/β-catenin signaling pathway in neurogenic regions of xenopus tadpole brain.in addition to its well-known role as an adipostat in adult mammals, leptin has diverse physiological and developmental actions in vertebrates. leptin has been shown to promote development of hypothalamic circuits and to induce mitosis in different brain areas of mammals. we investigated the ontogeny of leptin mrna, leptin actions on cell proliferation in the brain, and gene expression in the preoptic area/hypothalamus of tadpoles of xenopus laevis. the level of leptin mrna was low in premetamor ...201728533765
adhfe1: a novel enzyme involved in retinoic acid-dependent hox activation.retinoic acid (ra) signaling is a central pathway regulating anterior-posterior patterning of the embryo through its targets, the hox genes. ra is produced by two sequential oxidations from vitamin a (retinol) and this biosynthesis has to be regulated temporally, spatially and quantitatively. mining xenopus embryonic expression databases identified a novel component of the ra metabolic network, adhfe1. using xenopus laevis embryos as our experimental system we determined the temporal and spatial ...201728621427
foxd1 protein interacts with wnt and bmp signaling to differentially pattern mesoderm and neural tissue.the foxd1 gene (previously known as brain factor 2/bf2) is expressed during early xenopus laevis development. at gastrula stages, foxd1 is expressed in dorsal mesoderm regions fated for muscle and notochord, while at neurula stages, foxd1 is expressed in the forebrain region. previous studies in the neural plate showed that foxd1 protein acts as transcriptional repressor downstream of bmp antagonism, neuralizing the embryo to control anterior neural cell fates. foxd1 mesoderm function was not ri ...201728621426
roles of the cilium-associated gene ccdc11 in left-right patterning and in laterality disorders in humans.axial determination occurs during early stages of embryogenesis. flaws in laterality patterning result in abnormal positioning of visceral organs, as manifested in heterotaxy syndrome, or complete left-right inversion as in situs inversus totalis. these malformations are often associated with ciliopathies, as seen in primary ciliary dyskinesia. we have recently described a novel mutation in the coiled-coil domain-containing 11 (ccdc11) gene associated with laterality disorders in a consanguineou ...201728621423
α-conotoxin [s9a]txid potently discriminates between α3β4 and α6/α3β4 nicotinic acetylcholine receptors.α3β4 nachrs have been implicated in various pathophysiological conditions. however, the expression profile of α3β4 nachrs and α6/α3β4 nachrs overlap in a variety of tissues. to distinguish between these two subtypes, we redesigned peptide 1 (α-conotoxin txid), which inhibits α3β4 and α6/α3β4 nachr subtypes. we systematically mutated 1 to evaluate analogue selectivity for α3β4 vs α6/α3β4 nachrs expressed in xenopus laevis oocytes. one analogue, peptide 7 ([s9a]txid), had 46-fold greater potency f ...201728603989
tgf-β family signaling in early vertebrate development.tgf-β family ligands function in inducing and patterning many tissues of the early vertebrate embryonic body plan. nodal signaling is essential for the specification of mesendodermal tissues and the concurrent cellular movements of gastrulation. bone morphogenetic protein (bmp) signaling patterns tissues along the dorsal-ventral axis and simultaneously directs the cell movements of convergence and extension. after gastrulation, a second wave of nodal signaling breaks the symmetry between the lef ...201728600394
xenopus pitx3 target genes lhx1 and xnr5 are identified using a novel three-fluor flow cytometry-based analysis of promoter activation and repression.pitx3 plays a well understood role in directing development of lens, muscle fiber, and dopaminergic neurons; however, in xenopus laevis, it may also play a role in early gastrulation and somitogenesis. potential downstream targets of pitx3 possess multiple binding motifs that would not be readily accessible by conventional promoter analysis.201728598520
hplc-based activity profiling for gabaa receptor modulators in extracts: validation of an approach utilizing a larval zebrafish locomotor assay.gamma-aminobutyric acid type a (gabaa) receptors are major inhibitory neurotransmitter receptors in the central nervous system and a target for numerous clinically important drugs used to treat anxiety, insomnia, and epilepsy. a series of allosteric gabaa receptor agonists was identified previously with the aid of hplc-based activity profiling, whereby activity was tracked with an electrophysiological assay in xenopus laevis oocytes. to accelerate the discovery process, an approach has been esta ...201728485933
the role of nitric oxide during embryonic epidermis development of xenopus laevis.nitric oxide (no) is a potent radical molecule that participates in various biological processes such as vasodilation, cell proliferation, immune response and neurotransmission. no mainly activates soluble guanylate cyclase, leading to cgmp production and activation of protein kinase g and its downstream targets. here we report the essential role of no during embryonic epidermis development. xenopus embryonic epidermis has become a useful model reflecting human epithelial tissue composition. the ...201728483981
the nodulin 26-like intrinsic membrane protein osnip3;2 is involved in arsenite uptake by lateral roots in rice.previous studies have shown that the nodulin 26-like intrinsic membrane protein (nip) lsi1 (osnip2;1) is involved in arsenite [as(iii)] uptake in rice (oryza sativa). however, the role of other rice nips in as(iii) accumulation in planta remains unknown. in the present study, we investigated the role osnip3;2 in as(iii) uptake in rice. when expressed in xenopus laevis oocytes, osnip3;2 showed a high transport activity for as(iii). quantitative real-time rt-pcr showed that the expression of osnip ...201728505352
neun immunoreactivity in the brain of xenopus laevis.neuronal nuclear antigen (neun), discovered in mice brain cell nuclei by mullen et al. (1992), is used as an excellent marker of post-mitotic neurons in vertebrates. in this study, the expression pattern of neun was examined in the xenopus brain to explore phylogenetic differences in neun expression. anti-neun antibody showed selective staining in mouse and xenopus brain extracts, but the number and molecular weight of the bands differed in western blotting analysis. in immunostaining, anti-neun ...201728558928
opposing effects of valproic acid treatment mediated by histone deacetylase inhibitor activity in four transgenic x. laevis models of retinitis pigmentosa.retinitis pigmentosa (rp) is an inherited retinal degeneration (rd) that leads to blindness for which no treatment is available. rp is frequently caused by mutations in rhodopsin; in some animal models, rd is exacerbated by light. valproic acid (vpa) is a proposed treatment for rp and other neurodegenerative disorders, with a phase ii trial for rp under way. however, the therapeutic mechanism is unclear, with minimal research supporting its use in rp. we investigated the effects of vpa on xenopu ...201728490005
co-accumulation of cis-regulatory and coding mutations during the pseudogenization of the xenopus laevis homoeologs six6.l and six6.s.common models for the evolution of duplicated genes after genome duplication are subfunctionalization, neofunctionalization, and pseudogenization. although the crucial roles of cis-regulatory mutations in subfunctionalization are well-documented, their involvement in pseudogenization and/or neofunctionalization remains unclear. we addressed this issue by investigating the evolution of duplicated homeobox genes, six6.l and six6.s, in the allotetraploid frog xenopus laevis. based on a comparative ...201728501477
mutation of the inhibitory ethanol site in gabaa ρ1 receptors promotes tolerance to ethanol-induced motor incoordination.genes encoding the ρ1/2 subunits of gabaa receptors have been associated with alcohol (ethanol) dependence in humans, and ρ1 was also shown to regulate some of the behavioral effects of ethanol in animal models. ethanol inhibits gaba-mediated responses in wild-type (wt) ρ1, but not ρ1(t6'y) mutant receptors expressed in xenopus laevis oocytes, indicating the presence of an inhibitory site for ethanol in the second transmembrane helix. in this study, we found that ρ1(t6'y) receptors expressed in ...201728623169
two-electrode voltage-clamp recordings in xenopus laevis oocytes: reconstitution of abscisic acid activation of slac1 anion channel via pyl9 aba receptor.two-electrode voltage-clamp (tevc) recording in xenopus laevis oocytes provides a powerful method to investigate the functions and regulation of ion channel proteins. this approach provides a well-known tool to characterize ion channels or transporters expressed in xenopus laevis oocytes. the plasma membrane of the oocyte is impaled by two microelectrodes, one for voltage sensing and the other one for current injection. here we list a protocol that allows robust reconstitution of multi-component ...201728516122
functional assessment of sodium chloride cotransporter ncc mutants in polarized mammalian epithelial cells.the thiazide-sensitive sodium chloride cotransporter ncc is important for maintaining serum sodium (na+) and, indirectly, serum potassium (k+) levels. functional studies on ncc have used cell lines with native ncc expression, transiently transfected nonpolarized cell lines, or xenopus laevis oocytes. here, we developed the use of polarized madin-darby canine kidney type i (mdcki) mammalian epithelial cell lines with tetracycline-inducible human ncc expression to study ncc activity and membrane a ...201728515174
quercetin, morin, luteolin, and phloretin are dietary flavonoid inhibitors of monocarboxylate transporter 6.monocarboxylate transporter 6 (mct6; slc16a5) has been recognized for its role as a xenobiotic transporter, with characterized substrates probenecid, bumetanide, and nateglinide. to date, the impact of commonly ingested dietary compounds on mct6 function has not been investigated, and therefore, the objective of this study was to evaluate a variety of flavonoids for their potential mct6-specific interactions. flavonoids are a large group of polyphenolic phytochemicals found in commonly consumed ...201728513167
the gliotransmitter d-serine promotes synapse maturation and axonal stabilization in vivo.the nmdar is thought to play a key role in the refinement of connectivity in developing neural circuits. pharmacological blockade or genetic loss-of-function manipulations that prevent nmdar function during development result in the disorganization of topographic axonal projections. however, because nmdars contribute to overall glutamatergic neurotransmission, such loss-of-function experiments fail to adequately distinguish between the roles played by nmdars and neural activity in general. the g ...201728550169
mechanosensory stimulation evokes acute concussion-like behavior by activating girks coupled to muscarinic receptors in a simple vertebrate.most vertebrates show concussion responses when their heads are hit suddenly by heavy objects. previous studies have focused on the direct physical injuries to the neural tissue caused by the concussive blow. we study a similar behavior in a simple vertebrate, the xenopus laevis tadpole. we find that concussion-like behavior can be reliably induced by the mechanosensory stimulation of the head skin without direct physical impacts on the brain. head skin stimulation activates a cholinergic pathwa ...201728462392
the neuronal and astrocytic protein slc38a10 transports glutamine, glutamate, and aspartate, suggesting a role in neurotransmission.in brain cells, glutamine transporters are vital to monitor and control the levels of glutamate and gaba. there are 11 members of the slc38 family of amino acid transporters of which eight have been functionally characterized. here, we report the first histological and functional characterization of the previously orphan member, slc38a10. we used pairwise global sequence alignments to determine the sequence identity between the slc38 family members. slc38a10 was found to share 20-25% transmembra ...201728593130
high-quality frozen extracts of xenopus laevis eggs reveal size-dependent control of metaphase spindle micromechanics.cell-free extracts from unfertilized xenopus laevis eggs offer the opportunity for a variety of biochemical and biophysical assays for analyzing essential cell cycle events such as metaphase spindle assembly. however, the extracts often exhibit substantial variation in quality and have low storage stability, factors that hamper their experimental utility. here we report a simple two-step method for preparing frozen egg extracts that retain spindle assembly activity levels similar to those of fre ...201728592634
identification of α7 nicotinic acetylcholine receptor silent agonists based on the spirocyclic quinuclidine-δ2 -isoxazoline scaffold: synthesis and electrophysiological evaluation.compound 11 (3-(benzyloxy)-1'-methyl-1'-azonia-4h-1'-azaspiro[isoxazole-5,3'-bicyclo[2.2.2]octane] iodide) was selected from a previous set of nicotinic ligands as a suitable model compound for the design of new silent agonists of α7 nicotinic acetylcholine receptors (nachrs). silent agonists evoke little or no channel activation but can induce the α7 desensitized ds state, which is sensitive to a type ii positive allosteric modulator, such as pnu-120596. introduction of meta substituents into t ...201728494140
role of micrornas in zygotic genome activation: modulation of mrna during embryogenesis.a fundamental process occurring during early development is the zygotic genome activation, i.e., the initiation of transcription from the embryonic genome. before that step, cellular processes in the developing embryo are dictated by transcripts produced by the maternal genome and accumulated in the egg during oogenesis. the maternal-to-zygotic transition (mzt) involves both the clearance of maternal rnas and the initiation of transcription of the embryonic genome and is a tightly regulated proc ...201728456956
analysis of active transport by fluorescence recovery after photobleaching.fluorescence recovery after photobleaching (frap) is a well-established experimental technique to study binding and diffusion of molecules in cells. although a large number of analytical and numerical models have been developed to extract binding and diffusion rates from frap recovery curves, active transport of molecules is typically not included in the existing models that are used to estimate these rates. here we present a validated numerical method for estimating diffusion, binding/unbinding ...201728445762
use of xenopus frogs to study renal development/repair.the xenopus genus includes several members of aquatic frogs native to africa but is perhaps best known for the species xenopus laevis and xenopus tropicalis. these species were popularized as model organisms from as early as the 1800s and have been instrumental in expanding several biological fields including cell biology, environmental toxicology, regenerative biology, and developmental biology. in fact, much of what we know about the formation and maturation of the vertebrate renal system has ...201728409343
characterization of the transport activity of sglt2/map17, the renal low-affinity na+-glucose cotransporter.the cotransporter sglt2 is responsible for 90% of renal glucose reabsorption, and we recently showed that map17 appears to work as a required β-subunit. we report in the present study a detailed functional characterization of human sglt2 in coexpression with human map17 in xenopus laevis oocytes. addition of external glucose generates a large inward current in the presence of na, confirming an electrogenic transport mechanism. at a membrane potential of -50 mv, sglt2 affinity constants for gluco ...201728592437
anesthetic synergy between two n-alkanes.n-butane and n-pentane can both produce general anesthesia. both compounds potentiate γ-aminobutyric acid type a (gabaa) receptor function, but only butane inhibits n-methyl-d-aspartate (nmda) receptors. it was hypothesized that butane and pentane would exhibit anesthetic synergy due to their different actions on ligand-gated ion channels.201728583773
asymmetries in cell division, cell size, and furrowing in the xenopus laevis embryo.asymmetric cell divisions produce two daughter cells with distinct fate. during embryogenesis, this mechanism is fundamental to build tissues and organs because it generates cell diversity. in adults, it remains crucial to maintain stem cells. the enthusiasm for asymmetric cell division is not only motivated by the beauty of the mechanism and the fundamental questions it raises, but has also very pragmatic reasons. indeed, misregulation of asymmetric cell divisions is believed to have dramatic c ...201728409308
asymmetric localization and distribution of factors determining cell fate during early development of xenopus laevis.asymmetric division is a property of eukaryotic cells that is fundamental to the formation of higher life forms. despite its importance, the mechanism behind it remains elusive. asymmetry in the cell is induced by polarization of cell fate determinants that become unevenly distributed among progeny cells. so far dozens of determinants have been identified. xenopus laevis is an ideal system to study asymmetric cell division during early development, because of the huge size of its oocytes and ear ...201728409307
chromosomal passenger complex hydrodynamics suggests chaperoning of the inactive state by nucleoplasmin/nucleophosmin.the chromosomal passenger complex (cpc) is a conserved, essential regulator of cell division. as such, significant anti-cancer drug development efforts have been focused on targeting it, most notably by inhibiting its aurkb kinase subunit. the cpc is activated by aurkb-catalyzed autophosphorylation on multiple subunits, but how this regulates cpc interactions with other mitotic proteins remains unclear. we investigated the hydrodynamic behavior of the cpc in xenopus laevis egg cytosol using sucr ...201728404751
xenopus metamorphosis as a model to study thyroid hormone receptor function during vertebrate developmental transitions.a hormone-dependent developmental transition from aquatic to terrestrial existence occurs in all tetrapod vertebrates, such as birth, hatching, and metamorphosis. thyroid hormones (th) and their receptors (trs) are key players in the tissue transformations comprising vertebrate developmental transitions. the african clawed frog, xenopus, is a premier model for the role of trs in developmental transitions because of the numerous and dramatic th-dependent tissue transformations during metamorphosi ...201728363743
effect of triclosan on anuran development and growth in a larval amphibian growth and development assay.a larval amphibian growth and development assay was performed to evaluate the potential effects of environmentally-relevant concentrations of triclosan (tcs) on amphibian development and growth. xenopus laevis were exposed to tcs 0.0 (control), 6.3, 12.5 and 25.0 μg l-1 (estimated maximum tolerable concentration) until 10 weeks post-metamorphosis. at median metamorphosis time (nieuwkoop and faber stage 62), five larvae per replicate were collected for snout-vent length, hind limb length and body ...201728436085
daphnia magna and xenopus laevis as in vivo models to probe toxicity and uptake of quantum dots functionalized with gh625.the use of quantum dots (qds) for nanomedicine is hampered by their potential toxicologic effects and difficulties with delivery into the cell interior. we accomplished an in vivo study exploiting daphnia magna and xenopus laevis to evaluate both toxicity and uptake of qds coated with the membranotropic peptide gh625 derived from the glycoprotein h of herpes simplex virus and widely used for drug delivery studies. we evaluated and compared the effects of qds and gh625-qds on the survival, uptake ...201728435254
population-specific resequencing associates the atp-binding cassette subfamily c member 4 gene with gout in new zealand māori and pacific men.there is no evidence for a genetic association between organic anion transporters 1-3 (slc22a6, slc22a7, and slc22a8) and multidrug resistance protein 4 (mrp4; encoded by abcc4) with the levels of serum urate or gout. the māori and pacific (polynesian) population of new zealand has the highest prevalence of gout worldwide. the aim of this study was to determine whether any polynesian population-specific genetic variants in slc22a6-8 and abcc4 are associated with gout.201728371506
interaction and developmental activation of two neuroendocrine systems that regulate light-mediated skin pigmentation.lower vertebrates use rapid light-regulated changes in skin colour for camouflage (background adaptation) or during circadian variation in irradiance levels. two neuroendocrine systems, the eye/alpha-melanocyte-stimulating hormone (α-msh) and the pineal complex/melatonin circuits, regulate the process through their respective dispersion and aggregation of pigment granules (melanosomes) in skin melanophores. during development, xenopus laevis tadpoles raised on a black background or in the dark p ...201728371026
cul-2lrr-1 and ubxn-3 drive replisome disassembly during dna replication termination and mitosis.replisome disassembly is the final step of dna replication in eukaryotes, involving the ubiquitylation and cdc48-dependent dissolution of the cmg helicase (cdc45-mcm-gins). using caenorhabditis elegans early embryos and xenopus laevis egg extracts, we show that the e3 ligase cul-2lrr-1 associates with the replisome and drives ubiquitylation and disassembly of cmg, together with the cdc-48 cofactors ufd-1 and npl-4. removal of cmg from chromatin in frog egg extracts requires cul2 neddylation, and ...201728368371
upregulation of matrix metalloproteinase triggers transdifferentiation of retinal pigmented epithelial cells in xenopus laevis: a link between inflammatory response and regeneration.in adult xenopus eyes, when the whole retina is removed, retinal pigmented epithelial (rpe) cells become activated to be retinal stem cells and regenerate the whole retina. in the present study, using a tissue culture model, it was examined whether upregulation of matrix metalloproteinases (mmps) triggers retinal regeneration. soon after retinal removal, xmmp9 and xmmp18 were strongly upregulated in the tissues of the rpe and the choroid. in the culture, mmp expression in the rpe cells correspon ...201728371543
the modulation of two motor behaviors by persistent sodium currents in xenopus laevis tadpoles.persistent sodium currents (inap) are common in neuronal circuitries and have been implicated in several diseases, such as amyotrophic lateral sclerosis (als) and epilepsy. however, the role of inap in the regulation of specific behaviors is still poorly understood. in this study we have characterized inap and investigated its role in the swimming and struggling behavior of xenopus tadpoles. inap was identified in three groups of neurons, namely, sensory rohon-beard neurons (rb neurons), descend ...201728331009
novel short antimicrobial peptide isolated from xenopus laevis skin.a rich source of bioactive peptides, including a large number of antimicrobial peptides, has been found in amphibian skin. in this study, a novel short antimicrobial peptide was purified from xenopus laevis skin and characterised through reversed-phase high-performance liquid chromatography, edman degradation and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. the peptide was composed of six amino acids with a sequence of dedlde and thus named x. laevis antibacteria ...201728299865
when size matters: transient receptor potential vanilloid 4 channel as a volume-sensor rather than an osmo-sensor.mammalian cells are frequently exposed to stressors causing volume changes. the transient receptor potential vanilloid 4 (trpv4) channel translates osmotic stress into ion flux. the molecular mechanism coupling osmolarity to trpv4 activation remains elusive. trpv4 responds to isosmolar cell swelling and osmolarity translated via different aquaporins. trpv4 functions as a volume-sensing ion channel irrespective of the origin of the cell swelling.201728295351
asymmetrically reduced expression of hand1 homeologs involving a single nucleotide substitution in a cis-regulatory element.during vertebrate evolution, whole genome duplications resulted in a number of duplicated genes, some of which eventually changed their expression patterns and/or levels via alteration of cis-regulatory sequences. however, the initial process involved in such cis-regulatory changes remains unclear. therefore, we investigated this process by analyzing the duplicated hand1 genes of xenopus laevis (hand1.l and hand1.s), which were generated by allotetraploidization 17-18 million years ago, and comp ...201728359808
actomyosin-generated tension on cadherin is similar between dividing and non-dividing epithelial cells in early xenopus laevis embryos.epithelia represent a unique situation where polarized cells must maintain sufficiently strong cell-cell contacts to guarantee the epithelial integrity indispensable for barrier functions. nevertheless, epithelia must also keep sufficient plasticity which is crucial during development and morphogenesis. adherens junctions and mechanical forces produced by the actomyosin cytoskeleton are major players for epithelial integrity maintenance and plasticity regulations. to understand how the epitheliu ...201728327558
in situ microprobe single-cell capillary electrophoresis mass spectrometry: metabolic reorganization in single differentiating cells in the live vertebrate (xenopus laevis) embryo.knowledge of single-cell metabolism would provide a powerful look into cell activity changes as cells differentiate to all the tissues of the vertebrate embryo. however, single-cell mass spectrometry technologies have not yet been made compatible with complex three-dimensional changes and rapidly decreasing cell sizes during early development of the embryo. here, we bridge this technological gap by integrating capillary microsampling, microscale metabolite extraction, and capillary electrophores ...201728434226
endocrine disruption by environmental gestagens in amphibians - a short review supported by new in vitro data using gonads of xenopus laevis.endocrine disruption caused by various anthropogenic compounds is of persisting concern, especially for aquatic wildlife, because surface waters are the main sink of these so-called endocrine disruptors (ed). in the past, research focused on (anti)estrogenic, (anti)androgenic, and (anti)thyroidal substances, affecting primarily reproduction and development in vertebrates; however, other endocrine systems might be also targeted by ed. environmental gestagens, including natural progestogens (e.g. ...201728431277
frizzled 3 acts upstream of alcam during embryonic eye development.formation of a functional eye during vertebrate embryogenesis requires different processes such as cell differentiation, cell migration, cell-cell interactions as well as intracellular signalling processes. it was previously shown that the non-canonical wnt receptor frizzled 3 (fzd3) is required for proper eye formation, however, the underlying mechanism is poorly understood. here we demonstrate that loss of fzd3 induces severe malformations of the developing eye and that this defect is phenocop ...201728427856
xenopus egg extract: a powerful tool to study genome maintenance mechanisms.dna repair pathways are crucial to maintain the integrity of our genome and prevent genetic diseases such as cancer. there are many different types of dna damage and specific dna repair mechanisms have evolved to deal with these lesions. in addition to these repair pathways there is an extensive signaling network that regulates processes important for repair, such as cell cycle control and transcription. despite extensive research, dna damage repair and signaling are not fully understood. in vit ...201728427716
teratogenic hazard of bpei-coated silver nanoparticles to xenopus laevis.silver nanoparticles (agnps) are among the most exploited antimicrobial agents and are used in many consumer products. size and surface reactivity are critical physico-chemical properties responsible for nps toxicity, and surface coatings, often used to functionalize or stabilize agnps, can influence their toxic profile and biocompatibility. in the current study the developmental toxicity of (1) negatively charged citrate-coated agnps (cit-agnps), (2) positively charged branched polyethylenimine ...201728318347
characterization of microtubule buckling in living cells.microtubules are filamentous biopolymers involved in essential biological processes. they form key structures in eukaryotic cells, and thus it is very important to determine the mechanisms involved in the formation and maintenance of the microtubule network. microtubule bucklings are transient and localized events commonly observed in living cells and characterized by a fast bending and its posterior relaxation. active forces provided by molecular motors have been indicated as responsible for mo ...201728424847
the heterochronic gene lin28 regulates amphibian metamorphosis through disturbance of thyroid hormone function.metamorphosis is a classic example of developmental transition, which involves important morphological and physiological changes that prepare the organism for the adult life. it has been very well established that amphibian metamorphosis is mainly controlled by thyroid hormone (th). here, we show that the heterochronic gene lin28 is downregulated during xenopus laevis metamorphosis. lin28 overexpression before activation of th signaling delays metamorphosis and inhibits the expression of th targ ...201728359807
paxillin and embryonic polyadenylation binding protein (epabp) engage to regulate androgen-dependent xenopus laevis oocyte maturation - a model of kinase-dependent regulation of protein expression.steroid-triggered xenopus laevis oocyte maturation is an elegant physiologic model of nongenomic steroid signaling, as it proceeds completely independent of transcription. we previously demonstrated that androgens are the main physiologic stimulator of oocyte maturation in xenopus oocytes, and that the adaptor protein paxillin plays a crucial role in mediating this process through a positive feedback loop in which paxillin first enhances mos protein translation, ensued by erk2 activation and erk ...201728359799
pkc-mediated phosphorylation of nuclear lamins at a single serine residue regulates interphase nuclear size in xenopus and mammalian cells.how nuclear size is regulated is a fundamental cell-biological question with relevance to cancers, which often exhibit enlarged nuclei. we previously reported that conventional protein kinase c (cpkc) contributes to nuclear size reductions that occur during early xenopus development. here we report that pkc-mediated phosphorylation of lamin b3 (lb3) contributes to this mechanism of nuclear size regulation. by mapping pkc phosphorylation sites on lb3 and testing the effects of phosphomutants in x ...201728356420
spemann organizer transcriptome induction by early beta-catenin, wnt, nodal, and siamois signals in xenopus laevis.the earliest event in xenopus development is the dorsal accumulation of nuclear β-catenin under the influence of cytoplasmic determinants displaced by fertilization. in this study, a genome-wide approach was used to examine transcription of the 43,673 genes annotated in the xenopus laevis genome under a variety of conditions that inhibit or promote formation of the spemann organizer signaling center. loss of function of β-catenin with antisense morpholinos reproducibly reduced the expression of ...201728348214
osptr7 (osnpf8.1), a putative peptide transporter in rice, is involved in dimethylarsenate accumulation in rice grain.rice (oryza sativa) is a major dietary source of arsenic (as) for the population consuming rice as their staple food. rice grain contains both inorganic as and methylated as species, especially dimethyarsinate (dma). dma is highly mobile in long-distance translocation in plants, but the underlying mechanism remains unknown. in the present study, we showed that osptr7 (osnpf8.1), a putative peptide transporter in rice, was permeable to dma in xenopus laevis oocytes. transient expression of the os ...201728340032
jak-stat pathway activation in response to spinal cord injury in regenerative and non-regenerative stages of xenopus laevis.xenopus laevis tadpoles can regenerate the spinal cord after injury but this capability is lost during metamorphosis. comparative studies between pre-metamorphic and metamorphic xenopus stages can aid towards understanding the molecular mechanisms of spinal cord regeneration. analysis of a previous transcriptome-wide study suggests that, in response to injury, the jak-stat pathway is differentially activated in regenerative and non-regenerative stages. we characterized the activation of the jak- ...201728316792
glycans in the intestinal peptide transporter pept1 contribute to function and protect from proteolysis.despite the fact that many membrane proteins carry extracellular glycans, little is known about whether the glycan chains also affect protein function. we recently demonstrated that the proton-coupled oligopeptide transporter 1 (pept1) in the intestine is glycosylated at six asparagine residues (n50, n406, n439, n510, n515, and n532). mutagenesis-induced disruption of the individual n-glycosylation site n50, which is highly conserved among mammals, was detected to significantly enhance the pept1 ...201728336547
masculinization-related genes and cell-mass structures during early gonadal differentiation in the african clawed frog xenopus laevis.the african clawed frog xenopus laevis has a female heterogametic zz/zw-type sex-determining system. we previously discovered a w-linked female sex-determining gene dm-w that is involved in ovary formation, probably through the up-regulation of the estrogen synthesis genes cyp19a1 and foxl2. we also reported that a unique "mass-in-line structure", which disappears from zz gonads during early testicular development, might serve as the basis for ovary differentiation in zw gonads. however, the mol ...201728397603
pattern of neurogenesis and identification of neuronal progenitor subtypes during pallial development in xenopus laevis.the complexity of the pallium during evolution has increased dramatically in many different respects. the highest level of complexity is found in mammals, where most of the pallium (cortex) shows a layered organization and neurons are generated during development following an inside-out order, a sequence not observed in other amniotes (birds and reptiles). species-differences may be related to major neurogenetic events, from the neural progenitors that divide and produce all pallial cells. in ma ...201728396626
the mgcracgap sxip motif tethers centralspindlin to microtubule plus ends in xenopus laevis.centralspindlin, a complex of the kinesin-6-family member mklp1 and mgcracgap (also known as kif23 and racgap1, respectively), is required for cytokinesis and cell-cell junctions. during anaphase, centralspindlin accumulates at overlapping central spindle microtubules and directs contractile ring formation by recruiting the gef ect2 to the cell equator to activate rhoa. we found that mgcracgap localized to the plus ends of equatorial astral microtubules during cytokinesis in xenopus laevis embry ...201728389580
clinical and genetic spectrum of bartter syndrome type 3.bartter syndrome type 3 is a clinically heterogeneous hereditary salt-losing tubulopathy caused by mutations of the chloride voltage-gated channel kb gene (clcnkb), which encodes the clc-kb chloride channel involved in nacl reabsorption in the renal tubule. to study phenotype/genotype correlations, we performed genetic analyses by direct sequencing and multiplex ligation-dependent probe amplification and retrospectively analyzed medical charts for 115 patients with clcnkb mutations. functional a ...201728381550
a dominant mutation in nuclear receptor interacting protein 1 causes urinary tract malformations via dysregulation of retinoic acid signaling.congenital anomalies of the kidney and urinary tract (cakut) are the most common cause of ckd in the first three decades of life. however, for most patients with cakut, the causative mutation remains unknown. we identified a kindred with an autosomal dominant form of cakut. by whole-exome sequencing, we identified a heterozygous truncating mutation (c.279delg, p.trp93fs*) of the nuclear receptor interacting protein 1 gene (nrip1) in all seven affected members. nrip1 encodes a nuclear receptor tr ...201728381549
multiple origins of embryonic and tadpole myeloid cells in xenopus laevis.rabbit anti-serum against a myeloid-cell-specific peroxidase (mpo) of xenopus laevis was generated to identify myeloid cells in adult and larval animals. smears of blood samples from adult hematopoietic organs were co-stained with mpo and with xl-2, a mouse monoclonal antibody against a leukocyte common antigen. lymphocytes found in the thymus and spleen were xl-2+mpo- and granulocytes found in peripheral blood cells and the spleen were xl-2+mpo+, indicating that double-staining with these two a ...201728374149
a cellular mechanism for inverse effectiveness in multisensory integration.to build a coherent view of the external world, an organism needs to integrate multiple types of sensory information from different sources, a process known as multisensory integration (msi). previously, we showed that the temporal dependence of msi in the optic tectum of xenopus laevis tadpoles is mediated by the network dynamics of the recruitment of local inhibition by sensory input (felch et al., 2016). this was one of the first cellular-level mechanisms described for msi. here, we expand th ...201728315524
direct regulation of histidine ammonia-lyase 2 gene by thyroid hormone in the developing adult intestinal stem cells.most vertebrate organs use adult stem cells to maintain homeostasis and ensure proper repair when damaged. how such organ-specific stem cells are formed during vertebrate development is largely unexplored. we have been using the thyroid hormone (t3)-dependent amphibian metamorphosis to address this issue. early studies in xenopus laevis have shown that intestinal remodeling involves complete degeneration of the larval epithelium and de novo formation of adult stem cells through dedifferentiation ...201728323994
sall1 and sall4 repress pou5f3 family expression to allow neural patterning, differentiation, and morphogenesis in xenopus laevis.the embryonic precursor of the vertebrate central nervous system, the neural plate, is patterned along the anterior-posterior axis and shaped by morphogenetic movements early in development. we previously identified the genes sall1 and sall4, known regulators of pluripotency in other contexts, as transcriptional targets of developmental signaling pathways that regulate neural development. here, we demonstrate that these two genes are required for induction of posterior neural fates, the cell sha ...201728322736
functional organization of vestibulo-ocular responses in abducens motoneurons.vestibulo-ocular reflexes (vors) are the dominating contributors to gaze stabilization in all vertebrates. during horizontal head movements, abducens motoneurons form the final element of the reflex arc that integrates visuovestibular inputs into temporally precise motor commands for the lateral rectus eye muscle. here, we studied a possible differentiation of abducens motoneurons into subtypes by evaluating their morphology, discharge properties, and synaptic pharmacology in semi-intact in vitr ...201728292832
regulatory remodeling in the allo-tetraploid frog xenopus laevis.genome duplication has played a pivotal role in the evolution of many eukaryotic lineages, including the vertebrates. a relatively recent vertebrate genome duplication is that in xenopus laevis, which resulted from the hybridization of two closely related species about 17 million years ago. however, little is known about the consequences of this duplication at the level of the genome, the epigenome, and gene expression.201729065907
interaction of excitatory amino acid transporters 1 - 3 (eaat1, eaat2, eaat3) with n-carbamoylglutamate and n-acetylglutamate.inborn deficiency of the n-acetylglutamate synthase (nags) impairs the urea cycle and causes neurotoxic hyperammonemia. oral administration of n-carbamoylglutamate (ncg), a synthetic analog of n-acetylglutamate (nag), successfully decreases plasma ammonia levels in the affected children. due to structural similarities to glutamate, ncg may be absorbed in the intestine and taken up into the liver by excitatory amino acid transporters (eaats).201729055942
maturation of xenopus laevis oocytes under cadmium and lead exposures: cell biology investigations.since amphibians are recognised as good models to assess the quality of environments, only few studies have dealt with the impacts of chemical contaminants on their gametes, while toxic effects at this stage will alter all the next steps of their life cycle. therefore, we propose to investigate the oocyte maturation of xenopus laevis in cadmium- and lead-contaminated conditions. the impacts of cadmium and lead ions were explored on events involved in the hormone-dependent process of maturation. ...201729053961
the brain is required for normal muscle and nerve patterning during early xenopus development.possible roles of brain-derived signals in the regulation of embryogenesis are unknown. here we use an amputation assay in xenopus laevis to show that absence of brain alters subsequent muscle and peripheral nerve patterning during early development. the muscle phenotype can be rescued by an antagonist of muscarinic acetylcholine receptors. the observed defects occur at considerable distances from the head, suggesting that the brain provides long-range cues for other tissue systems during develo ...201728943634
the nitrate transporter family protein ljnpf8.6 controls the n-fixing nodule activity.n-fixing nodules are new organs formed on legume roots as a result of the beneficial interaction with soil bacteria, rhizobia. the nodule functioning is still a poorly characterized step of the symbiotic interaction, as only a few of the genes induced in n-fixing nodules have been functionally characterized. we present here the characterization of a member of the lotus japonicus nitrate transporter1/peptide transporter family, ljnpf8.6 the phenotypic characterization carried out in independent l ...201728931627
beyond mouse cancer models: three-dimensional human-relevant in vitro and non-mammalian in vivo models for photodynamic therapy.the proper design of experiments is a critical step for each study in order to obtain reproducible and reliable data. taking into account constant competitiveness in the quickly developing biomedical sciences and the availability of sophisticated techniques, the choice and establishment of an experimental model system are essential for a successful research project. currently, various sophisticated in vitro and in vivo models are being designed and developed in order to replace the use of mammal ...201728927532
identification of regions responsible for the function of the plant k+ channels kat1 and akt2 in saccharomyces cerevisiae and xenopus laevis oocytes.the arabidopsis k+ channel kat1 complements in k+-limited medium the growth of the k+ uptake defective saccharomyces cerevisiae mutant strain cy162, while another k+ channel, akt2, does not. to gain insight into the structural basis for this difference, we constructed 12 recombinant chimeric channels from these two genes. when expressed in cy162, only three of these chimeras fully rescued the growth of cy162 under k+-limited conditions. we conclude that the transmembrane core region of kat1 is i ...201728933647
rare gabra3 variants are associated with epileptic seizures, encephalopathy and dysmorphic features.genetic epilepsies are caused by mutations in a range of different genes, many of them encoding ion channels, receptors or transporters. while the number of detected variants and genes increased dramatically in the recent years, pleiotropic effects have also been recognized, revealing that clinical syndromes with various degrees of severity arise from a single gene, a single mutation, or from different mutations showing similar functional defects. accordingly, several genes coding for gabaa rece ...201729053855
comparative early life stage toxicity of the african clawed frog, xenopus laevis following exposure to selected herbicide formulations applied to eradicate alien plants in south africa.the rise in pesticides application has increased the need for better understanding of their ecological impacts. the global amphibian declines, for example, have been positively correlated with pesticides use. the differential susceptibility in the developmental stages of amphibians to chemical substances are still largely unknown. we examined the 96-h differential toxicity responses of embryos, premetamorphic and transitional larval stage of xenopus laevis, to six formulated aquatic herbicide pr ...201729051999
a molecular atlas of the developing ectoderm defines neural, neural crest, placode, and nonneural progenitor identity in vertebrates.during vertebrate neurulation, the embryonic ectoderm is patterned into lineage progenitors for neural plate, neural crest, placodes and epidermis. here, we use xenopus laevis embryos to analyze the spatial and temporal transcriptome of distinct ectodermal domains in the course of neurulation, during the establishment of cell lineages. in order to define the transcriptome of small groups of cells from a single germ layer and to retain spatial information, dorsal and ventral ectoderm was subdivid ...201729049289
geraniin is a diuretic by inhibiting the na+:k+:2cl- cotransporter, nkcc2.geranium seemannii peyr is a perennial plant endemic in central mexico that has been widely used for its diuretic effect, but the responsible compound of this effect is unknown as well as the mechanism by which the diuretic effect is achieved. geraniin is one of the compounds isolated from this kind of geranium. this study was designed to determinate whether geraniin possesses diuretic activity and to elucidate the mechanism of action. geraniin was extracted and purified from geranium seemannii ...201729046296
differentiation-dependent antiviral capacities of amphibian (xenopus laevis) macrophages.infections by ranaviruses such as frog virus 3 (fv3) are significantly contributing to the worldwide amphibian population declines. notably, amphibian macrophages (mφs) are important to both the fv3 infection strategies and the immune defense against this pathogen. however, the mechanisms underlying amphibian mφ fv3 susceptibility and resistance remain unknown. mφ differentiation is mediated by signaling through the colony-stimulating factor-1 receptor (csf-1r), which is now known to be bound by ...201729259133
tight junctions negatively regulate mechanical forces applied to adherens junctions in vertebrate epithelial tissue.epithelia are layers of polarised cells tightly bound to each other by adhesive contacts. epithelia act as barriers between an organism and its external environment. understanding how epithelia maintain their essential integrity while remaining sufficiently plastic to allow events such as cytokinesis to take place is a key biological problem. in vertebrates, the remodelling and reinforcement of adherens junctions maintains epithelial integrity during cytokinesis. the involvement of tight junctio ...201729246943
metabolic comparison of dorsal versus ventral cells directly in the live 8-cell frog embryo by microprobe single-cell ce-esi-ms.single-cell mass spectrometry (ms) empowers the characterization of metabolomic changes as cells differentiate to different tissues during early embryogenesis. using whole-cell dissection and capillary electrophoresis electrospray ionization (ce-esi) ms, we recently uncovered metabolic cell-to-cell differences in the 8- and 16-cell embryo of the south african clawed frog (xenopus laevis), raising the question whether metabolic cell heterogeneity is also detectable across the dorsal-ventral axis ...201729062391
biophysical characterization of genetically encoded voltage sensor asap1: dynamic range improvement.recent work has introduced a new fluorescent voltage sensor, asap1, which can monitor rapid trains of action potentials in cultured neurons. this indicator is based on the gallus gallus voltage-sensitive phosphatase with the phosphatase domain removed and a circularly permuted gfp placed in the s3-s4 linker. however, many of the biophysical details of this indicator remain unknown. in this work, we study the biophysical properties of asap1. using the cut-open voltage clamp technique, we have sim ...201729108650
pfkfb4 control of akt signaling is essential for premigratory and migratory neural crest formation.neural crest (nc) specification comprises an early phase, initiating immature nc progenitors formation at neural plate stage, and a later phase at neural fold stage, resulting in a functional premigratory nc that is able to delaminate and migrate. we found that the nc gene regulatory network triggers upregulation of pfkfb4 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4) during this late specification phase. as shown in previous studies, pfkfb4 controls akt signaling in gastrulas and gly ...201729038306
sonic hedgehog antagonists reduce size and alter patterning of the frog inner ear.sonic hedgehog (shh) signaling plays a major role in vertebrate development, from regulation of proliferation to the patterning of various organs. in amniotes, shh affects dorsoventral patterning in the inner ear but affects anteroposterior patterning in teleost ears. it remains unknown how altered function of shh relates to morphogenetic changes that coincide with the evolution of limbs and novel auditory organs in the ear. in this study, we used the tetrapod, xenopus laevis, to test how increa ...201729030893
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