Publications

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extracellular ca2+ is required for fertilization in the african clawed frog, xenopus laevis.the necessity of extracellular ca2+ for fertilization and early embryonic development in the african clawed frog, xenopus laevis, is controversial. ca2+ entry into x. laevis sperm is reportedly required for the acrosome reaction, yet fertilization and embryonic development have been documented to occur in high concentrations of the ca2+ chelator bapta. here we sought to resolve this controversy.201728114360
molecular features of the l-type amino acid transporter 2 determine different import and export profiles for thyroid hormones and amino acids.the l-type amino acid transporter 2 (lat2) imports amino acids (aa) and also certain thyroid hormones (th), e.g. 3,3'-t2 and t3, but not rt3 and t4. we utilized lat2 mutations (y130a, n133s, f242w) that increase 3,3'-t2 import and focus here on import and export capacity for aa, t4, t3, bch and derivatives thereof to delineate molecular features. transport studies and analysis of competitive inhibition of import by radiolabelled th and aa were performed in xenopus laevis oocytes. only y130a, a p ...201728108384
diclofenac can exhibit estrogenic modes of action in male xenopus laevis, and affects the hypothalamus-pituitary-gonad axis and mating vocalizations.diclofenac (dcf) is a non-steroidal analgesic and antiphlogistic. due to its tremendous use, dcf can be found in the environment, especially in sewage, but also surface waters, ground and drinking water. previous studies indicated that dcf can modulate the reproductive physiology of fish by altering the expression of important key enzymes of the hypothalamus-pituitary-gonad-axis (hpg-axis) and might act as an estrogenic endocrine disrupting chemical (edc). other studies, however, demonstrated th ...201728107717
the nedd4 binding protein 3 is required for anterior neural development in xenopus laevis.the fezzin family member nedd4-binding protein 3 (n4bp3) is known to regulate axonal and dendritic branching. here, we show that n4bp3 is expressed in the neural tissue of the early xenopus laevis embryo including the eye, the brain and neural crest cells. knockdown of n4bp3 in the xenopus anterior neural tissue results in severe developmental impairment of the eye, the brain and neural crest derived cranial cartilage structures. moreover, we demonstrate that n4bp3 depletion leads to a significa ...201728104388
spinal cord regeneration in xenopus laevis.here we present a protocol for the husbandry of xenopus laevis tadpoles and froglets, and procedures to study spinal cord regeneration. this includes methods to induce spinal cord injury (sci); dna and morpholino electroporation for genetic studies; in vivo imaging for cell analysis; a swimming test to measure functional recovery; and a convenient model for screening for new compounds that promote neural regeneration. these protocols establish x. laevis as a unique model organism for understandi ...201728102835
automated mitotic spindle tracking suggests a link between spindle dynamics, spindle orientation, and anaphase onset in epithelial cells.proper spindle positioning at anaphase onset is essential for normal tissue organization and function. here we develop automated spindle-tracking software and apply it to characterize mitotic spindle dynamics in the xenopus laevis embryonic epithelium. we find that metaphase spindles first undergo a sustained rotation that brings them on-axis with their final orientation. this sustained rotation is followed by a set of striking stereotyped rotational oscillations that bring the spindle into near ...201728100633
scaling of pattern formations and morphogen gradients.the concentration gradient of morphogens provides positional information for an embryo and plays a pivotal role in pattern formation of tissues during the developmental processes. morphogen-dependent pattern formations show robustness despite various perturbations. although tissues usually grow and dynamically change their size during histogenesis, proper patterns are formed without the influence of size variations. furthermore, even when the blastula embryo of xenopus laevis is bisected into do ...201728097650
high-throughput analysis reveals novel maternal germline rnas crucial for primordial germ cell preservation and proper migration.during oogenesis, hundreds of maternal rnas are selectively localized to the animal or vegetal pole, including determinants of somatic and germline fates. although microarray analysis has identified localized determinants, it is not comprehensive and is limited to known transcripts. here, we utilized high-throughput rna-sequencing analysis to comprehensively interrogate animal and vegetal pole rnas in the fully grown xenopus laevis oocyte. we identified 411 (198 annotated) and 27 (15 annotated) ...201728096217
xenopus as a model for studies in mechanical stress and cell division.we exist in a physical world, and cells within biological tissues must respond appropriately to both environmental forces and forces generated within the tissue to ensure normal development and homeostasis. cell division is required for normal tissue growth and maintenance, but both the direction and rate of cell division must be tightly controlled to avoid diseases of over-proliferation such as cancer. recent studies have shown that mechanical cues can cause mitotic entry and orient the mitotic ...201728095623
tools for live imaging of active rho gtpases in xenopus.rho family gtpases are signaling molecules that orchestrate cytoskeletal dynamics in a variety of cellular processes. because they effect localized changes to the cytoskeleton only in their active (gtp-bound) conformation, the ability to monitor the active state of rho gtpases in space and time is critical for understanding their function. here, we summarize popular tools used for live imaging of active rho gtpases, outlining advantages and drawbacks of these approaches. additionally, we highlig ...201728095620
xenopus egg extract to study regulation of genome-wide and locus-specific dna replication.faithful dna replication, coupled with accurate repair of dna damage, is essential to maintain genome stability and relies on different dna metabolism genes. many of these genes are involved in the assembly of replication origins, in the coordination of dna repair to protect replication forks progression in the presence of dna damage and in the replication of repetitive chromatin regions. some dna metabolism genes are essential in higher eukaryotes, suggesting the existence of specialized mechan ...201728095613
xenopus laevis as a model system to study cytoskeletal dynamics during axon pathfinding.the model system, xenopus laevis, has been used in innumerable research studies and has contributed to the understanding of multiple cytoskeletal components, including actin, microtubules, and neurofilaments, during axon pathfinding. xenopus developmental stages have been widely characterized, and the xenopus genome has been sequenced, allowing gene expression modifications through exogenous molecules. xenopus cell cultures are ideal for long periods of live imaging because they are easily obtai ...201728095612
quantifying the relative contributions of different solute carriers to aggregate substrate transport.determining the contributions of different transporter species to overall cellular transport is fundamental for understanding the physiological regulation of solutes. we calculated the relative activities of solute carrier (slc) transporters using the michaelis-menten equation and global fitting to estimate the normalized maximum transport rate for each transporter (vmax). data input were the normalized measured uptake of the essential neutral amino acid (aa) l-leucine (leu) from concentration-d ...201728091567
high variability of expression profiles of homeologous genes for wnt, hh, notch, and hippo signaling pathways in xenopus laevis.cell signaling pathways, such as wnt, hedgehog (hh), notch, and hippo, are essential for embryogenesis, organogenesis, and tissue homeostasis. in this study, we analyzed 415 genes involved in these pathways in the allotetraploid frog, xenopus laevis. most genes are retained in two subgenomes called l and s (193 homeologous gene pairs and 29 singletons). this conservation rate of homeologs is much higher than that of all genes in the x. laevis genome (86.9% vs 60.2%). among singletons, 24 genes a ...201728089430
reassessment of glut7 and glut9 as putative fructose and glucose transporters.although increased dietary fructose consumption is associated with metabolic impairments, the mechanisms and regulation of intestinal fructose absorption are poorly understood. glut5 is considered to be the main intestinal fructose transporter. other glut family members, such as glut7 and glut9 are also expressed in the intestine and were shown to transport fructose and glucose. a conserved isoleucine-containing motif (nxi) was proposed to be essential for fructose transport capacity of glut7 an ...201728083649
calpain-mediated proteolysis of talin and fak regulates adhesion dynamics necessary for axon guidance.guidance of axons to their proper synaptic target sites requires spatially and temporally precise modulation of biochemical signals within growth cones. ionic calcium (ca2+) is an essential signal for axon guidance that mediates opposing effects on growth cone motility. the diverse effects of ca2+ arise from the precise localization of ca2+ signals into microdomains containing specific ca2+ effectors. for example, differences in the mechanical and chemical composition of the underlying substrata ...201728069919
de novo mutations in smchd1 cause bosma arhinia microphthalmia syndrome and abrogate nasal development.bosma arhinia microphthalmia syndrome (bams) is an extremely rare and striking condition characterized by complete absence of the nose with or without ocular defects. we report here that missense mutations in the epigenetic regulator smchd1 mapping to the extended atpase domain of the encoded protein cause bams in all 14 cases studied. all mutations were de novo where parental dna was available. biochemical tests and in vivo assays in xenopus laevis embryos suggest that these mutations may behav ...201728067911
mefloquine inhibits voltage dependent nav1.4 channel by overlapping the local anaesthetic binding site.mefloquine constitutes a multitarget antimalaric that inhibits cation currents. however, the effect and the binding site of this compound on na+ channels is unknown. to address the mechanism of action of mefloquine, we employed two-electrode voltage clamp recordings on xenopus laevis oocytes, site-directed mutagenesis of the rat na+ channel, and a combined in silico approach using molecular dynamics and docking protocols. we found that mefloquine: i) inhibited nav1.4 currents (ic50 =60μm), ii) s ...201728057491
eomesodermin-at dawn of cell fate decisions during early embryogenesis.proteins of the large family of t-box transcription factors are implicated in a broad spectrum of developmental processes. loss-of-function mutations of t-box(tbx) factors frequently cause severe embryonic phenotypes, often resulting from defects in cell fate specification and lineage differentiation. this review summarizes current knowledge on the functions of the t-box transcription factor eomesodermin (eomes) from postfertilization development until gastrulation stages of vertebrate embryos. ...201728057273
mutations in gabrb3: from febrile seizures to epileptic encephalopathies.to examine the role of mutations in gabrb3 encoding the β3 subunit of the gabaa receptor in individual patients with epilepsy with regard to causality, the spectrum of genetic variants, their pathophysiology, and associated phenotypes.201728053010
global decay of mrna is a hallmark of apoptosis in aging xenopus eggs.cytoplasmic mrnas are specifically degraded in somatic cells as a part of early apoptotic response. however, no reports have been presented so far concerning mrna fate in apoptotic gametes. in the present study, we analyzed the content of various cytoplasmic mrnas in aging oocytes and eggs of the african clawed frog, xenopus laevis. to circumvent large gene expression variation among the individual oocytes and eggs, single-cell monitoring of transcript levels has been implemented, using multiple ...201728045588
apetx4, a novel sea anemone toxin and a modulator of the cancer-relevant potassium channel kv10.1.the human ether-à-go-go channel (heag1 or kv10.1) is a cancer-relevant voltage-gated potassium channel that is overexpressed in a majority of human tumors. peptides that are able to selectively inhibit this channel can be lead compounds in the search for new anticancer drugs. here, we report the activity-guided purification and electrophysiological characterization of a novel kv10.1 inhibitor from the sea anemone anthopleura elegantissima. purified sea anemone fractions were screened for inhibit ...201728902151
depolarization of the conductance-voltage relationship in the nav1.5 mutant, e1784k, is due to altered fast inactivation.e1784k is the most common mixed long qt syndrome/brugada syndrome mutant in the cardiac voltage-gated sodium channel nav1.5. e1784k shifts the midpoint of the channel conductance-voltage relationship to more depolarized membrane potentials and accelerates the rate of channel fast inactivation. the depolarizing shift in the midpoint of the conductance curve in e1784k is exacerbated by low extracellular ph. we tested whether the e1784k mutant shifts the channel conductance curve to more depolarize ...201728898267
the effect of 4-hydroxybenzaldehyde on the γ-aminobutyric acid type a receptor.the α1β2γ2 subtype of gabaa receptors is the most commonly found gabaa receptor subtype in the mammalian cortex and hippocampus. it is expressed heterologously in the xenopus laevis oocyte as a α1β2γ2s/l subtype for application as an in vitro model for the screening of compounds that modulate receptor activities. in fact, 4-hydroxybenzaldehyde (4-hb) has been identified as one of the major components in dendrocalamus asper bamboo shoots in our previous study, and the current study showed that at ...201728894409
ultrafast flavin photoreduction in an oxidized animal (6-4) photolyase through an unconventional tryptophan tetrad.photolyases are flavoenzymes repairing uv-induced lesions in dna, which may be activated by a photoreduction of their fad cofactor. in most photolyases, this photoreduction proceeds by electron transfer along a chain of three tryptophan (trp) residues, connecting the flavin to the protein surface. much less studied, animal (6-4) photolyases (repairing pyrimidine-pyrimidone (6-4) photoproducts) are particularly interesting as they were recently shown to have a longer electron transfer chain, coun ...201728890968
sumo co-expression modifies kv 11.1 channel activity.the voltage-gated potassium channel kv 11.1 is the molecular basis for the ikr current, which plays an important role in cardiac physiology. its malfunction is associated with both inherited and acquired cardiac arrhythmias. native currents differ from those in experimental models, suggesting additional regulatory mechanisms. we hypothesized that the post-translational modification sumoylation fine-tunes channel activity.201728888063
interleukin-11 induces and maintains progenitors of different cell lineages during xenopus tadpole tail regeneration.unlike mammals, xenopus laevis tadpoles possess high ability to regenerate their lost organs. in amphibians, the main source of regenerated tissues is lineage-restricted tissue stem cells, but the mechanisms underlying induction, maintenance and differentiation of these stem/progenitor cells in the regenerating organs are poorly understood. we previously reported that interleukin-11 (il-11) is highly expressed in the proliferating cells of regenerating xenopus tadpole tails. here, we show that i ...201728887447
dextmp: deep dive into text for predicting moonlighting proteins.moonlighting proteins (mps) are an important class of proteins that perform more than one independent cellular function. mps are gaining more attention in recent years as they are found to play important roles in various systems including disease developments. mps also have a significant impact in computational function prediction and annotation in databases. currently mps are not labeled as such in biological databases even in cases where multiple distinct functions are known for the proteins. ...201728881966
loss of fourth electron-transferring tryptophan in animal (6-4) photolyase impairs dna repair activity in bacterial cells.(6-4) photolyases [(6-4)pls] are flavoproteins that use blue light to repair the ultraviolet-induced pyrimidine(6-4)pyrimidone photoproduct in dna. their flavin adenine dinucleotide (fad) cofactor can be reduced to its repair-active fadh- form by a photoinduced electron transfer reaction. in animal (6-4)pls, a chain of four trp residues was suggested to be involved in a stepwise transfer of an oxidation hole from the flavin to the surface of the protein. here, we investigated the effect of mutat ...201728880077
methylisothiazolinone toxicity and inhibition of wound healing and regeneration in planaria.methylisothiazolinone (mit) is a common biocide used in cosmetic and industrial settings. studies have demonstrated that mit is a human sensitizer, to the extent that in 2013 mit was named allergen of the year. recently, we showed that mit exposure in xenopus laevis (the african clawed frog) inhibits wound healing and tail regeneration. however, it is unknown whether mit affects these processes in other animals. here, we investigated the effects of mit exposure in planaria-non-parasitic freshwat ...201728869924
in vitro reconstitution of the endoplasmic reticulum.reconstitution of cellular organelles in vitro offers the possibility to perform quantitative and qualitative experiments in a controlled environment that cannot be done with the same accuracy in living cells. following a previous report, the subsequent list of protocols describes how to reconstitute and quantify a tubular er network in vitro based on purified microsomes from culture cells and cytosol from xenopus laevis egg extracts. biological material preparation and reconstitution assays req ...201728862340
advances in the use of xenopus for successful drug screening.understanding embryogenesis currently relies largely on the control of gene expression via several signaling pathways. many of the embryonic signaling pathways guiding embryological events are implicated in diseases that lack effective cure or treatment. because of the large number and size of the eggs, the rapid development of the embryos and the fact they are amenable to pharmacological, surgical and genetic techniques, xenopus laevis has been successfully used in searching for compounds that ...201728846034
dual control of pcdh8l/pcns expression and function in xenopus laevis neural crest cells by adam13/33 via the transcription factors tfap2α and arid3a.adam13/33 is a cell surface metalloprotease critical for cranial neural crest (cnc) cell migration. it can cleave multiple substrates including itself, fibronectin, ephrinb, cadherin-11, pcdh8 and pcdh8l (this work). cleavage of cadherin-11 produces an extracellular fragment that promotes cnc migration. in addition, the adam13 cytoplasmic domain is cleaved by gamma secretase, translocates into the nucleus and regulates multiple genes. here, we show that adam13 interacts with the arid3a/dril1/bri ...201728829038
assembly rules for gabaa receptor complexes in the brain.gabaa receptor (gabaar) pentamers are assembled from a pool of 19 subunits, and variety in subunit combinations diversifies gabaar functions to tune brain activity. pentamers with distinct subunit compositions localize differentially at synaptic and non-synaptic sites to mediate phasic and tonic inhibition, respectively. despite multitudes of theoretical permutations, limited subunit combinations have been identified in the brain. currently, no molecular model exists for combinatorial gabaar ass ...201728816653
the crystal structure of full-length sizzled from xenopus laevis yields insights into wnt-antagonistic function of secreted frizzled-related proteins.the wnt-signaling pathway is crucial to cell proliferation, differentiation, and migration. the secreted frizzled-related proteins (sfrps) represent the largest family of secreted wnt inhibitors. however, their function in antagonizing wnt signaling has remained somewhat controversial. here, we report the crystal structure of sizzled from xenopus laevis, the first full-length structure of an sfrp. tethered by an inter-domain disulfide bond and a linker, the n-terminal cysteine-rich domain (crd) ...201728808056
clathrodin, hymenidin and oroidin, and their synthetic analogues as inhibitors of the voltage-gated potassium channels.we have prepared three alkaloids from the agelas sponges, clathrodin, hymenidin and oroidin, and a series of their synthetic analogues, and evaluated their inhibitory effect against six isoforms of the kv1 subfamily of voltage-gated potassium channels, kv1.1-kv1.6, expressed in chinese hamster ovary (cho) cells using automated patch clamp electrophysiology assay. the most potent inhibitor was the (e)-n-(3-(2-amino-1h-imidazol-4-yl)allyl)-4,5-dichloro-1h-pyrrole-2-carboxamide (6g) with ic50 value ...201728802123
both nuclear size and dna amount contribute to midblastula transition timing in xenopus laevis.during early xenopus laevis embryogenesis both nuclear and cell volumes decrease with the nuclear-to-cytoplasmic (n/c) volume ratio reaching a maximum at the midblastula transition (mbt). at the mbt, embryonic transcription is upregulated and cell cycles lengthen. early studies demonstrated a role for the dna-to-cytoplasmic ratio in the control of mbt timing. by altering nuclear size, we previously showed that the n/c volume ratio also contributes to proper mbt timing. here we examine the relati ...201728801588
role of aqp9 in transport of monomethyselenic acid and selenite.aqp9 is an aquaglyceroporin with a very broad substrate spectrum. in addition to its orthodox nutrient substrates, aqp9 also transports multiple neutral and ionic arsenic species including arsenic trioxide, monomethylarsenous acid (masiii) and dimethylarsenic acid (dmav). here we discovered a new group of aqp9 substrates which includes two clinical relevant selenium species. we showed that aqp9 efficiently transports monomethylselenic acid (msea) with a preference for acidic ph, which has been d ...201728798983
in vivo analysis of the neurovascular niche in the developing xenopus brain.the neurovascular niche is a specialized microenvironment formed by the interactions between neural progenitor cells (npcs) and the vasculature. while it is thought to regulate adult neurogenesis by signaling through vascular-derived soluble cues or contacted-mediated cues, less is known about the neurovascular niche during development. in xenopus laevis tadpole brain, npcs line the ventricle and extend radial processes tipped with endfeet to the vascularized pial surface. using in vivo labeling ...201728795134
comprehensive analyses of hox gene expression in xenopus laevis embryos and adult tissues.from whole genome sequencing of an allotetraploid frog, xenopus laevis, two homeologous sets (l and s) of four hox clusters a through d (hoxa.l/s, hoxb.l/s, hoxc.l/s, and hoxd.l/s) and 13 paralogous groups (pgs) with 76 genes were identified, allowing us to carry out the first comprehensive analyses of hox gene expression in vertebrates. expression of all hox genes during development and in adult tissues was analyzed by rna-sequencing. the expression levels of most hox genes were similar between ...201728791673
the α2β2 isoform combination dominates the astrocytic na+ /k+ -atpase activity and is rendered nonfunctional by the α2.g301r familial hemiplegic migraine type 2-associated mutation.synaptic activity results in transient elevations in extracellular k+ , clearance of which is critical for sustained function of the nervous system. the k+ clearance is, in part, accomplished by the neighboring astrocytes by mechanisms involving the na+ /k+ -atpase. the na+ /k+ -atpase consists of an α and a β subunit, each with several isoforms present in the central nervous system, of which the α2β2 and α2β1 isoform combinations are kinetically geared for astrocytic k+ clearance. while transcr ...201728787093
hmmr mediates anterior neural tube closure and morphogenesis in the frog xenopus.development of the central nervous system requires orchestration of morphogenetic processes which drive elevation and apposition of the neural folds and their fusion into a neural tube. the newly formed tube gives rise to the brain in anterior regions and continues to develop into the spinal cord posteriorly. conspicuous differences between the anterior and posterior neural tube become visible already during neural tube closure (ntc). planar cell polarity (pcp)-mediated convergent extension (ce) ...201728778799
combining cytotoxicity assessment and xenopus laevis phenotypic abnormality assay as a predictor of nanomaterial safety.the african clawed frog, xenopus laevis, has been used as an efficient pre-clinical screening tool to predict drug safety during the early stages of the drug discovery process. x. laevis is a relatively inexpensive model that can be used in whole organism high-throughput assays whilst maintaining a high degree of homology to the higher vertebrate models often used in scientific research. despite an ever-increasing volume of biomedical nanoparticles (nps) in development, their unique physico-chem ...201728777439
tectal corticotropin-releasing factor (crf) neurons respond to fasting and a reactive stressor in the african clawed frog, xenopus laevis.it is well established that hypothalamic neurons producing the peptide corticotropin-releasing factor (crf) play a key role in stress adaptation, including reduction of food intake when a threat or stressor is present. we have previously reported on the presence of an intrinsic crf signaling system within the optic tectum (ot), a brain area that plays a key role in visually guided prey capture/predator avoidance decisions. to better understand the potential role of tectal crf neurons in regulati ...201728774755
the zahn drawings: new illustrations of xenopus embryo and tadpole stages for studies of craniofacial development.the embryos and tadpoles of the frog xenopus are increasingly important subjects for studies of the development of the head and face - studies that are providing novel and crucial insight into the causes and prevention of a suite of devastating birth defects, as well as basic evolutionary and developmental biology. however, many studies are conducted on a range of embryonic stages that are not fully represented in the beloved xenopus resource, nieuwkoop and faber's classic normal table of xenopu ...201728765211
modeling dominant and recessive forms of retinitis pigmentosa by editing three rhodopsin-encoding genes in xenopus laevis using crispr/cas9.the utility of xenopus laevis, a common research subject for developmental biology, retinal physiology, cell biology, and other investigations, has been limited by lack of a robust gene knockout or knock-down technology. here we describe manipulation of the x. laevis genome using crispr/cas9 to model the human disorder retinitis pigmentosa, and to introduce point mutations or exogenous dna sequences. we introduced and characterized in-frame and out-of-frame insertions and deletions in three gene ...201728761125
essential roles of thyroid hormone-regulated hyaluronan/cd44 signaling in adult stem cell development during xenopus laevis intestinal remodeling.in the amphibian intestine during metamorphosis, thyroid hormone (th) induces some larval epithelial cells to dedifferentiate into stem cells, which generate the adult epithelium analogous to the mammalian intestinal epithelium. we have previously shown that the canonical wnt signaling pathway is involved in adult epithelial development in the xenopus laevis intestine. to understand the function of this pathway more precisely, we here focused on cd44, a major wnt target, which has been identifie ...201728758360
smarcal1-mediated fork reversal triggers mre11-dependent degradation of nascent dna in the absence of brca2 and stable rad51 nucleofilaments.brca2 deficiency causes mre11-dependent degradation of nascent dna at stalled forks, leading to cell lethality. to understand the molecular mechanisms underlying this process, we isolated xenopus laevis brca2. we demonstrated that brca2 protein prevents single-stranded dna gap accumulation at replication fork junctions and behind them by promoting rad51 binding to replicating dna. without brca2, forks with persistent gaps are converted by smarcal1 into reversed forks, triggering extensive mre11- ...201728757209
fetax assay for evaluation of developmental toxicity.the frog embryo teratogenesis assay xenopus (fetax) test is a development toxicity screening test. due to the small amount of compound needed and the capability to study organogenesis in a short period of time (96 h), fetax test constitutes an efficient development toxicity alert test when performed early in drug safety development. the test is conducted on fertilized xenopus laevis mid-blastula-stage eggs over the organogenesis period. compound teratogenic potential is determined after analysis ...201728748472
lethal digenic mutations in the k+ channels kir4.1 (kcnj10) and slack (kcnt1) associated with severe-disabling seizures and neurodevelopmental delay.a 2-yr-old boy presented profound developmental delay, failure to thrive, ataxia, hypotonia, and tonic-clonic seizures that caused the death of the patient. targeted and whole exome sequencing revealed two heterozygous missense variants: a novel mutation in the kcnj10 gene that encodes for the inward-rectifying k+ channel kir4.1 and another previously characterized mutation in kcnt1 that encodes for the na+-activated k+ channel known as slo2.2 or slack. the objectives of this study were to perfo ...201728747464
tonoplast-localized nitrate uptake transporters involved in vacuolar nitrate efflux and reallocation in arabidopsis.a great proportion of nitrate taken up by plants is stored in vacuoles. vacuolar nitrate accumulation and release is of great importance to nitrate reallocation and efficient utilization. however, how plants mediate nitrate efflux from vacuoles to cytoplasm is largely unknown. the current study identified npf5.11, npf5.12 and npf5.16 as vacuolar nitrate efflux transporters in arabidopsis. histochemical analysis showed that npf5.11, npf5.12 and npf5.16 were expressed preferentially in root pericy ...201728743909
xenopus laevis m18bp1 directly binds existing cenp-a nucleosomes to promote centromeric chromatin assembly.vertebrate centromeres are epigenetically defined by nucleosomes containing the histone h3 variant, cenp-a. cenp-a nucleosome assembly requires the three-protein mis18 complex (mis18α, mis18β, and m18bp1) that recruits the cenp-a chaperone hjurp to centromeres, but how the mis18 complex recognizes centromeric chromatin is unknown. using xenopus egg extract, we show that direct, cell-cycle-regulated binding of m18bp1 to cenp-a nucleosomes recruits the mis18 complex to interphase centromeres to pr ...201728743005
histone methyltransferase dot1l is a coactivator for thyroid hormone receptor during xenopus development.histone modifications are associated with transcriptional regulation by diverse transcription factors. genome-wide correlation studies have revealed that histone activation marks and repression marks are associated with activated and repressed gene expression, respectively. among the histone activation marks is histone h3 k79 methylation, which is carried out by only a single methyltransferase, disruptor of telomeric silencing-1-like (dot1l). we have been studying thyroid hormone (t3)-dependent ...201728739643
splice variants of ph-sensitive chloride channel identify a key determinant of ivermectin sensitivity in the larvae of the silkworm bombyx mori.the ph-sensitive chloride channels (phcls) are broadly expressed in insects, but little is known about their physiologic role, diversity, and sensitivity to insecticides acting on relevant chloride channels. here we have sequenced 50 transcripts of the phcl-1 gene from the brain, third thoracic ganglion (t3g), and midgut of larvae of silkworm bombyx mori it was found that >50 variants were expressed with distinct splicing in the t3g compared with the brain and midgut. of the variants detected, v ...201728739571
a g326e substitution in the glutamate-gated chloride channel 3 (glucl3) of the two-spotted spider mite tetranychus urticae abolishes the agonistic activity of macrocyclic lactones.the macrocyclic lactones abamectin and milbemectin are frequently used to control phytophagous mites such as tetranychus urticae. consequently, resistance has developed and was genetically linked with substitutions in the glutamate-gated chloride channel (glucl) subunits tuglucl1 and tuglucl3. here, we functionally validated a g326e substitution in tuglucl3 by functional expression in xenopus laevis oocytes followed by two-electrode voltage-clamp electrophysiology.201728736919
neuronal degeneration and regeneration induced by axotomy in the olfactory epithelium of xenopus laevis.the olfactory epithelium (oe) has the remarkable capability to constantly replace olfactory receptor neurons (orns) due to the presence of neural stem cells (nscs). for this reason, the oe provides an excellent model to study neurogenesis and neuronal differentiation. in the present work, we induced neuronal degeneration in the oe of xenopus laevis larvae by bilateral axotomy of the olfactory nerves. we found that axotomy induces specific- neuronal death through apoptosis between 24 and 48h post ...201728719101
conserved gene regulatory module specifies lateral neural borders across bilaterians.the lateral neural plate border (npb), the neural part of the vertebrate neural border, is composed of central nervous system (cns) progenitors and peripheral nervous system (pns) progenitors. in invertebrates, pns progenitors are also juxtaposed to the lateral boundary of the cns. whether there are conserved molecular mechanisms determining vertebrate and invertebrate lateral neural borders remains unclear. using single-cell-resolution gene-expression profiling and genetic analysis, we present ...201728716930
cip29 is phosphorylated following activation of the dna damage response in xenopus egg extracts.acting through a complex signalling network, dna lesions trigger a range of cellular responses including dna repair, cell cycle arrest, altered gene expression and cell death, which help to limit the mutagenic effects of such dna damage. rna processing factors are increasingly being recognised as important targets of dna damage signalling, with roles in the regulation of gene expression and also more directly in the promotion of dna repair. in this study, we have used a xenopus laevis egg extrac ...201728715428
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
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
apolipoprotein c-i mediates wnt/ctnnb1 signaling during neural border formation and is required for neural crest development.in vertebrates, the neural crest and placodes originate in the neural border, which is located between the neural plate and epidermal ectoderm. the neural crest and placodes give rise to a vast array of cell types. formation of neural crest is a multi-step process, in which wnt signals are used reiteratively, but it is currently not clear if a wnt signal is required for neural border formation. here, we have identified apolipoprotein c-i (apoc1) in a screen for genes regulated by wnt/ctnnb1 sign ...201728695961
the effect of pungent and tingling compounds from piper nigrum l. on background k+ currents.black peppercorns (piper nigrum l.) elicit a pungent and tingling oral impression. their pungency is partially explained by the agonist activity of some of their active principles, especially piperine, on trp channels. however, we recently showed that piperine, as well as other pungent compounds, also possess a marked effect on two-pore domain (kcnk, k2p) k+ channels. members of this family play a key role in maintaining the resting membrane potential of excitable cells. interestingly, tingling ...201728694780
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
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
acetylcholinesterase plays a non-neuronal, non-esterase role in organogenesis.acetylcholinesterase (ache) is crucial for degrading acetylcholine at cholinergic synapses. in vitro studies suggest that, in addition to its role in nervous system signaling, ache can also modulate non-neuronal cell properties, although it remains controversial whether ache functions in this capacity in vivo here, we show that ache plays an essential non-classical role in vertebrate gut morphogenesis. exposure of xenopus embryos to ache-inhibiting chemicals results in severe defects in intestin ...201728684626
maitotoxin is a potential selective activator of the endogenous transient receptor potential canonical type 1 channel in xenopus laevis oocytes.maitotoxin (mtx) is the most potent marine toxin known to date. it is responsible for a particular human intoxication syndrome called ciguatera fish poisoning (cfp). several reports indicate that mtx is an activator of non-selective cation channels (nscc) in different cell types. the molecular identity of these channels is still an unresolved topic, and it has been proposed that the transient receptor potential (trp) channels are involved in this effect. in xenopus laevis oocytes, mtx at picomol ...201728672825
the tyrosine y2502.39 in frizzled 4 defines a conserved motif important for structural integrity of the receptor and recruitment of disheveled.frizzleds (fzds) are unconventional g protein-coupled receptors, which activate diverse intracellular signaling pathways via the phosphoprotein disheveled (dvl) and heterotrimeric g proteins. the interaction interplay of fzds with dvl and g proteins is complex, involves different regions of fzd and the potential dynamics are poorly understood. in the present study, we aimed to characterize the function of a highly conserved tyrosine (y2502.39) in the intracellular loop 1 (il1) of human fzd4. we ...201728668722
developmental neurogenesis in mouse and xenopus is impaired in the absence of nosip.genetic deletion of nosip in mice causes holoprosencephaly, however, the function of nosip in neurogenesis is currently unknown.201728663132
a multi-tiered, in vivo, quantitative assay suite for environmental disruptors of thyroid hormone signaling.the essential role of thyroid hormone (th) signaling in mammalian development warrants the examination of man-made chemicals for its disruption. among vertebrate species, the molecular components of th signaling are highly conserved, including the thyroid hormone receptors (trs), their heterodimer binding partners the retinoid-x receptors (rxrs), and their dna recognition sequences (tres). this molecular conservation allows examination of potential th disruption in the tractable, in vivo model s ...201728662416
renal localization and regulation by dietary phosphate of the mct14 orphan transporter.mct14 is an orphan transporter belonging to the slc16 transporter family mediating the transport of monocarboxylates, aromatic amino acids, creatine, and thyroid hormones. the expression, tissue localization, regulation, and function of mct14 are unknown. in mouse mct14 mrna abundance is highest in kidney. using a newly developed and validated antibody, mct14 was localized to the luminal membrane of the thick ascending limb of the loop of henle colocalizing in the same cells with uromodulin and ...201728662032
a method for detailed movement pattern analysis of tadpole startle response.prolonged space flight, specifically microgravity, presents a problem for space exploration. animal models with altered connections of the vestibular ear, and thus altered gravity sensation, would allow the examination of the effects of microgravity and how various countermeasures can establish normal function. we describe an experimental apparatus to monitor the effects of ear manipulations to generate asymmetric gravity input on the tadpole escape response. to perform the movement pattern anal ...201728653338
switch-like behavior enables wnt11 concentration specific response during dorso-ventral axis formation in xenopus laevis.wnt signaling plays a role in diverse processes such as cell proliferation, differentiation, migration or cell polarity. dysfunction of wnt signaling is associated with human diseases and aging. wnts can activate several interacting intracellular signaling pathways, in particular the so called canonical and non-canonical pathways. the canonical wnt response leads to a stabilization of cytoplasmic β-catenin whereas non-canonical wnt signaling can result in the activation of calcium-calmodulin dep ...201728648560
ensemble and single-molecule analysis of non-homologous end joining in frog egg extracts.non-homologous end joining (nhej) repairs the majority of dna double-strand breaks in human cells, yet the detailed order of events in this process has remained obscure. here, we describe how to employ xenopus laevis egg extract for the study of nhej. the egg extract is easy to prepare in large quantities, and it performs efficient end joining that requires the core end joining proteins ku, dna-pkcs, xlf, xrcc4, and dna ligase iv. these factors, along with the rest of the soluble proteome, are p ...201728645371
xenopus laevis as model system to study dna damage response and replication fork stability.although many players of the dna damage response and dna repair have been identified in several systems their biochemical role is still poorly understood. the use of the xenopus laevis egg extract cell-free system allowed biochemical dissection of dna replication and cell cycle events in a complex biological context. the possibility of manipulating the protein content by using protein depletion procedures makes egg extract a powerful system to study proteins whose inactivation results in cellula ...201728645370
adipose tissue macrophages develop from bone marrow-independent progenitors in xenopus laevis and mouse.atms have a metabolic impact in mammals as they contribute to metabolically harmful at inflammation. the control of the atm number may have therapeutic potential; however, information on atm ontogeny is scarce. whereas it is thought that atms develop from circulating monocytes, various tissue-resident mϕs are capable of self-renewal and develop from bm-independent progenitors without a monocyte intermediate. here, we show that amphibian at contains self-renewing atms that populate the at before ...201728642277
using short-term bioassays to evaluate the endocrine disrupting capacity of the pesticides linuron and fenoxycarb.several short-term whole-organism bioassays based on transgenic aquatic models are now under validation by the oecd (organization for economic co-operation and development) to become standardized test guidelines for the evaluation of the endocrine activity of substances. evaluation of the endocrine disrupting capacity of pesticides will be a domain of applicability of these future reference tests. the herbicide linuron and the insecticide fenoxycarb are two chemicals commonly used in agricultura ...201728634053
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
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
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
cells from subcutaneous tissues contribute to scarless skin regeneration in xenopus laevis froglets.mammals cannot regenerate the dermis and other skin structures after an injury and instead form a scar. however, a xenopus laevis froglet can regenerate scarless skin, including the dermis and secretion glands, on the limbs and trunk after skin excision. subcutaneous tissues in the limbs and trunk consist mostly of muscles. although subcutaneous tissues beneath a skin injury appear disorganized, the cellular contribution of these underlying tissues to skin regeneration remains unclear.201728618059
loops d, e and g in the drosophila dα1 subunit contribute to high neonicotinoid sensitivity of dα1-chicken β2 nicotinic acetylcholine receptor.neonicotinoid insecticides interact with the orthosteric site formed at subunit interfaces of insect nicotinic ach (nach) receptors. however, their interactions with the orthosteric sites at α-non α and α-α subunit interfaces remain poorly understood. the aim of this study was to elucidate the mechanism of neonicotinoid actions using the drosophila dα1-chicken β2 hybrid nach receptor.201728616862
global realized niche divergence in the african clawed frog xenopus laevis.although of crucial importance for invasion biology and impact assessments of climate change, it remains widely unknown how species cope with and adapt to environmental conditions beyond their currently realized climatic niches (i.e., those climatic conditions existing populations are exposed to). the african clawed frog xenopus laevis, native to southern africa, has established numerous invasive populations on multiple continents making it a pertinent model organism to study environmental niche ...201728616199
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
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
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
inhibition of insect olfactory behavior by an airborne antagonist of the insect odorant receptor co-receptor subunit.response to volatile environmental chemosensory cues is essential for insect survival. the odorant receptor (or) family is an important class of receptors that detects volatile molecules; guiding insects towards food, mates, and oviposition sites. ors are odorant-gated ion channels, consisting of a variable odorant specificity subunit and a conserved odorant receptor co-receptor (orco) subunit, in an unknown stoichiometry. the orco subunit possesses an allosteric site to which modulators can bin ...201728562598
the flexible cytoplasmic loop 3 contributes to the substrate affinity of human monocarboxylate transporters.human monocarboxylate transporters (hmcts/slc16as) mediate the transport of small molecular weight monocarboxylates. among hmcts, hmct1 exhibits high-affinity l-lactate transport and broad substrate recognition, whereas hmct4 shows highly specific substrate recognition and low-affinity l-lactate transport, indicating that hmct1 and hmct4 have different roles in the body. however, the molecular mechanism of transporter-mediated substrate transport remains unknown. the aim of this study is to iden ...201728559188
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
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