Publications

iron is a substrate of the plasmodium falciparum chloroquine resistance transporter pfcrt in xenopus oocytes.	the chloroquine resistance transporter of the human malaria parasite plasmodium falciparum, pfcrt, is an important determinant of resistance to several quinoline and quinoline-like antimalarial drugs. pfcrt also plays an essential role in the physiology of the parasite during development inside erythrocytes. however, the function of this transporter besides its role in drug resistance is still unclear. using electrophysiological and flux experiments conducted on pfcrtexpressing xenopus laevis oo ...	2017	28768767
multi-omics analysis sheds light on the evolution and the intracellular lifestyle strategies of spotted fever group rickettsia spp.	arthropod-borne rickettsia species are obligate intracellular bacteria which are pathogenic for humans. within this genus, rickettsia slovaca and rickettsia conorii cause frequent and potentially severe infections, whereas rickettsia raoultii and rickettsia massiliae cause rare and milder infections. all four species belong to spotted fever group (sfg) rickettsiae. however, r. slovaca and r. raoultii cause scalp eschar and neck lymphadenopathy (senlat) and are mainly associated with dermacentor ...	2017	28775717
toxicity effects of functionalized quantum dots, gold and polystyrene nanoparticles on target aquatic biological models: a review.	nano-based products are widespread in several sectors, including textiles, medical-products, cosmetics, paints and plastics. nanosafety and safe-by-design are driving nanoparticle (np) production and applications through np functionalization (@nps). indeed, @nps frequently present biological effects that differ from the parent material. this paper reviews the impact of quantum dots (qds), gold nanoparticles (aunps), and polystyrene-cored nps (psnps), evidencing the role of np functionalization i ...	2017	28858240
molecular evolution of two distinct dmrt1 promoters for germ and somatic cells in vertebrate gonads.	the transcription factor dmrt1 has important functions in two distinct processes, somatic-cell masculinization and germ-cell development in mammals. however, it is unknown whether the functions are conserved during evolution, and what mechanism underlies its expression in the two cell lineages. our analysis of the xenopus laevis and silurana tropicalis dmrt1 genes indicated the presence of two distinct promoters: one upstream of the noncoding first exon (ncex1), and one within the first intron. ...	2017	27927791
amphibase: a new genomic resource for non-model amphibian species.	more than five thousand genes annotated in the recently published xenopus laevis and xenopus tropicalis genomes do not have a candidate orthologous counterpart in other vertebrate species. to determine whether these sequences represent genuine amphibian-specific genes or annotation errors, it is necessary to analyze them alongside sequences from other amphibian species. however, due to large genome sizes and an abundance of repeat sequences, there are limited numbers of gene sequences available ...	2017	28095648
first parasitological study of the african clawed frog (xenopus laevis, amphibia) in chile.	introduced species can arrive into new territories with parasites; however, these species are expected to face lower parasite richness than in their original regions. both introduced hosts and parasites can affect native fauna. since their release into the wild in chile following laboratory use, xenopus laevis daudin, 1802 has widely spread throughout central chile. the only pathogen described on the host is the fungus batrachochytrium dendrobatidis longcore, pessier, nichols, 1999; thus, this i ...	2017	28746452
analysis of cell size in the gastrula of ten frog species reveals a correlation of egg with cell sizes, and a conserved pattern of small cells in the marginal zone.	we investigated the relationship between egg and cell sizes in the early gastrula of ten species of frogs with eggs of 1,100-3,500 μm diameters. we asked whether differences in cell size of the vegetal region, blastocoel roof, and marginal zone of the early gastrula were associated with egg size. alternatively, we proposed that cell size differences may associate with gastrulation characteristics. the analyzed species were as follows: xenopus laevis, engystomops randi, engystomops coloradorum, e ...	2017	27381278
three-dimensional reconstruction of the cranial and anterior spinal nerves in early tadpoles of xenopus laevis (pipidae, anura).	xenopus laevis is one of the most widely used model organism in neurobiology. it is therefore surprising, that no detailed and complete description of the cranial nerves exists for this species. using classical histological sectioning in combination with fluorescent whole mount antibody staining and micro-computed tomography we prepared a detailed innervation map and a freely-rotatable three-dimensional (3d) model of the cranial nerves and anterior-most spinal nerves of early x. laevis tadpoles. ...	2017	29218708
effects of a commonly used glyphosate-based herbicide formulation on early developmental stages of two anuran species.	environmental contamination, especially due to the increasing use of pesticides, is suggested to be one out of six main reasons for the global amphibian decline. adverse effects of glyphosate-based herbicides on amphibians have been already discussed in several studies with different conclusions, especially regarding sublethal effects at environmentally relevant concentrations. therefore, we studied the acute toxic effects (mortality, growth, and morphological changes) of the commonly used glyph ...	2017	27785717
comparative micrornaome analysis of the testis and ovary of the chinese giant salamander.	micrornas (mirnas) are 18-24 nucleotides non-coding rnas that regulate gene expression by post-transcriptional suppression of mrna. the chinese giant salamander (cgs, andrias davidianus), which is an endangered species, has become one of the important models of animal evolution; however, no mirna studies on this species have been conducted. in this study, two small rna libraries of cgs ovary and testis were constructed using deep sequencing technology. a bioinformatics pipeline was developed to ...	2017	28630098
genomic epidemiology of the emerging pathogen batrachochytrium dendrobatidis from native and invasive amphibian species in chile.	emerging fungal diseases represent a threat to food security, animal and human health worldwide. amphibian chytridiomycosis, caused by the fungus batrachochytrium dendrobatidis (bd), has been associated with catastrophic and well-documented amphibian population declines and extinctions. for the first time, bd was cultured from native and non-native wild amphibians in chile. phylogenomic analyses revealed that chilean isolates avs2, avs4 and avs7 group within the global panzootic lineage of bd (b ...	2017	29205924
comparative study of diclofenac-induced embryotoxicity and teratogenesis in xenopus laevis and lithobates catesbeianus, using the frog embryo teratogenesis assay: xenopus (fetax).	water is an increasingly deteriorated, limited natural resource due to population increase and industrialization. also, the widespread use of pharmaceuticals in modern society leads to their presence in domestic, hospital and industrial effluents. due to their analgesic properties, some of the most commonly used pharmaceuticals are nonsteroidal anti-inflammatory drugs (nsaids). high concentrations of one these products, diclofenac (dcf), have been detected in effluents and water bodies of differ ...	2017	27644024
vitamin a induced homeotic hindlimb formation on dorsal and ventral sides of regenerating tissue of amputated tails of japanese brown frog tadpoles.	when anuran tadpoles are treated with vitamin a after tail amputation, hindlimb-like structures can be generated instead of the lost tail part at the amputation site. this homeotic transformation was initially expected to be a key to understanding the body plan of vertebrates. unfortunately, homeotic limb formation has been reproduced in only some indian frog species and a european species, but not in experimental anurans such as xenopus laevis or rana catesbeiana. consequently, this fascinating ...	2017	29094344
transcriptomic and macroevolutionary evidence for phenotypic uncoupling between frog life history phases.	anuran amphibians undergo major morphological transitions during development, but the contribution of their markedly different life-history phases to macroevolution has rarely been analysed. here we generate testable predictions for coupling versus uncoupling of phenotypic evolution of tadpole and adult life-history phases, and for the underlying expression of genes related to morphological feature formation. we test these predictions by combining evidence from gene expression in two distantly r ...	2017	28504275
expression of the aquaglyceroporin hc-9 in a freeze-tolerant amphibian that accumulates glycerol seasonally.	as ambient temperatures fall in the autumn, freeze-tolerant cope's gray treefrogs, dryophytes chrysoscelis (formerly hyla chrysoscelis), accumulate glycerol as a cryoprotective agent. we hypothesized that these treefrogs express an ortholog of the mammalian aquaglyceroporin aqp9 and that aqp9 expression is upregulated in the cold to facilitate glycerol transport. we sequenced 1790 bp from cloned cdna that codes for a 315 amino acid protein, hc-9, containing the predicted six transmembrane spanni ...	2017	28784850
expression of cyclin d1, cyclin d2, and n-myc in embryos of the direct developing frog eleutherodactylus coqui, with a focus on limbs.	species of frogs that develop directly have removed the tadpole from their ontogeny and form adult structures precociously. to see whether cell cycle regulators could be involved in this altered embryogenesis, we examined the expression of ccnd1, ccnd2, and mycn in embryos of the direct developing frog, eleutherodactylus coqui. notable differences compared to embryos of xenopus laevis, a species with a tadpole, included prominent expression of ccnd2 in the midbrain and ccnd1 in the mandibular ne ...	2017	23473789
quantitative comparative analysis of the nasal chemosensory organs of anurans during larval development and metamorphosis highlights the relative importance of chemosensory subsystems in the group.	the anuran peripheral olfactory system is composed of a number of subsystems, represented by distinct neuroepithelia. these include the main olfactory epithelium and vomeronasal organ (found in most tetrapods) and three specialized epithelia of anurans: the buccal-exposed olfactory epithelium of larvae, and the olfactory recess and middle chamber epithelium of postmetamorphic animals. to better characterize the developmental changes in these subsystems across the life cycle, morphometric changes ...	2017	28503895
differences in mobility at the range edge of an expanding invasive population of xenopus laevis in the west of france.	theoretical models predict that spatial sorting at the range edge of expanding populations should favor individuals with increased mobility relative to individuals at the center of the range. despite the fact that empirical evidence for the evolution of locomotor performance at the range edge is rare, data on cane toads support this model. however, whether this can be generalized to other species remains largely unknown. here, we provide data on locomotor stamina and limb morphology in individua ...	2017	28100805
competition and feeding ecology in two sympatric xenopus species (anura: pipidae).	the widespread african clawed frog (xenopus laevis) occurs in sympatry with the iucn endangered cape platanna (xenopus gilli) throughout its entire range in the south-western cape, south africa. in order to investigate aspects of the interspecific competition between populations of x. laevis and x. gilli, an assessment of their niche differentiation was conducted through a comprehensive study on food composition and trophic niche structure at two study sites: the cape of good hope (cogh) and kle ...	2017	28439453
limited genomic consequences of hybridization between two african clawed frogs, xenopus gilli and x. laevis (anura: pipidae).	the cape platanna, xenopus gilli, an endangered frog, hybridizes with the african clawed frog, x. laevis, in south africa. estimates of the extent of gene flow between these species range from pervasive to rare. efforts have been made in the last 30 years to minimize hybridization between these two species in the west population of x. gilli, but not the east populations. to further explore the impact of hybridization and the efforts to minimize it, we examined molecular variation in one mitochon ...	2017	28439068
chromosome divergence during evolution of the tetraploid clawed frogs, xenopus mellotropicalis and xenopus epitropicalis as revealed by zoo-fish.	whole genome duplication (wgd) generates new species and genomic redundancy. in african clawed frogs of the genus xenopus, this phenomenon has been especially important in that (i) all but one extant species are polyploid and (ii) whole genome sequences of some species provide an evidence for genomic rearrangements prior to or after wgd. within xenopus in the subgenus silurana, at least one allotetraploidization event gave rise to three extant tetraploid (2n = 4x = 40) species-xenopus mellotropi ...	2017	28545147
spinal cord cells from pre-metamorphic stages differentiate into neurons and promote axon growth and regeneration after transplantation into the injured spinal cord of non-regenerative xenopus laevis froglets.	mammals are unable to regenerate its spinal cord after a lesion, meanwhile, anuran amphibians are capable of spinal cord regeneration only as larvae, and during metamorphosis, this capability is lost. sox2/3+ cells present in the spinal cord of regenerative larvae are required for spinal cord regeneration. here we evaluate the effect of the transplantation of spinal cord cells from regenerative larvae into the resected spinal cord of non-regenerative stages (nr-stage). donor cells were able to s ...	2017	29326551
microprobe capillary electrophoresis mass spectrometry for single-cell metabolomics in live frog (xenopus laevis) embryos.	the quantification of small molecules in single cells raises new potentials for better understanding the basic processes that underlie embryonic development. to enable single-cell investigations directly in live embryos, new analytical approaches are needed, particularly those that are sensitive, selective, quantitative, robust, and scalable to different cell sizes. here, we present a protocol that enables the in situ analysis of metabolism in single cells in freely developing embryos of the sou ...	2017	29286491
a glyphosate micro-emulsion formulation displays teratogenicity in xenopus laevis.	glyphosate is the active ingredient in broad-spectrum herbicide formulations used in agriculture, domestic area and aquatic weed control worldwide. its market is growing steadily concurrently with the cultivation of glyphosate-tolerant transgenic crops and emergence of weeds less sensitive to glyphosate. ephemeral and lentic waters near to agricultural lands, representing favorite habitats for amphibian reproduction and early life-stage development, may thus be contaminated by glyphosate based h ...	2017	29306033
bioelectric regulation of innate immune system function in regenerating and intact xenopus laevis.	two key inputs that regulate regeneration are the function of the immune system, and spatial gradients of transmembrane potential (vmem). endogenous bioelectric signaling in somatic tissues during regenerative patterning is beginning to be understood, but its role in the context of immune response has never been investigated. here, we show that vmem levels modulate innate immunity activity in xenopus laevis embryos. we developed an assay in which x. laevis embryos are infected with a uropathogen ...	2017	29302351
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 ...	2017	29108650
influence of the rdl a301s mutation in the brown planthopper nilaparvata lugens on the activity of phenylpyrazole insecticides.	we discovered the a301s mutation in the rdl gaba-gated chloride channel of fiprole resistant rice brown planthopper, nilaparvata lugens populations by dna sequencing and snp calling via rnaseq. ethiprole selection of two field n. lugens populations resulted in strong resistance to both ethiprole and fipronil and resulted in fixation of the a301s mutation, as well as the emergence of another mutation, q359e in one of the selected strains. to analyse the roles of these mutations in resistance to p ...	2017	29107231
identification of novel cis-regulatory elements of eya1 in xenopus laevis using bac recombineering.	the multifunctional eya1 protein plays important roles during the development of cranial sensory organs and ganglia, kidneys, hypaxial muscles and several other organs in vertebrates. eya1 is encoded by a complex locus with candidate cis-regulatory elements distributed over a 329 kbp wide genomic region in xenopus. consequently, very little is currently known about how expression of eya1 is controlled by upstream regulators. here we use a library of xenopus tropicalis genomic sequences in bacter ...	2017	29101371
frizzled-7 is required for xenopus heart development.	wnt signalling regulates cardiogenesis during specification of heart tissue and the morphogenetic movements necessary to form the linear heart. wnt11-mediated non-canonical signalling promotes early cardiac development whilst wnt11-r, which is expressed later, also signals through the non-canonical pathway to promote heart development. it is unclear which frizzled proteins mediate these interactions. frizzled-7 (fzd7) is expressed during gastrulation in the mesodermal cells fated to become heart ...	2017	29101100
4-aminopyridine: a pan voltage-gated potassium channel inhibitor that enhances kv 7.4 currents and inhibits noradrenaline-mediated contraction of rat mesenteric small arteries.	kv 7.4 and kv 7.5 channels are regulators of vascular tone. 4-aminopyridine (4-ap) is considered a broad inhibitor of voltage-gated potassium (kv ) channels, with little inhibitory effect on kv 7 family members at mmol concentrations. however, the effect of 4-ap on kv 7 channels has not been systematically studied. the aim of this study was to investigate the pharmacological activity of 4-ap on kv 7.4 and kv 7.5 channels and characterize the effect of 4-ap on rat resistance arteries.	2017	29156097
a nonredundant role for the trpm6 channel in neural tube closure.	in humans, germline mutations in trpm6 cause autosomal dominant hypomagnesemia with secondary hypocalcemia disorder. loss of trpm6 in mice also perturbs cellular magnesium homeostasis but additionally results in early embryonic lethality and neural tube closure defects. to define the mechanisms by which trpm6 influences neural tube closure, we functionally characterized the role of trpm6 during early embryogenesis in xenopus laevis. the expression of xenopus trpm6 (xtrpm6) is elevated at the ons ...	2017	29142255
developmental changes in spinal neuronal properties, motor network configuration and neuromodulation at free-swimming stages of xenopus frog tadpoles.	we describe a novel preparation of the isolated brainstem and spinal cord from pro-metamorphic tadpole stages of the south african clawed frog (xenopus laevis) that permits whole cell patch-clamp recordings from neurons in the ventral spinal cord. previous research on earlier stages of the same species has provided one of the most detailed understandings of the design and operation of a cpg circuit. here we have addressed how development sculpts complexity from this more basic circuit. the prepa ...	2017	29142093
it's not all black and white: visual scene parameters influence optokinetic reflex performance in xenopus laevis tadpoles.	the maintenance of visual acuity during active and passive body motion is ensured by gaze-stabilizing reflexes that aim at minimizing retinal image slip. for the optokinetic reflex (okr), large-field visual motion of the surround forms the essential stimulus that activates eye movements. properties of the moving visual world influence cognitive motion perception and the estimation of visual image velocity. therefore, the performance of brainstem-mediated visuo-motor behaviors might also depend o ...	2017	29141881
overland movement in african clawed frogs (xenopus laevis): empirical dispersal data from within their native range.	dispersal forms are an important component of the ecology of many animals, and reach particular importance for predicting ranges of invasive species. african clawed frogs (xenopus laevis) move overland between water bodies, but all empirical studies are from invasive populations with none from their native southern africa. here we report on incidents of overland movement found through a capture-recapture study carried out over a three year period in overstrand, south africa. the maximum distance ...	2017	29134157
specific inhibition of gpcr-independent g protein signaling by a rationally engineered protein.	activation of heterotrimeric g proteins by cytoplasmic nonreceptor proteins is an alternative to the classical mechanism via g protein-coupled receptors (gpcrs). a subset of nonreceptor g protein activators is characterized by a conserved sequence named the gα-binding and activating (gba) motif, which confers guanine nucleotide exchange factor (gef) activity in vitro and promotes g protein-dependent signaling in cells. gba proteins have important roles in physiology and disease but remain greatl ...	2017	29133411
towards functional selectivity for α6β3γ2 gabaa receptors: a series of novel pyrazoloquinolinones.	the gabaa receptors are ligand-gated ion channels, which play an important role in neurotransmission. their variety of binding sites serves as an appealing target for many clinically relevant drugs. here, we explored the functional selectivity of modulatory effects at specific extracellular α+/β- interfaces, using a systematically varied series of pyrazoloquinolinones.	2017	29127702
wall following in xenopus laevis is barrier-driven.	the tendency of animals to follow boundaries within their environment can serve as a strategy for spatial learning or defensive behaviour. we examined whether xenopus laevis tadpoles and froglets employ such a strategy by characterizing their swimming pattern in a square tank with shallow water. trajectories obtained from video recordings were analysed for proximity to the nearest wall. with the exception of young larvae, the vast majority of animals (both tadpoles and froglets) spent a dispropo ...	2017	29119247
nuclear pore complex plasticity during developmental process as revealed by super-resolution microscopy.	nuclear pore complex (npc) is of paramount importance for cellular processes since it is the unique gateway for molecular exchange through the nucleus. unraveling the modifications of the npc structure in response to physiological cues, also called nuclear pore plasticity, is key to the understanding of the selectivity of this molecular machinery. as a step towards this goal, we use the optical super-resolution microscopy method called direct stochastic optical reconstruction microscopy (dstorm) ...	2017	29116248
the rice high-affinity k+ transporter oshkt2;4 mediates mg2+ homeostasis under high-mg2+ conditions in transgenic arabidopsis.	rice (oryza sativa; background nipponbare) contains nine hkt (high-affinity k+ transport)-like genes encoding membrane proteins belonging to the superfamily of ktr/trk/hkt. oshkts have been proposed to include four selectivity filter-pore-forming domains homologous to the bacterial k+ channel kcsa, and are separated into oshkt1s with na+-selective activity and oshkt2s with na+-k+ symport activity. as a member of the oshkt2 subfamily, oshkt2;4 renders mg2+ and ca2+ permeability for yeast cells an ...	2017	29114257
xenopus laevis as a model organism for the study of spinal cord formation, development, function and regeneration.	the spinal cord is the first central nervous system structure to develop during vertebrate embryogenesis, underscoring its importance to the organism. because of its early formation, accessibility to the developing spinal cord in amniotes is challenging, often invasive and the experimental approaches amenable to model systems like mammals are limited. in contrast, amphibians, in general and the african-clawed frog xenopus laevis, in particular, offer model systems in which the formation of the s ...	2017	29218002
interaction of purinergic p2x4 and p2x7 receptor subunits.	p2x4 and p2x7 are members of the p2x receptor family, comprising seven isoforms (p2x1-p2x7) that form homo- and heterotrimeric non-specific cation channels gated by extracellular atp. p2x4 and p2x7 are widely coexpressed, particularly in secretory epithelial cells and immune and inflammatory cells, and regulate inflammation and nociception. although functional heteromerization has been established for p2x2 and p2x3 subunits expressed in sensory neurons, there are contradictory reports regarding ...	2017	29213241
spindle-to-cortex communication in cleaving frog eggs.	during cytokinesis, the mitotic spindle communicates with the cell cortex to position a cleavage furrow that will cut through the cell in the plane defined by the metaphase plate. we investigated the molecular basis of this communication in xenopus laevis eggs, where the signal has to travel ∼400 µm in ∼30 min to reach the cortex from the first anaphase spindle. at anaphase onset, huge microtubule asters grow out from the poles of the spindle and meet at the plane previously defined by the metap ...	2017	29196560
the ectodomain of cadherin-11 binds to erbb2 and stimulates akt phosphorylation to promote cranial neural crest cell migration.	during development, a multi-potent group of cells known as the cranial neural crest (cnc) migrate to form craniofacial structures. proper migration of these cells requires proteolysis of cell adhesion molecules, such as cadherins. in xenopus laevis, preventing extracellular cleavage of cadherin-11 impairs cnc migration. however, overexpression of the soluble cleavage product (ec1-3) is capable of rescuing this phenotype. the mechanism by which ec1-3 promotes cnc migration has not been investigat ...	2017	29190819
tissue-specific gene inactivation in xenopus laevis: knockout of lhx1 in the kidney with crispr/cas9.	studying genes involved in organogenesis is often difficult because many of these genes are also essential for early development. the allotetraploid frog, xenopus laevis, is commonly used to study developmental processes, but because of the presence of two homeologs for many genes, it has been difficult to use as a genetic model. few studies have successfully used crispr in amphibians, and currently there is no tissue-targeted knockout strategy described in xenopus the goal of this study is to d ...	2017	29187504
evaluating the longevity of surgically extracted xenopus laevis oocytes for the study of nematode ligand-gated ion channels.	xenopus laevis oocytes have been extensively used as a heterologous expression system for the study of ion channels. while used successfully worldwide as tool for expressing and characterizing ion channels from a wide range of species, the limited longevity of oocytes once removed from the animal can pose significant challenges. in this study, we evaluate a simple and useful method that extends the longevity of xenopus oocytes after removal from the animal and quantitatively assessed the reliabi ...	2017	29185074
quantification of size effect on protein rotational mobility in cells by 19f nmr spectroscopy.	protein diffusion in living cells might differ significantly from that measured in vitro. little is known about the effect of globular protein size on rotational diffusion in cells because each protein has distinct surface properties, which result in different interactions with cellular components. to overcome this problem, the b1 domain of protein g (gb1) and several concatemers of the protein were labeled with 5-fluorotryptophan and studied by 19f nmr in escherichia coli cells, xenopus laevis ...	2017	29184995
the r81t mutation in the nicotinic acetylcholine receptor of aphis gossypii is associated with neonicotinoid insecticide resistance with differential effects for cyano- and nitro-substituted neonicotinoids.	the cotton aphid, aphis gossypii glover, is one of the most agriculturally important insect pests. neonicotinoid insecticides and sulfoxaflor have generally shown excellent control of a. gossypii, but these aphids have recently developed resistance against neonicotinoid insecticides. we previously characterized a field-collected a. gossypii kushima clone that showed higher resistance to nitro-substituted neonicotinoids, such as imidacloprid, than to cyano-substituted neonicotinoids, such as acet ...	2017	29183611
targeted base editing via rna-guided cytidine deaminases in xenopus laevis embryos.	genome editing using programmable nucleases such as crispr/cas9 or cpf1 has emerged as powerful tools for gene knock-out or knock-in in various organisms. while most genetic diseases are caused by point mutations, these genome-editing approaches are inefficient in inducing single-nucleotide substitutions. recently, cas9-linked cytidine deaminases, named base editors (bes), have been shown to convert cytidine to uridine efficiently, leading to targeted single-base pair substitutions in human cell ...	2017	29179261
rnas coordinate nuclear envelope assembly and dna replication through elys recruitment to chromatin.	upon fertilisation, the sperm pronucleus acquires the competence to replicate the genome through a cascade of events that link chromatin remodelling to nuclear envelope formation. the factors involved have been partially identified and are poorly characterised. here, using xenopus laevis egg extracts we show that rnas are required for proper nuclear envelope assembly following sperm dna decondensation. although chromatin remodelling and pre-replication complex formation occur normally, rna-deple ...	2017	29242643
functional reintegration of sensory neurons and transitional dendritic reduction of mitral/tufted cells during injury-induced recovery of the larval xenopus olfactory circuit.	understanding the mechanisms involved in maintaining lifelong neurogenesis has a clear biological and clinical interest. in the present study, we performed olfactory nerve transection on larval xenopus to induce severe damage to the olfactory circuitry. we surveyed the timing of the degeneration, subsequent rewiring and functional regeneration of the olfactory system following injury. a range of structural labeling techniques and functional calcium imaging were performed on both tissue slices an ...	2017	29234276
the human dna glycosylases neil1 and neil3 excise psoralen-induced dna-dna cross-links in a four-stranded dna structure.	interstrand cross-links (icls) are highly cytotoxic dna lesions that block dna replication and transcription by preventing strand separation. previously, we demonstrated that the bacterial and human dna glycosylases nei and neil1 excise unhooked psoralen-derived icls in three-stranded dna via hydrolysis of the glycosidic bond between the crosslinked base and deoxyribose sugar. furthermore, neil3 from xenopus laevis has been shown to cleave psoralen- and abasic site-induced icls in xenopus egg ex ...	2017	29234069
antagonistic effect of dopamine structural analogues on human gabaρ1 receptor.	gabaergic and dopaminergic pathways are co-localized in several areas of the central nervous system and recently several reports have shown co-release of both neurotransmitters. the gaba-a receptor (β and ρ1 subunits) is modulated by dopamine (da) and, interestingly, gabaρ1 can be modulated by several biogenic amines. here we explored the effects of the metabolites of the dopaminergic pathway and other structural analogues of da on gabaρ1 and the da gated ion channel (lgc-53) from caenorhabditis ...	2017	29234054
increasing the length and hydrophobicity of the c-terminal sequence of transthyretin strengthens its binding affinity to retinol binding protein.	transthyretin (ttr) is a transporter for thyroid hormone (th) and retinol, the latter via binding with retinol binding protein (rbp). both the n-terminal and c-terminal regions of the ttr subunit are located in close proximity to the central binding channel for ligands. during the evolution of vertebrates, these regions changed in length and hydropathy. the changes in the n-terminal sequence were demonstrated to affect the binding affinities for ths and rbp. here, the effects of changes in the c ...	2017	29226076
species specific rna a-to-i editing of mosquito rdl modulates gaba potency and influences agonistic, potentiating and antagonistic actions of ivermectin.	the insect gaba receptor, rdl, is the target of several classes of pesticides. the peptide sequences of rdl are generally highly conserved between diverse insects. however, rna a-to-i editing can effectively alter amino acid residues of rdl in a species specific manner, which can affect the potency of gaba and possibly insecticides. we report here that rna a-to-i editing alters the gene products of rdl in three mosquito disease vectors, recoding five amino acid residues in rdl of aedes aegypti a ...	2017	29223796
rna helicase mov10 is essential for gastrulation and cns development.	mov10 is an rna helicase that modulates access of argonaute 2 to microrna recognition elements in mrnas. we examined the role of mov10 in xenopus laevis development and show a critical role for mov10 in gastrulation and in the development of the central nervous system.	2017	29266590
dynamic intramolecular regulation of the histone chaperone nucleoplasmin controls histone binding and release.	nucleoplasmin (npm) is a highly conserved histone chaperone responsible for the maternal storage and zygotic release of histones h2a/h2b. npm contains a pentameric n-terminal core domain and an intrinsically disordered c-terminal tail domain. though intrinsically disordered regions are common among histone chaperones, their roles in histone binding and chaperoning remain unclear. using an nmr-based approach, here we demonstrate that the xenopus laevis npm tail domain controls the binding of hist ...	2017	29263320
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 ...	2017	29259133
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 ...	2017	29246943
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 ...	2017	28902151
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 ...	2017	28898267
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 ...	2017	28894409
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 ...	2017	28890968
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.	2017	28888063
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 ...	2017	28887447
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. ...	2017	28881966
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 ...	2017	28880077
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 ...	2017	28869924
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 ...	2017	28862340
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 ...	2017	28846034
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 ...	2017	28829038
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 ...	2017	28816653
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) ...	2017	28808056
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 ...	2017	28802123
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 ...	2017	28801588
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 ...	2017	28798983
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 ...	2017	28795134
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 ...	2017	28791673
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 ...	2017	28787093
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) ...	2017	28778799
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 ...	2017	28777439
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 ...	2017	28774755
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 ...	2017	28765211
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 ...	2017	28761125
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 ...	2017	28758360
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- ...	2017	28757209
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 ...	2017	28748472
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 ...	2017	28747464
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 ...	2017	28743909
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 ...	2017	28743005
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 ...	2017	28739643
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 ...	2017	28739571
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.	2017	28736919
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 ...	2017	28719101
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 ...	2017	28716930
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 ...	2017	28715428
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 ...	2017	28709293
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 ...	2017	28708941
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 ...	2017	28702127
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 ...	2017	28700927
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 ...	2017	28697335