Publications

ras-dva1 small gtpase regulates telencephalon development in xenopus laevis embryos by controlling fgf8 and agr signaling at the anterior border of the neural plate.	we previously found that the small gtpase ras-dva1 is essential for the telencephalic development in xenopus laevis because ras-dva1 controls the fgf8-mediated induction of foxg1 expression, a key telencephalic regulator. in this report, we show, however, that ras-dva1 and foxg1 are expressed in different groups of cells; whereas ras-dva1 is expressed in the outer layer of the anterior neural fold, foxg1 and fgf8 are activated in the inner layer from which the telencephalon is derived. we resolv ...	2014	24570397
the cryocapsule: simplifying correlative light to electron microscopy.	correlating complementary multiple scale images of the same object is a straightforward means to decipher biological processes. light microscopy and electron microscopy are the most commonly used imaging techniques, yet despite their complementarity, the experimental procedures available to correlate them are technically complex. we designed and manufactured a new device adapted to many biological specimens, the cryocapsule, that simplifies the multiple sample preparation steps, which at present ...	2014	24533564
the effects of pesticide exposure on ultraviolet-b radiation avoidance behavior in tadpoles.	effects of contaminants on behavior may have important consequences on wildlife populations because behaviors such as predation, predator avoidance, reproduction, and social interaction can affect population dynamics. as a common environmental stressor, ultraviolet-b (uvb) radiation causes various deleterious effects and some aquatic organisms actively avoid uvb radiation in water. however, the extent to which environmental contaminants can impair uvb avoidance has not been evaluated, which may ...	2014	24589757
a voltage dependent non-inactivating na+ channel activated during apoptosis in xenopus oocytes.	ion channels in the plasma membrane are important for the apoptotic process. different types of voltage-gated ion channels are up-regulated early in the apoptotic process and block of these channels prevents or delays apoptosis. in the present investigation we examined whether ion channels are up-regulated in oocytes from the frog xenopus laevis during apoptosis. the two-electrode voltage-clamp technique was used to record endogenous ion currents in the oocytes. during staurosporine-induced apop ...	2014	24586320
rfx7 is required for the formation of cilia in the neural tube.	regulatory factor x (rfx) transcription factors are important for development and are likely involved in the pathogenesis of serious human diseases including ciliopathies. while seven rfx genes have been identified in vertebrates and several rfx transcription factors have been reported to be regulators of ciliogenesis, the role of rfx7 in development including ciliogenesis is not known. here we show that rfx7 in xenopus laevis is expressed in the neural tube, eye, otic vesicles, and somites. kno ...	2014	24530844
evidence for expression and function of angiotensin ii receptor type 1 in pulmonary epithelial cells.	there is a growing evidence that the peptide hormone angiotensin ii (angii) can act as an auto-/paracrine mediator to regulate epithelial ion transport processes. the present study focused on the impact of angii on transepithelial ion transport in pulmonary epithelia. transcripts for the angii receptor type 1 (atr1) were detected in lungs of xenopus laevis and h441 cells (human pulmonary epithelial cell line). native xenopus lung preparations were used for ussing chamber recordings and apically ...	2014	24530803
changes in oscillatory dynamics in the cell cycle of early xenopus laevis embryos.	during the early development of xenopus laevis embryos, the first mitotic cell cycle is long (∼85 min) and the subsequent 11 cycles are short (∼30 min) and clock-like. here we address the question of how the cdk1 cell cycle oscillator changes between these two modes of operation. we found that the change can be attributed to an alteration in the balance between wee1/myt1 and cdc25. the change in balance converts a circuit that acts like a positive-plus-negative feedback oscillator, with spikes o ...	2014	24523664
wiring the retinal circuits activated by light during early development.	light information is sorted by neuronal circuits to generate image-forming (if) (interpretation and tracking of visual objects and patterns) and non-image-forming (nif) tasks. among the nif tasks, photic entrainment of circadian rhythms, the pupillary light reflex, and sleep are all associated with physiological responses, mediated mainly by a small group of melanopsin-expressing retinal ganglion cells (mrgcs). using xenopus laevis as a model system, and analyzing the c-fos expression induced by ...	2014	24521229
degradation of m(r) 25,000 protein by cathepsin l-like protease in xenopus laevis oocytes.	a phosphorylated protein with a molecular mass of 25,000 (pp25) is involved in xenopus laevis vitellogenin b1 and partially overlaps with phosvitin and lipovitellin 2. the protease responsible for pp25 degradation was studied in vitro since this occurs during embryogenesis. initially, a protease thought to be a contaminant of the purified pp25 preparation was analyzed and an antipain-sensitive protease presumed to be involved. when commercially available proteases were examined, pp25 was not deg ...	2014	24510540
cleavage of the symbiosis receptor-like kinase ectodomain promotes complex formation with nod factor receptor 5.	plants form root symbioses with fungi and bacteria to improve their nutrient supply. symbiosis receptor-like kinase (symrk) is required for phosphate-acquiring arbuscular mycorrhiza, as well as for the nitrogen-fixing root nodule symbiosis of legumes and actinorhizal plants, but its precise function was completely unclear. here we show that the extracytoplasmic region of symrk, which comprises three leucine-rich repeats (lrrs) and a malectin-like domain (mld) related to a carbohydrate-binding pr ...	2014	24508172
distinct permeation profiles of the connexin 30 and 43 hemichannels.	connexin 43 (cx43) hemichannels may form open channels in the plasma membrane when exposed to specific stimuli, e.g. reduced extracellular concentration of divalent cations, and allow passage of fluorescent molecules and presumably a range of smaller physiologically relevant molecules. however, the permeability profile of cx43 hemichannels remains unresolved. exposure of cx43-expressing xenopus laevis oocytes to divalent cation free solution induced a gadolinium-sensitive uptake of the fluoresce ...	2014	24503060
vertical signalling involves transmission of hox information from gastrula mesoderm to neurectoderm.	development and patterning of neural tissue in the vertebrate embryo involves a set of molecules and processes whose relationships are not fully understood. classical embryology revealed a remarkable phenomenon known as vertical signalling, a gastrulation stage mechanism that copies anterior-posterior positional information from mesoderm to prospective neural tissue. vertical signalling mediates unambiguous copying of complex information from one tissue layer to another. in this study, we report ...	2014	25514127
involvement of histidine residue his382 in ph regulation of mct4 activity.	monocarboxylate transporter 4 (mct4) is a ph-dependent bi-directional lactate transporter. transport of lactate via mct4 is increased by extracellular acidification. we investigated the critical histidine residue involved in ph regulation of mct4 function. transport of lactate via mct4 was measured by using a xenopus laevis oocyte expression system. mct4-mediated lactate transport was inhibited by zn2+ in a ph physiological condition but not in an acidic condition. the histidine modifier depc (d ...	2014	25919709
negative regulation of the creatine transporter slc6a8 by spak and osr1.	transport regulation involves several kinases including spak (sps1-related proline/alanine-rich kinase) and osr1 (oxidative stress-responsive kinase 1), which are under control of wnk (with-no-k[lys]) kinases. the present study explored whether spak and/or osr1 participate in the regulation of the creatine transporter creat (slc6a8), which accomplishes na+ coupled cellular uptake of creatine in several tissues including kidney, intestine, heart, skeletal muscle and brain.	2014	25531585
pancreatic carcinoma in an african clawed frog (xenopus laevis).	this report describes the histologic features of a pancreatic carcinoma in an adult female african clawed frog (xenopus laevis). the animal was found to be in poor body condition and subsequently euthanized for a complete necropsy. histologically, the pancreas was effaced by packets of polyhedral cells consistent with a pancreatic islet cell carcinoma. metastatic disease was not identified. pancreatic tumors are uncommon in amphibians, and this report is the first to describe a pancreatic carcin ...	2014	25527022
apkc phosphorylates p27xic1, providing a mechanistic link between apicobasal polarity and cell-cycle control.	during the development of the nervous system, apicobasally polarized stem cells are characterized by a shorter cell cycle than nonpolar progenitors, leading to a lower differentiation potential of these cells. however, how polarization might be directly linked to the kinetics of the cell cycle is not understood. here, we report that apicobasally polarized neuroepithelial cells in xenopus laevis have a shorter cell cycle than nonpolar progenitors, consistent with mammalian systems. we show that t ...	2014	25490266
calcium-dependent neuroepithelial contractions expel damaged cells from the developing brain.	both developing and adult organisms need efficient strategies for wound repair. in adult mammals, wounding triggers an inflammatory response that can exacerbate tissue injury and lead to scarring. in contrast, embryonic wounds heal quickly and with minimal inflammation, but how this is achieved remains incompletely understood. using in vivo imaging in the developing brain of xenopus laevis, we show that atp release from damaged cells and subsequent activation of purinergic receptors induce long- ...	2014	25468753
microtubule nucleation remote from centrosomes may explain how asters span large cells.	a major challenge in cell biology is to understand how nanometer-sized molecules can organize micrometer-sized cells in space and time. one solution in many animal cells is a radial array of microtubules called an aster, which is nucleated by a central organizing center and spans the entire cytoplasm. frog (here xenopus laevis) embryos are more than 1 mm in diameter and divide with a defined geometry every 30 min. like smaller cells, they are organized by asters, which grow, interact, and move t ...	2014	25468969
subcellular metabolite and lipid analysis of xenopus laevis eggs by laesi mass spectrometry.	xenopus laevis eggs are used as a biological model system for studying fertilization and early embryonic development in vertebrates. most methods used for their molecular analysis require elaborate sample preparation including separate protocols for the water soluble and lipid components. in this study, laser ablation electrospray ionization (laesi), an ambient ionization technique, was used for direct mass spectrometric analysis of x. laevis eggs and early stage embryos up to five cleavage cycl ...	2014	25506922
differential regulation of the glutamate transporters glt-1 and glast by gsk3β.	the glutamate transporters glast and glt-1 are mainly expressed in glial cells and regulate glutamate levels in the synapses. glast and glt-1 are the targets of several signaling pathways. in this study we explore the possible functional interaction between these transporters and gsk3β. this kinase is involved in multiple cellular processes including neuronal development and synaptic plasticity. to evaluate whether glt-1 and glast were regulated by gsk3β, we coexpressed these proteins in heterol ...	2014	25454285
left-right patterning in xenopus conjoined twin embryos requires serotonin signaling and gap junctions.	a number of processes operating during the first cell cleavages enable the left-right (lr) axis to be consistently oriented during xenopus laevis development. prior work showed that secondary organizers induced in frog embryos after cleavage stages (i.e. conjoined twins arising from ectopic induced primary axes) correctly pattern their own lr axis only when a primary (early) organizer is also present. this instructive effect confirms the unique lr patterning functions that occur during early emb ...	2014	25896280
optogenetics in developmental biology: using light to control ion flux-dependent signals in xenopus embryos.	developmental bioelectricity, electrical signaling among non-excitable cells, is now known to regulate proliferation, apoptosis, gene expression, and patterning during development. the extraordinary temporal and spatial resolution offered by optogenetics could revolutionize the study of bioelectricity the same way it has revolutionized neuroscience. there is, however, no guide to adapting optogenetics to patterning systems. to fill this gap, we used optogenetic reagents, both proteins and photoc ...	2014	25896279
long-range gap junctional signaling controls oncogene-mediated tumorigenesis in xenopus laevis embryos.	in addition to the immediate microenvironment, long-range signaling may be an important component of cancer. molecular-genetic analyses have implicated gap junctions-key mediators of cell-cell communication-in carcinogenesis. we recently showed that the resting voltage potential of distant cell groups is a key determinant of metastatic transformation and tumor induction. here, we show in the xenopus laevis model that gap junctional communication (gjc) is a modulator of the long-range bioelectric ...	2014	25646081
transmembrane signal transduction in oocyte maturation and fertilization: focusing on xenopus laevis as a model animal.	fertilization is a cell biological phenomenon of crucial importance for the birth of new life in a variety of multicellular and sexual reproduction species such as algae, animal and plants. fertilization involves a sequence of events, in which the female gamete "egg" and the male gamete "spermatozoon (sperm)" develop, acquire their functions, meet and fuse with each other, to initiate embryonic and zygotic development. here, it will be briefly reviewed how oocyte cytoplasmic components are orche ...	2014	25546390
dynein light intermediate chains maintain spindle bipolarity by functioning in centriole cohesion.	cytoplasmic dynein 1 (dynein) is a minus end-directed microtubule motor protein with many cellular functions, including during cell division. the role of the light intermediate chains (lics; dync1li1 and 2) within the complex is poorly understood. in this paper, we have used small interfering rnas or morpholino oligonucleotides to deplete the lics in human cell lines and xenopus laevis early embryos to dissect the lics' role in cell division. we show that although dynein lacking lics drives micr ...	2014	25422374
identifying direct targets of transcription factor rfx2 that coordinate ciliogenesis and cell movement.	recently, using the frog xenopus laevis as a model system, we showed that transcription factor rfx2 coordinates many genes involved in ciliogenesis and cell movement in multiciliated cells (chung et al., 2014). to our knowledge, it was the first paper to utilize the genomic resources, including genome sequences and interim gene annotations, from the ongoing xenopus laevis genome project. for researchers who are interested in the application of genomics and systems biology approaches in xenopus s ...	2014	25419512
assessment of natural variation in the first pore domain of the tomato hkt1;2 transporter and characterization of mutated versions of slhkt1;2 expressed in xenopus laevis oocytes and via complementation of the salt sensitive athkt1;1 mutant.	single nucleotide polymorphisms (snps) within the coding sequence of hkt transporters are important for the functioning of these transporters in several plant species. to unravel the functioning of hkt transporters analysis of natural variation and multiple site-directed mutations studies are crucial. also the in vivo functioning of hkt proteins, via complementation studies performed with athkt1;1 plants, could provide essential information about these transporters. in this work, we analyzed the ...	2014	25408697
the olfactory system as a model to study axonal growth patterns and morphology in vivo.	the olfactory system has the unusual capacity to generate new neurons throughout the lifetime of an organism. olfactory stem cells in the basal portion of the olfactory epithelium continuously give rise to new sensory neurons that extend their axons into the olfactory bulb, where they face the challenge to integrate into existing circuitry. because of this particular feature, the olfactory system represents a unique opportunity to monitor axonal wiring and guidance, and to investigate synapse fo ...	2014	25406975
an adhesome comprising laminin, dystroglycan and myosin iia is required during notochord development in xenopus laevis.	dystroglycan (dg) is a transmembrane receptor for laminin that must be expressed at the right time and place in order to be involved in notochord morphogenesis. the function of dg was examined in xenopus laevis embryos by knockdown of dg and overexpression and replacement of the endogenous dg with a mutated form of the protein. this analysis revealed that dg is required for correct laminin assembly, for cell polarization during mediolateral intercalation and for proper differentiation of vacuole ...	2014	25359726
nucleotide bound to rab11a controls localization in rod cells but not interaction with rhodopsin.	precise vectorial transport of rhodopsin is essential for rod photoreceptor health and function. mutations that truncate or extend the c terminus of rhodopsin disrupt this transport, and lead to retinal degeneration and blindness in human patients and in mouse models. here we show that such mutations disrupt the binding of rhodopsin to the small gtpase rab11a. the rhodopsin-rab11a interaction is a direct binding interaction that does not depend on the nucleotide binding state of rab11a. expressi ...	2014	25378153
spak dependent regulation of peptide transporters pept1 and pept2.	spak (ste20-related proline/alanine-rich kinase) is a powerful regulator of renal tubular ion transport and blood pressure. moreover, spak contributes to the regulation of cell volume. little is known, however, about a role of spak in the regulation or organic solutes. the present study thus addressed the influence of spak on the peptide transporters pept1 and pept2.	2014	25376088
optogenetic control of apoptosis in targeted tissues of xenopus laevis embryos.	killerred (kr) is a recently discovered fluorescent protein that, when activated with green light, releases reactive oxygen species (ros) into the cytoplasm, triggering apoptosis in a kr-expressing cell. this property allows for the use of kr as a means of killing cells in an organism with great temporal and spatial specificity, while minimizing the nonspecific effects that can result from mechanical or chemical exposure damage techniques. such optogenetic control of cell death, and the resultin ...	2014	25374461
recruitment of gβγ controls the basal activity of g-protein coupled inwardly rectifying potassium (girk) channels: crucial role of distal c terminus of girk1.	the g-protein coupled inwardly rectifying potassium (girk, or kir3) channels are important mediators of inhibitory neurotransmission via activation of g-protein coupled receptors (gpcrs). girk channels are tetramers comprising combinations of subunits (girk1-4), activated by direct binding of the gβγ subunit of gi/o proteins. heterologously expressed girk1/2 exhibit high, gβγ-dependent basal currents (ibasal) and a modest activation by gpcr or coexpressed gβγ. inversely, the girk2 homotetramers ...	2014	25384780
the virtual xenbase: transitioning an online bioinformatics resource to a private cloud.	as a model organism database, xenbase has been providing informatics and genomic data on xenopus (silurana) tropicalis and xenopus laevis frogs for more than a decade. the xenbase database contains curated, as well as community-contributed and automatically harvested literature, gene and genomic data. a gbrowse genome browser, a blast+ server and stock center support are available on the site. when this resource was first built, all software services and components in xenbase ran on a single phy ...	2014	25380782
cell volume changes regulate slick (slo2.1), but not slack (slo2.2) k+ channels.	slick (slo2.1) and slack (slo2.2) channels belong to the family of high-conductance k+ channels and have been found widely distributed in the cns. both channels are activated by na+ and cl- and, in addition, slick channels are regulated by atp. therefore, the roles of these channels in regulation of cell excitability as well as ion transport processes, like regulation of cell volume, have been hypothesized. it is the aim of this work to evaluate the sensitivity of slick and slack channels to sma ...	2014	25347289
polyubiquitylation drives replisome disassembly at the termination of dna replication.	resolution of replication forks during termination of dna replication is essential for accurate duplication of eukaryotic genomes. here we present evidence consistent with the idea that polyubiquitylation of a replisome component (mcm7) leads to its disassembly at the converging terminating forks because of the action of the p97/vcp/cdc48 protein remodeler. using xenopus laevis egg extract, we have shown that blocking polyubiquitylation results in the prolonged association of the active helicase ...	2014	25342805
diurnal variation of tight junction integrity associates inversely with matrix metalloproteinase expression in xenopus laevis corneal epithelium: implications for circadian regulation of homeostatic surface cell desquamation.	the corneal epithelium provides a protective barrier against pathogen entrance and abrasive forces, largely due to the intercellular junctional complexes between neighboring cells. after a prescribed duration at the corneal surface, tight junctions between squamous surface cells must be disrupted to enable them to desquamate as a component of the tissue homeostatic renewal. we hypothesize that matrix metalloproteinase (mmps) are secreted by corneal epithelial cells and cleave intercellular junct ...	2014	25412440
carbon monoxide (co) is a novel inhibitor of connexin hemichannels.	hemichannels (hcs) are hexamers of connexins that can form gap-junction channels at points of cell contacts or "free hcs" at non-contacting regions. hcs are involved in paracrine and autocrine cell signaling, and under pathological conditions may induce and/or accelerate cell death. therefore, studies of hc regulation are of great significance. nitric oxide affects the activity of cx43 and cx46 hcs, whereas carbon monoxide (co), another gaseous transmitter, modulates the activity of several ion ...	2014	25384983
vitamin supplementation by gut symbionts ensures metabolic homeostasis in an insect host.	despite the demonstrated functional importance of gut microbes, our understanding of how animals regulate their metabolism in response to nutritionally beneficial symbionts remains limited. here, we elucidate the functional importance of the african cotton stainer's (dysdercus fasciatus) association with two actinobacterial gut symbionts and subsequently examine the insect's transcriptional response following symbiont elimination. in line with bioassays demonstrating the symbionts' contribution ...	2014	25339726
differential expression of arid5b isoforms in xenopus laevis pronephros.	arid5b belongs to the arid family of transcription factors characterised by a helix-turn-helix motif- based dna-binding domain called arid (a-t rich interaction domain). in human, alternative splicing leads to long and short isoforms (isoform1 and 2, respectively) which differ in their n-terminal part. in this study, we report the cloning and expression pattern of xenopus laevis arid5b. we have isolated a full length cdna that shows homology with the human arid5b isoform1. furthermore, 5'race ex ...	2014	25354457
lack of negatively charged residues at the external mouth of kir2.2 channels enable the voltage-dependent block by external mg2+.	kir channels display voltage-dependent block by cytosolic cations such as mg2+ and polyamines that causes inward rectification. in fact, cations can regulate k channel activity from both the extracellular and intracellular sides. previous studies have provided insight into the up-regulation of kir channel activity by extracellular k+ concentration. in contrast, extracellular mg2+ has been found to reduce the amplitude of the single-channel current at milimolar concentrations. however, little is ...	2014	25350118
sulfonylureas suppress the stimulatory action of mg-nucleotides on kir6.2/sur1 but not kir6.2/sur2a katp channels: a mechanistic study.	sulfonylureas, which stimulate insulin secretion from pancreatic β-cells, are widely used to treat both type 2 diabetes and neonatal diabetes. these drugs mediate their effects by binding to the sulfonylurea receptor subunit (sur) of the atp-sensitive k(+) (katp) channel and inducing channel closure. the mechanism of channel inhibition is unusually complex. first, sulfonylureas act as partial antagonists of channel activity, and second, their effect is modulated by mgadp. we analyzed the molecul ...	2014	25348414
nkx2.5 is involved in myeloid cell differentiation at anterior ventral blood islands in the xenopus embryo.	we have shown previously that two populations of myeloid cells emerge in the anterior and posterior ventral blood islands (avbi and pvbi) at the different stages in xenopus laevis embryo. in order to elucidate the regulatory mechanism of myeloid cell differentiation in the avbi, we examined the role of nkx2.5, an essential transcription factor for heart differentiation, in regulation of the myeloid cell differentiation in this region. knockdown of endogenous nkx2.5 by introducing mo into the dor ...	2014	25283688
gd(iii)-pymta label is suitable for in-cell epr.	distance measurement in the nanometer range by electron paramagnetic resonance spectroscopy (epr) in combination with site-directed spin labeling is a very powerful tool to monitor the structure and dynamics of biomacromolecules in their natural environment. however, in-cell application is hampered by the short lifetime of the commonly used nitroxide spin labels in the reducing milieu inside a cell. here, we demonstrate that the gd(iii) based spin label gd-pymta is suitable for in-cell epr. gd-p ...	2014	25325832
regulation of clc-2 activity by spak and osr1.	spak (sps1-related proline/alanine-rich kinase) and osr1 (oxidative stress-responsive kinase 1) are powerful regulators of diverse transport processes. both kinases are activated by cell shrinkage and participate in stimulation of regulatory cell volume increase (rvi). execution of rvi involves inhibition of cl- channels. the present study explored whether spak and/or osr1 regulate the activity of the cl- channel clc-2.	2014	25323061
calcium signaling and meiotic exit at fertilization in xenopus egg.	calcium is a universal messenger that mediates egg activation at fertilization in all sexually reproducing species studied. however, signaling pathways leading to calcium generation and the mechanisms of calcium-induced exit from meiotic arrest vary substantially among species. here, we review the pathways of calcium signaling and the mechanisms of meiotic exit at fertilization in the eggs of the established developmental model, african clawed frog, xenopus laevis. we also discuss calcium involv ...	2014	25322156
transporters involved in renal excretion of n-carbamoylglutamate, an orphan drug to treat inborn n-acetylglutamate synthase deficiency.	inborn defects in n-acetylglutamate (nag) synthase (nags) cause a reduction of nag, an essential cofactor for the initiation of the urea cycle. as a consequence, blood ammonium concentrations are elevated, leading to severe neurological disorders. the orphan drug n-carbamoylglutamate (ncg; carbaglu), efficiently overcomes nags deficiency. however, not much is known about the transporters involved in the uptake, distribution, and elimination of the divalent organic anion ncg. organic anion-transp ...	2014	25354943
two different vestigial like 4 genes are differentially expressed during xenopus laevis development.	the vestigial gene (vg) was first characterized in drosophila and several homologues were identified in vertebrates and called vestigial like 1-4 (vgll1-4). vgll proteins interact with the transcription factors tef-1 and mef-2 through a conserved region called tondu (tdu). vgll4s are characterized by two tandem tdu domains which differentiate them from other members of the vestigial family. in xenopus two genes were identified as vgll4. our bioinformatic analysis demonstrated that these two gene ...	2014	25354458
twin xenopus laevis embryos appearing from flattened eggs.	remarkable progress has recently been made in molecular biology of double axis formation in xenopus laevis. leaving aside, for the time being, the problem of the gene expressions regulating xenopus laevis development, here i show that pulse treatment could induce formation of a secondary axis in a fertilized xenopus laevis egg. at 3 min after insemination, metal oxides were added to xenopus fertilized eggs, and then twin embryos appeared. zirconium oxide (zro2) was the most effective metal oxide ...	2014	25311141
phosphorylation and arginine methylation mark histone h2a prior to deposition during xenopus laevis development.	stored, soluble histones in eggs are essential for early development, in particular during the maternally controlled early cell cycles in the absence of transcription. histone post-translational modifications (ptms) direct and regulate chromatin-templated transactions, so understanding the nature and function of pre-deposition maternal histones is essential to deciphering mechanisms of regulation of development, chromatin assembly, and transcription. little is known about histone h2a pre-deposit ...	2014	25302076
liquid chromatography tandem mass spectrometry method using solid-phase extraction and bead-beating-assisted matrix solid-phase dispersion to quantify the fungicide tebuconazole in controlled frog exposure study: analysis of water and animal tissue.	this paper presents the development, optimization, and validation of a lc-ms/ms methodology to determine the concentration of the antifungal drug and fungicide tebuconazole in a controlled exposure study of african clawed frogs (xenopus laevis). the method is validated on animal tank water and on tissue from exposed and non-exposed adult x. laevis. using solid-phase extraction (spe), the analytical method allows for quantification of tebuconazole at concentrations as low as 3.89 pg ml(-1) in 10 ...	2014	25277103
atomic force microscopy on plasma membranes from xenopus laevis oocytes containing human aquaporin 4.	atomic force microscopy (afm) is a unique tool for imaging membrane proteins in near-native environment (embedded in a membrane and in buffer solution) at ~1 nm spatial resolution. it has been most successful on membrane proteins reconstituted in 2d crystals and on some specialized and densely packed native membranes. here, we report on afm imaging of purified plasma membranes from xenopus laevis oocytes, a commonly used system for the heterologous expression of membrane proteins. isoform m23 of ...	2014	25277091
cathepsin b contributes to na+ hyperabsorption in cystic fibrosis airway epithelial cultures.	in cystic fibrosis (cf) lung disease, the absence of functional cf transmembrane conductance regulator results in cl(-)/hco3 (-) hyposecretion and triggers na(+) hyperabsorption through the epithelial na(+) channel (enac), which contribute to reduced airway surface liquid (asl) ph and volume. prostasin, a membrane-anchored serine protease with trypsin-like substrate specificity has previously been shown to activate enac in cf airways. however, prostasin is typically inactive below ph 7.0, sugges ...	2014	25260629
upregulation of eif5b controls cell-cycle arrest and specific developmental stages.	proliferation arrest and distinct developmental stages alter and decrease general translation yet maintain ongoing translation. the factors that support translation in these conditions remain to be characterized. we investigated an altered translation factor in three cell states considered to have reduced general translation: immature xenopus laevis oocytes, mouse es cells, and the transition state of proliferating mammalian cells to quiescence (g0) upon growth-factor deprivation. our data revea ...	2014	25261552
a cycloartane glycoside derived from actaea racemosa l. modulates gabaa receptors and induces pronounced sedation in mice.	23-o-acetylshengmanol 3-o-β-d-xylopyranoside (ac-sm) isolated from actaea racemosa l.-an herbal remedy for the treatment of mild menopausal disorders-has been recently identified as a novel efficacious modulator of gabaa receptors composed of α1-, β2-, and γ2s-subunits. in the present study, we analyzed a potential subunit-selective modulation of gaba-induced chloride currents (igaba) at gaba concentrations eliciting 3-8% of the maximal gaba response (ec3-8) through nine gabaa receptor isoforms ...	2014	25161170
sperm and spermatids contain different proteins and bind distinct egg factors.	spermatozoa are more efficient at supporting normal embryonic development than spermatids, their immature, immediate precursors. this suggests that the sperm acquires the ability to support embryonic development during spermiogenesis (spermatid to sperm maturation). here, using xenopus laevis as a model organism, we performed 2-d fluorescence difference gel electrophoresis (2d-dige) and mass spectrometry analysis of differentially expressed proteins between sperm and spermatids in order to ident ...	2014	25244019
diverse functions of kindlin/fermitin proteins during embryonic development in xenopus laevis.	the kindlin/fermitin family includes three proteins involved in regulating integrin ligand-binding activity and adhesion. loss-of-function mutations in kindlins1 and 3 have been implicated in kindler syndrome and leukocyte adhesion deficiency iii (lad-iii) respectively, whereas kindlin2 null mice are embryonic lethal. post translational regulation of cell-cell and cell-ecm adhesion has long been presumed to be important for morphogenesis, however, few specific examples of activation-dependent ch ...	2014	25173804
electrophysiological characterization of human na⁺/taurocholate cotransporting polypeptide (hntcp) heterologously expressed in xenopus laevis oocytes.	the na(+)/taurocholate cotransporting polypeptide (ntcp) plays a major role in na(+)-dependent bile acid uptake into hepatocytes. the purpose of the present study was to establish the heterologous expression of human ntcp (hntcp) in xenopus laevis oocytes and to elucidate whether the transport of bile acid via hntcp is electrogenic using electrophysiological techniques. first, we evaluated the uptake of taurocholate (tca) by hntcp heterologously expressed in xenopus oocytes utilizing [(3)h]-labe ...	2014	25168282
circadian genes, xbmal1 and xnocturnin, modulate the timing and differentiation of somites in xenopus laevis.	we have been investigating whether xbmal1 and xnocturnin play a role in somitogenesis, a cyclic developmental process with an ultradian period. previous work from our lab shows that circadian genes (xperiod1, xperiod2, xbmal1, and xnocturnin) are expressed in developing somites. somites eventually form the vertebrae, muscles of the back, and dermis. in xenopus, a pair of somites is formed about every 50 minutes from anterior to posterior. we were intrigued by the co-localization of circadian gen ...	2014	25238599
extracellular gentamicin reduces the activity of connexin hemichannels and interferes with purinergic ca(2+) signaling in hela cells.	gap junction channels (gjcs) and hemichannels (hcs) are composed of protein subunits termed connexins (cxs) and are permeable to ions and small molecules. in most organs, gjcs communicate the cytoplasm of adjacent cells, while hcs communicate the intra and extracellular compartments. in this way, both channel types coordinate physiological responses of cell communities. cx mutations explain several genetic diseases, including about 50% of autosomal recessive non-syndromic hearing loss. however, ...	2014	25237294
aqp4 plasma membrane trafficking or channel gating is not significantly modulated by phosphorylation at cooh-terminal serine residues.	aquaporin 4 (aqp4) is the predominant water channel in the mammalian brain and is mainly expressed in the perivascular glial endfeet at the brain-blood interface. aqp4 serves as a water entry site during brain edema formation, and regulation of aqp4 may therefore be of therapeutic interest. phosphorylation of aquaporins can regulate plasma membrane localization and, possibly, the unit water permeability via gating of the aqp channel itself. in vivo phosphorylation of six serine residues in the c ...	2014	25231107
the calcium-dependent ribonuclease xendou promotes er network formation through local rna degradation.	how cells shape and remodel organelles in response to cellular signals is a poorly understood process. using xenopus laevis egg extract, we found that increases in cytosolic calcium lead to the activation of an endogenous ribonuclease, xendou. a fraction of xendou localizes to the endoplasmic reticulum (er) and is required for nuclear envelope assembly and er network formation in a catalysis-dependent manner. using a purified vesicle fusion assay, we show that xendou functions on the surface of ...	2014	25287301
expression, purification, and structural insights for the human uric acid transporter, glut9, using the xenopus laevis oocytes system.	the urate transporter, glut9, is responsible for the basolateral transport of urate in the proximal tubule of human kidneys and in the placenta, playing a central role in uric acid homeostasis. glut9 shares the least homology with other members of the glucose transporter family, especially with the glucose transporting members glut1-4 and is the only member of the glut family to transport urate. the recently published high-resolution structure of xyle, a bacterial d-xylose transporting homologue ...	2014	25286413
the need of mmp-2 on the sperm surface for xenopus fertilization: its role in a fast electrical block to polyspermy.	monospermic fertilization in the frog, xenopus laevis, is ensured by a fast-rising, positive fertilization potential to prevent polyspermy on the fertilized egg, followed by a slow block with the formation of a fertilization envelope over the egg surface. in this paper, we found that not only the enzymatic activity of sperm matrix metalloproteinase-2 (mmp-2) was necessary for a sperm to bind and/or pass through the extracellular coat of vitelline envelope, but also the hemopexin (hpx) domain of ...	2014	25296387
correlative light and electron microscopy for a free-floating spindle in xenopus laevis egg extracts.	cryoimmobilization is an optimal method of preserving sample ultrastructure in electron microscopy studies. however, cryoimmobilization is limited to thin samples and this limitation may necessitate the isolation of the structure of interest. for cellular structures that are found in low number, or only during certain phases of the cell cycle, an added benefit of isolation is the possibility to concentrate the structures. we developed a method to perform correlative light and electron microscopy ...	2014	25287839
using plustiptracker software to measure microtubule dynamics in xenopus laevis growth cones.	microtubule (mt) plus-end-tracking proteins (+tips) localize to the growing plus-ends of mts and regulate mt dynamics(1,2). one of the most well-known and widely-utilized +tips for analyzing mt dynamics is the end-binding protein, eb1, which binds all growing mt plus-ends, and thus, is a marker for mt polymerization(1). many studies of eb1 behavior within growth cones have used time-consuming and biased computer-assisted, hand-tracking methods to analyze individual mts(1-3). our approach is to q ...	2014	25225829
5-mehtyltetrahydrofolate rescues alcohol-induced neural crest cell migration abnormalities.	alcohol is detrimental to early development. fetal alcohol spectrum disorders (fasd) due to maternal alcohol abuse results in a series of developmental abnormalities including cranial facial dysmorphology, ocular anomalies, congenital heart defects, microcephaly and intellectual disabilities. previous studies have been shown that ethanol exposure causes neural crest (nc) apoptosis and perturbation of neural crest migration. however, the underlying mechanism remains elusive. in this report we inv ...	2014	25223405
photoactivation-induced instability of rhodopsin mutants t4k and t17m in rod outer segments underlies retinal degeneration in x. laevis transgenic models of retinitis pigmentosa.	retinitis pigmentosa (rp) is an inherited neurodegenerative disease involving progressive vision loss, and is often linked to mutations in the rhodopsin gene. mutations that abolish n-terminal glycosylation of rhodopsin (t4k and t17m) cause sector rp in which the inferior retina preferentially degenerates, possibly due to greater light exposure of this region. transgenic animal models expressing rhodopsin glycosylation mutants also exhibit light exacerbated retinal degeneration (rd). in this stu ...	2014	25274813
cdc6 controls dynamics of the first embryonic m-phase entry and progression via cdk1 inhibition.	cdc6 is essential for s-phase to initiate dna replication. it also regulates m-phase exit by inhibiting the activity of the major m-phase protein kinase cdk1. here we show that addition of recombinant cdc6 to xenopus embryo cycling extract delays the m-phase entry and inhibits cdk1 during the whole m-phase. down regulation of endogenous cdc6 accelerates the m-phase entry, abolishes the initial slow and progressive phase of histone h1 kinase activation and increases the level of cdk1 activity dur ...	2014	25264619
role for endocytosis of a constitutively active gpcr (gpr185) in releasing vertebrate oocyte meiotic arrest.	vertebrate oocytes are naturally arrested at prophase of meiosis i for sustained periods of time before resuming meiosis in a process called oocyte maturation that prepares the egg for fertilization. members of the constitutively active gpr3/6/12 family of g-protein coupled receptors represent important mediators of meiotic arrest. in the frog oocyte the gpr3/12 homolog gprx (renamed gpr185) has been shown to sustain meiotic arrest by increasing intracellular camp levels through gαsβγ. here we s ...	2014	25220151
activation of sox3 gene by thyroid hormone in the developing adult intestinal stem cell during xenopus metamorphosis.	the maturation of the intestine into the adult form involves the formation of adult stem cells in a thyroid hormone (t3)-dependent process in vertebrates. in mammals, this takes place during postembryonic development, a period around birth when the t3 level peaks. due to the difficulty of manipulating late-stage, uterus-enclosed embryos, very little is known about the development of the adult intestinal stem cells. interestingly, the remodeling of the intestine during the t3-dependent amphibian ...	2014	25211587
thyroid hormone-regulated wnt5a/ror2 signaling is essential for dedifferentiation of larval epithelial cells into adult stem cells in the xenopus laevis intestine.	amphibian intestinal remodeling, where thyroid hormone (t3) induces some larval epithelial cells to become adult stem cells analogous to the mammalian intestinal ones, serves as a unique model for studying how the adult stem cells are formed. to clarify its molecular mechanisms, we here investigated roles of non-canonical wnt signaling in the larval-to-adult intestinal remodeling during xenopus laevis metamorphosis.	2014	25211363
identification of dehydroabietc acid from boswellia thurifera resin as a positive gabaa receptor modulator.	in a two-microelectrode voltage clamp assay with xenopus laevis oocytes, a petroleum ether extract (100 μg/ml) of the resin of boswellia thurifera (burseraceae) potentiated gaba-induced chloride currents (igaba) through receptors of the subtype α₁β₂γ₂s by 319.8% ± 79.8%. with the aid of hplc-based activity profiling, three known terpenoids, dehydroabietic acid (1), incensole (2), and akba (3), were identified in the active fractions of the extract. structure elucidation was achieved by means of ...	2014	25200370
chibby functions in xenopus ciliary assembly, embryonic development, and the regulation of gene expression.	wnt signaling and ciliogenesis are core features of embryonic development in a range of metazoans. chibby (cby), a basal-body associated protein, regulates β-catenin-mediated wnt signaling in the mouse but not drosophila. here we present an analysis of cby's embryonic expression and morphant phenotypes in xenopus laevis. cby rna is supplied maternally, negatively regulated by snail2 but not twist1, preferentially expressed in the neuroectoderm, and regulates β-catenin-mediated gene expression. r ...	2014	25220153
getting to know your neighbor: cell polarization in early embryos.	polarization of early embryos along cell contact patterns--referred to in this paper as radial polarization--provides a foundation for the initial cell fate decisions and morphogenetic movements of embryogenesis. although polarity can be established through distinct upstream mechanisms in caenorhabditis elegans, xenopus laevis, and mouse embryos, in each species, it results in the restriction of par polarity proteins to contact-free surfaces of blastomeres. in turn, par proteins influence cell f ...	2014	25267293
the bile acid receptor tgr5 activates the trpa1 channel to induce itch in mice.	patients with cholestatic disease have increased systemic concentrations of bile acids (bas) and profound pruritus. the g-protein-coupled ba receptor 1 tgr5 (encoded by gpbar1) is expressed by primary sensory neurons; its activation induces neuronal hyperexcitability and scratching by unknown mechanisms. we investigated whether the transient receptor potential ankyrin 1 (trpa1) is involved in ba-evoked, tgr5-dependent pruritus in mice.	2014	25194674
allosteric modulation of alpha4beta2 nicotinic acetylcholine receptors by hepes.	a number of new positive allosteric modulators (pams) have been reported that enhance responses of neuronal alpha7 and alpha4beta2 nicotinic acetylcholine receptor subtypes to orthosteric ligands. pams represent promising new leads for the development of therapeutic agents for disorders involving alterations in nicotinic neurotransmission including autism, alzheimer's and parkinson's disease. during our recent studies of alpha4beta2 pams, we identified a novel effect of 4-(2-hydroxyethyl)-1-pipe ...	2014	22732654
effects of tributyltin on metamorphosis and gonadal differentiation of xenopus laevis at environmentally relevant concentrations.	tributyltin (tbt), a well known endocrine disruptor, has high teratogenicity to embryos of amphibian (xenopus tropicalis). an amphibian metamorphosis assay (ama) and a complete ama (cama) were conducted for tbt. in ama, the body weight, the snout-to-vent length and the hind limb length of x. laevis tadpoles were decreased in tributyltin chloride (tbtcl; 12.5-200 ng/l) treatment groups after 7 days exposure. tbt greatly retarded the development of tadpoles, decreased the number of follicle and in ...	2014	22903176
rna-binding protein vg1rbp regulates terminal arbor formation but not long-range axon navigation in the developing visual system.	local synthesis of β-actin is required for attractive turning responses to guidance cues of growth cones in vitro but its functional role in axon guidance in vivo is poorly understood. the transport and translation of β-actin mrna is regulated by the rna-binding protein, vg1rbp (zipcode-binding protein-1). to examine whether vg1rbp plays a role in axon navigation in vivo, we disrupted vg1rbp function in embryonic xenopus laevis retinal ganglion cells by expressing a dominant-negative vg1rbp and ...	2014	23853158
evidence and uptake routes for zinc oxide nanoparticles through the gastrointestinal barrier in xenopus laevis.	the developmental toxicity of nanostructured materials, as well as their impact on the biological barriers, represents a crucial aspect to be assessed in a nanosafety policy framework. nanosized metal oxides have been demonstrated to affect xenopus laevis embryonic development, with nzno specifically targeting the digestive system. to study the mechanisms of the nzno-induced intestinal lesions, we tested two different nominally sized zno nanoparticles (nps) at effective concentrations. advanced ...	2014	23848496
the ets transcription factor etv1 mediates fgf signaling to initiate proneural gene expression during xenopus laevis retinal development.	fibroblast growth factor signaling plays a significant role in the developing eye, regulating both patterning and neurogenesis. members of the pea3/etv4-subfamily of ets-domain transcription factors (etv1, etv4, and etv5) are transcriptional activators that are downstream targets of fgf/mapk signaling, but whether they are required for eye development is unknown. we show that in the developing xenopus laevis retina, etv1 is transiently expressed at the onset of retinal neurogenesis. we found tha ...	2014	24219979
chromatin immunoprecipitation and deep sequencing in xenopus tropicalis and xenopus laevis.	chromatin immunoprecipitation and deep sequencing (chip-seq) represents a powerful tool for identifying the genomic targets of transcription factors, chromatin remodeling factors, and histone modifications. the frogs xenopus laevis and xenopus tropicalis have historically been outstanding model systems for embryology and cell biology, with emerging utility as highly accessible embryos for genome-wide studies. here we focus on the particular strengths and limitations of xenopus cell biology and g ...	2014	24064036
characterization of the hypothalamus of xenopus laevis during development. ii. the basal regions.	the expression patterns of conserved developmental regulatory transcription factors and neuronal markers were analyzed in the basal hypothalamus of xenopus laevis throughout development by means of combined immunohistochemical and in situ hybridization techniques. the connectivity of the main subdivisions was investigated by in vitro tracing techniques with dextran amines. the basal hypothalamic region is topologically rostral to the basal diencephalon and is composed of the tuberal (rostral) an ...	2014	24122702
novel task channels inhibitors derived from dihydropyrrolo[2,1-a]isoquinoline.	task channels belong to the family of k(+) channels with 4 transmembrane segments and 2 pore domains (4tm/2p) per subunit. these channels have been related to apoptosis in cerebellar granule neurons (cgn), as well as cancer in other tissues. task current is regulated by hormones, neurotransmitters, anesthetics and divalent cations, which are not selective. recently, there has been found some organic compounds that inhibit task current selectively. in order to find other modulators, we report her ...	2014	24212057
morpholino studies in xenopus brain development.	antisense morpholino oligonucleotides (mos) have become a valuable method to knock down protein levels, to block mrna splicing, and to interfere with mirna function. mos are widely used to alter gene expression during development of xenopus and zebra fish, where they are typically injected into the fertilized egg or blastomeres. here, we present methods to use electroporation to target delivery of mos to the central nervous system of xenopus laevis or xenopus tropicalis tadpoles. briefly, mo ele ...	2014	24048933
hydrostatic pressure activates atp-sensitive k+ channels in lung epithelium by atp release through pannexin and connexin hemichannels.	lungs of air-breathing vertebrates are constantly exposed to mechanical forces and therefore are suitable for investigation of mechanotransduction processes in nonexcitable cells and tissues. freshly dissected xenopus laevis lungs were used for transepithelial short-circuit current (isc) recordings and were exposed to increased hydrostatic pressure (hp; 5 cm fluid column, modified ussing chamber). i(sc) values obtained under hp (i(5cm)) were normalized to values before hp (i(0cm)) application (i ...	2014	24048216
gaba(a) receptor transmembrane amino acids are critical for alcohol action: disulfide cross-linking and alkyl methanethiosulfonate labeling reveal relative location of binding sites.	alcohols and inhaled anesthetics modulate gaba(a) receptor (gaba(a)r) function via putative binding sites within the transmembrane regions. the relative position of the amino acids lining these sites could be either inter- or intra-subunit. we introduced cysteines in relevant tm locations and tested the proximity of cysteine pairs using oxidizing and reducing agents to induce or break disulfide bridges between cysteines, and thus change gaba-mediated currents in wild-type and mutant α1β2γ2 gaba( ...	2014	24117469
the unique α4+/-α4 agonist binding site in (α4)3(β2)2 subtype nicotinic acetylcholine receptors permits differential agonist desensitization pharmacology versus the (α4)2(β2)3 subtype.	selected nicotinic agonists were used to activate and desensitize high-sensitivity (hs) (α4)2(β2)3) or low-sensitivity (ls) (α4)3(β2)2) isoforms of human α4β2-nicotinic acetylcholine receptors (nachrs). function was assessed using (86)rb(+) efflux in a stably transfected sh-ep1-hα4β2 human epithelial cell line, and two-electrode voltage-clamp electrophysiology in xenopus laevis oocytes expressing concatenated pentameric hs or ls α4β2-nachr constructs (hsp and lsp). unlike previously studied agon ...	2014	24190916
gender-related sensitivity of development and growth to real microgravity in xenopus laevis.	exposure of organisms to microgravity can induce morphological, physiological, and behavioral modifications which normalize after re-entry in 1g-condition within hours to few weeks. development of xenopus laevis tadpoles, their metamorphosis, and adults' growth were monitored for 3 years after their flight on the 12-day soyuz mission tma13 to the international space station. at onset of microgravity, tadpoles had just developed the hind limb (stage 47) or forelimb bud (stage 50). recordings duri ...	2014	24123857
monitoring gene expression in a single xenopus oocyte using multiple cytoplasmic collections and quantitative rt-pcr.	oocytes and eggs of the african clawed frog, xenopus laevis, are commonly used in gene expression studies. however, monitoring transcript levels in the individual living oocytes remains challenging. to address this challenge, we used a technique based on multiple repeated collections of nanoliter volumes of cytoplasmic material from a single oocyte. transcript quantification was performed by quantitative rt-pcr. the technique allowed monitoring of heterologous gene expression in a single oocyte ...	2014	24165194
novel animal pole-enriched maternal mrnas are preferentially expressed in neural ectoderm.	many animals utilize maternal mrnas to pre-pattern the embryo before the onset of zygotic transcription. in xenopus laevis, vegetal factors specify the germ line, endoderm, and dorsal axis, but there are few studies demonstrating roles for animal-enriched maternal mrnas. therefore, we carried out a microarray analysis to identify novel maternal transcripts enriched in 8-cell-stage animal blastomeres.	2014	24155242
the gafa domain of phosphodiesterase-6 contains a rod outer segment localization signal.	photoreceptor phosphodiesterase-6 (pde6) is a peripheral membrane protein synthesized in the inner segment of photoreceptor cells. newly synthesized pde6 is transported to the outer segment (os) where it serves as a key effector enzyme in the phototransduction cascade. proper localization of pde6 in photoreceptors is critically important to the function and survival of photoreceptor cells. the mechanism of pde6 transport to the os remains largely unknown. in this study, we investigated potential ...	2014	24147783
distinct patterns of hsp30 and hsp70 degradation in xenopus laevis a6 cells recovering from thermal stress.	heat shock proteins (hsps) are molecular chaperones that assist in protein synthesis, folding and degradation and prevent stress-induced protein aggregation. in this study, we examined the pattern of accumulation of hsp30 and hsp70 in xenopus laevis a6 kidney epithelial cells recovering from heat shock. immunoblot analysis revealed the presence of elevated levels of hsp30 after 72h of recovery. however, the relative levels of hsp70 declined to near control levels after 24h. the relative levels o ...	2014	24231468
steroid exposure during larval development of xenopus laevis affects mrna expression of the reproductive pituitary-gonadal axis in a sex- and stage-dependent manner.	steroids are known to influence the reproductive pituitary-gonadal axis in adult amphibians. here, we studied the effects of hormones on pituitary and gonadal mrna expression during the development of xenopus laevis. tadpoles at nf 58 (prometamorphosis) and at nf 66 (freshly metamorphosed) were exposed for three days to 17β-estradiol (e2), tamoxifen (tam), testosterone (t), dihydrotestosterone (dht) at 10(-7)m, and flutamide (flu) at 10(-6)m. in both genders at nf 58 and 66, t and dht decreased ...	2014	24239592
restriction of the xenopus deadsouth mrna to the primordial germ cells is ensured by multiple mechanisms.	deadsouth mrna encoding the rna helicase ddx25 is a component of the germ plasm in xenopus laevis. we investigated the mechanisms underlying its specific mrna expression in primordial germ cells (pgcs). based on our previous findings of several microrna mir-427 recognition elements (mres) in the 3' untranslated region of the mrna, we first examined whether deadsouth mrna was degraded by mir-427 targeting in somatic cells. injection of antisense mir-427 oligomer and reporter mrna for mutated mres ...	2014	24291337
functional properties of human ferroportin, a cellular iron exporter reactive also with cobalt and zinc.	iron homeostasis is achieved by regulating the intestinal absorption of the metal and its recycling by macrophages. iron export from enterocytes or macrophages to blood plasma is thought to be mediated by ferroportin under the control of hepcidin. although ferroportin was identified over a decade ago, little is understood about how it works. we expressed in xenopus oocytes a human ferroportin-enhanced green fluorescent protein fusion protein and observed using confocal microscopy its exclusive p ...	2014	24304836
targeted mutagenesis of multiple and paralogous genes in xenopus laevis using two pairs of transcription activator-like effector nucleases.	transcription activator-like effector nucleases (talens) have been extensively used in genome editing in various organisms. in some cases, however, it is difficult to efficiently disrupt both paralogous genes using a single pair of talens in xenopus laevis because of its polyploidy. here, we report targeted mutagenesis of multiple and paralogous genes using two pairs of talens in x. laevis. first, we show simultaneous targeted mutagenesis of three genes, tyrosinase paralogues (tyra and tyrb) and ...	2014	24329851
grin2b mutations in west syndrome and intellectual disability with focal epilepsy.	to identify novel epilepsy genes using a panel approach and describe the functional consequences of mutations.	2014	24272827
purinergic receptor-induced ca2+ signaling in the neuroepithelium of the vomeronasal organ of larval xenopus laevis.	purinergic signaling has considerable impact on the functioning of the nervous system, including the special senses. purinergic receptors are expressed in various cell types in the retina, cochlea, taste buds, and the olfactory epithelium. the activation of these receptors by nucleotides, particularly adenosine-5'-triphosphate (atp) and its breakdown products, has been shown to tune sensory information coding to control the homeostasis and to regulate the cell turnover in these organs. while the ...	2014	24271060
dominant-negative effects of kcnq2 mutations are associated with epileptic encephalopathy.	mutations in kcnq2 and kcnq3, encoding the voltage-gated potassium channels kv 7.2 and kv 7.3, are known to cause benign familial neonatal seizures mainly by haploinsufficiency. here, we set out to determine the disease mechanism of 7 de novo missense kcnq2 mutations that were recently described in patients with a severe epileptic encephalopathy including pharmacoresistant seizures and pronounced intellectual disability.	2014	24318194