| a hierarchy of h3k4me3 and h3k27me3 acquisition in spatial gene regulation in xenopus embryos. | epigenetic mechanisms set apart the active and inactive regions in the genome of multicellular organisms to produce distinct cell fates during embryogenesis. here, we report on the epigenetic and transcriptome genome-wide maps of gastrula-stage xenopus tropicalis embryos using massive parallel sequencing of cdna (rna-seq) and dna obtained by chromatin immunoprecipitation (chip-seq) of histone h3 k4 and k27 trimethylation and rna polymerase ii (rnapii). these maps identify promoters and transcrib ... | 2009 | 19758566 |
| the curious case of bivalent marks. | bivalently marked chromatin, containing both histone h3 lysine 4 (h3k4) and h3k27 trimethylation, is a hallmark of developmentally regulated paused promoters in mammalian embryonic stem cells. in this issue of developmental cell, akkers et al. report that xenopus tropicalis embryos transition through early development without the requirement for bivalently marked promoters. | 2009 | 19758552 |
| systematic and single cell analysis of xenopus piwi-interacting rnas and xiwi. | piwi proteins and piwi-interacting rnas (pirnas) are essential for germ cell development, but analysis of the molecular mechanisms of these ribonucleoproteins remains challenging in most animal germ cells. to address this challenge, we systematically characterized xiwi, a xenopus piwi homologue, and pirnas from xenopus eggs and oocytes. we used the large size of xenopus eggs to analyze small rnas at the single cell level, and find abundant pirnas and large pirna clusters in the xenopus tropicali ... | 2009 | 19713941 |
| spontaneous calcium spike activity in embryonic spinal neurons is regulated by developmental expression of the na+, k+-atpase beta3 subunit. | different types and patterns of spontaneous electrical activity drive many aspects of neuronal differentiation. neurons in the developing xenopus spinal cord exhibit calcium spikes, which regulate gene transcription and neurotransmitter specification. the ionic currents necessary for spike production have been described. however, the mechanisms that generate the onset of this activity and the basis of its regulation remain unclear. although signaling molecules appear to act on plasma membrane re ... | 2009 | 19535599 |
| rapid gynogenetic mapping of xenopus tropicalis mutations to chromosomes. | pilot forward genetic screens in xenopus tropicalis have isolated over 60 recessive mutations. here we present a simple method for mapping mutations to chromosomes using gynogenesis and centromeric markers. when coupled with available genomic resources, gross mapping facilitates evaluation of candidate genes as well as higher resolution linkage studies. using gynogenesis, we have mapped the genetic locations of the 10 x. tropicalis centromeres, and performed fluorescence in situ hybridization to ... | 2009 | 19441086 |
| resources and transgenesis techniques for functional genomics in xenopus. | recent developments in genomic resources and high-throughput transgenesis techniques have allowed xenopus to 'metamorphose' from a classic model for embryology to a leading-edge experimental system for functional genomics. this process has incorporated the fast-breeding diploid frog, xenopus tropicalis, as a new model-system for vertebrate genomics and genetics. sequencing of the x. tropicalis genome is nearly complete, and its comparison with mammalian sequences offers a reliable guide for the ... | 2009 | 19382936 |
| working map of the lampbrush chromosomes of xenopus tropicalis: a new tool for cytogenetic analyses. | the amphibian xenopus tropicalis, whose genome has been recently sequenced, has become an important model organism for vertebrate developmental genetics. the development of cytogenetic tools in this new model organism should contribute to an understanding of the organization of the amphibian genome and the mapping of a variety of loci of interest. in this respect, oocyte lampbrush chromosomes are particularly useful for the localization of genomic sequences expressed during oogenesis. we have co ... | 2009 | 19334284 |
| temporal and spatial expression of fgf ligands and receptors during xenopus development. | fibroblast growth factor (fgf) signalling plays a major role during early vertebrate development. it is involved in the specification of the mesoderm, control of morphogenetic movements, patterning of the anterior-posterior axis, and neural induction. in mammals, 22 fgf ligands have been identified, which can be grouped into seven subfamilies according to their sequence homology and function. we have cloned 17 fgf genes from xenopus tropicalis and have analysed their temporal expression by rt-pc ... | 2009 | 19322767 |
| bio-electrospraying living xenopus tropicalis embryos: investigating the structural, functional and biological integrity of a model organism. | bio-electrosprays, a recently pioneered direct cell engineering approach, have been demonstrated to handle living cells including stem cells for the development of active specialized and unspecialized microenvironments. this electric field driven technique is currently undergoing vigorous development where the technique is racing towards possible clinical utility. although this direct cell engineering approach has been elucidated to have no significant effects on the processed cells from a molec ... | 2009 | 19305925 |
| overlapping functions of cdx1, cdx2, and cdx4 in the development of the amphibian xenopus tropicalis. | using xenopus tropicalis, we present the first analysis of the developmental effects that result from knocking down the function of the three cdx genes present in the typical vertebrate genome. knockdowns of individual cdx genes lead to a similar range of posterior defects; compound cdx knockdowns result in increasingly severe posterior truncations, accompanied by posterior shifts and reduction of 5' hox gene expression. we provide evidence that cdx and wnt3a genes are components of a positive f ... | 2009 | 19301404 |
| analysis of c/d box snorna genes in vertebrates: the number of copies decreases in placental mammals. | c/d box small nucleolar rnas (snornas) guide site-specific 2'-o-methylation of rnas. nearly all c/d box snornas with known targets are involved in rrna modification. in vertebrates, snornas are encoded in introns of various genes and their processing is coupled with splicing of host gene pre-mrna. here, the genes encoding c/d box snornas that guide 2'-o-methylation of rrna were identified and analyzed in vertebrate genomes. the number of copies of most c/d box snorna genes proved to be lower in ... | 2009 | 19272437 |
| identification of novel transcripts with differential dorso-ventral expression in xenopus gastrula using serial analysis of gene expression. | recent evidence from global studies of gene expression indicates that transcriptomes are more complex than expected. xenopus has been typically used as a model organism to study early embryonic development, particularly dorso-ventral patterning. in order to identify novel transcripts involved in dorso-ventral patterning, we compared dorsal and ventral transcriptomes of xenopus tropicalis at the gastrula stage using serial analysis of gene expression (sage). | 2009 | 19210784 |
| distribution of (ttaggg)n telomeric sequences in karyotypes of the xenopus species complex. | the chromosomal distribution of the conserved vertebrate telomeric (ttaggg)(n) sequence was studied by fluorescence in situ hybridization (fish) in four xenopus species and the triploid silurana tropicalis. as expected, hybridization signals were observed at the distal ends of every chromosome in all species. in addition, the hybridization pattern demonstrates varied organization of (ttaggg)(n) sequences in the different karyotypes. in x. borealis and x. muelleri hybridization signals intensely ... | 2008 | 19188711 |
| xenopus tropicalis as a test system for developmental and reproductive toxicity. | the usefulness of xenopus tropicalis as a model species to investigate endocrine disruption and developmental reproductive toxicity was assessed. in our test system tadpoles were exposed to test substances from shortly after hatching until metamorphosis, including the period of gonadal differentiation. effects on the sex hormone and thyroid hormone axes were evidenced as skewed sex ratios, malformations of reproductive organs, altered cytochrome (cyp19) (aromatase) activity, and gene expression ... | 2009 | 19184736 |
| expression of xenopus tropicalis hnf6/onecut-1. | onecut genes belong to a family of transcription factors that are known to be important in embryonic development. in the present study, we analyzed the pattern of expression of onecut-1/hnf6 in xenopus tropicalis using rt-pcr and whole mount in situ hybridization. expression of the xenopus tropicalis onecut-1/hnf6 gene was found to be conserved in the neural tube, the sensory placodes and in the anterior ventral endoderm in a domain consistent with the developing liver primordium. | 2009 | 19123138 |
| lef1 plays a role in patterning the mesoderm and ectoderm in xenopus tropicalis. | tcf/lef hmg box transcription factors are nuclear effectors of the canonical wnt signaling pathway, which function in cell fate specification. lef1 is required for the development of tissues and organs that depend on epithelial mesenchymal interactions. here, we report the effects of lef1 loss of function on early development in x. tropicalis. depletion of lef1 affects gene expression already during gastrulation and results in abnormal differentiation of cells derived from ectoderm and mesoderm. ... | 2009 | 19123129 |
| loss of reep4 causes paralysis of the xenopus embryo. | members of the reep (receptor expression enhancing protein) family contain a tb2/dp1, hva22 domain that is involved in intracellular trafficking and secretion. consistent with the presence of this domain, reep1 and reep3 enhance the expression of odorant and taste receptors in mammals, while mutation of these genes causes defects in neural development. reep4 was identified in the course of a functional antisense morpholino oligonucleotide screen searching for genes involved in the early developm ... | 2009 | 19123125 |
| studying wnt signaling in xenopus. | xenopus is an established and powerful model system for the study of wnt signaling in vertebrates. above all, the relatively large size of the embryos enables microinjection experiments, which have led to key discoveries not only about the functional role of wnt signaling in vertebrate embryos, but also about the molecular mechanisms of wnt signaling in vertebrate cells. a major advantage of the xenopus model is the ability to obtain large numbers of embryos, which develop relatively rapidly and ... | 2008 | 19109718 |
| cloning and expression analysis of the anterior parahox genes, gsh1 and gsh2 from xenopus tropicalis. | gsx class proteins are members of the parahox homeodomain transcription factor family with conserved roles in specification and patterning of the nervous system. we report the cloning of two gsx genes, gsh1 and gsh2, from the frog xenopus tropicalis. we demonstrate the existence of a single, intact xenopus parahox cluster, containing gsh1, pdx, and cdx2, plus three degenerate clusters containing gsh2, cdx1, and cdx4. anterior expression boundaries of genes from the intact parahox cluster are co- ... | 2009 | 19097192 |
| clotrimazole exposure modulates aromatase activity in gonads and brain during gonadal differentiation in xenopus tropicalis frogs. | clotrimazole is a pharmaceutical used for treatment of fungal infections. it has been found in surface waters outside municipal wastewater treatment plants but data are scarce regarding its effects on aquatic organisms. it is known that clotrimazole and other imidazole fungicides are inhibitors of the enzyme aromatase (cyp 19). aromatase converts androgens into estrogens and is suggested to be involved in the sex differentiation in amphibians. the aim of the present study was to evaluate effects ... | 2009 | 19036460 |
| sex-specific expression of sox9 during gonadogenesis in the amphibian xenopus tropicalis. | to investigate the role of sox9 gene in amphibian gonadogenesis, we analyzed its expression during male and female gonadogenesis in xenopus tropicalis. the results showed that in both sexes sox9 mrna and protein were first detectable after metamorphosis when the gonads were well differentiated and remained present until the adult stage. in the testis, sox9 expression was restricted to the nucleus of sertoli-like cells, similarly to what has been observed in other vertebrates suggesting a conserv ... | 2008 | 18816826 |
| comparative study and expression analysis of the interferon gamma gene locus cytokines in xenopus tropicalis. | using bioinformatics approach, the genome locus containing interleukin (il)-22, il-26, and interferon gamma (ifn-gamma) genes has been identified in the amphibian, xenopus tropicalis. like that in other vertebrates such as fish, birds, and mammals, the xenopus il-22, il-26, and ifn-gamma are clustered in the same chromosome and the adjacent genes are conserved. the genomic structures of the xenopus il-22, il-26, and ifn-gamma gene were identical to that of their mammalian counterparts. the xenop ... | 2008 | 18726591 |
| reproductive toxicity in xenopus tropicalis after developmental exposure to environmental concentrations of ethynylestradiol. | reproductive disorders in wildlife and humans have been linked to developmental exposure to endocrine disrupting chemicals. in frog tadpoles, environmental concentrations of ethynylestradiol (ee(2)) disrupt gonadal differentiation which results in female-biased sex ratios at metamorphosis indicating sex-reversal of genotypic males. it is not known if developmental exposure to estrogens results in reduced reproductive success in amphibians. the objective of this work was to investigate if exposur ... | 2009 | 18692912 |
| skeletogenesis in xenopus tropicalis: characteristic bone development in an anuran amphibian. | in mammals and birds, most of the skeletal bones develop via endochondral ossification. chondrocytes in the cartilaginous anlagen undergo processes of maturation such as hypertrophy, calcification and apoptosis. concomitantly, osteoblasts are recruited to replace the cartilage scaffold gradually with bone matrix and become osteocytes in the trabecular bones. throughout the successive development of bones, several gene products have been identified as being the components of the molecular mechani ... | 2008 | 18692165 |
| comparative genomics approach to the expression of figalpha, one of the earliest marker genes of oocyte differentiation in medaka (oryzias latipes). | we analyzed molecular cascades of sex differentiation in medaka gonads by examining the transcriptional regulation of the oocyte-expressed gene, figalpha. we first confirmed that figalpha is one of the earliest marker genes of oocyte differentiation by quantitative rt-pcr and in situ hybridization. expression of putative figalpha target genes, zpc4 and zpb, followed that of figalpha. a meiosis-specific gene, scp3, showed expression temporally and spatially similar to figalpha. to characterize th ... | 2008 | 18678233 |
| kazrina is required for axial elongation and epidermal integrity in xenopus tropicalis. | kazrin is a recently described desmosomal protein that binds the cornified envelope precursor periplakin. in this study, we have examined kazrin isoform a expression during the development of xenopus tropicalis and investigated the consequences of its depletion. whole mount in situ hybridisation revealed that kazrina mrna is expressed throughout the embryo at least until tadpole stages. xenopus tropicalis embryos that had been injected with antisense morpholino oligonucleotides directed against ... | 2008 | 18498100 |
| expression of micrornas during embryonic development of xenopus tropicalis. | micrornas (mirnas) are short, non-coding rnas that regulate gene expression and have prominent roles during early embryo development and organogenesis. we set out to determine the expression pattern of mirnas in the developmental model system, xenopus tropicalis. we made probes to predicted primary-mirna transcripts and performed in situ hybridization. our data show conserved and novel tissue-specific expression patterns during embryogenesis that suggest functional roles during development. | 2008 | 18440877 |
| xenopus v1r vomeronasal receptor family is expressed in the main olfactory system. | to date, over 100 vomeronasal receptor type 1 (v1r) genes have been identified in rodents. v1r is specifically expressed in the rodent vomeronasal organ (vno) and is thought to be responsible for pheromone reception. recently, 21 putatively functional v1r genes were identified in the genome database of the amphibian xenopus tropicalis. amphibians are the first vertebrates to possess a vno. in order to determine at which point during evolution the vertebrate v1r genes began to function in the vom ... | 2008 | 18238827 |
| early aspects of gonadal sex differentiation in xenopus tropicalis with reference to an antero-posterior gradient. | in an effort to contribute to the development of xenopus tropicalis as an amphibian model system, we carried out a detailed histological analysis of the process of gonadal sex differentiation and were able to find evidence that gonadal differentiation in x. tropicalis follows an antero-posterior gradient. although the main reason for the presence of a gradient of sex differentiation is still unknown, this gradient enabled us to define the early events that signal ovarian and testicular different ... | 2008 | 18213628 |
| distribution of polymorphic and non-polymorphic microsatellite repeats in xenopus tropicalis. | the results of our bioinformatics analysis have found over 91,000 di-, tri-, and tetranucleotide microsatellites in our survey of 25% of the x. tropicalis genome, suggesting there may be over 360,000 within the entire genome. within the x. tropicalis genome, dinucleotide (78.7%) microsatellites vastly out numbered tri- and tetranucleotide microsatellites. similarly, at-rich repeats are overwhelmingly dominant. the four at-only motifs (at, aat, aaat, and aatt) account for 51,858 out of 91,304 mic ... | 2008 | 19812773 |
| injection-mediated transposon transgenesis in xenopus tropicalis and the identification of integration sites by modified extension primer tag selection (epts) linker-mediated pcr. | the generation of transgenic lines is vital to many genetic strategies and provides useful reagents for cell labeling and lineage-tracing experiments. transposon-based systems offer simple, yet robust, platforms for transgenesis in the frog. here, we provide a protocol for a microinjection-based transposon transgenesis method using a 'natural breeding' strategy for the collection of xenopus tropicalis embryos. this method uses co-injection of a plasmid containing a transposon substrate together ... | 2007 | 18007633 |
| the olig family: phylogenetic analysis and early gene expression in xenopus tropicalis. | the olig genes form a small subfamily of basic helix-loop-helix transcription factors. they were discovered in 2000 as genes required for oligodendrocyte lineage specification. since then, olig genes have been identified in various vertebrate species and corresponding sequences accumulated within genomic databases. until now, three groups of olig genes have been characterized. our phylogenetic analysis demonstrates the existence of a fourth group, which we named olig4. genes of the four olig gro ... | 2007 | 17554554 |
| decoding development in xenopus tropicalis. | xenopus tropicalis is rapidly being adopted as a model organism for developmental biology research and has enormous potential for increasing our understanding of how embryonic development is controlled. in recent years there has been a well-organized initiative within the xenopus community, funded largely through the support of the national institutes of health in the us, to develop x. tropicalis as a new genetic model system with the potential to impact diverse fields of research. concerted eff ... | 2007 | 17549727 |
| identification and expression-profiling of xenopus tropicalis mirnas including plant mirna-like rnas at metamorphosis. | small rnas (mir159-like rnas) identical to some plant mir159s were found in xenopus tropicalis mirna cdna libraries (30 mirna families consisting of 75 unique sequences). preferential expression of this rna species was found in neural tissues during development. a sequence matching to this rna species was not found in the 21 available animal's genome databases, but its resembling sequences associated with transposons were found in the x. tropicalis database. a possibility of horizontal transfer ... | 2007 | 17544400 |
| a novel amphibian tier 2 testing protocol: a 30-week exposure of xenopus tropicalis to the antiandrogen flutamide. | in 1996, the u.s. congress mandated the development of a screening program for endocrine-disrupting chemicals (edcs) using validated test systems. subsequently, the endocrine disruptor screening and testing advisory committee recommended the development of a standardized amphibian assay for tier 2 testing of edcs. for that reason, a tier 2 testing protocol using xenopus (silurana) tropicalis and a 30-week, flow-through exposure to the antiandrogen flutamide from stage 46 tadpoles through sexuall ... | 2007 | 17373522 |
| localization of the single copy gene mdh2 on xenopus tropicalis chromosomes by fish-tsa. | a single copy gene, mitochondrial malate dehydrogenase 2 (mdh2), was localized on xenopus tropicalis chromosomes by fluorescence in situ hybridization coupled with tyramide signal amplification (fish-tsa). the respective cdna was cloned and sequenced. the labeled probe hybridized with a subcentromeric region of the long arms of homologous chromosomes 3. results of comparison of the gene localization with previously mapped x. laevis paralogs strongly suggest a common evolutionary origin of chromo ... | 2007 | 17268187 |
| defining synphenotype groups in xenopus tropicalis by use of antisense morpholino oligonucleotides. | to identify novel genes involved in early development, and as proof-of-principle of a large-scale reverse genetics approach in a vertebrate embryo, we have carried out an antisense morpholino oligonucleotide (mo) screen in xenopus tropicalis, in the course of which we have targeted 202 genes expressed during gastrula stages. mos were designed to complement sequence between -80 and +25 bases of the initiating aug codons of the target mrnas, and the specificities of many were tested by (i) designi ... | 2006 | 17112317 |
| monomeric mature protein of nodal-related 3 activates xbra expression. | nodal and related proteins play central roles in axes formation, mesendoderm induction, neural patterning, and left-right development. however, xenopus nodal-related 3 (xnr3) has unique activities in regulating neural induction and convergent extension movements. xnr3 is distinguished from other transforming growth factor-beta superfamily members by the absence of the seventh conserved cysteine at the c terminus of the protein, and little is known about the molecular mechanism of xnr3 action. in ... | 2007 | 17089091 |
| expression of enzymes involved in thyroid hormone metabolism during the early development of xenopus tropicalis. | there are significant indications that amphibians require th (thyroid hormones) prior to their involvement in the regulation of metamorphosis and before the development of a functional thyroid. | 2007 | 17073826 |
| tol2 transposon-mediated transgenesis in xenopus tropicalis. | the diploid frog xenopus tropicalis is becoming a powerful developmental genetic model system. sequencing of the x. tropicalis genome is nearing completion and several labs are embarking on mutagenesis screens. we are interested in developing insertional mutagenesis strategies in x. tropicalis. transposon-mediated insertional mutagenesis, once used exclusively in plants and invertebrate systems, is now more widely applicable to vertebrates. the first step in developing transposons as tools for m ... | 2006 | 16906529 |
| phylogenetic analysis of the tenascin gene family: evidence of origin early in the chordate lineage. | tenascins are a family of glycoproteins found primarily in the extracellular matrix of embryos where they help to regulate cell proliferation, adhesion and migration. in order to learn more about their origins and relationships to each other, as well as to clarify the nomenclature used to describe them, the tenascin genes of the urochordate ciona intestinalis, the pufferfish tetraodon nigroviridis and takifugu rubripes and the frog xenopus tropicalis were identified and their gene organization a ... | 2006 | 16893461 |
| identification of igf, a hinge-region-containing ig class, and igd in xenopus tropicalis. | only three ig isotypes, igm, igx, and igy, were previously known in amphibians. here, we describe a heavy-chain isotype in xenopus tropicalis, igf (encoded by c(phi)), with only two constant region domains. igf is similar to amphibian igy in sequence, but the gene contains a hinge exon, making it the earliest example, in evolution, of an ig isotype with a separately encoded genetic hinge. we also characterized a gene for the heavy chain of igd, located immediately 3' of c(mu), that shares featur ... | 2006 | 16877547 |
| genetic screens for mutations affecting development of xenopus tropicalis. | we present here the results of forward and reverse genetic screens for chemically-induced mutations in xenopus tropicalis. in our forward genetic screen, we have uncovered 77 candidate phenotypes in diverse organogenesis and differentiation processes. using a gynogenetic screen design, which minimizes time and husbandry space expenditures, we find that if a phenotype is detected in the gynogenetic f2 of a given f1 female twice, it is highly likely to be a heritable abnormality (29/29 cases). we ... | 2006 | 16789825 |
| two distinct domains in pro-region of nodal-related 3 are essential for bmp inhibition. | the transforming growth factor-beta (tgf-beta) superfamily member, xenopus nodal-related 3 (xnr3), induces neural tissues through inhibition of bone morphogenetic proteins (bmps). we recently identified an inhibitory mechanism in which the pro-region of xenopus tropicalis nodal-related 3 (xtnr3) physically interacts with bmp ligands. here, we show that disulfide-linked heterodimerization does not contribute to bmp inhibition by xtnr3 and that the xtnr3 mature region, overexpression of which can ... | 2006 | 16762322 |
| developmental expression of foxj1.2, foxj2, and foxq1 in xenopus tropicalis. | members of the fox gene family exhibit remarkably restricted patterns of expression where they have interesting, required functions during development. we have analyzed the developmental expression patterns of three members of the fox gene family, foxj1.2, foxj2, and foxq1, which have not been previously described in xenopus. foxj1.2 is expressed in the otic vesicle during late neurula stages and is then also expressed in the presumptive nephrostomes of the pronephros during tailbud stages. foxj ... | 2006 | 16461016 |
| twisted gastrulation is required for forebrain specification and cooperates with chordin to inhibit bmp signaling during x. tropicalis gastrulation. | in the developing vertebrate embryo, proper dorsal-ventral patterning relies on bmp antagonists secreted by the organizer during gastrulation. the bmp antagonist chordin has a complex interaction with bmps that is governed in part by its interaction with the secreted protein twisted gastrulation (tsg). in different contexts, tsg has activity as either a bmp agonist or as a bmp antagonist. using morpholino oligonucleotides in xenopus tropicalis, we show that reducing tsg gene product results in a ... | 2006 | 16321373 |
| fgf signal interpretation is directed by sprouty and spred proteins during mesoderm formation. | vertebrate gastrulation requires coordination of mesoderm specification with morphogenetic movements. while both of these processes require fgf signaling, it is not known how mesoderm specification and cell movements are coordinated during gastrulation. the related sprouty and spred protein families are recently discovered regulators of receptor tyrosine kinase signaling. we identified two genes for each family in xenopus tropicalis: xtsprouty1, xtsprouty2, xtspred1, and xtspred2. in gain- and l ... | 2005 | 15866160 |
| characterization of multiple lineages of tc1-like elements within the genome of the amphibian xenopus tropicalis. | we have used genomic sequencing data extracted from the first assembly of the xenopus tropicalis genome combined with a degenerated pcr approach to identify multiple lineages of tc1 related transposable elements. full-length elements were isolated in each lineage and were characterized. most of them exhibit the typical characteristics of tc1-like elements (tles). an open reading frame (orf) encoding a 340-350 aa transposase containing a [d, d(34)e] signature was found as well as conserved invert ... | 2005 | 15777729 |
| identification of novel genes affecting mesoderm formation and morphogenesis through an enhanced large scale functional screen in xenopus. | the formation of mesoderm is an important developmental process of vertebrate embryos, which can be broken down into several steps; mesoderm induction, patterning, morphogenesis and differentiation. although mesoderm formation in xenopus has been intensively studied, much remains to be learned about the molecular events responsible for each of these steps. furthermore, the interplay between mesoderm induction, patterning and morphogenesis remains obscure. here, we describe an enhanced functional ... | 2005 | 15763210 |
| identification of mutants in inbred xenopus tropicalis. | xenopus tropicalis offers the potential for genetic analysis in an amphibian. in order to take advantage of this potential, we have been inbreeding strains of frogs for future mutagenesis. while inbreeding a population of nigerian frogs, we identified three mutations in the genetic background of this strain. these mutations are all recessive embryonic lethals. we show that multigenerational mutant analysis is feasible and demonstrate that mutations can be identified, propagated, and readily char ... | 2005 | 15763207 |
| depletion of three bmp antagonists from spemann's organizer leads to a catastrophic loss of dorsal structures. | transplanted spemann's organizer induces dorsal embryonic cell fates such as the nervous system and somites, but in normal development, elimination of individual organizer signals (such as the bone morphogenetic protein [bmp] antagonists) has surprisingly modest effects on these tissues. thus, the role of bmp antagonists may be limited to fine tuning the size of the dorsal domain. however, at least five bmp antagonists are specifically expressed in the organizer, and all can mimic aspects of org ... | 2005 | 15737935 |
| 1.15 a crystal structure of the x. tropicalis spred1 evh1 domain suggests a fourth distinct peptide-binding mechanism within the evh1 family. | the recently described spred protein family has been implicated in the modulation of receptor tyrosine kinase signalling. we report the crystal structure of the enabled/vasodilator-stimulated phosphoprotein homology-1 (evh1) domain from xenopus tropicalis spred1, solved to 1.15 a resolution. this structure confirms that the spred evh1 adopts the pleckstrin-homology fold, with a similar secondary structure to enabled. a translation of one of the peptide-binding groove beta-strands narrows this gr ... | 2005 | 15710406 |
| strategy for profiling and structure elucidation of mucin-type oligosaccharides by mass spectrometry. | a strategy combining accurate mass determination, tandem mass spectrometry, structure homology, and exoglycosidases is described that allows the structural characterization of mucin-type o-linked oligosaccharides. the method is used to profile with quantitation the o-linked oligosaccharide (both neutral and anionic) components of the only diploid xenopus frog, xenopus tropicalis. collision-induced dissociation was used to determine connectivity, to identify previously characterized oligosacchari ... | 2004 | 15481946 |
| analysis of the tcf-3 promoter during early development of xenopus. | xtcf-3 functions as a transcriptional regulator in the canonical wnt signaling cascade and can repress or activate downstream target genes. expression of xtcf-3 is differentially regulated in time and place during development (molenaar et al. [1998] mech dev. 75:151-154), but little is known about the mechanisms that control transcriptional activation and repression. a 15-kb genomic fragment of tcf-3 sequences from xenopus tropicalis was cloned, including the 5' untranslated region; exons 1, 2, ... | 2004 | 15376330 |
| defining a large set of full-length clones from a xenopus tropicalis est project. | amphibian embryos from the genus xenopus are among the best species for understanding early vertebrate development and for studying basic cell biological processes. xenopus, and in particular the diploid xenopus tropicalis, is also ideal for functional genomics. understanding the behavior of genes in this accessible model system will have a significant and beneficial impact on the understanding of similar genes in other vertebrate systems. here we describe the analysis of 219,270 x. tropicalis e ... | 2004 | 15223350 |
| pilot morpholino screen in xenopus tropicalis identifies a novel gene involved in head development. | the diploid frog x. tropicalis has recently been adopted as a model genetic system, but loss-of-function screens in xenopus have not yet been performed. we have undertaken a pilot functional knockdown screen in x. tropicalis for genes involved in nervous system development by injecting antisense morpholino (mo) oligos directed against x. tropicalis mrnas. twenty-six genes with primary expression in the nervous system were selected as targets based on an expression screen previously conducted in ... | 2004 | 14745953 |
| evaluation of xenopus tropicalis as an alternative test organism for frog embryo teratogenesis assay--xenopus (fetax). | as a formal recommendation from an interagency coordinating committee for the validation of alternative methods (iccvam) workshop review of the frog embryo teratogenesis assay--xenopus (fetax) developmental toxicity model, the use of xenopus tropicalis as an alternative test species for this model was evaluated. three test substances with varying developmental toxicity potentials were evaluated using fetax modified to accommodate the use of x. tropicalis. two separate definitive concentration-re ... | 2003 | 12953658 |
| chromosome mapping of xenopus tropicalis using the g- and ag-bands: tandem duplication and polyploidization of larvae heads. | developmental cytogenetic analyses of xenopus tropicalis larvae from two origins were performed on stage 27-34 heads treated with colchicine. standard g-band karyotyping using trypsin and chromosome mapping of 184 bands were examined. although the main karyotype was 2n = 20, polyploidy (3n = 30 or 4n = 40) and aneuploidy were detected in each individual treated with colchicine, even those treated for only 1 h. the percentage of polyploid karyotypes was 10-20% across the total of measured metapha ... | 2002 | 12392576 |
| structure and expression of xenopus tropicalis bmp-2 and bmp-4 genes. | the xenopus tropicalis bmp-2 and bmp-4 genes have been cloned and sequenced. a comparison with the corresponding genes from x. laevis reveals that the bmp-4 genes are conserved at a higher extent than the bmp-2 genes. this is especially evident for the intron sequences, but is also reflected by the exon sequences. while the amino acids of x. tropicalis and x. laevis bmp-4 proteins diverge at about 4%, those of bmp-2 proteins diverge at about 7%. by reverse transcriptase polymerase chain reaction ... | 2001 | 11677055 |
| the development of xenopus tropicalis transgenic lines and their use in studying lens developmental timing in living embryos. | the generation of reporter lines for observing lens differentiation in vivo demonstrates a new strategy for embryological manipulation and allows us to address a long-standing question concerning the timing of the onset of differentiation. xenopus tropicalis was used to make gfp reporter lines with (gamma)1-crystallin promoter elements directing gfp expression within the early lens. x. tropicalis is a close relative of x. laevis that shares the same ease of tissue manipulation with the added ben ... | 2000 | 10751168 |
| frog genetics: xenopus tropicalis jumps into the future. | | 1998 | 9676522 |
| phylogenetic relationships of the pipid frogs xenopus and silurana: an integration of ribosomal dna and morphology. | relationships of the pipid frog genus silurana (= xenopus tropicalis group of some authors) are of particular interest to developmental and molecular biologists because of the purported ancestral (i.e., unduplicated) karyotype of s. tropicalis relative to the genus xenopus. although most previous studies have assumed that silurana is the sister group of xenopus, recent morphological work suggests that silurana is more closely related both to the south american genus pipa and to the african gener ... | 1990 | 2385174 |
| changing the rna polymerase specificity of u snrna gene promoters. | the promoter of a xenopus tropicalis u6 gene can be transcribed by both rna polymerases ii and iii. two distinct elements, a tata-like sequence and the region of transcription initiation, are only required for transcription by rna polymerase iii, while further common elements are required for transcription by both polymerases. based on the unusually stringent requirement for a purine at the normal position of polymerase iii transcription initiation and on the properties of mutants in this region ... | 1988 | 3180217 |
| nucleotide sequence of the xenopus tropicalis larval beta globin gene. | | 1987 | 3697074 |
| karyotype analysis of xenopus tropicalis gray, pipidae. | | 1973 | 4780767 |
| paired box 9 (pax9), the rna polymerase ii transcription factor, regulates human ribosome biogenesis and craniofacial development. | dysregulation of ribosome production can lead to a number of developmental disorders called ribosomopathies. despite the ubiquitous requirement for these cellular machines used in protein synthesis, ribosomopathies manifest in a tissue-specific manner, with many affecting the development of the face. here we reveal yet another connection between craniofacial development and making ribosomes through the protein paired box 9 (pax9). pax9 functions as an rna polymerase ii transcription factor to re ... | 2020 | 32813698 |
| assessment of databases to determine the validity of β- and γ-carbonic anhydrase sequences from vertebrates. | the inaccuracy of dna sequence data is becoming a serious problem, as the amount of molecular data is multiplying rapidly and expectations are high for big data to revolutionize life sciences and health care. in this study, we investigated the accuracy of dna sequence data from commonly used databases using carbonic anhydrase (ca) gene sequences as generic targets. cas are ancient metalloenzymes that are present in all unicellular and multicellular living organisms. among the eight distinct fami ... | 2020 | 32393172 |
| beta-hydroxysteroid dehydrogenase genes in orange-spotted grouper (epinephelus coioides): genome-wide identification and expression analysis during sex reversal. | beta-hydroxysteroid dehydrogenases (β-hsds) are a group of steroidogenic enzymes that are involved in steroid biosynthesis and metabolism, and play a crucial role in mammalian physiology and development, including sex determination and differentiation. in the present study, a genome-wide analysis identified the numbers of β-hsd genes in orange-spotted grouper (epinephelus coioides) (19), human (homo sapiens) (22), mouse (mus musculus) (24), chicken (gallus gallus) (16), xenopus (xenopus tropical ... | 2020 | 32194632 |
| modeling of genome-wide polyadenylation signals in xenopus tropicalis. | alternative polyadenylation (apa) is an important post-transcriptional modification event to process messenger rna (mrna) for transcriptional termination, transport, and translation. in the present study, we characterized poly(a) signals in xenopus tropicalis using 70,918 highly confident poly(a) sites derived from 16,511 protein-coding genes to understand their roles in the regulation of embryo development and gender difference. we examined potential factors, including the gene length, the numb ... | 2019 | 31333724 |
| advancing genetic and genomic technologies deepen the pool for discovery in xenopus tropicalis. | xenopus laevis and xenopus tropicalis have long been used to drive discovery in developmental, cell, and molecular biology. these dual frog species boast experimental strengths for embryology including large egg sizes that develop externally, well-defined fate maps, and cell-intrinsic sources of nutrients that allow explanted tissues to grow in culture. development of the xenopus cell extract system has been used to study cell cycle and dna replication. xenopus tadpole tail and limb regeneration ... | 2019 | 31254427 |
| expression, purification and crystallization of the novel xenopus tropicalis aldh16b1, a homologue of human aldh16a1. | aldh16 is a novel family of the aldehyde dehydrogenase (aldh) superfamily with unique structural characteristics that distinguish it from the other aldh superfamily members. in addition to structural characteristics, there is an evolutionary-related grouping within the aldh 16 genes. the aldh16 isozymes in frog, lower animals, and bacteria possess a critical cys residue in their active site, which is absent from aldh16 in mammals and fish. genomic analysis and plasma metabolomic studies have ass ... | 2019 | 30894314 |
| search for potential reading frameshifts in cds from arabidopsis thaliana and other genomes. | a new mathematical method for potential reading frameshift detection in protein-coding sequences (cds) was developed. the algorithm is adjusted to the triplet periodicity of each analysed sequence using dynamic programming and a genetic algorithm. this does not require any preliminary training. using the developed method, cds from the arabidopsis thaliana genome were analysed. in total, the algorithm found 9,930 sequences containing one or more potential reading frameshift(s). this is ∼21% of al ... | 2019 | 30726896 |
| unexpected metabolic disorders induced by endocrine disruptors in xenopus tropicalis provide new lead for understanding amphibian decline. | despite numerous studies suggesting that amphibians are highly sensitive to endocrine disruptors (eds), both their role in the decline of populations and the underlying mechanisms remain unclear. this study showed that frogs exposed throughout their life cycle to ed concentrations low enough to be considered safe for drinking water, developed a prediabetes phenotype and, more commonly, a metabolic syndrome. female xenopus tropicalis exposed from tadpole stage to benzo(a)pyrene or triclosan at co ... | 2018 | 29686083 |
| a comparative genomics study of carbohydrate/glucose metabolic genes: from fish to mammals. | glucose plays a key role as an energy source in most mammals, but its importance in fish appears to be limited that so far seemed to belong to diabetic humans only. several laboratories worldwide have made important efforts in order to better understand this strange phenotype observed in fish. however, the mechanism of carbohydrate/glucose metabolism is astonishingly complex. why basal glycaemia is different between fish and mammals and how carbohydrate metabolism is different amongst organisms ... | 2018 | 29642853 |
| conservation and divergence of protein pathways in the vertebrate heart. | heart disease is the leading cause of death in the western world. attaining a mechanistic understanding of human heart development and homeostasis and the molecular basis of associated disease states relies on the use of animal models. here, we present the cardiac proteomes of 4 model vertebrates with dual circulatory systems: the pig (sus scrofa), the mouse (mus musculus), and 2 frogs (xenopus laevis and xenopus tropicalis). determination of which proteins and protein pathways are conserved and ... | 2019 | 31490923 |
| a new evolutionary model for the vertebrate actin family including two novel groups. | database surveys in the vertebrate model organisms: chicken (gallus gallus), western clawed frog (xenopus tropicalis), anole lizard (anolis carolinensis) and zebrafish (danio rerio) indicate that in some of these species the number of actin paralogues differs from the well-established six paralogues in mouse (mus musculus). to investigate differential functions of actins and for establishing disease models it is important to know how actins in the different model organisms relate to each other a ... | 2019 | 31560986 |
| investigation of non-cb1, non-cb2 win55212-2-sensitive g-protein-coupled receptors in the brains of mammals, birds, and amphibians. | previous studies have found non-cb1 non-cb2 g-protein-coupled receptors in rodents that are activated by the aminoalkylindole cannabinoid agonist win55212-2. this work obtained evidence for the presence or absence of similar receptors in the brains of other mammals, birds and amphibians. | 2018 | 30376752 |
| alignment of alzheimer's disease amyloid β-peptide and klotho. | the cause of alzheimer's disease (ad) is poorly understood. in 1991, the amyloid hypothesis postulated that β-amyloid (aβ) accumulation is a key element. it follows that clearing the brain of aβ would be beneficial, which has not been the case. therefore, aβ is likely a result, not a cause, of ad and may be protective rather than harmful. the apolipoprotein e4 (apoe4) allele is the strongest genetic risk factor for ad. klotho (kl), encoded by the kl gene, may be another ad-related protein. fgf21 ... | 2020 | 32999998 |
| characterization of a novel thyrotropin-releasing hormone receptor, trhr3, in chickens. | the physiological roles of thyrotropin-releasing hormone (trh) are proposed to be mediated by trh receptors (trhr), which have been divided into 3 subtypes, namely, trhr1, trhr2, and trhr3, in vertebrates. although 2 trh receptors (trhr1 and trhr3) have been predicted to exist in birds, it remains unclear whether trhr3 is a functional trh receptor similar to trhr1. here, we reported the functionality and tissue expression of trhr3 in chickens. the cloned chicken trhr3 (ctrhr3) encodes a receptor ... | 2020 | 32115036 |
| lampreys, the jawless vertebrates, contain three pax6 genes with distinct expression in eye, brain and pancreas. | the transcription factor pax6 is crucial for the development of the central nervous system, eye, olfactory system and pancreas, and is implicated in human disease. while a single pax6 gene exists in human and chicken, pax6 occurs as a gene family in other vertebrates, with two members in elephant shark, xenopus tropicalis and anolis lizard and three members in teleost fish such as stickleback and medaka. however, the complement of pax6 genes in jawless vertebrates (cyclostomes), the sister group ... | 2019 | 31863055 |
| sea version 3.0: a comprehensive extension and update of the super-enhancer archive. | super-enhancers (ses) are critical for the transcriptional regulation of gene expression. we developed the super-enhancer archive version 3.0 (sea v. 3.0, http://sea.edbc.org) to extend se research. sea v. 3.0 provides the most comprehensive archive to date, consisting of 164 545 super-enhancers. of these, 80 549 are newly identified from 266 cell types/tissues/diseases using an optimized computational strategy, and 52 have been experimentally confirmed with manually curated references. we now s ... | 2020 | 31667506 |
| "lost and found": snorna annotation in the xenopus genome and implications for evolutionary studies. | small nucleolar rnas (snornas) function primarily as guide rnas for posttranscriptional modification of rrnas and spliceosomal snrnas, both of which are functionally important and evolutionarily conserved molecules. it is commonly believed that snornas and the modifications they mediate are highly conserved across species. however, most relevant data on snorna annotation and rna modification are limited to studies on human and yeast. here, we used rna-sequencing data from the giant oocyte nucleu ... | 2020 | 31553476 |
| the snps in myod gene from normal muscle developing individuals have no effect on muscle mass. | myogenic differentiation 1 (myod) is a crucial master switch in regulating muscle-specific gene transcription. forced expression of myod is equipped to induce several cell lineages into myoblast, which then differentiate and fuse into myotube. pig is one of the most significant livestock supplying meat, and has been classified into lean, fat and miniature pig breeds. however, the mechanisms underlying muscle mass variation among different pig breeds have remained unclear. considering the importa ... | 2019 | 31477002 |
| comparative transcriptome reveal the potential adaptive evolutionary genes in andrias davidianus. | to search the evidence of molecular evolution mechanism for aquatic and cave habitat in andrias davidianus, the evolution analysis was carried out among several species transcriptome data. the transcriptome data of notophthalmus viridescens, xenopus tropicalis, cynops pyrrhogaster, hynobius chinensis and a. davidianus were obtained from the genbank and reassembled except xenopus tropicalis. the blast search of transcriptome data obtained 1244 single-copy orthologous genes among five species. a p ... | 2018 | 29483849 |
| a role for sox9 in post-transcriptional processes: insights from the amphibian oocyte. | sox9 is a member of the gene family of sox transcription factors, which is highly conserved among vertebrates. it is involved in different developmental processes including gonadogenesis. in all amniote species examined thus far, sox9 is expressed in the sertoli cells of the male gonad, suggesting an evolutionarily conserved role in testis development. however, in the anamniotes, fishes and amphibians, it is also expressed in the oocyte but the significance of such an expression remains to be el ... | 2018 | 29740094 |
| spindle assembly in egg extracts of the marsabit clawed frog, xenopus borealis. | egg extracts of the african clawed frog xenopus laevis have provided a cell-free system instrumental in elucidating events of the cell cycle, including mechanisms of spindle assembly. comparison with extracts from the diploid western clawed frog, xenopus tropicalis, which is smaller at the organism, cellular and subcellular levels, has enabled the identification of spindle size scaling factors. we set out to characterize the marsabit clawed frog, xenopus borealis, which is intermediate in size b ... | 2018 | 29573195 |
| amiodarone bioconcentration and suppression of metamorphosis in xenopus. | trace concentrations of a number of pharmaceutically active compounds have been detected in the aquatic environment in many countries, where they are thought to have the potential to exert adverse effects on non-target organisms. amiodarone (amd) is one such high-risk compound commonly used in general hospitals. amd is known to alter normal thyroid hormone (th) function, although little information is available regarding the specific mechanism by which this disruption occurs. anuran tadpole meta ... | 2020 | 32956954 |
| maximizing crispr/cas9 phenotype penetrance applying predictive modeling of editing outcomes in xenopus and zebrafish embryos. | crispr/cas9 genome editing has revolutionized functional genomics in vertebrates. however, crispr/cas9 edited f0 animals too often demonstrate variable phenotypic penetrance due to the mosaic nature of editing outcomes after double strand break (dsb) repair. even with high efficiency levels of genome editing, phenotypes may be obscured by proportional presence of in-frame mutations that still produce functional protein. recently, studies in cell culture systems have shown that the nature of cris ... | 2020 | 32887910 |
| conservation of glomerular organization in the main olfactory bulb of anuran larvae. | the glomerular array in the olfactory bulb of many vertebrates is segregated into molecularly and anatomically distinct clusters linked to different olfactory functions. in anurans, glomerular clustering is so far only described in xenopus laevis. we traced olfactory projections to the bulb in tadpoles belonging to six distantly related anuran species in four families (pipidae, hylidae, bufonidae, dendrobatidae) and found that glomerular clustering is remarkably conserved. the general bauplan co ... | 2020 | 32792916 |
| polyploidization and pseudogenization in allotetraploid frog xenopus laevis promote the evolution of aquaporin family in higher vertebrates. | aquaporins (aqps), as members of the major intrinsic protein (mip) superfamily, facilitated the permeation of water and other solutes and are involved in multiple biological processes. aqp family exists in almost all living organisms and is highly diversified in vertebrates in both classification and function due to genome wide duplication. while some aqp orthologs have been lost in higher vertebrates through evolution. | 2020 | 32727380 |
| differences in intrinsic tubulin dynamic properties contribute to spindle length control in xenopus species. | the function of cellular organelles relates not only to their molecular composition but also to their size. however, how the size of dynamic mesoscale structures is established and maintained remains poorly understood [1-3]. mitotic spindle length, for example, varies several-fold among cell types and among different organisms [4]. although most studies on spindle size control focus on changes in proteins that regulate microtubule dynamics [5-8], the contribution of the spindle's main building b ... | 2020 | 32386526 |
| multidirectional changes in parameters related to sulfur metabolism in frog tissues exposed to heavy metal-related stress. | the investigations showed changes of the cystathionine γ-lyase (cth), 3-mercaptopyruvate sulfurtransferase (mpst) and rhodanese (tst) activity and gene expression in the brain, heart, liver, kidney, skeletal muscles and testes in frogs pelophylaxridibundus, xenopuslaevis and xenopus tropicalis in response to pb2+, hg2+ and cd2+ stress. the results were analyzed jointly with changes in the expression of selected antioxidant enzymes (cytoplasmic and mitochondrial superoxide dismutase, glutathione ... | 2020 | 32283689 |
| simple embryo injection of long single-stranded donor templates with the crispr/cas9 system leads to homology-directed repair in xenopus tropicalis and xenopus laevis. | we report model experiments in which simple microinjection of fertilized eggs has been used to effectively perform homology-directed repair (hdr)-mediated gene editing in the two xenopus species used most frequently for research: x. tropicalis and x. laevis. we have used long single-stranded dnas having phosphorothioate modifications as donor templates for hdr at targeted genomic sites using the clustered regularly interspaced short palindromic repeats/crispr-associated protein 9 (crispr/cas9) s ... | 2020 | 32277804 |
| organ-specific requirements for thyroid hormone receptor ensure temporal coordination of tissue-specific transformations and completion of xenopus metamorphosis. | background: thyroid hormone (triiodothyronine [t3]) is essential for the development throughout vertebrates. anuran metamorphosis mimics mammalian postembryonic development, a period around birth when plasma t3 level peaks and many organs/tissues mature into their adult forms. compared with the uterus-enclosed mammalian embryos, tadpoles can be easily manipulated to study the roles of t3 and t3 receptors (trs) in tissue remodeling and adult organ development. we and others have previously knocke ... | 2020 | 31854240 |
| serotonin and mucxs release by small secretory cells depend on xpod, a ssc specific marker gene. | mucus secretion and ciliary motility are hallmarks for muco-ciliary epithelia (mce). both, mammalian airways as well as the less complex epidermis of xenopus embryos show cilia-driven mucus flow to protect the organism against harmful effects by exogenous pathogens or pollutants. four cell types set up the epidermal mce in xenopus. multi-ciliated cells (mccs) generate an anterior to posterior flow of mucus. ion secreting cells (iscs) are characterized by the expression of ion transporters, presu ... | 2020 | 31705622 |
| kif2a scales meiotic spindle size in hymenochirus boettgeri. | size is a fundamental feature of biological systems that affects physiology at all levels. for example, the dynamic, microtubule-based spindle that mediates chromosome segregation scales to a wide range of cell sizes across different organisms and cell types. xenopus frog species possess a variety of egg and meiotic spindle sizes, and differences in activities or levels of microtubule-associated proteins in the egg cytoplasm between xenopus laevis and xenopus tropicalis have been shown to accoun ... | 2019 | 31630945 |
| morpholino studies in xenopus brain development. | antisense morpholino oligonucleotides (mos) have become a valuable method to knockdown protein levels, to block with mrna splicing and to interfere with mirna function. mos are widely used to alter gene expression in development of xenopus and zebrafish, 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 electr ... | 2020 | 31552666 |
| characteristics of in vivo model systems for ovarian cancer studies. | an understanding of the molecular pathogenesis and heterogeneity of ovarian cancer holds promise for the development of early detection strategies and novel, efficient therapies. in this review, we discuss the advantages and limitations of animal models available for basic and preclinical studies. the fruit fly model is suitable mainly for basic research on cellular migration, invasiveness, adhesion, and the epithelial-to-mesenchymal transition. higher-animal models allow to recapitulate the arc ... | 2019 | 31540126 |
| novel vectors for functional interrogation of xenopus orfeome coding sequences. | the current xenopus orfeome contains ~10,250 validated, full-length cdna sequences without stop codons from xenopus laevis and ~3,970 from xenopus tropicalis cloned into gateway-compatible entry vectors. to increase the utility of the orfeome, we have constructed the gateway-compatible destination vectors pdxtp and pdxtr, which in combination can control the spatial and temporal expression of any open reading frame (orf). pdxtp receives a promoter/enhancer of interest, which controls the spatial ... | 2019 | 31403250 |
| evolution of cis-regulatory modules for the head organizer gene goosecoid in chordates: comparisons between branchiostoma and xenopus. | in cephalochordates (amphioxus), the notochord runs along the dorsal to the anterior tip of the body. in contrast, the vertebrate head is formed anterior to the notochord, as a result of head organizer formation in anterior mesoderm during early development. a key gene for the vertebrate head organizer, goosecoid (gsc), is broadly expressed in the dorsal mesoderm of amphioxus gastrula. amphioxus gsc expression subsequently becomes restricted to the posterior notochord from the early neurula. thi ... | 2019 | 31388442 |