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amphioxus alcohol dehydrogenase is a class 3 form of single type and of structural conservation but with unique developmental expression.the coding region of amphioxus alcohol dehydrogenase class 3 (adh3) has been characterized from two species, branchiostoma lanceolatum and branchiostoma floridae. the species variants have residue differences at positions that result in only marginal functional distinctions. activity measurements show a class 3 glutathione-dependent formaldehyde dehydrogenase, with kcat/km values about threefold those of the human class 3 adh enzyme. only a single adh3 form is identified in each of the two amphi ...200011054102
amphioxus evx genes: implications for the evolution of the midbrain-hindbrain boundary and the chordate tailbud.evx genes are widely used in animal development. in vertebrates they are crucial in gastrulation, neurogenesis, appendage development and tailbud formation, whilst in protostomes they are involved in gastrulation and neurogenesis, as well as segmentation at least in drosophila. we have cloned the evx genes of amphioxus (branchiostoma floridae), and analysed their expression to understand how the functions of evx have evolved between invertebrates and vertebrates, and in particular at the origin ...200111543613
minisatellite instability at the adh locus reveals somatic polymorphism in amphioxus.amphioxus (subphylum cephalochordata) is the closest living relative to vertebrates and widely used for phylogenetic analyses of vertebrate gene evolution. amphioxus genes are highly polymorphic, but the origin and nature of this variability is unknown. we have analyzed the alcohol dehydrogenase locus (adh3) in two amphioxus species (branchiostoma lanceolatum and branchiostoma floridae) and found that genetic variation is related to repetitive dna sequences, mainly minisatellites. small pool-pcr ...200212087171
isolation of amphicasp-3/7, an ancestral caspase from amphioxus (branchiostoma floridae). evolutionary considerations for vertebrate caspases.caspases are a large family of cysteine proteases that play an essential role as effectors of apoptosis in metazoans. thirteen different caspases have been identified in vertebrates so far, and their function in apoptotic or inflammatory responses is well documented. we have taken advantage of the broadly accepted condition of amphioxus (cephalochordata, branchiostoma floridae) as the closest living relative to vertebrates to study the molecular evolution of caspases. here we report for the firs ...200212232796
complex history of a chromosomal paralogy region: insights from amphioxus aromatic amino acid hydroxylase genes and insulin-related genes.aromatic amino acid hydroxylase (aaah) genes and insulin-like genes form part of an extensive paralogy region shared by human chromosomes 11 and 12, thought to have arisen by tetraploidy in early vertebrate evolution. cloning of a complementary dna (cdna) for an amphioxus (branchiostoma floridae) hydroxylase gene (amphipah) allowed us to investigate the ancestry of the human chromosome 11/12 paralogy region. molecular phylogenetic evidence reveals that amphipah is orthologous to vertebrate pheny ...199812572601
evolution of the proto-mhc ancestral region: more evidence for the plesiomorphic organisation of human chromosome 9q34 region.the present day structure of the vertebrate major histocompatibility complex (mhc) and its three paralogous regions has always been a focus of interest. in a recent study, nine human anchor genes located in the mhc region were cloned from a branchiostoma floridae (amphioxus) cosmid library. the identification and analysis of 31 surrounding genes led to the most probable model of two rounds of en bloc duplication giving rise to these regions. these events were estimated to have occurred after the ...200314530884
phylogenetic relationships of the fox (forkhead) gene family in the bilateria.the forkhead or fox gene family encodes putative transcription factors. there are at least four fox genes in yeast, 16 in drosophila melanogaster (dm) and 42 in humans. recently, vertebrate fox genes have been classified into 17 groups named foxa to foxq. here, we extend this analysis to invertebrates, using available sequences from d. melanogaster, anopheles gambiae (ag), caenorhabditis elegans (ce), the sea squirt ciona intestinalis (ci) and amphioxus branchiostoma floridae (bf), from which we ...200314563554
amino acids defining the acyl pocket of an invertebrate cholinesterase.amphioxus (branchiostoma floridae) cholinesterase 2 (che2) hydrolyzes acetylthiocholine (asch) almost exclusively. we constructed a homology model of che2 on the basis of torpedo californica acetylcholinesterase (ache) and found that the acyl pocket of the enzyme resembles that of drosophila melanogaster ache, which is proposed to be comprised of phe330 (phe290 in t. californica ache) and phe440 (val400), rather than leu328 (phe288) and phe330 (phe290), as in vertebrate ache. in che2, the homolo ...200314662305
evolutionary perspective on annexin calcium-binding domains.molecular systematic analysis of the annexin gene superfamily characterized the evolutionary origin, frequency and range of structural variation in calcium interaction domains that are considered intrinsic for membrane targeting and ion channel function. approximately 36% of annexin repeat domains in an estimated 100 distinct subfamilies contained amino acid changes consistent with the functional loss of type two calcium-binding sites. at least 11% of annexin domains contained a novel k/h/rgd mo ...200415590063
the genomic environment around the aromatase gene: evolutionary insights.the cytochrome p450 aromatase (cyp19), catalyses the aromatisation of androgens to estrogens, a key mechanism in vertebrate reproductive physiology. a current evolutionary hypothesis suggests that cyp19 gene arose at the origin of vertebrates, given that it has not been found outside this clade. the human cyp19 gene is located in one of the proposed mhc-paralogon regions (hsa15q). at present it is unclear whether this genomic location is ancestral (which would suggest an invertebrate origin for ...200516098224
construction of a bac library for chinese amphioxus branchiostoma belcheri and identification of clones containing amphi-pax genes.amphioxus is a crucial organism for the study of vertebrate evolution. although a genomic bac library of branchiostoma floridae has been constructed, we report here another bac library construction of its distant relative species branchiostoma belcheri. the amphioxus bac library established in present study consists of 45,312 clones arrayed in one hundred and eighteen 384-well plates. the average insert fragment size was 120 kb estimated by pulsed field gel electrophoresis (pfge) analysis of 318 ...200516172535
getting closer to a pre-vertebrate genome: the non-ltr retrotransposons of branchiostoma floridae.non-ltr retrotransposons are common in vertebrate genomes and although present in invertebrates they appear at a much lower frequency. the cephalochordate amphioxus is the closest living relative to vertebrates and has been considered a good model for comparative analyses of genome expansions during vertebrate evolution. with the aim to assess the involvement of transposable elements in these events, we have analysed the non-ltr retrotransposons of branchiostoma floridae. in silico searches have ...200616733533
identification and characterisation of five novel miniature inverted-repeat transposable elements (mites) in amphioxus (branchiostoma floridae).as the sister group to vertebrates, amphioxus is consistently used as a model of genome evolution for understanding the invertebrate/vertebrate transition. the amphioxus genome has not undergone massive duplications like those in the vertebrates or disruptive rearrangements like in the genome of ciona, a urochordate, making it an ideal evolutionary model. transposable elements have been linked to many genomic evolutionary changes including increased genome size, modified gene expression, massive ...200616733534
expression of amphipou-iv in the developing neural tube and epidermal sensory neural precursors in amphioxus supports a conserved role of class iv pou genes in the sensory cells development.pou genes play a prominent role in the nervous system differentiation of several organism models, and in particular, they are involved in the differentiation of sensory neurons in numerous invertebrate and vertebrate species. in the present report, cloning and expression profile of a class iv pou gene in amphioxus was assessed for understanding its role in the sensory systems development. a single class iv gene, amphipou-iv was isolated from the amphioxus branchiostoma floridae. from a phylogene ...200616773340
fgfrl1, a fibroblast growth factor receptor-like gene, is found in the cephalochordate branchiostoma floridae but not in the urochordate ciona intestinalis.fgfrl1 is a novel member of the fibroblast growth factor receptor family that controls the formation of musculoskeletal tissues. some vertebrates, including man, cow, dog, mouse, rat and chicken, possess a single copy the fgfrl1 gene. teleostean fish have two copies, fgfrl1a and fgfrl1b, because they have undergone a whole genome duplication. vertebrates belong to the chordates, a phylum that also includes the subphyla of the cephalochordates (e.g. branchiostoma floridae) and urochordates (tunic ...200616887372
novel acetylcholinesterase target site for malaria mosquito control.current anticholinesterase pesticides were developed during world war ii and are toxic to mammals because they target a catalytic serine residue of acetylcholinesterases (aches) in insects and in mammals. a sequence analysis of aches from 73 species and a three-dimensional model of a malaria-carrying mosquito (anopheles gambiae) ache (agache) reported here show that c286 and r339 of agache are conserved at the opening of the active site of aches in 17 invertebrate and four insect species, respec ...200617183688
bfcbr: a cannabinoid receptor ortholog in the cephalochordate branchiostoma floridae (amphioxus).a gene encoding an ortholog of vertebrate cb(1)/cb(2) cannabinoid receptors was recently identified in the urochordate ciona intestinalis (cicbr; [elphick, m.r., satou, y., satoh, n., 2003. the invertebrate ancestry of endocannabinoid signalling: an orthologue of vertebrate cannabinoid receptors in the urochordate ciona intestinalis. gene 302, 95-101.]). here a cannabinoid receptor ortholog (bfcbr) has been identified in the cephalochordate branchiostoma floridae. bfcbr is encoded by a single ex ...200717553639
cis-regulation of the amphioxus engrailed gene: insights into evolution of a muscle-specific enhancer.to gain insights into the relation between evolution of cis-regulatory dna and evolution of gene function, we identified tissue-specific enhancers of the engrailed gene of the basal chordate amphioxus (branchiostoma floridae) and compared their ability to direct expression in both amphioxus and its nearest chordate relative, the tunicate ciona intestinalis. in amphioxus embryos, the native engrailed gene is expressed in three domains - the eight most anterior somites, a few cells in the central ...200717624741
origin and evolution of vertebrate abca genes: a story from amphioxus.previous studies showed that the vertebrate abca subfamily, one subgroup of the atp-binding-cassette superfamily, has evolved rapidly in terms of gene duplication and loss. to further uncover the evolutionary history of the abca subfamily, we characterized abca members of two amphioxus species (branchiostoma floridae and b. belcheri), the closest living invertebrate relative to vertebrates. phylogenetic analysis indicated that these two species have the same set of abca genes (both containing si ...200717964083
characterization, developmental expression and evolutionary features of the huntingtin gene in the amphioxus branchiostoma floridae.huntington's disease is an inherited neurodegenerative disorder that is caused by the expansion of an n-terminal polyq stretch in the huntingtin protein. in order to investigate the hypothesis that huntingtin was already involved in development of the nervous system in the last common ancestor of chordates, we isolated and characterised the huntingtin homologue from the amphioxus branchiostoma floridae. in the present paper the amphioxus general term must be referred to branchiostoma floridae.200718005438
thermal denaturation of wild type and mutant recombinant acetylcholinesterase from amphioxus: effects of the temperature of in vitro expression and of reversible inhibitors.we have studied the thermal inactivation at 37 degrees c of wild type and mutant che2 (c310a, f312i, c466a, c310a/f312i, and c310a/c466a) from amphioxus (branchiostoma floridae) expressed in vitro in cos-7 monkey cells under three sets of conditions: 30 degrees c for 48 h, 30 degrees c for 24 h and 37 degrees c for 24 h, and 37 degrees c for 48 h. we found biphasic denaturation curves for all enzymes and conditions, except wild type and c310a che2 expressed at 30 degrees c for 48 h. generally, s ...200818677525
unexpectedly large number of conserved noncoding regions within the ancestral chordate hox cluster.the single amphioxus hox cluster contains 15 genes and may well resemble the ancestral chordate hox cluster. we have sequenced the hox genomic complement of the european amphioxus branchiostoma lanceolatum and compared it to the american species, branchiostoma floridae, by phylogenetic footprinting to gain insights into the evolution of hox gene regulation in chordates. we found that hox intergenic regions are largely conserved between the two amphioxus species, especially in the case of genes l ...200818791732
homeodb: a database of homeobox gene diversity.the homeobox genes are a large and diverse group of genes, many of which play important roles in the embryonic development of animals. comparative study of homeobox genes, both within and between species, requires an evolutionary-based classification. homeodb was designed and implemented as a manually curated database to collect and present homeobox genes in an evolutionarily structured way, allowing genes, gene families and gene classes to be compared between species more readily than was possi ...200818803769
the secretin gpcrs descended from the family of adhesion gpcrs.the adhesion g-protein-coupled receptors (gpcrs) are the most complex gene family among gpcrs with large genomic size, multiple introns, and a fascinating flora of functional domains, though the evolutionary origin of this family has been obscure. here we studied the evolution of all class b (7tm2)-related genes, including the adhesion, secretin, and methuselah families of gpcrs with a focus on nine genomes. we found that the cnidarian genome of nematostella vectensis has a remarkably rich set o ...200918845549
characterization of the neurohypophysial hormone gene loci in elephant shark and the japanese lamprey: origin of the vertebrate neurohypophysial hormone genes.vasopressin and oxytocin are mammalian neurohypophysial hormones with distinct functions. vasopressin is involved mainly in osmoregulation and oxytocin is involved primarily in parturition and lactation. jawed vertebrates contain at least one homolog each of vasopressin and oxytocin, whereas only a vasopressin-family hormone, vasotocin, has been identified in jawless vertebrates. the genes encoding vasopressin and oxytocin are closely linked tail-to-tail in eutherian mammals whereas their homolo ...200919243634
amphioxus: beginning of vertebrate and end of invertebrate type gnrh receptor lineage.in vertebrates, activation of the gnrh receptor is necessary to initiate the reproductive cascade. however, little is known about the characteristics of gnrh receptors before the vertebrates evolved. recently genome sequencing was completed for amphioxus, branchiostoma floridae. to understand the gnrh receptors (gnrhr) from this most basal chordate, which is also classified as an invertebrate, we cloned and characterized four gnrhr cdnas encoded in the amphioxus genome. we found that incubation ...200919264870
molecular identification of larvae of a tetraphyllidean tapeworm (platyhelminthes: eucestoda) in a razor clam as an alternative intermediate host in the life cycle of acanthobothrium brevissime.dwarf razor clams (ensis minor) in the gulf of mexico are known to be infected with plerocercoid larvae of a tetraphyllidean tapeworm. here, we show that these larvae live unencysted in the intestinal lumen of the clam. morphologically, the larvae are similar to (although significantly larger than) tapeworm larvae previously described living in the gut of amphioxus (branchiostoma floridae) from the same habitat. sequence data from the d2 region of the 28s rdna from clam-infecting larvae were ide ...200919366282
conservation of the glucan phosphatase laforin is linked to rates of molecular evolution and the glucan metabolism of the organism.lafora disease (ld) is a fatal autosomal recessive neurodegenerative disease. a hallmark of ld is cytoplasmic accumulation of insoluble glucans, called lafora bodies (lbs). mutations in the gene encoding the phosphatase laforin account for approximately 50% of ld cases, and this gene is conserved in all vertebrates. we recently demonstrated that laforin is the founding member of a unique class of phosphatases that dephosphorylate glucans.200919545434
ng peptides: a novel family of neurophysin-associated neuropeptides.neurophysins are prohormone-derived polypeptides that are required for biosynthesis of the neurohypophyseal hormones vasopressin and oxytocin. accordingly, mutations in the neurophysin domain of the human vasopressin gene can cause diabetes insipidus. the association of neurophysins with vasopressin/oxytocin-type peptides dates back to the common ancestor of bilaterian animals and until recently it was thought to be unique. this textbook perspective on neurophysins changed with the discovery of ...201020303398
improving hox protein classification across the major model organisms.the family of hox-proteins has been a major focus of research for over 30 years. hox-proteins are crucial to the correct development of bilateral organisms, however, some uncertainty remains as to which hox-proteins are functionally equivalent across different species. initial classification of hox-proteins was based on phylogenetic analysis of the 60 amino acid homeodomain. this approach was successful in classifying hox-proteins with differing homeodomains, but the relationships of hox-protein ...201020520839
nebulin: a study of protein repeat evolution.protein domain repeats are common in proteins that are central to the organization of a cell, in particular in eukaryotes. they are known to evolve through internal tandem duplications. however, the understanding of the underlying mechanisms is incomplete. to shed light on repeat expansion mechanisms, we have studied the evolution of the muscle protein nebulin, a protein that contains a large number of actin-binding nebulin domains. nebulin proteins have evolved from an invertebrate precursor co ...201020643138
new insights into the evolution of metazoan cadherins.mining newly sequenced genomes of basal metazoan organisms reveals the evolutionary origin of modern protein families. specific cell-cell adhesion and intracellular communication are key processes in multicellular animals, and members of the cadherin superfamily are essential players in these processes. mammalian genomes contain over 100 genes belonging to this superfamily. by a combination of tblastn and profile hidden markov model analyses, we made an exhaustive search for cadherins and compil ...201120817718
branchiostoma floridae has separate healing and sealing enzymes for 5'-phosphate rna ligation.animal cells have two trna splicing pathways: (i) a 5'-p ligation mechanism, where the 5'-phosphate of the 3' trna half becomes the junction phosphate of the new phosphodiester linkage, and (ii) a 3'-p ligation process, in which the 3'-phosphate of the 5' trna half turns into the junction phosphate. although both activities are known to exist in animals, in almost three decades of investigation, neither of the two rna ligases has been identified. here we describe a gene from the chordate branchi ...201020837552
genomic organization and gene expression of the multiple globins in atlantic cod: conservation of globin-flanking genes in chordates infers the origin of the vertebrate globin clusters.the vertebrate globin genes encoding the α- and β-subunits of the tetrameric hemoglobins are clustered at two unlinked loci. the highly conserved linear order of the genes flanking the hemoglobins provides a strong anchor for inferring common ancestry of the globin clusters. in fish, the number of α-β-linked globin genes varies considerably between different sublineages and seems to be related to prevailing physico-chemical conditions. draft sequences of the atlantic cod genome enabled us to det ...201020961401
a neurotropic herpesvirus infecting the gastropod, abalone, shares ancestry with oyster herpesvirus and a herpesvirus associated with the amphioxus genome.with the exception of the oyster herpesvirus oshv-1, all herpesviruses characterized thus far infect only vertebrates. some cause neurological disease in their hosts, while others replicate or become latent in neurological tissues. recently a new herpesvirus causing ganglioneuritis in abalone, a gastropod, was discovered. molecular analysis of new herpesviruses, such as this one and others, still to be discovered in invertebrates, will provide insight into the evolution of herpesviruses.201021062506
flanking genes of an essential gene give information about the evolution of metazoa.we collected as much information as possible on new lamin genes and their flanking genes. the number of lamin genes varies from 1 to 4 depending more or less on the phylogenetic position of the species. strong genome drift is recognised by fewer and unusually placed introns and a change in flanking genes. this applies to the nematode caenorhabditis elegans, the insect drosophila melanogaster, the urochordate ciona intestinalis, the annelid capitella teleta and the planaria schmidtea mediterranea ...201021163549
characterization of the deleted in autism 1 protein family: implications for studying cognitive disorders.autism spectrum disorders (asds) are a group of commonly occurring, highly-heritable developmental disabilities. human genes c3orf58 or deleted in autism-1 (dia1) and cxorf36 or deleted in autism-1 related (dia1r) are implicated in asd and mental retardation. both gene products encode signal peptides for targeting to the secretory pathway. as evolutionary medicine has emerged as a key tool for understanding increasing numbers of human diseases, we have used an evolutionary approach to study dia1 ...201121283809
phosphoethanolamine methyltransferases in phosphocholine biosynthesis: functions and potential for antiparasite therapy.s-adenosyl-l-methionine (sam)-dependent methyltransferases represent a diverse group of enzymes that catalyze the transfer of a methyl group from a methyl donor sam to nitrogen, oxygen, sulfur or carbon atoms of a large number of biologically active large and small molecules. these modifications play a major role in the regulation of various biological functions such as gene expression, signaling, nuclear division and metabolism. the three-step sam-dependent methylation of phosphoethanolamine to ...201121303393
conserved eukaryotic fusogens can fuse viral envelopes to cells.caenorhabditis elegans proteins aff-1 and eff-1 [c. elegans fusion family (ceff) proteins] are essential for developmental cell-to-cell fusion and can merge insect cells. to study the structure and function of aff-1, we constructed vesicular stomatitis virus (vsv) displaying aff-1 on the viral envelope, substituting the native fusogen vsv glycoprotein. electron microscopy and tomography revealed that aff-1 formed distinct supercomplexes resembling pentameric and hexameric "flowers" on pseudoviru ...201121436398
dynamic evolution of ciks (traf3ip2/act1) in metazoans.ciks (traf3ip2/act1) is important for inflammatory responses and autoimmunity control through its dual functions in cd40l/baff and il17 signaling in mammalians. in this study, we performed comparative and evolutionary analyses of cikss from metazoans. although nematode (caenorabditis elegans) and sea urchin (strongylocentrotus purpuratus) have il17 and il17 receptors, we found no ciks in their genomes. the ancient ciks-like (ciksl) genes from the invertebrates lottia (lottia gigantea) and amphio ...201121527283
genomics reveal ancient forms of stanniocalcin in amphioxus and tunicate.stanniocalcin (stc) is present throughout vertebrates, including humans, but a structure for stc has not been identified in animals that evolved before bony fish. the origin of this pleiotropic hormone known to regulate calcium is not clear. in the present study, we have cloned three stanniocalcins from two invertebrates, the tunicate ciona intestinalis and the amphioxus branchiostoma floridae. both species are protochordates with the tunicates as the closest living relatives to vertebrates. amp ...201021558190
the adhesion gpcrs; gene repertoire, phylogeny and evolution.the adhesion family is unique among the gpcr (g protein-coupled receptor) families because of several features including long n-termini with multiple domains. the gene repertoire has recently been mined in great detail in several species including mouse, rat, dog, chicken and the early vertebrate branchiostoma (branchiostoma floridae) and one of the most primitive animals, the cniderian nematostella (nematostella vectensis). there is a one-to-one relationship of the rodent (mouse and rat) and hu ...201021618822
unexpected diversity in shisa-like proteins suggests the importance of their roles as transmembrane adaptors.the shisa family of single-transmembrane proteins is characterized by an n-terminal cysteine-rich domain and a proline-rich c-terminal region. its founding member, xenopus shisa, promotes head development by antagonizing wnt and fgf signaling. recently, a mouse brain-specific shisa protein ckamp44 (shisa9) was shown to play an important role in ampa receptor desensitization. we used sequence similarity searches against protein, genome and est databases to study the evolutionary origin and phylog ...201122120523
Inducible galectins are expressed in the inflamed pharynx of the ascidian Ciona intestinalis.Although ascidians belong to a key group in chordate phylogenesis, amino acid sequences of Ciona intestinalis galectin-CRDs (CiLgals-a and -b) have been retained too divergent from vertebrate galectins. In the present paper, to contribute in disclosing Bi-CRD galectin evolution a novel attempt was carried out on CiLgals-a and -b CRDs phylogenetic analysis, and their involvement in ascidian inflammatory responses was shown. CiLgals resulted aligned with Bi-CRD galectins from vertebrates (Xenopus ...201222085774
fine structure of the excretory system of amphioxus (branchiostoma floridae) and its response to osmotic stress. 20164831093
s-nitrosogluthathione reductase activity of amphioxus adh3: insights into the nitric oxide metabolism.nitric oxide (no) is a signalling molecule involved in many physiological functions. an important via of no action is through the s-nitrosylation of proteins, a post-translational modification that regulates the activity of enzymes, protein-protein interactions and signal transduction pathways. alcohol dehydrogenase class iii (adh3) recognises s-nitrosoglutathione (gsno), the main reservoir of non-protein s-nitrosothiol, and functions as an effective gsno reductase (gsnor) and as a safeguard aga ...200616763671
the amphioxus (branchiostoma floridae) genome contains a highly diversified set of g protein-coupled receptors.g protein-coupled receptors (gpcrs) are one of the largest families of genes in mammals. branchiostoma floridae (amphioxus) is one of the species most closely related species to vertebrates.200818199322
characterization of evolutionarily conserved micrornas in amphioxus.amphioxus is an extant species closest to the ancestry of vertebrates. observation of microrna (mirna) distribution of amphioxus would lend some hints for evolutionary research of vertebrates. in this study, using the publicly available scaffold data of the florida amphioxus (branchiostoma floridae) genome, we screened and characterized homologs of mirnas that had been identified in other species. in total, 68 pieces of such homologs were obtained and classified into 33 families. most of these m ...020451158
genomic analysis of the immune gene repertoire of amphioxus reveals extraordinary innate complexity and diversity.it has been speculated that before vertebrates evolved somatic diversity-based adaptive immunity, the germline-encoded diversity of innate immunity may have been more developed. amphioxus occupies the basal position of the chordate phylum and hence is an important reference to the evolution of vertebrate immunity. here we report the first comprehensive genomic survey of the immune gene repertoire of the amphioxus branchiostoma floridae. it has been reported that the purple sea urchin has a vastl ...200818562681
the amphioxus genome illuminates vertebrate origins and cephalochordate biology.cephalochordates, urochordates, and vertebrates evolved from a common ancestor over 520 million years ago. to improve our understanding of chordate evolution and the origin of vertebrates, we intensively searched for particular genes, gene families, and conserved noncoding elements in the sequenced genome of the cephalochordate branchiostoma floridae, commonly called amphioxus or lancelets. special attention was given to homeobox genes, opsin genes, genes involved in neural crest development, nu ...200818562680
evolutionary history of the alpha2,8-sialyltransferase (st8sia) gene family: tandem duplications in early deuterostomes explain most of the diversity found in the vertebrate st8sia genes.the animal sialyltransferases, which catalyze the transfer of sialic acid to the glycan moiety of glycoconjugates, are subdivided into four families: st3gal, st6gal, st6galnac and st8sia, based on acceptor sugar specificity and glycosidic linkage formed. despite low overall sequence identity between each sialyltransferase family, all sialyltransferases share four conserved peptide motifs (l, s, iii and vs) that serve as hallmarks for the identification of the sialyltransferases. currently, twent ...200818811928
expression of germline markers in three species of amphioxus supports a preformation mechanism of germ cell development in cephalochordates.in a previous study, we showed that the cephalochordate amphioxus branchiostoma floridae has localized maternal transcripts of conserved germ cell markers vasa and nanos in its early embryos. these results provided strong evidence to support a preformation mechanism for primordial germ cell (pgc) development in b. floridae.201323777831
molecular characterization and expression patterns of the big defensin gene in freshwater mussel (hyriopsis cumingii).antimicrobial peptides (amps), of which big defensins are examples, are an important component of the natural defenses of most living organisms, and possess remarkable microbicidal activities. in the present study, using expressed-sequence tag sequences from a cdna library and race, the full-length cdna sequence of the big defensin gene from the triangle-shell pearl mussel, hyriopsis cumingii, (hcbd), was cloned. the gene consists of a 5'-untranslated region (utr) of 166 bp, a 3'-utr region of 9 ...201424615035
lanfp10-a, first functional fluorescent protein whose chromophore contains the elusive mutation g67a.since green fluorescent protein (gfp) was first successfully expressed in heterologous systems in 1994, many genes encoding other natural autofluorescent proteins (afps) have been cloned and subsequently modified by protein engineering to improve their physicochemical properties. throughout this twenty-two-year period, glycine 67 (gly67) has been regarded as the only amino acid in the entire protein family that is essential for the formation of the different reported chromophores. in this work, ...201627418528
structure of a variable lymphocyte receptor-like protein from the amphioxus branchiostoma floridae.discovery of variable lymphocyte receptors (vlrs) in agnathans (jawless fish) has brought the origin of adaptive immunity system (ais) forward to 500 million years ago accompanying with the emergence of vertebrates. previous findings indicated that amphioxus, a representative model organism of chordate, also possesses some homologs of the basic components of tcr/bcr-based ais, but it remains unknown if there exist any components of vlr-based ais in amphioxus. bioinformatics analyses revealed the ...201626821753
evolution of selenoproteins in the metazoan.the selenocysteine (sec) containing proteins, selenoproteins, are an important group of proteins present throughout all 3 kingdoms of life. with the rapid progression of selenoprotein research in the post-genomic era, application of bioinformatics methods to the identification of selenoproteins in newly sequenced species has become increasingly important. although selenoproteins in human and other vertebrates have been investigated, studies of primitive invertebrate selenoproteomes are rarely re ...201222943432
cloning and expression of a chitinase gene from eisenia fetida.chitin is the second most abundant biopolymer in nature and is an important resource. in this study, we identified a chitinase gene, named eisenia fetida-chitinase (ef-chi) gene, of 1494 base pairs (bp) that encodes a protein of 498 amino acids as indicated by the corresponding mrna sequence. the amino acid sequence of ef-chi was similar to those of chitinases from eisenia andrei (99%), branchiostoma floridae (50%) and oryzias latipes (49%), and a gene encoding mature ef-chi was expressed in the ...201728373044
calcitonin-typical suppression of osteoclastic activity by amphioxus calcitonin superfamily peptides and insights into the evolutionary conservation and diversity of their structures.calcitonin (ct) is a hormone that decreases serum calcium level by suppressing osteoclastic activity in the vertebrate bone. in vertebrates, the structure-function relationship of cts has been studied extensively. we recently identified three ct superfamily peptides, bf-ctfp1 to 3, and clarified the molecular and functional characteristics of their receptor and receptor activity-modifying protein in amphioxus, branchiostoma floridae. however, the ct activity of bf-ctfps has yet to be investigate ...201728062302
the evolution of genes encoding for green fluorescent proteins: insights from cephalochordates (amphioxus).green fluorescent protein (gfp) was originally found in cnidarians, and later in copepods and cephalochordates (amphioxus) (branchiostoma spp). here, we looked for gfp-encoding genes in asymmetron, an early-diverged cephalochordate lineage, and found two such genes closely related to some of the branchiostoma gfps. dim fluorescence was found throughout the body in adults of asymmetron lucayanum, and, as in branchiostoma floridae, was especially intense in the ripe ovaries. spectra of the fluores ...201627311567
expression analysis of eight amphioxus genes involved in the wnt/β-catenin signaling pathway.the wnt/β-catenin signaling pathway plays a crucial role in the embryonic development of metazoans. although the pathway has been studied extensively in many model animals, its function in amphioxus, the most primitive chordate, remains largely uncharacterized. to obtain basic data for functional analysis, we identified and isolated seven genes (lrp5/6, dvl, apc, ckiα, ckiδ, gsk3β, and gro) of the wnt/β-catenin signaling pathway from the amphioxus (branchiostoma floridae) genome. phylogenetic an ...201627265651
tcf/lef regulates the gsx parahox gene in central nervous system development in chordates.the parahox genes play an integral role in the anterior-posterior (a-p) patterning of the nervous system and gut of most animals. the parahox cluster is an ideal system in which to study the evolution and regulation of developmental genes and gene clusters, as it displays similar regulatory phenomena to its sister cluster, the hox cluster, but offers a much simpler system with only three genes.201626940763
evidence for conservation of the calcitonin superfamily and activity-regulating mechanisms in the basal chordate branchiostoma floridae: insights into the molecular and functional evolution in chordates.the calcitonin (ct)/ct gene-related peptide (cgrp) family is conserved in vertebrates. the activities of this peptide family are regulated by a combination of two receptors, namely the calcitonin receptor (ctr) and the ctr-like receptor (clr), and three receptor activity-modifying proteins (ramps). furthermore, ramps act as escort proteins by translocating clr to the cell membrane. recently, ct/cgrp family peptides have been identified or inferred in several invertebrates. however, the molecular ...201626644465
on the origin of vertebrate somites.somites, blocks of mesoderm tissue located on either side of the neural tube in the developing vertebrate embryo, are derived from mesenchymal cells in the presomitic mesoderm (psm) and are a defining characteristic of vertebrates. in vertebrates, the somite segmental boundary is determined by notch signalling and the antagonistic relationship of the downstream targets of notch, lfng, and delta1 in the anterior psm. the presence of somites in the basal chordate amphioxus (branchiostoma floridae) ...201526613046
molecular signatures that are distinctive characteristics of the vertebrates and chordates and supporting a grouping of vertebrates with the tunicates.members of the phylum chordata and the subphylum vertebrata are presently distinguished solely on the basis of morphological characteristics. the relationship of the vertebrates to the two non-vertebrate chordate subphyla is also a subject of debate. analyses of protein sequences have identified multiple conserved signature indels (csis) that are specific for chordata or for vertebrata. five csis in 4 important proteins are specific for the vertebrata, whereas two other csis are uniquely found i ...201626419477
prevertebrate local gene duplication facilitated expansion of the neuropeptide gpcr superfamily.in humans, numerous genes encode neuropeptides that comprise a superfamily of more than 70 genes in approximately 30 families and act mainly through rhodopsin-like g protein-coupled receptors (gpcrs). two rounds of whole-genome duplication (2r wgd) during early vertebrate evolution greatly contributed to proliferation within gene families; however, the mechanisms underlying the initial emergence and diversification of these gene families before 2r wgd are largely unknown. in this study, we analy ...201526337547
gene regulation in amphioxus: an insight from transgenic studies in amphioxus and vertebrates.cephalochordates, commonly known as amphioxus or lancelets, are the most basal subphylum of chordates. cephalochordates are thus key to understanding the origin of vertebrates and molecular mechanisms underlying vertebrate evolution. the evolution of developmental control mechanisms during invertebrate-to-vertebrate transition involved not only gene duplication events, but also specific changes in spatial and temporal expression of many genes. to get insight into the spatiotemporal regulation of ...201526094865
discovery of germline-related genes in cephalochordate amphioxus: a genome wide survey using genome annotation and transcriptome data.the generation of germline cells is a critical process in the reproduction of multicellular organisms. studies in animal models have identified a common repertoire of genes that play essential roles in primordial germ cell (pgc) formation. however, comparative studies also indicate that the timing and regulation of this core genetic program vary considerably in different animals, raising the intriguing questions regarding the evolution of pgc developmental mechanisms in metazoans. cephalochordat ...201525847029
functional pairing of class b1 ligand-gpcr in cephalochordate provides evidence of the origin of pth and pacap/glucagon receptor family.several hypotheses have been proposed regarding the origin and evolution of the secretin family of peptides and receptors. however, identification of homologous ligand-receptor pairs in invertebrates and vertebrates is difficult because of the low levels of sequence identity between orthologs of distant species. in this study, five receptors structurally related to the vertebrate class b1 g protein-coupled receptor (gpcr) family were characterized from amphioxus (branchiostoma floridae). phyloge ...201525841489
hybrids between the florida amphioxus (branchiostoma floridae) and the bahamas lancelet (asymmetron lucayanum): developmental morphology and chromosome counts.the cephalochordate genera branchiostoma and asymmetron diverged during the mesozoic era. in spite of the long separation of the parental clades, eggs of the florida amphioxus, b. floridae, when fertilized with sperm of the bahamas lancelet, a. lucayanum (and vice versa), develop through embryonic and larval stages. the larvae reach the chordate phylotypic stage (i.e., the pharyngula), characterized by a dorsal nerve cord, notochord, perforate pharynx, and segmented trunk musculature. after abou ...201525745097
evolution of the new vertebrate head by co-option of an ancient chordate skeletal tissue.a defining feature of vertebrates (craniates) is a pronounced head that is supported and protected by a robust cellular endoskeleton. in the first vertebrates, this skeleton probably consisted of collagenous cellular cartilage, which forms the embryonic skeleton of all vertebrates and the adult skeleton of modern jawless and cartilaginous fish. in the head, most cellular cartilage is derived from a migratory cell population called the neural crest, which arises from the edges of the central nerv ...201525487155
surveying genetic variants and molecular phylogeny of cerebral cavernous malformation gene, ccm3/pdcd10.the three cerebral cavernous malformations (ccms) genes namely ccm1/krit1, ccm2/mgc4607 and ccm3/pdcd10 have been identified for which mutations cause cerebral cavernous malformations. however, the protein products of these genes involved in forming ccm signaling, are still poorly understood imposing an urgent need to understand these genes and their signaling processes in details. so far involvement of ccm3/pdcd10 in the cavernous angioma has been characterized from biochemical and biophysical ...201425451273
characterization of peptide qrfp (26rfa) and its receptor from amphioxus, branchiostoma floridae.a peptide ending with rfamide (arg-phe-amide) was discovered independently by three different laboratories in 2003 and named 26rfa or qrfp. in mammals, a longer version of the peptide, 43 amino acids, was identified and found to bind to the orphan g protein-coupled receptor gpr103. we searched the genome database of branchiostoma floridae (bfl) for receptor sequences related to those that bind peptides ending with rfa or rya (including receptors for npff, prlh, gnih, and npy). one receptor clust ...201525449662
unexpected multiplicity of qrfp receptors in early vertebrate evolution.the neuropeptide qrfp, also called 26rfa, and its g protein-coupled receptor gpr103 have been identified in all vertebrates investigated. in mammals, this peptide-receptor pair has been found to have several effects including stimulation of appetite. recently, we reported that a qrfp peptide is present in amphioxus, branchiostoma floridae, and we also identified a qrfp receptor (qrfpr) that mediates a functional response to sub-nanomolar concentrations of the amphioxus peptide as well as short a ...201425386115
the transcriptome of an amphioxus, asymmetron lucayanum, from the bahamas: a window into chordate evolution.cephalochordates, the sister group of tunicates plus vertebrates, have been called "living fossils" due to their resemblance to fossil chordates from cambrian strata. the genome of the cephalochordate branchiostoma floridae shares remarkable synteny with vertebrates and is free from whole-genome duplication. we performed rna sequencing from larvae and adults of asymmetron lucayanum, a cephalochordate distantly related to b. floridae. comparisons of about 430 orthologous gene groups among both ce ...201425240057
genome-wide survey and expression analysis of the bhlh-pas genes in the amphioxus branchiostoma floridae reveal both conserved and diverged expression patterns between cephalochordates and vertebrates.the bhlh-pas transcription factors are found in both protostomes and deuterostomes. they are involved in many developmental and physiological processes, including regional differentiation of the central nervous system, tube-formation, hypoxia signaling, aromatic hydrocarbon sensing, and circadian rhythm regulation. to understand the evolution of these genes in chordates, we analyzed the bhlh-pas genes of the basal chordate amphioxus (branchiostoma floridae).201424959341
sequencing and analysis of the transcriptome of the acorn worm ptychodera flava, an indirect developing hemichordate.hemichordates are the sister group of echinoderms, and together they are closely related to chordates within the deuterostome lineage. therefore, hemichordates represent an important animal group for the understanding of both the evolution of developmental mechanisms in deuterostome animals and the origin of chordates. recently, the majority of studies investigating hemichordates have focused on the direct-developing enteropneust hemichordate saccoglossus kowalevskii; few have focused on the ind ...201424823299
withdrawn: structural and mechanistic studies of hydroperoxide conversions catalyzed by a cyp74 clan epoxy alcohol synthase from amphioxus (branchiostoma floridae).this manuscript has been withdrawn by the author.201424379219
at the transition from invertebrates to vertebrates, a novel gnrh-like peptide emerges in amphioxus.gonadotropin-releasing hormone (gnrh) is a critical reproductive regulator in vertebrates. homologous peptides are also found in invertebrates, with a variety of characterized functions. in the amphioxus, an invertebrate that provides the best model for the transition to vertebrates, four gnrh receptors (gnrhrs) were previously described, but their native ligands were not identified. using a more sensitive search methodology with hidden markov models, we identified the first gnrh-like peptide co ...201424361996
neuregulin signaling in pieces--evolution of the gene family.paracrine and juxtacrine signaling via proteins expressed on the cell surface are an integral part of metazoan biology. more than one-half billion years ago epidermal growth factor (egf) and its cognate receptor formed a functional binding partnership, which has been conserved through evolution in essentially all eubilaterate members of the animal kingdom. early chordates spawned offspring of these seminal genes to begin the creation of new gene families and an expanded cell-cell signaling netwo ...201424283952
characterisation of amphiamr11, an amphioxus (branchiostoma floridae) d2-dopamine-like g protein-coupled receptor.the evolution of the biogenic amine signalling system in vertebrates is unclear. however, insights can be obtained from studying the structures and signalling properties of biogenic amine receptors from the protochordate, amphioxus, which is an invertebrate species that exists at the base of the chordate lineage. here we describe the signalling properties of amphiamr11, an amphioxus (branchiostoma floridae) g protein-coupled receptor which has structural similarities to vertebrate α2-adrenergic ...201324265838
the cephalochordate branchiostoma genome contains 26 intermediate filament (if) genes: implications for evolution of chordate if proteins.we analyzed the draft genome of the cephalochordate branchiostoma floridae (b. floridae) for genes encoding intermediate filament (if) proteins. from 26 identified if genes 13 were not reported before. four of the new if genes belong to the previously established branchiostoma if group a, four to the branchiostoma if group b, one is homologous to the type ii keratin e2 while the remaining four new if sequences n1 to n4 could not be readily classified in any of the previously established branchio ...201324246581
expression of carbonic anhydrase, cystic fibrosis transmembrane regulator (cftr) and v-h(+)-atpase in the lancelet branchiostoma lanceolatum (pallas, 1774).sequencing of the amphioxus genome revealed that it contains a basic set of chordate genes involved in development and cell signaling. despite the availability of genomic data, up till now no studies have been addressed on the comprehension of the amphioxus osmoregulation. using primers designed on branchiostoma floridae carbonic anhydrase (ca) ii, cystic fibrosis transmembrane regulator (cftr) and v-h(+)-atpase, a 100bp long region, containing the protein region recognized by the respective ant ...201424220283
pgbd5: a neural-specific intron-containing piggybac transposase domesticated over 500 million years ago and conserved from cephalochordates to humans.piggybac domain (pgbd) transposons are found in organisms ranging from fungi to humans. three domesticated piggybac elements have been described. in the ciliates paramecium tetraurelia and tetrahymena thermophila, homologs known as piggymacs excise internal eliminated sequences from germline micronuclear dna during regeneration of the new somatic macronucleus. in primates, a pgbd3 element inserted into the cockayne syndrome group b (csb) gene over 43 mya serves as an alternative 3' terminal exon ...201324180413
remarkable similarities between the hemichordate (saccoglossus kowalevskii) and vertebrate gpcr repertoire.saccoglossus kowalevskii (the acorn worm) is a hemichordate belonging to the superphylum of deuterostome bilateral animals. hemichordates are sister group to echinoderms, and closely related to chordates. s. kowalevskii has chordate like morphological traits and serves as an important model organism, helping developmental biologists to understand the evolution of the central nervous system (cns). despite being such an important model organism, the signalling system repertoire of the largest fami ...201323685280
comparative genomic and phylogenetic analyses of the intelectin gene family: implications for their origin and evolution.intelectin is a newly characterized gene family involved in early embryogenesis, host-pathogen interactions and iron metabolism. in this study, we searched the genomes of metazoans by extensive blast survey and found no intelectin homologs in invertebrate metazoans but 12 in amphioxus branchiostoma floridae and 21 in ascidians ciona intestinalis. some ascidians oocyte cortical granule lectins (cgls) have unknown insertion sequences between fibrinogen-related domain (fred) and intelectin domain, ...201323643964
global view of the evolution and diversity of metazoan neuropeptide signaling.neuropeptides are signaling molecules that commonly act via g protein-coupled receptors (gpcrs) and are generated in neurons by proneuropeptide (pnp) cleavage. present in both cnidarians and bilaterians, neuropeptides represent an ancient and widespread mode of neuronal communication. due to the inherent difficulties of analyzing highly diverse and repetitive pnps, the relationships among different families are often elusive. using similarity-based clustering and sensitive similarity searches, i ...201323637342
characterisation of amphiamr4, an amphioxus (branchiostoma floridae) α₂-adrenergic-like g-protein-coupled receptor.little is known about the evolutionary relationship between vertebrate adrenergic receptors and invertebrate octopamine and tyramine receptors. the complexity of the adrenergic signalling system is believed to be an innovation of the vertebrate lineage but the presence of noradrenaline has been reported in some invertebrate species. the cephalochordate, amphioxus (branchiostoma floridae), is an ideal model organism for studying the evolution of vertebrate gpcrs, given its unique position at the ...201323183848
putative chitin synthases from branchiostoma floridae show extracellular matrix-related domains and mosaic structures.the transition from unicellular to multicellular life forms requires the development of a specialized structural component, the extracellular matrix (ecm). in metazoans, there are two main supportive systems, which are based on chitin and collagen/hyaluronan, respectively. chitin is the major constituent of fungal cell walls and arthropod exoskeleton. however, presence of chitin/chitooligosaccharides has been reported in lower chordates and during specific stages of vertebrate development. in th ...201223084775
evolution of the vertebrate paralemmin gene family: ancient origin of gene duplicates suggests distinct functions.paralemmin-1 is a protein implicated in plasma membrane dynamics, the development of filopodia, neurites and dendritic spines, as well as the invasiveness and metastatic potential of cancer cells. however, little is known about its mode of action, or about the biological functions of the other paralemmin isoforms: paralemmin-2, paralemmin-3 and palmdelphin. we describe here evolutionary analyses of the paralemmin gene family in a broad range of vertebrate species. our results suggest that the fo ...201222855693
the function and developmental expression of alternatively spliced isoforms of amphioxus and xenopus laevis pax2/5/8 genes: revealing divergence at the invertebrate to vertebrate transition.pax genes encode highly conserved transcription factors vital for metazoan development. pax transcripts, particularly those in group ii (pax2/5/8), are extensively alternatively spliced. this study compares the transcriptional activation capacity and developmental stage-specific expression of major isoforms of group ii pax proteins in amphioxus (branchiostoma floridae) and in xenopus laevis. the comparison reveals considerable divergence of splice forms between the lineages, with the x. laevis g ...201222791613
evolution of thrombin and other hemostatic proteases by survey of protochordate, hemichordate, and echinoderm genomes.protochordate genomes enable a prevalence of hemostasis evolution. broad searches were performed for homologs of human serine proteases of hemostasis on the genomes of branchiostoma floridae, saccoglossus kowalevskii, and strongylocentrotus purpuratus. sequences were analyzed by multiple bioinformatic tools. the survey revealed numerous homologous components. amphioxus was rich in some serine proteases not accompanied by gamma-carboxyglutamic or kringle domains similar more to thrombin than to o ...201222752046
systematic investigation of amphioxus (branchiostoma floridae) micrornas.micrornas (mirnas) participate in various biological processes via controlling gene activity. amphioxus is the best available stand-in as the proximate invertebrate ancestor of the vertebrates. here, we systematically investigated the mirnas in amphioxus. first, we identified 245 candidate amphioxus mirnas, in which 183 mirnas were firstly reported. second, we gave evidences to support a birth-and-death process of mirna genes in some families and gave implications for the functional diversificat ...201222750802
sequencing and analysis of the mediterranean amphioxus (branchiostoma lanceolatum) transcriptome.the basally divergent phylogenetic position of amphioxus (cephalochordata), as well as its conserved morphology, development and genetics, make it the best proxy for the chordate ancestor. particularly, studies using the amphioxus model help our understanding of vertebrate evolution and development. thus, interest for the amphioxus model led to the characterization of both the transcriptome and complete genome sequence of the american species, branchiostoma floridae. however, recent technical im ...201222590565
a genome-wide view of transcription factor gene diversity in chordate evolution: less gene loss in amphioxus?previous studies of gene diversity in the homeobox superclass have shown that the florida amphioxus branchiostoma floridae has undergone remarkably little gene family loss. here we use a combined blast and hmm search strategy to assess the family level diversity of four other transcription factor superclasses: the paired/pax genes, tbx genes, fox genes and sox genes. we apply this across genomes from five chordate taxa, including b. floridae and ciona intestinalis, plus two outgroup taxa. our re ...201222441554
transposon diversity is higher in amphioxus than in vertebrates: functional and evolutionary inferences.transposable elements (tes) are main components of eukaryote genomes-up to 50% in some vertebrates-which can replicate and jump to new locations. tes contribute to shape genome evolution, actively by creating new genes (or exons) or altering gene expression as consequence of transposition, and passively by serving as illegitimate recombinational hotspots. analysis of amphioxus tes can help to shed light on the ancestral status of chordate tes and to understand genome evolution in cephalochordate ...201222389043
the carboxylesterase/cholinesterase gene family in invertebrate deuterostomes.carboxylesterase/cholinesterase family members are responsible for controlling the nerve impulse, detoxification and various developmental functions, and are a major target of pesticides and chemical warfare agents. comparative structural analysis of these enzymes is thus important. the invertebrate deuterostomes (phyla echinodermata and hemichordata and subphyla urochordata and cephalochordata) lie in the transition zone between invertebrates and vertebrates, and are thus of interest to the stu ...201222210164
development and evolution of the lateral plate mesoderm: comparative analysis of amphioxus and lamprey with implications for the acquisition of paired fins.possession of paired appendages is regarded as a novelty that defines crown gnathostomes and allows sophisticated behavioral and locomotive patterns. during embryonic development, initiation of limb buds in the lateral plate mesoderm involves several steps. first, the lateral plate mesoderm is regionalized into the cardiac mesoderm (cm) and the posterior lateral plate mesoderm (plpm). second, in the plpm, hox genes are expressed in a collinear manner to establish positional values along the ante ...201121864524
evolution of retinoid and steroid signaling: vertebrate diversification from an amphioxus perspective.although the physiological relevance of retinoids and steroids in vertebrates is very well established, the origin and evolution of the genetic machineries implicated in their metabolic pathways is still very poorly understood. we investigated the evolution of these genetic networks by conducting an exhaustive survey of components of the retinoid and steroid pathways in the genome of the invertebrate chordate amphioxus (branchiostoma floridae). due to its phylogenetic position at the base of cho ...201121856648
a nonselenoprotein from amphioxus deiodinates triac but not t3: is triac the primordial bioactive thyroid hormone?thyroid hormone (th) is important for metamorphosis in many species, including the cephalochordate branchiostoma floridae, a marine invertebrate (amphioxus) living in warmer coastal areas. branchiostoma expresses a th receptor, which is activated by 3,3',5-triiodothyroacetic acid (ta(3)) but not by t(3). the branchiostoma genome also contains multiple genes coding for proteins homologous to iodothyronine deiodinases in vertebrates, selenoproteins catalyzing the activation or inactivation of th. ...201121652724
evolution of the reproductive endocrine system in chordates.the cephalochordate, amphioxus, is phylogenetically placed at the most primitive position in the chordate clade. despite many studies on the endocrine system of amphioxus, definitive evidence has not been reported for the presence an endocrine system comparable to the pituitary-gonadal axis, which is important in the regulation of reproduction in vertebrates. recent genome analyses in the amphioxus, branchiostoma floridae, showed that it does not have any pituitary hormone genes except the thyro ...201021558187
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