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Linda Z. Holland - One of the best experts on this subject based on the ideXlab platform.
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Laboratory Culture and Mutagenesis of Amphioxus (Branchiostoma Floridae).
Methods in Molecular Biology, 2020Co-Authors: Linda Z. HollandAbstract:Cephalochordates (amphioxus) are invertebrate chordates closely related to vertebrates. As they are evolving very slowly, they are proving to be very appropriate for developmental genetics studies aimed at understanding how vertebrates evolved from their invertebrate ancestors. To date, techniques for gene knockdown and overexpression have been developed, but methods for continuous breeding cultures and generating germline mutants have been developed only recently. Here we describe methods for continuous laboratory breeding cultures of the cephalochordate Branchiostoma Floridae and the TALEN and Tol2 methods for mutagenesis. Included are strategies for analyzing the mutants and raising successive generations to obtain homozygotes. These methods should be applicable to any warm water species of cephalochordates with a relatively short generation time of 3-4 months and a life span of 3 years or more.
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Asymmetric localization of germline markers Vasa and Nanos during early development in the amphioxus Branchiostoma Floridae.
Developmental Biology, 2011Co-Authors: Yen-ta Chen, Yi-jyun Luo, Linda Z. HollandAbstract:The origin of germline cells was a crucial step in animal evolution. Therefore, in both developmental biology and evolutionary biology, the mechanisms of germline specification have been extensively studied over the past two centuries. However, in many animals, the process of germline specification remains unclear. Here, we show that in the cephalochordate amphioxus Branchiostoma Floridae, the germ cell-specific molecular markers Vasa and Nanos become localized to the vegetal pole cytoplasm during oogenesis and are inherited asymmetrically by a single blastomere during cleavage. After gastrulation, this founder cell gives rise to a cluster of progeny that display typical characters of primordial germ cells (PGCs). Blastomeres separated at the two-cell stage grow into twin embryos, but one of the twins fails to develop this Vasa-positive cell population, suggesting that the vegetal pole cytoplasm is required for the formation of putative PGCs in amphioxus embryos. Contrary to the hypothesis that cephalochordates may form their PGCs by epigenesis, our data strongly support a preformation mode of germ cell specification in amphioxus. In addition to the early localization of their maternal transcripts in the putative PGCs, amphioxus Vasa and Nanos are also expressed zygotically in the tail bud, which is the posterior growth zone of amphioxus. Thus, in addition to PGC specification, amphioxus Vasa and Nanos may also function in highly proliferating somatic stem cells.
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a cdna resource for the cephalochordate amphioxus Branchiostoma Floridae
Development Genes and Evolution, 2008Co-Authors: Jr-kai Yu, Linda Z. Holland, Yuji Kohara, Mingchih Wang, Tadasu Shini, Noriyuki Satoh, Yutaka SatouAbstract:Cephalochordates are the basal invertebrate chordates within the phylum Chordata. They are widely used as a model system for research in evolutionary developmental biology (EvoDevo) to understand the basic patterning mechanisms for the chordate body plan and the origin of vertebrates. Recently, the genome of the cephalochordate Branchiostoma Floridae was sequenced, which further brings this organism to the front for comparative genomic studies. In this paper, we report the generation of large-scale 5′- and 3′-expressed sequence tags (ESTs) from B. Floridae and the complementary deoxyribonucleic acid (cDNA) resource for this species. Both 5′- and 3′-ESTs were sequenced for approximately 140,000 cDNA clones derived from five developmental stages, and the cDNA clones were subsequently grouped into independent clusters using 3′-EST sequences. We identified 21,229 cDNA clusters, and each corresponds to a unique transcript species from B. Floridae. We then chose 24,020 cDNA clones representing all of these 21,229 clusters to generate the “Branchiostoma Floridae Gene Collection Release 1.” We also constructed a database with a searchable interface for this EST dataset and the related information on “Branchiostoma Floridae Gene Collection Release 1.” This set of cDNA clones along with our cDNA database will serve as an important resource for future research in this basal chordate. This Gene Collection and the original 140,000 individual cDNA clones are available to the research community upon request.
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a cdna resource for the cephalochordate amphioxus Branchiostoma Floridae
Development Genes and Evolution, 2008Co-Authors: Jr-kai Yu, Linda Z. Holland, Yuji Kohara, Mingchih Wang, Tadasu Shini, Noriyuki Satoh, Yutaka SatouAbstract:Cephalochordates are the basal invertebrate chordates within the phylum Chordata. They are widely used as a model system for research in evolutionary developmental biology (EvoDevo) to understand the basic patterning mechanisms for the chordate body plan and the origin of vertebrates. Recently, the genome of the cephalochordate Branchiostoma Floridae was sequenced, which further brings this organism to the front for comparative genomic studies. In this paper, we report the generation of large-scale 5′- and 3′-expressed sequence tags (ESTs) from B. Floridae and the complementary deoxyribonucleic acid (cDNA) resource for this species. Both 5′- and 3′-ESTs were sequenced for approximately 140,000 cDNA clones derived from five developmental stages, and the cDNA clones were subsequently grouped into independent clusters using 3′-EST sequences. We identified 21,229 cDNA clusters, and each corresponds to a unique transcript species from B. Floridae. We then chose 24,020 cDNA clones representing all of these 21,229 clusters to generate the “Branchiostoma Floridae Gene Collection Release 1.” We also constructed a database with a searchable interface for this EST dataset and the related information on “Branchiostoma Floridae Gene Collection Release 1.” This set of cDNA clones along with our cDNA database will serve as an important resource for future research in this basal chordate. This Gene Collection and the original 140,000 individual cDNA clones are available to the research community upon request.
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Amphicoup-TF, a nuclear orphan receptor of the lancelet Branchiostoma Floridae, is implicated in retinoic acid signalling pathways.
Development Genes and Evolution, 2000Co-Authors: Marie-claire Langlois, Nicholas D. Holland, Hector Escriva, Vincent Laudet, Jean-marc Vanacker, Christophe Quéva, Linda Z. HollandAbstract:In vertebrates, the orphan nuclear receptors of the COUP-TF group function as negative transcriptional regulators that inhibit the hormonal induction of target genes mediated by classical members of the nuclear hormone superfamily, such as the retinoic acid receptors (RARs) or the thyroid hormone receptors (TRs). To investigate the evolutionary conservation of the roles of COUP-TF receptors as negative regulators in the retinoid and thyroid hormone pathways, we have characterized AmphiCOUP-TF, the homologue of COUP-TFI and COUP-TFII, in the chordate amphioxus (Branchiostoma Floridae), the closest living invertebrate relative of the vertebrates. Electrophoretic mobility shift assays (EMSA) showed that AmphiCOUP-TF binds to a wide variety of response elements, as do its vertebrate homologues. Furthermore, AmphiCOUP-TF is a transcriptional repressor that strongly inhibits retinoic acid-mediated transactivation. In situ hybridizations revealed expression of AmphiCOUP-TF in the nerve cord of late larvae, in a region corresponding to hindbrain and probably anterior spinal cord. Although the amphioxus nerve cord appears unsegmented at the gross anatomical level, this pattern reflects segmentation at the cellular level with stripes of expressing cells occurring adjacent to the ends and the centers of each myotomal segment, which may include visceral motor neurons and somatic motor neurons respectively, among other cells. A comparison of the expression pattern of AmphiCOUP-TF with those of its vertebrate homologues, suggests that the roles of COUP-TF in patterning of the nerve cord evolved prior to the split between the amphioxus and vertebrate lineages. Furthermore, in vitro data also suggest that Amphi-COUP-TF acts as a negative regulator of signalling by other nuclear receptors such as RAR, TR or ER.
L.z. Holland - One of the best experts on this subject based on the ideXlab platform.
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Amphi-COUP-TF, a nuclear orphan receptor of the lancelet Branchiostoma Floridae, is implicated in retinoic acid signaling pathways.
Development Genes and Evolution, 2000Co-Authors: Marie-claire Langlois, Hector Escriva, Vincent Laudet, Jean-marc Vanacker, Christophe Quéva, N.d. Holland, L.z. HollandAbstract:In vertebrates, the orphan nuclear receptors of the COUP-TF group function as negative transcriptionalregulators that inhibit the hormonal induction of targetgenes mediated by classical members of the nuclear hor-mone superfamily, such as the retinoic acid receptors(RARs) or the thyroid hormone receptors (TRs). To in-vestigate the evolutionary conservation of the roles of COUP-TF receptors as negative regulators in the retinoidand thyroid hormone pathways, we have characterizedAmphiCOUP-TF, the homologue of COUP-TFI andCOUP-TFII, in the chordate amphioxus ( Branchiostoma Floridae ), the closest living invertebrate relative of thevertebrates. Electrophoretic mobility shift assays(EMSA) showed that AmphiCOUP-TF binds to a widevariety of response elements, as do its vertebrate homo-logues. Furthermore, AmphiCOUP-TF is a transcription-al repressor that strongly inhibits retinoic acid-mediatedtransactivation. In situ hybridizations revealed expres-sion of AmphiCOUP-TF in the nerve cord of late larvae,in a region corresponding to hindbrain and probably an-terior spinal cord. Although the amphioxus nerve cordappears unsegmented at the gross anatomical level, thispattern reflects segmentation at the cellular level withstripes of expressing cells occurring adjacent to the endsand the centers of each myotomal segment, which mayinclude visceral motor neurons and somatic motor neu-rons respectively, among other cells. A comparison of the expression pattern of AmphiCOUP-TF with those of its vertebrate homologues, suggests that the roles of COUP-TF in patterning of the nerve cord evolved priorto the split between the amphioxus and vertebrate lineag-es. Furthermore, in vitro data also suggest that Amphi-COUP-TF acts as a negative regulator of signalling byother nuclear receptors such as RAR, TR or ER.
Mario Pestarino - One of the best experts on this subject based on the ideXlab platform.
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Expression of the orphan nuclear receptor NR4A in a putative adenohypophyseal homologue of amphioxus.
Annals of the New York Academy of Sciences, 2009Co-Authors: Simona Candiani, Luca Moronti, Mario PestarinoAbstract:Nur77, Nurr1, and NOR-1 form a subfamily (the NR4A/Nur subfamily) of transcription factors belonging to the family of nuclear receptors. In this report, we characterized the single member of such a subfamily in the amphioxus Branchiostoma Floridae. Developmental expression analysis of AmphiNR4A showed transcripts limited to the putative adenohypophyseal homologue of amphioxus.
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Comprehensive survey and classification of homeobox genes in the genome of amphioxus, Branchiostoma Floridae
Development Genes and Evolution, 2008Co-Authors: Naohito Takatori, Mario Pestarino, Simona Candiani, Hidetoshi Saiga, Thomas Butts, David E K Ferrier, Peter W. H. HollandAbstract:The homeobox genes comprise a large and diverse gene superfamily, many of which encode transcription factors with pivotal roles in the embryonic development of animals. We searched the assembled draft genome sequence of an amphioxus, Branchiostoma Floridae , for genes possessing homeobox sequences. Phylogenetic analysis was used to divide these into gene families and classes. The 133 amphioxus homeobox genes comprise 60 ANTP class genes, 29 PRD genes (excluding Pon and Pax1/9 ), nine TALE genes, seven POU genes, seven LIM genes, five ZF genes, four CUT genes, four HNF genes, three SINE genes, one CERS gene, one PROS gene, and three unclassified genes. Ten of the 11 homeobox gene classes are less diverse in amphioxus than humans, as a result of gene duplication on the vertebrate lineage. Amphioxus possesses at least one member for all of the 96 homeobox gene families inferred to be present in the common ancestor of chordates, including representatives of the Msxlx, Bari, Abox, Nk7, Ro, and Repo gene families that have been lost from tunicates and vertebrates. We find duplication of several homeobox genes in the cephalochordate lineage (Mnx, Evx, Emx, Vent, Nk1, Nedx, Uncx, Lhx2/9, Hmbox, Pou3, and Irx) and several divergent genes that probably originated by extensive sequence divergence (Hx, Ankx, Lcx, Acut, Atale, Azfh, Ahbx, Muxa, Muxb, Aprd1–6, and Ahnf). The analysis reveals not only the repertoire of amphioxus homeobox genes but also gives insight into the evolution of chordate homeobox genes.
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The amphioxus immune system
ISJ-Invertebrate Survival Journal, 2007Co-Authors: Mario Pestarino, Manuela Parodi, Diana Oliveri, Simona CandianiAbstract:The cephalochordate amphioxus is the closest living invertebrate relative of the vertebrates and therefore it can provide useful insights on the evolution of the adaptive immune system. In fact some components of the immune system are present in amphioxus but many other features are lacking. A proto-MHC region has been identified by chromosome walking and the presence of T cell receptor has been demonstrated despite the absence of true lymphocytes. Moreover a further important step on the study of the amphioxus immune system is represented by the recent availability of the genome of Branchiostoma Floridae that will allow to better understand how many genes code for immunological molecules involved in adaptive immune system pathways of amphioxus.
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Characterization, developmental expression and evolutionary features of the huntingtin gene in the amphioxus Branchiostoma Floridae
BMC Developmental Biology, 2007Co-Authors: Simona Candiani, Mario Pestarino, Elena Cattaneo, Marzia TartariAbstract:Background 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.
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AmphiD1/β, a dopamine D1/β-adrenergic receptor from the amphioxus Branchiostoma Floridae: evolutionary aspects of the catecholaminergic system during development
Development Genes and Evolution, 2005Co-Authors: Simona Candiani, Manuela Parodi, Diana Oliveri, Patrizio Castagnola, Mario PestarinoAbstract:Catecholamine receptors mediate wide-ranging functions in vertebrates and invertebrates but are largely unknown in invertebrate chordates such as amphioxus. Catecholaminergic cells have been described in amphioxus adults, but few data are known about the transmembrane signal transduction pathways and the expression pattern of related receptors during development. In Branchiostoma Floridae , we cloned a full-length cDNA ( AmphiD1/β ) that corresponds to the dopamine D1/β receptor previously cloned from a related species of amphioxus, Branchiostoma lanceolatum , but no expression studies have been performed for such receptor in amphioxus. In B. Floridae , AmphiD1/β encodes a polypeptide with typical G-protein-coupled receptor features, characterized by highest sequence similarity with D1 dopamine and β-adrenergic receptors. The expression of AmphiD1/β mRNA in different regions of the cerebral vesicle corresponds to that of D1-like receptors in vertebrate homologous structures. Furthermore, in situ experiments show that during development, the expression in the nervous system is restricted to cells located anteriorly. A further expression was found in larvae at the level of the endostyle, but it has no counterpart in the predominant expression domains of vertebrate dopamine and/or adrenergic receptor genes. At the same time, we compared the dopaminergic system, consisting of AmphiTH -expressing cells, with the AmphiD1/β expression. In conclusion, the identification of the AmphiD1/β receptor provides further basis for understanding the evolutionary history of the dopaminergic system at the transition from invertebrates and vertebrates.
Marie-claire Langlois - One of the best experts on this subject based on the ideXlab platform.
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Amphicoup-TF, a nuclear orphan receptor of the lancelet Branchiostoma Floridae, is implicated in retinoic acid signalling pathways.
Development Genes and Evolution, 2000Co-Authors: Marie-claire Langlois, Nicholas D. Holland, Hector Escriva, Vincent Laudet, Jean-marc Vanacker, Christophe Quéva, Linda Z. HollandAbstract:In vertebrates, the orphan nuclear receptors of the COUP-TF group function as negative transcriptional regulators that inhibit the hormonal induction of target genes mediated by classical members of the nuclear hormone superfamily, such as the retinoic acid receptors (RARs) or the thyroid hormone receptors (TRs). To investigate the evolutionary conservation of the roles of COUP-TF receptors as negative regulators in the retinoid and thyroid hormone pathways, we have characterized AmphiCOUP-TF, the homologue of COUP-TFI and COUP-TFII, in the chordate amphioxus (Branchiostoma Floridae), the closest living invertebrate relative of the vertebrates. Electrophoretic mobility shift assays (EMSA) showed that AmphiCOUP-TF binds to a wide variety of response elements, as do its vertebrate homologues. Furthermore, AmphiCOUP-TF is a transcriptional repressor that strongly inhibits retinoic acid-mediated transactivation. In situ hybridizations revealed expression of AmphiCOUP-TF in the nerve cord of late larvae, in a region corresponding to hindbrain and probably anterior spinal cord. Although the amphioxus nerve cord appears unsegmented at the gross anatomical level, this pattern reflects segmentation at the cellular level with stripes of expressing cells occurring adjacent to the ends and the centers of each myotomal segment, which may include visceral motor neurons and somatic motor neurons respectively, among other cells. A comparison of the expression pattern of AmphiCOUP-TF with those of its vertebrate homologues, suggests that the roles of COUP-TF in patterning of the nerve cord evolved prior to the split between the amphioxus and vertebrate lineages. Furthermore, in vitro data also suggest that Amphi-COUP-TF acts as a negative regulator of signalling by other nuclear receptors such as RAR, TR or ER.
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Amphi-COUP-TF, a nuclear orphan receptor of the lancelet Branchiostoma Floridae, is implicated in retinoic acid signaling pathways.
Development Genes and Evolution, 2000Co-Authors: Marie-claire Langlois, Hector Escriva, Vincent Laudet, Jean-marc Vanacker, Christophe Quéva, N.d. Holland, L.z. HollandAbstract:In vertebrates, the orphan nuclear receptors of the COUP-TF group function as negative transcriptionalregulators that inhibit the hormonal induction of targetgenes mediated by classical members of the nuclear hor-mone superfamily, such as the retinoic acid receptors(RARs) or the thyroid hormone receptors (TRs). To in-vestigate the evolutionary conservation of the roles of COUP-TF receptors as negative regulators in the retinoidand thyroid hormone pathways, we have characterizedAmphiCOUP-TF, the homologue of COUP-TFI andCOUP-TFII, in the chordate amphioxus ( Branchiostoma Floridae ), the closest living invertebrate relative of thevertebrates. Electrophoretic mobility shift assays(EMSA) showed that AmphiCOUP-TF binds to a widevariety of response elements, as do its vertebrate homo-logues. Furthermore, AmphiCOUP-TF is a transcription-al repressor that strongly inhibits retinoic acid-mediatedtransactivation. In situ hybridizations revealed expres-sion of AmphiCOUP-TF in the nerve cord of late larvae,in a region corresponding to hindbrain and probably an-terior spinal cord. Although the amphioxus nerve cordappears unsegmented at the gross anatomical level, thispattern reflects segmentation at the cellular level withstripes of expressing cells occurring adjacent to the endsand the centers of each myotomal segment, which mayinclude visceral motor neurons and somatic motor neu-rons respectively, among other cells. A comparison of the expression pattern of AmphiCOUP-TF with those of its vertebrate homologues, suggests that the roles of COUP-TF in patterning of the nerve cord evolved priorto the split between the amphioxus and vertebrate lineag-es. Furthermore, in vitro data also suggest that Amphi-COUP-TF acts as a negative regulator of signalling byother nuclear receptors such as RAR, TR or ER.
Vincent Laudet - One of the best experts on this subject based on the ideXlab platform.
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Additional file 4: of Lineage-specific duplication of amphioxus retinoic acid degrading enzymes (CYP26) resulted in sub-functionalization of patterning and homeostatic roles
2017Co-Authors: João Carvalho, Vincent Laudet, Maria Theodosiou, Jie Chen, Pascale Chevret, Susana Alvarez, Angel De Lera, Jenifer Croce, Michael SchubertAbstract:Conserved retinoic acid response elements (RAREs) found in the Branchiostoma lanceolatum, Branchiostoma belcheri, and Branchiostoma Floridae CYP26 clusters. B. lanceolatum RAREs recognized and bound by the B. lanceolatum RAR/RXR heterodimer in vitro (Fig. 8) are indicated in black, RAREs that do not associate with the B. lanceolatum RAR/RXR heterodimer in vitro are shown in grey. The in vitro validated B. lanceolatum RAREs composed of two direct repeats (DRs) and separated by a 5 nucleotide spacer (i.e. the validated B. lanceolatum DR5-type RAREs) were used to calculate a consensus B. lanceolatum DR5 RARE by multiple expectation maximization algorithm for motif elicitation (MEME) analysis. (XLSX 77 kb
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Additional file 3: of Lineage-specific duplication of amphioxus retinoic acid degrading enzymes (CYP26) resulted in sub-functionalization of patterning and homeostatic roles
2017Co-Authors: JoĂŁo Carvalho, Vincent Laudet, Maria Theodosiou, Jie Chen, Pascale Chevret, Susana Alvarez, Angel De Lera, Jenifer Croce, Michael SchubertAbstract:Comparative dating tree for the CYP26 subfamily. Divergence dates of the CYP26 sequences were estimated using fossil-based calibration intervals. Cladogram node dates represent estimation of the mean node height and the highest posterior density intervals fixed at 95% are shown in parentheses. Geological era abbreviations: Cam, Cambrian; Car, Carboniferous; Cre, Cretaceous; Dev, Devonian; Jur, Jurassic; Ord, Ordovician; Per, Permian; Sil, Silurian; Tri, Triassic. Species name abbreviations: B.b., Branchiostoma belcheri (in blue); B.f., Branchiostoma Floridae (in red); B.l., Branchiostoma lanceolatum (in green); C.g., Crassostrea gigas; C.i., Ciona intestinalis; C.m., Callorhinchus milii; C.t., Capitella teleta; D.r., Danio rerio; G.a., Gasterosteus aculeatus; G.g., Gallus gallus; H.s., Homo sapiens; L.a. Lingula anatina; L.c., Latimeria chalumnae; L.e., Leucoraja erinacea; L.g., Lottia gigantea; L.j., Lethenteron japonicum; L.o., Lepisosteus oculatus; M.d., Monodelphis domestica; M.m., Mus musculus; O.b., Octopus bimaculoides; O.l., Oryzias latipes; P.c., Priapulus caudatus; P.f., Ptychodera flava; P.m., Petromyzon marinus; S.k., Saccoglossus kowalevskii; S.p., Strongylocentrotus purpuratus; T.r., Takifugu rubripes; X.t., Xenopus tropicalis. (PDF 271 kb
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An amphioxus orthologue of the estrogen receptor that does not bind estradiol: Insights into estrogen receptor evolution
BMC Evolutionary Biology, 2008Co-Authors: Mathilde Paris, Ingemar Pongratz, Katarina Pettersson, Michael Schubert, Stephanie Bertrand, Hector Escriva, Vincent LaudetAbstract:Background The origin of nuclear receptors (NRs) and the question whether the ancestral NR was a liganded or an unliganded transcription factor has been recently debated. To obtain insight into the evolution of the ligand binding ability of estrogen receptors (ER), we comparatively characterized the ER from the protochordate amphioxus (Branchiostoma Floridae), and the ER from lamprey (Petromyzon marinus), a basal vertebrate.
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Amphicoup-TF, a nuclear orphan receptor of the lancelet Branchiostoma Floridae, is implicated in retinoic acid signalling pathways.
Development Genes and Evolution, 2000Co-Authors: Marie-claire Langlois, Nicholas D. Holland, Hector Escriva, Vincent Laudet, Jean-marc Vanacker, Christophe Quéva, Linda Z. HollandAbstract:In vertebrates, the orphan nuclear receptors of the COUP-TF group function as negative transcriptional regulators that inhibit the hormonal induction of target genes mediated by classical members of the nuclear hormone superfamily, such as the retinoic acid receptors (RARs) or the thyroid hormone receptors (TRs). To investigate the evolutionary conservation of the roles of COUP-TF receptors as negative regulators in the retinoid and thyroid hormone pathways, we have characterized AmphiCOUP-TF, the homologue of COUP-TFI and COUP-TFII, in the chordate amphioxus (Branchiostoma Floridae), the closest living invertebrate relative of the vertebrates. Electrophoretic mobility shift assays (EMSA) showed that AmphiCOUP-TF binds to a wide variety of response elements, as do its vertebrate homologues. Furthermore, AmphiCOUP-TF is a transcriptional repressor that strongly inhibits retinoic acid-mediated transactivation. In situ hybridizations revealed expression of AmphiCOUP-TF in the nerve cord of late larvae, in a region corresponding to hindbrain and probably anterior spinal cord. Although the amphioxus nerve cord appears unsegmented at the gross anatomical level, this pattern reflects segmentation at the cellular level with stripes of expressing cells occurring adjacent to the ends and the centers of each myotomal segment, which may include visceral motor neurons and somatic motor neurons respectively, among other cells. A comparison of the expression pattern of AmphiCOUP-TF with those of its vertebrate homologues, suggests that the roles of COUP-TF in patterning of the nerve cord evolved prior to the split between the amphioxus and vertebrate lineages. Furthermore, in vitro data also suggest that Amphi-COUP-TF acts as a negative regulator of signalling by other nuclear receptors such as RAR, TR or ER.
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Amphi-COUP-TF, a nuclear orphan receptor of the lancelet Branchiostoma Floridae, is implicated in retinoic acid signaling pathways.
Development Genes and Evolution, 2000Co-Authors: Marie-claire Langlois, Hector Escriva, Vincent Laudet, Jean-marc Vanacker, Christophe Quéva, N.d. Holland, L.z. HollandAbstract:In vertebrates, the orphan nuclear receptors of the COUP-TF group function as negative transcriptionalregulators that inhibit the hormonal induction of targetgenes mediated by classical members of the nuclear hor-mone superfamily, such as the retinoic acid receptors(RARs) or the thyroid hormone receptors (TRs). To in-vestigate the evolutionary conservation of the roles of COUP-TF receptors as negative regulators in the retinoidand thyroid hormone pathways, we have characterizedAmphiCOUP-TF, the homologue of COUP-TFI andCOUP-TFII, in the chordate amphioxus ( Branchiostoma Floridae ), the closest living invertebrate relative of thevertebrates. Electrophoretic mobility shift assays(EMSA) showed that AmphiCOUP-TF binds to a widevariety of response elements, as do its vertebrate homo-logues. Furthermore, AmphiCOUP-TF is a transcription-al repressor that strongly inhibits retinoic acid-mediatedtransactivation. In situ hybridizations revealed expres-sion of AmphiCOUP-TF in the nerve cord of late larvae,in a region corresponding to hindbrain and probably an-terior spinal cord. Although the amphioxus nerve cordappears unsegmented at the gross anatomical level, thispattern reflects segmentation at the cellular level withstripes of expressing cells occurring adjacent to the endsand the centers of each myotomal segment, which mayinclude visceral motor neurons and somatic motor neu-rons respectively, among other cells. A comparison of the expression pattern of AmphiCOUP-TF with those of its vertebrate homologues, suggests that the roles of COUP-TF in patterning of the nerve cord evolved priorto the split between the amphioxus and vertebrate lineag-es. Furthermore, in vitro data also suggest that Amphi-COUP-TF acts as a negative regulator of signalling byother nuclear receptors such as RAR, TR or ER.