18 results on '"Claudia Lohs"'
Search Results
2. Circadian and Circalunar Clock Interactions in a Marine Annelid
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Juliane Zantke, Tomoko Ishikawa-Fujiwara, Enrique Arboleda, Claudia Lohs, Katharina Schipany, Natalia Hallay, Andrew D. Straw, Takeshi Todo, and Kristin Tessmar-Raible
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Biology (General) ,QH301-705.5 - Abstract
Life is controlled by multiple rhythms. Although the interaction of the daily (circadian) clock with environmental stimuli, such as light, is well documented, its relationship to endogenous clocks with other periods is little understood. We establish that the marine worm Platynereis dumerilii possesses endogenous circadian and circalunar (monthly) clocks and characterize their interactions. The RNAs of likely core circadian oscillator genes localize to a distinct nucleus of the worm’s forebrain. The worm’s forebrain also harbors a circalunar clock entrained by nocturnal light. This monthly clock regulates maturation and persists even when circadian clock oscillations are disrupted by the inhibition of casein kinase 1δ/ε. Both circadian and circalunar clocks converge on the regulation of transcript levels. Furthermore, the circalunar clock changes the period and power of circadian behavior, although the period length of the daily transcriptional oscillations remains unaltered. We conclude that a second endogenous noncircadian clock can influence circadian clock function.
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- 2013
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- View/download PDF
3. Insight into the Transmission Biology and Species-Specific Functional Capabilities of Tsetse (Diptera: Glossinidae) Obligate Symbiont Wigglesworthia
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Rita V. M. Rio, Rebecca E. Symula, Jingwen Wang, Claudia Lohs, Yi-neng Wu, Anna K. Snyder, Robert D. Bjornson, Kenshiro Oshima, Bryan S. Biehl, Nicole T. Perna, Masahira Hattori, and Serap Aksoy
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Microbiology ,QR1-502 - Abstract
ABSTRACT Ancient endosymbionts have been associated with extreme genome structural stability with little differentiation in gene inventory between sister species. Tsetse flies (Diptera: Glossinidae) harbor an obligate endosymbiont, Wigglesworthia, which has coevolved with the Glossina radiation. We report on the ~720-kb Wigglesworthia genome and its associated plasmid from Glossina morsitans morsitans and compare them to those of the symbiont from Glossina brevipalpis. While there was overall high synteny between the two genomes, a large inversion was noted. Furthermore, symbiont transcriptional analyses demonstrated host tissue and development-specific gene expression supporting robust transcriptional regulation in Wigglesworthia, an unprecedented observation in other obligate mutualist endosymbionts. Expression and immunohistochemistry confirmed the role of flagella during the vertical transmission process from mother to intrauterine progeny. The expression of nutrient provisioning genes (thiC and hemH) suggests that Wigglesworthia may function in dietary supplementation tailored toward host development. Furthermore, despite extensive conservation, unique genes were identified within both symbiont genomes that may result in distinct metabolomes impacting host physiology. One of these differences involves the chorismate, phenylalanine, and folate biosynthetic pathways, which are uniquely present in Wigglesworthia morsitans. Interestingly, African trypanosomes are auxotrophs for phenylalanine and folate and salvage both exogenously. It is possible that W. morsitans contributes to the higher parasite susceptibility of its host species. IMPORTANCE Genomic stasis has historically been associated with obligate endosymbionts and their sister species. Here we characterize the Wigglesworthia genome of the tsetse fly species Glossina morsitans and compare it to its sister genome within G. brevipalpis. The similarity and variation between the genomes enabled specific hypotheses regarding functional biology. Expression analyses indicate significant levels of transcriptional regulation and support development- and tissue-specific functional roles for the symbiosis previously not observed in obligate mutualist symbionts. Retention of the genetically expensive flagella within these small genomes was demonstrated to be significant in symbiont transmission and tailored to the unique tsetse fly reproductive biology. Distinctions in metabolomes were also observed. We speculate an additional role for Wigglesworthia symbiosis where infections with pathogenic trypanosomes may depend upon symbiont species-specific metabolic products and thus influence the vector competence traits of different tsetse fly host species.
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- 2012
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4. Wolbachia symbiont infections induce strong cytoplasmic incompatibility in the tsetse fly Glossina morsitans.
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Uzma Alam, Jan Medlock, Corey Brelsfoard, Roshan Pais, Claudia Lohs, Séverine Balmand, Jozef Carnogursky, Abdelaziz Heddi, Peter Takac, Alison Galvani, and Serap Aksoy
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Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
Tsetse flies are vectors of the protozoan parasite African trypanosomes, which cause sleeping sickness disease in humans and nagana in livestock. Although there are no effective vaccines and efficacious drugs against this parasite, vector reduction methods have been successful in curbing the disease, especially for nagana. Potential vector control methods that do not involve use of chemicals is a genetic modification approach where flies engineered to be parasite resistant are allowed to replace their susceptible natural counterparts, and Sterile Insect technique (SIT) where males sterilized by chemical means are released to suppress female fecundity. The success of genetic modification approaches requires identification of strong drive systems to spread the desirable traits and the efficacy of SIT can be enhanced by identification of natural mating incompatibility. One such drive mechanism results from the cytoplasmic incompatibility (CI) phenomenon induced by the symbiont Wolbachia. CI can also be used to induce natural mating incompatibility between release males and natural populations. Although Wolbachia infections have been reported in tsetse, it has been a challenge to understand their functional biology as attempts to cure tsetse of Wolbachia infections by antibiotic treatment damages the obligate mutualistic symbiont (Wigglesworthia), without which the flies are sterile. Here, we developed aposymbiotic (symbiont-free) and fertile tsetse lines by dietary provisioning of tetracycline supplemented blood meals with yeast extract, which rescues Wigglesworthia-induced sterility. Our results reveal that Wolbachia infections confer strong CI during embryogenesis in Wolbachia-free (Gmm(Apo)) females when mated with Wolbachia-infected (Gmm(Wt)) males. These results are the first demonstration of the biological significance of Wolbachia infections in tsetse. Furthermore, when incorporated into a mathematical model, our results confirm that Wolbachia can be used successfully as a gene driver. This lays the foundation for new disease control methods including a population replacement approach with parasite resistant flies. Alternatively, the availability of males that are reproductively incompatible with natural populations can enhance the efficacy of the ongoing sterile insect technique (SIT) applications by eliminating the need for chemical irradiation.
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- 2011
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5. Roquin targets mRNAs in a 3'-UTR-specific manner by different modes of regulation
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Gesine Behrens, Andreas Schlundt, Joao C. Guimaraes, Jacek Jemielity, Mihaela Zavolan, Vigo Heissmeyer, Michael Sattler, Kristin Reiche, Helmut Holtmann, Sven Brenner, Jörg Hackermüller, Cristina López-Rodríguez, Anne Hoffmann, Claudia Lohs, Katharina Essig, Nina Kronbeck, Joanna Kowalska, and Publica
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0301 basic medicine ,Translation ,Science ,RNA Stability ,Ubiquitin-Protein Ligases ,Response element ,Amino Acid Motifs ,General Physics and Astronomy ,Autoimmunity ,Plasma protein binding ,Biology ,Response Elements ,RNA decay ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Gene expression ,Animals ,Humans ,RNA folding ,RNA, Messenger ,lcsh:Science ,Psychological repression ,3' Untranslated Regions ,Regulation of gene expression ,Messenger RNA ,Multidisciplinary ,Binding Sites ,Base Sequence ,Three prime untranslated region ,General Chemistry ,NFKBID ,Cell biology ,030104 developmental biology ,Cross-Linking Reagents ,Gene Expression Regulation ,Protein Biosynthesis ,Nucleic Acid Conformation ,lcsh:Q ,Ribonucleosides ,Transcriptome ,030217 neurology & neurosurgery ,HeLa Cells ,Protein Binding - Abstract
The RNA-binding proteins Roquin-1 and Roquin-2 redundantly control gene expression and cell-fate decisions. Here, we show that Roquin not only interacts with stem–loop structures, but also with a linear sequence element present in about half of its targets. Comprehensive analysis of a minimal response element of the Nfkbid 3′-UTR shows that six stem–loop structures cooperate to exert robust and profound post-transcriptional regulation. Only binding of multiple Roquin proteins to several stem–loops exerts full repression, which redundantly involved deadenylation and decapping, but also translational inhibition. Globally, most Roquin targets are regulated by mRNA decay, whereas a small subset, including the Nfat5 mRNA, with more binding sites in their 3′-UTRs, are also subject to translational inhibition. These findings provide insights into how the robustness and magnitude of Roquin-mediated regulation is encoded in complex cis-elements.
- Published
- 2018
6. Tissue distribution and transmission routes for the tsetse fly endosymbionts
- Author
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Serap Aksoy, Claudia Lohs, Séverine Balmand, Abdelaziz Heddi, Biologie Fonctionnelle, Insectes et Interactions (BF2I), Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon, Université de Lyon (COMUE), Yale University, Partenaires INRAE, Max F Perutz Labs, INRA, INSA de Lyon, program 'Improving SIT for tsetse flies through research on their symbionts and pathogens', FAO/IAEA Coordinated Research Program, NIH [AI06892, GM069449], and Monell Foundation
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Glossina ,SYMBIOTIC BACTERIA ,HOST ,Sodalis ,food.ingredient ,Tsetse Flies ,[SDV]Life Sciences [q-bio] ,WOLBACHIA INFECTIONS ,Zoology ,Wigglesworthia glossinidia ,Article ,03 medical and health sciences ,food ,Enterobacteriaceae ,FISH ,parasitic diseases ,Animals ,Transmission ,Symbiosis ,Wigglesworthia ,In Situ Hybridization, Fluorescence ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Endosymbiont ,0303 health sciences ,WIGGLESWORTHIA-GLOSSINIDIA ,biology ,Obligate ,Tsetse fly ,030306 microbiology ,Ecology ,fungi ,Sodalis glossinidius ,food and beverages ,Bacteriome ,INSECT ,ANTIMICROBIAL PEPTIDES ,biology.organism_classification ,REPRODUCTION ,GLOSSINA-MORSITANS-MORSITANS ,APHACYRTHOSIPHON-PISUM ,MUTUALIST WIGGLESWORTHIA ,Wolbachia - Abstract
International audience; The tsetse fly Glossina is the vector of the protozoan Trypanosoma brucei spp., which causes Human and Animal African Trypanosomiasis in sub-Saharan African countries. To supplement their unbalanced vertebrate bloodmeal diet, flies permanently harbor the obligate bacterium Wigglesworthia glossinidia, which resides in bacteriocytes in the midgut bacteriome organ as well as in milk gland organ. Tsetse flies also harbor the secondary facultative endosymbionts (S-symbiont) Sodalis glossinidius that infects various tissues and Wolbachia that infects germ cells. Tsetse flies display viviparous reproductive biology where a single embryo hatches and completes its entire larval development in utero and receives nourishments in the form of milk secreted by mother's accessory glands (milk glands). To analyze the precise tissue distribution of the three endosymbiotic bacteria and to infer the way by which each symbiotic partner is transmitted from parent to progeny, we conducted a Fluorescence In situ Hybridization (FISH) study to survey bacterial spatial distribution across the fly tissues. We show that bacteriocytes are mono-infected with Wigglesworthia, while both Wigglesworthia and Sodalis are present in the milk gland lumen. Sodalis was further seen in the uterus, spermathecae, fat body, milk and intracellular in the milk gland cells. Contrary to Wigglesworthia and Sodalis, Wolbachia were the only bacteria infecting oocytes, trophocytes, and embryos at early embryonic stages. Furthermore, Wolbachia were not seen in the milk gland and in the fat body. This work further highlights the diversity of symbiont interactions in multipartner associations and supports two maternal routes of symbiont inheritance in the tsetse fly: Wolbachia through oocytes, and, Wigglesworthia and Sodalis by means of milk gland bacterial infection at early post-embryonic stages. Copyright (c) International Atomic Energy Agency 2013. Published by Elsevier Inc. All Rights Reserved.
- Published
- 2013
7. Roquin Paralogs 1 and 2 Redundantly Repress the Icos and Ox40 Costimulator mRNAs and Control Follicular Helper T Cell Differentiation
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Claudia Lohs, Helmut Blum, Elisabeth Kremmer, Marc Schmidt-Supprian, Wolfgang Wurst, Jessica Zöller, Vigo Heissmeyer, Katharina U. Vogel, Mathias Heikenwalder, Stephanie L. Edelmann, Frauke Neff, Arianna Bertossi, Kai P. Hoefig, Gitta Anne Heinz, Dirk Repsilber, Klaus Heger, Arie Geerlof, Katharina M. Jeltsch, Sebastian C. Warth, and Joel A. Schick
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Cellular differentiation ,Cell ,Lymphocyte Activation ,Mice ,0302 clinical medicine ,metabolism [CD4 Antigens] ,Gene expression ,Immunology and Allergy ,Receptor ,metabolism [Repressor Proteins] ,Mice, Knockout ,genetics [Ubiquitin-Protein Ligases] ,0303 health sciences ,genetics [Cell Differentiation] ,Effector ,Cell Differentiation ,T-Lymphocytes, Helper-Inducer ,Cell biology ,genetics [Inducible T-Cell Co-Stimulator Protein] ,Infectious Diseases ,medicine.anatomical_structure ,CD4 Antigens ,metabolism [Inducible T-Cell Co-Stimulator Protein] ,Protein Binding ,Ubiquitin-Protein Ligases ,T cell ,Immunology ,metabolism [Receptors, OX40] ,Biology ,metabolism [RNA, Messenger] ,Inducible T-Cell Co-Stimulator Protein ,03 medical and health sciences ,metabolism [Ubiquitin-Protein Ligases] ,Icos protein, mouse ,medicine ,Animals ,Humans ,immunology [T-Lymphocytes, Helper-Inducer] ,ddc:610 ,RNA, Messenger ,Gene ,030304 developmental biology ,genetics [Lymphocyte Activation] ,Receptors, OX40 ,Mice, Mutant Strains ,Mice, Inbred C57BL ,Repressor Proteins ,genetics [Repressor Proteins] ,HEK293 Cells ,Rc3h1 protein, mouse ,genetics [Receptors, OX40] ,roquin-2 protein, mouse ,030215 immunology ,IRF4 - Abstract
The Roquin-1 protein binds to messenger RNAs (mRNAs) and regulates gene expression posttranscriptionally. A single point mutation in Roquin-1, but not gene ablation, increases follicular helper T (Tfh) cell numbers and causes lupus-like autoimmune disease in mice. In Tcells, we did not identify a unique role for the much lower expressed paralog Roquin-2. However, combined ablation of both genes induced accumulation of Tcells with an effector and follicular helper phenotype. We showed that Roquin-1 and Roquin-2 proteins redundantly repressed the mRNA of inducible costimulator (Icos) and identified the Ox40 costimulatory receptor as another shared mRNA target. Combined acute deletion increased Ox40 signaling, as well as Irf4 expression, and imposed Tfh differentiation on CD4+ Tcells. These data imply that both proteins maintain tolerance by preventing inappropriate Tcell activation and Tfh cell differentiation, and that Roquin-2 compensates in the absence of Roquin-1, but not in the presence of its mutated form.
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- 2013
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8. Molecular characterization of two novel milk proteins in the tsetse fly (Glossina morsitans morsitans)
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Serap Aksoy, Guangxiao Yang, Claudia Lohs, and Geoffrey M. Attardo
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Male ,Tsetse Flies ,Offspring ,Molecular Sequence Data ,Gene Expression ,Genes, Insect ,Article ,RNA interference ,Gene expression ,Genetics ,Animals ,Tissue Distribution ,Amino Acid Sequence ,Molecular Biology ,Peptide sequence ,Gene ,Sex Characteristics ,Gene knockdown ,Sequence Homology, Amino Acid ,biology ,fungi ,food and beverages ,Tsetse fly ,Milk Proteins ,biology.organism_classification ,Phenotype ,Fertility ,Larva ,Insect Science ,Insect Proteins ,Female ,RNA Interference - Abstract
Milk proteins are an essential component of viviparous reproduction in the tsetse fly. Milk proteins are synthesized in and secreted from the milk gland tissue and constitute 50% of the secretions from which the intrauterine larva derives its nourishment. To understand milk protein function and regulation during viviparous reproduction, milk proteins need to be identified and characterized.Two putative unknown secretory proteins (GmmMGP2 and GmmMGP3) were selected by bioinformatic analysis of tissue specific tsetse cDNA libraries. RT-PCR analysis was performed to verify their milk gland/fat body specific expression profile. Detailed characterization of developmental and tissue specific expression of these proteins was performed by northern blot analysis and fluorescent in situ hybridization. Functional analysis of the milk gland proteins during the tsetse gonotrophic cycle was performed using RNA interference (RNAi).The predicted proteins from gmmmgp2 and gmmmgp3 are small approximately 22 kD and contain a high proportion of hydrophobic amino acids and potential phosphorylation sites. Expression of both genes is tissue specific to the secretory cells of the milk gland. Transcript abundance for both genes increases over the course of intrauterine larval development and parallels that of gmmmgp, a well characterized milk protein gene considered to be the major milk protein. Phenotypic analysis of flies after RNA interference treatment revealed a significant effect upon fecundity in the gmmmgp2 knockdown flies, but not the gmmmgp3 flies. Knockdown of gmmmgp2 resulted in disruption of ovulation and consequent oocyte accumulation and degradation. Gmmmgp2 knockdown also had a significant impact on fly mortality.This work identifies two novel genes, the proteins of which appear to function in response to intrauterine larvigenesis in tsetse. These proteins may be nutritional components of the milk secretions provided to the larva from the mother. Phenotypic data from knockdown of gmmmgp2 suggests that this protein may also have a regulatory function given the defect in ovulation observed in knockdown flies. Further analysis of these genes will be important (in conjunction with other milk proteins) for identification of transcriptional regulation mechanisms that direct milk gland/pregnancy specific gene expression.
- Published
- 2010
9. Cleavage of roquin and regnase-1 by the paracaspase MALT1 releases their cooperatively repressed targets to promote T(H)17 differentiation
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Nina Rehage, Katharina U. Vogel, Claudia Lohs, Axel Kallies, Arie Geerlof, Desheng Hu, Helmut Holtmann, Elisabeth Kremmer, Mingui Fu, Jenny E. Stehklein, Katharina M. Jeltsch, Jürgen Ruland, Achim Weber, Sven Brenner, Stephanie L. Edelmann, Daniel Nagel, Marc Schmidt-Supprian, Daniel Krappmann, Maciej Lech, Nina A. Martin, Ingo Schmitz, Gitta Anne Heinz, Hans-Joachim Anders, Mathias Heikenwalder, Sebastian C. Warth, Renee Gloury, Jessica Zöller, Vigo Heissmeyer, University of Zurich, and Heissmeyer, Vigo
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genetic structures ,Cellular differentiation ,Mice ,0302 clinical medicine ,Mice, Inbred NOD ,Immunology and Allergy ,Nuclear protein ,Lung ,Mice, Knockout ,0303 health sciences ,Mice, Inbred BALB C ,Lymphocyte differentiation ,Intracellular Signaling Peptides and Proteins ,Signal transducing adaptor protein ,Nuclear Proteins ,RNA-Binding Proteins ,Cell Differentiation ,Paracaspase ,3. Good health ,Cell biology ,Neoplasm Proteins ,medicine.anatomical_structure ,Caspases ,Interferon Regulatory Factors ,2723 Immunology and Allergy ,T cell ,Ubiquitin-Protein Ligases ,Immunology ,Receptors, Antigen, T-Cell ,610 Medicine & health ,Biology ,Cell Line ,Inducible T-Cell Co-Stimulator Protein ,03 medical and health sciences ,Ribonucleases ,10049 Institute of Pathology and Molecular Pathology ,medicine ,Animals ,Humans ,Amino Acid Sequence ,RNA, Messenger ,Transcription factor ,030304 developmental biology ,Adaptor Proteins, Signal Transducing ,2403 Immunology ,Binding Sites ,Interleukin-6 ,Proteins ,Molecular biology ,Mice, Inbred C57BL ,MALT1 ,HEK293 Cells ,Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein ,Th17 Cells ,Genes, rel ,Sequence Alignment ,030215 immunology - Abstract
Humoral autoimmunity paralleled by the accumulation of follicular helper T cells (T(FH) cells) is linked to mutation of the gene encoding the RNA-binding protein roquin-1. Here we found that T cells lacking roquin caused pathology in the lung and accumulated as cells of the T(H)17 subset of helper T cells in the lungs. Roquin inhibited T(H)17 cell differentiation and acted together with the endoribonuclease regnase-1 to repress target mRNA encoding the T(H)17 cell-promoting factors IL-6, ICOS, c-Rel, IRF4, IκBNS and IκBζ. This cooperation required binding of RNA by roquin and the nuclease activity of regnase-1. Upon recognition of antigen by the T cell antigen receptor (TCR), roquin and regnase-1 proteins were cleaved by the paracaspase MALT1. Thus, this pathway acts as a 'rheostat' by translating TCR signal strength via graded inactivation of post-transcriptional repressors and differential derepression of targets to enhance T(H)17 differentiation.
- Published
- 2014
10. TALENs mediate efficient and heritable mutation of endogenous genes in the marine annelid Platynereis dumerilii
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Alessandrea Polo, Kristin Tessmar-Raible, Agne Valinciute, Florian Raible, Olga Antonova, Natalia Hallay, Claudia Lohs, and Stephanie C Bannister
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Genotyping Techniques ,Zygote ,Molecular Sequence Data ,invertebrate ,Biology ,Investigations ,medicine.disease_cause ,Frameshift mutation ,03 medical and health sciences ,0302 clinical medicine ,Genome editing ,evolution ,Genetics ,medicine ,Animals ,genome editing ,DNA Cleavage ,Gene ,030304 developmental biology ,Sequence Deletion ,Regulation of gene expression ,0303 health sciences ,Transcription activator-like effector nuclease ,Mutation ,Base Sequence ,Effector ,Methods, Technology, and Resources ,Reproducibility of Results ,marine ,Polychaeta ,DNA Restriction Enzymes ,biology.organism_classification ,Larva ,Genetic Engineering ,chronobiology ,030217 neurology & neurosurgery ,Platynereis - Abstract
Platynereis dumerilii is a marine polychaete and an established model system for studies of evolution and development. Platynereis is also a re-emerging model for studying the molecular basis of circalunar reproductive timing: a biological phenomenon observed in many marine species. While gene expression studies have provided new insight into patterns of gene regulation, a lack of reverse genetic tools has so far limited the depth of functional analyses in this species. To address this need, we established customized transcriptional activator-like effector nucleases (TALENs) as a tool to engineer targeted modifications in Platynereis genes. By adapting a workflow of TALEN construction protocols and mutation screening approaches for use in Platynereis, we engineered frameshift mutations in three endogenous Platynereis genes. We confirmed that such mutations are heritable, demonstrating that TALENs can be used to generate homozygous knockout lines in P. dumerilii. This is the first use of TALENs for generating genetic knockout mutations in an annelid model. These tools not only open the door for detailed in vivo functional analyses, but also can facilitate further technical development, such as targeted genome editing.
- Published
- 2014
11. Stable transgenesis in the marine annelid Platynereis dumerilii sheds new light on photoreceptor evolution
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Florian Raible, Ruth M. Fischer, Kristin Tessmar-Raible, Vinoth Babu Veedin Rajan, Benjamin Backfisch, Claudia Lohs, and Enrique Arboleda
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0106 biological sciences ,Opsin ,Evolution of the eye ,genetic structures ,Green Fluorescent Proteins ,Molecular Sequence Data ,Biology ,010603 evolutionary biology ,01 natural sciences ,Photoreceptor cell ,Animals, Genetically Modified ,03 medical and health sciences ,medicine ,Animals ,Zebrafish ,In Situ Hybridization ,030304 developmental biology ,DNA Primers ,0303 health sciences ,Multidisciplinary ,Microscopy, Confocal ,Base Sequence ,Opsins ,Gene Expression Profiling ,Neural tube ,Gene Transfer Techniques ,Polychaeta ,Anatomy ,Sequence Analysis, DNA ,Biological Sciences ,biology.organism_classification ,Biological Evolution ,Immunohistochemistry ,eye diseases ,medicine.anatomical_structure ,Ventral nerve cord ,Photoreceptor Cells, Invertebrate ,PAX6 ,sense organs ,Neuroscience ,Platynereis - Abstract
Research in eye evolution has mostly focused on eyes residing in the head. In contrast, noncephalic light sensors are far less understood and rather regarded as evolutionary innovations. We established stable transgenesis in the annelid Platynereis , a reference species for evolutionary and developmental comparisons. EGFP controlled by cis -regulatory elements of r-opsin , a characteristic marker for rhabdomeric photoreceptors, faithfully recapitulates known r-opsin expression in the adult eyes, and marks a pair of pigment-associated frontolateral eyelets in the brain. Unexpectedly, transgenic animals revealed an additional series of photoreceptors in the ventral nerve cord as well as photoreceptors that are located in each pair of the segmental dorsal appendages (notopodia) and project into the ventral nerve cord. Consistent with a photosensory function of these noncephalic cells, decapitated animals display a clear photoavoidance response. Molecular analysis of the receptors suggests that they differentiate independent of pax6 , a gene involved in early eye development of many metazoans, and that the ventral cells may share origins with the Hesse organs in the amphioxus neural tube. Finally, expression analysis of opn4×-2 and opn4m-2 , two zebrafish orthologs of Platynereis r-opsin , reveals that these genes share expression in the neuromasts, known mechanoreceptors of the lateral line peripheral nervous system. Together, this establishes that noncephalic photoreceptors are more widespread than assumed, and may even reflect more ancient aspects of sensory systems. Our study marks significant advance for the understanding of photoreceptor cell (PRC) evolution and development and for Platynereis as a functional lophotrochozoan model system.
- Published
- 2013
12. Wolbachia symbiont infections induce strong cytoplasmic incompatibility in the tsetse fly glossina morsitans
- Author
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Séverine Balmand, Serap Aksoy, Claudia Lohs, Alison P. Galvani, Roshan Pais, Jan Medlock, Uzma Alam, Abdelaziz Heddi, Peter Takac, Jozef Carnogursky, Corey L. Brelsfoard, Yale University, Partenaires INRAE, Biologie Fonctionnelle, Insectes et Interactions (BF2I), Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon, Institute of Zoology, Section of Molecular and Applied Zoology, Slovak Academy of Sciences (SAS), This work received support from NIH AI06892, GM069449 and Ambrose Monell Foundation awards to SA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript., and Aksoy, Serap
- Subjects
Male ,Cytoplasm ,parasitology ,[SDV]Life Sciences [q-bio] ,Wigglesworthia glossinidia ,Sterile insect technique ,tsetse flies genetics ,transmission par vecteur ,lcsh:QH301-705.5 ,In Situ Hybridization, Fluorescence ,Disease Resistance ,Genetics ,0303 health sciences ,Ecology ,Applied Mathematics ,Sodalis glossinidius ,flies glossina ,phenotype ,tsetse flies microbiology ,insect vectors ,virology ,microbiology ,3. Good health ,Wigglesworthia ,Wolbachia ,Female ,Cytoplasmic incompatibility ,Research Article ,lcsh:Immunologic diseases. Allergy ,Tsetse Flies ,Immunology ,Biology ,03 medical and health sciences ,Aposymbiotic ,parasitic diseases ,Animals ,Pest Control, Biological ,Symbiosis ,Molecular Biology ,030304 developmental biology ,030306 microbiology ,fungi ,Tsetse fly ,Models, Theoretical ,mouche tsé tsé ,biology.organism_classification ,Fertility ,lcsh:Biology (General) ,maladie du sommeil ,lcsh:RC581-607 ,Mathematics - Abstract
Tsetse flies are vectors of the protozoan parasite African trypanosomes, which cause sleeping sickness disease in humans and nagana in livestock. Although there are no effective vaccines and efficacious drugs against this parasite, vector reduction methods have been successful in curbing the disease, especially for nagana. Potential vector control methods that do not involve use of chemicals is a genetic modification approach where flies engineered to be parasite resistant are allowed to replace their susceptible natural counterparts, and Sterile Insect technique (SIT) where males sterilized by chemical means are released to suppress female fecundity. The success of genetic modification approaches requires identification of strong drive systems to spread the desirable traits and the efficacy of SIT can be enhanced by identification of natural mating incompatibility. One such drive mechanism results from the cytoplasmic incompatibility (CI) phenomenon induced by the symbiont Wolbachia. CI can also be used to induce natural mating incompatibility between release males and natural populations. Although Wolbachia infections have been reported in tsetse, it has been a challenge to understand their functional biology as attempts to cure tsetse of Wolbachia infections by antibiotic treatment damages the obligate mutualistic symbiont (Wigglesworthia), without which the flies are sterile. Here, we developed aposymbiotic (symbiont-free) and fertile tsetse lines by dietary provisioning of tetracycline supplemented blood meals with yeast extract, which rescues Wigglesworthia-induced sterility. Our results reveal that Wolbachia infections confer strong CI during embryogenesis in Wolbachia-free (GmmApo) females when mated with Wolbachia-infected (GmmWt) males. These results are the first demonstration of the biological significance of Wolbachia infections in tsetse. Furthermore, when incorporated into a mathematical model, our results confirm that Wolbachia can be used successfully as a gene driver. This lays the foundation for new disease control methods including a population replacement approach with parasite resistant flies. Alternatively, the availability of males that are reproductively incompatible with natural populations can enhance the efficacy of the ongoing sterile insect technique (SIT) applications by eliminating the need for chemical irradiation., Author Summary Infections with the parasitic bacterium Wolbachia are widespread in insects and cause a number of reproductive modifications, including cytoplasmic incompatibility (CI). There is growing interest in Wolbachia, as CI may be able to drive desired phenotypes such as disease resistance traits, into natural populations. Although Wolbachia infections had been reported in the medically and agriculturally important tsetse, their functional role was unknown. This is because attempts to cure tsetse of Wolbachia by antibiotic treatment damages the obligate mutualist Wigglesworthia, without which the flies are sterile. Here we have succeeded in the development of Wolbachia free and still fertile tsetse lines. Mating experiments for the first time provides evidence of strong CI in tsetse. We have incorporated our empirical data in a mathematical model and show that Wolbachia infections can be harnessed in tsetse to drive desirable phenotypes into natural populations in few generations. This finding provides additional support for the application of genetic approaches, which aim to spread parasite resistance traits in natural populations as a novel disease control method. Alternatively, releasing Wolbachia infected males can enhance Sterile Insect applications, as this will reduce the fecundity of natural females either uninfected or carrying a different strain of Wolbachia.
- Published
- 2011
13. The obligate mutualist Wigglesworthia glossinidia influences reproduction, digestion, and immunity processes of its host, the tsetse fly
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Jingwen Wang, Roshan Pais, Serap Aksoy, Yineng Wu, and Claudia Lohs
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Male ,Sodalis ,food.ingredient ,Tsetse Flies ,Zoology ,Wigglesworthia glossinidia ,Applied Microbiology and Biotechnology ,Polymerase Chain Reaction ,Hemoglobins ,food ,Enterobacteriaceae ,Invertebrate Microbiology ,Animals ,Symbiosis ,Wigglesworthia ,In Situ Hybridization, Fluorescence ,Ecology ,biology ,Obligate ,fungi ,Sodalis glossinidius ,Immunity ,Tsetse fly ,Bacteriome ,biology.organism_classification ,Survival Analysis ,Anti-Bacterial Agents ,Fertility ,Immunology ,Digestion ,Female ,Food Science ,Biotechnology - Abstract
Tsetse flies (Diptera: Glossinidae) are vectors for trypanosome parasites, the agents of the deadly sleeping sickness disease in Africa. Tsetse also harbor two maternally transmitted enteric mutualist endosymbionts: the primary intracellular obligate Wigglesworthia glossinidia and the secondary commensal Sodalis glossinidius . Both endosymbionts are transmitted to the intrauterine progeny through the milk gland secretions of the viviparous female. We administered various antibiotics either continuously by per os supplementation of the host blood meal diet or discretely by hemocoelic injections into fertile females in an effort to selectively eliminate the symbionts to study their individual functions. A symbiont-specific PCR amplification assay and fluorescence in situ hybridization analysis were used to evaluate symbiont infection outcomes. Tetracycline and rifampin treatments eliminated all tsetse symbionts but reduced the fecundity of the treated females. Ampicillin treatments did not affect the intracellular Wigglesworthia localized in the bacteriome organ and retained female fecundity. The resulting progeny of ampicillin-treated females, however, lacked Wigglesworthia but still harbored the commensal Sodalis . Our results confirm the presence of two physiologically distinct Wigglesworthia populations: the bacteriome-localized Wigglesworthia involved with nutritional symbiosis and free-living Wigglesworthia in the milk gland organ responsible for maternal transmission to the progeny. We evaluated the reproductive fitness, longevity, digestion, and vectorial competence of flies that were devoid of Wigglesworthia . The absence of Wigglesworthia completely abolished the fertility of females but not that of males. Both the male and female Wigglesworthia -free adult progeny displayed longevity costs and were significantly compromised in their blood meal digestion ability. Finally, while the vectorial competence of the young newly hatched adults without Wigglesworthia was comparable to that of their wild-type counterparts, older flies displayed higher susceptibility to trypanosome infections, indicating a role for the mutualistic symbiosis in host immunobiology. The ability to rear adult tsetse that lack the obligate Wigglesworthia endosymbionts will now enable functional investigations into this ancient symbiosis.
- Published
- 2008
14. Analysis of milk gland structure and function in Glossina morsitans: Milk protein production, symbiont populations and fecundity
- Author
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Uzma Alam, Serap Aksoy, Suleyman Yildirim, Abdelaziz Heddi, Geoffrey M. Attardo, Claudia Lohs, Biologie Fonctionnelle, Insectes et Interactions (BF2I), Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)
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Sodalis ,food.ingredient ,Tsetse Flies ,Physiology ,Context (language use) ,In situ hybridization ,Wigglesworthia glossinidia ,Article ,03 medical and health sciences ,food ,fluids and secretions ,stomatognathic system ,Enterobacteriaceae ,Botany ,Animals ,Secretion ,Symbiosis ,Wigglesworthia ,030304 developmental biology ,0303 health sciences ,biology ,030306 microbiology ,Reproduction ,Sodalis glossinidius ,food and beverages ,biology.organism_classification ,Cell biology ,Fertility ,Insect Science ,1-1-1 Article périodique à comité de lecture ,Insect Proteins ,Female ,[SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis - Abstract
1-ACL (articles avec comité de lecture); A key process in the tsetse reproductive cycle is the transfer of essential nutrients and bacterial symbionts from mother to intrauterine offspring. The tissue mediating this transfer is the milk gland. This work focuses upon the localization and function of two milk proteins (milk gland protein (GmmMGP) and transferrin (GmmTsf)) and the tsetse endosymbionts (Sodalis and Wigglesworthia), in the context of milk gland physiology. Fluorescent in situ hybridization (FISH) and immunohistochemical analysis confirm that the milk gland secretory cells synthesize and secrete milk gland protein and transferrin. Knockdown of gmmmgp by double stranded RNA (dsRNA) mediated RNA interference results in reduction of tsetse fecundity, demonstrating its functional importance in larval nutrition and development. Bacterial species-specific in situ hybridizations of milk gland sections reveal large numbers of Sodalis and Wigglesworthia within the lumen of the milk gland. Sodalis is also localized within the cytoplasm of the secretory cells. Within the lumen, Wigglesworthia localize close to the channels leading to the milk storage reservoir of the milk gland secretory cells. We discuss the significance of the milk gland in larval nutrition and in transmission of symbiotic bacteria to developing offspring.
- Published
- 2008
15. Scube2 mediates Hedgehog signalling in the zebrafish embryo
- Author
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David G Keenan, Danielle Fischer, Carol Wicking, Claudia Lohs, Philippe Gautier, Timothy Evans, John C. Maule, Peter D. Currie, and Georgina E Hollway
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Receptor complex ,animal structures ,Embryo, Nonmammalian ,Receptors, Cell Surface ,Receptors, G-Protein-Coupled ,Animals ,Hedgehog Proteins ,Sonic hedgehog ,Molecular Biology ,Hedgehog ,Zebrafish ,Floor plate ,Genetics ,Extracellular Matrix Proteins ,biology ,Cell Biology ,Zebrafish Proteins ,biology.organism_classification ,Smoothened Receptor ,Protein Transport ,Mutation ,biology.protein ,Trans-Activators ,Hedgehog Family ,Signal transduction ,Smoothened ,Developmental Biology ,Signal Transduction - Abstract
The Hedgehog family of secreted morphogens specifies the fate of a large number of different cell types within invertebrate and vertebrate embryos, including the muscle cell precursors of the embryonic myotome of zebrafish. Formation of Hedgehog-sensitive muscle fates is disrupted within homozygous zebrafish mutants of the “you”-type class, the majority of which disrupt components of the Hedgehog (HH) signal transduction pathway. We have undertaken a phenotypic and molecular characterisation of one of these mutants, you, which we show results from mutations within the zebrafish orthologue of the mammalian gene scube2. This gene encodes a member of the Scube family of proteins, which is characterised by several protein motifs including EGF and CUB domains. Epistatic and molecular analyses position Scube2 function upstream of Smoothened (Smoh), the signalling component of the HH receptor complex, suggesting that Scube2 may act during HH signal transduction prior to, or during, receipt of the HH signal at the plasma membrane. In support of this model we show that scube2 has homology to cubilin, which encodes an endocytic receptor involved in protein trafficking suggesting a possible mode of function for Scube2 during HH signal transduction.
- Published
- 2005
16. Zebrafish fgfr1 is a member of the fgf8 synexpression group and is required for fgf8 signalling at the midbrain-hindbrain boundary
- Author
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Michael Brand, Steffen Scholpp, Casper Groth, Michael Lardelli, and Claudia Lohs
- Subjects
Mesoderm ,animal structures ,Fibroblast Growth Factor 8 ,Molecular Sequence Data ,Hindbrain ,Biology ,Fibroblast growth factor ,Evolution, Molecular ,FGF8 ,Mesencephalon ,Genetics ,medicine ,Animals ,Amino Acid Sequence ,Receptor, Fibroblast Growth Factor, Type 1 ,Cloning, Molecular ,Zebrafish ,Phylogeny ,Sequence Homology, Amino Acid ,Fibroblast growth factor receptor 1 ,Synexpression ,Receptor Protein-Tyrosine Kinases ,biology.organism_classification ,Receptors, Fibroblast Growth Factor ,Cell biology ,Fibroblast Growth Factors ,Rhombencephalon ,stomatognathic diseases ,medicine.anatomical_structure ,Phenotype ,embryonic structures ,Developmental biology ,Developmental Biology ,Signal Transduction - Abstract
FGFR1 is an important signalling molecule during embryogenesis and in adulthood. FGFR1 mutations in human may lead to developmental defects and pathological conditions, including cancer and Alzheimer's disease. Here, we describe cloning and expression analysis of the zebrafish fibroblast growth factor receptor 1 ( fgfr1). Initially, fgfr1 is expressed in the adaxial mesoderm with transcripts distinctly localised to the anterior portion of each half-somite. Hereupon, fgfr1 is also strongly expressed in the otic vesicles, branchial arches and the brain, especially at the midbrain-hindbrain boundary (MHB). The expression patterns of fgfr1 and fgf8 are strikingly similar and knock-down of fgfr1 phenocopies many aspects observed in the fgf8 mutant acerebellar, suggesting that Fgf8 exerts its function mainly by binding to FgfR1.
- Published
- 2004
17. Engrailed and Fgf8 act synergistically to maintain the boundary between diencephalon and mesencephalon
- Author
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Steffen Scholpp, Claudia Lohs, and Michael Brand
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animal structures ,Fibroblast Growth Factor 8 ,PAX6 Transcription Factor ,Hindbrain ,Nerve Tissue Proteins ,Biology ,Cell fate determination ,Midbrain ,FGF8 ,Mesencephalon ,medicine ,Animals ,Paired Box Transcription Factors ,Diencephalon ,Eye Proteins ,Molecular Biology ,Zebrafish ,Homeodomain Proteins ,Neural tube ,Gene Expression Regulation, Developmental ,Anatomy ,Zebrafish Proteins ,engrailed ,Fibroblast Growth Factors ,Repressor Proteins ,medicine.anatomical_structure ,nervous system ,embryonic structures ,Forebrain ,Neuroscience ,Neural plate ,Developmental Biology ,Signal Transduction ,Transcription Factors - Abstract
Specification of the forebrain, midbrain and hindbrain primordia occurs during gastrulation in response to signals that pattern the gastrula embryo. Following establishment of the primordia, each brain part is thought to develop largely independently from the others under the influence of local organizing centers like the midbrain-hindbrain boundary (MHB, or isthmic) organizer. Mechanisms that maintain the integrity of brain subdivisions at later stages are not yet known. To examine such mechanisms in the anterior neural tube, we have studied the establishment and maintenance of the diencephalic-mesencephalic boundary (DMB). We show that maintenance of the DMB requires both the presence of a specified midbrain and a functional MHB organizer. Expression of pax6.1 , a key regulator of forebrain development, is posteriorly suppressed by the Engrailed proteins, Eng2 and Eng3. Mis-expression of eng3 in the forebrain primordium causes downregulation of pax6.1 , and forebrain cells correspondingly change their fate and acquire midbrain identity. Conversely, in embryos lacking both eng2 and eng3 , the DMB shifts caudally into the midbrain territory. However, a patch of midbrain tissue remains between the forebrain and the hindbrain primordia in such embryos. This suggests that an additional factor maintains midbrain cell fate. We find that Fgf8 is a candidate for this signal, as it is both necessary and sufficient to repress pax6.1 and hence to shift the DMB anteriorly independently of the expression status of eng2 / eng3 . By examining small cell clones that are unable to receive an Fgf signal, we show that cells in the presumptive midbrain neural plate require an Fgf signal to keep them from following a forebrain fate. Combined loss of both Eng2/Eng3 and Fgf8 leads to complete loss of midbrain identity, resulting in fusion of the forebrain and the hindbrain primordia. Thus, Eng2/Eng3 and Fgf8 are necessary to maintain midbrain identity in the neural plate and thereby position the DMB. This provides an example of a mechanism needed to maintain the subdivision of the anterior neural plate into forebrain and midbrain.
- Published
- 2003
18. Features of the ancestral bilaterian inferred from Platynereis dumerilii ParaHox genes
- Author
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Guillaume Balavoine, Florian Raible, Nicolas Dray, Sylvie Samain, Detlev Arendt, Ghislaine Magdelenat, Béatrice Ségurens, David E. K. Ferrier, Claire Jubin, Jerome H.L. Hui, Natalia Korchagina, European Molecular Biology Laboratory [Heidelberg] (EMBL), Department of Zoology, University of Oxford, University of Oxford [Oxford], Cellules Souches et Développement, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Génomique d'Evry (IG), Institut de Biologie François JACOB (JACOB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Structure et évolution des génomes (SEG), CNS-Université d'Évry-Val-d'Essonne (UEVE)-Centre National de la Recherche Scientifique (CNRS), Centre de génétique moléculaire (CGM), Centre National de la Recherche Scientifique (CNRS), The Royal Society, BBSRC, University of St Andrews. School of Biology, University of St Andrews. Marine Alliance for Science & Technology Scotland, University of St Andrews. Scottish Oceans Institute, University of Oxford, Faculty of Life Sciences, Michael Smith Building, University of Manchester, University of Manchester [Manchester], Max Perutz Labs (MFPL), Medizinische Universität Wien = Medical University of Vienna-University of Vienna [Vienna], Department of Molecular, Cellular and Developmental Biology, Yale University, Yale University [New Haven], Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Jacques Monod (IJM (UMR_7592)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Scottish Oceans Institute [University of St Andrews] (SOI), School of Biology [University of St Andrews], University of St Andrews [Scotland]-University of St Andrews [Scotland], Work in the authors' laboratory is funded by the BBSRC and Royal Society (JHLH, NK, DEKF), the Marine Genomics Europe Network of Excellence (GOCE-04-505403 (D.A. and FR)), and the CNRS, ANR (BLAN-0294) and FRM (ND and GB)., The authors thank Heidi Snyman and Claudia Lohs for technical support, and Peter Holland for advice and support. JHLH was supported by the Hong Kong and China Oxford Scholarship Funds, and the Merton College Domus scholarship., MFPL, The Scottish Oceans Institute, University of St Andrews, and University of St Andrews [Scotland]
- Subjects
Bacterial Artificial Chromosome Clone ,Physiology ,QH301 Biology ,Lineage (evolution) ,Gene Expression ,MESH: Amino Acid Sequence ,Plant Science ,Contig Mapping ,0302 clinical medicine ,Structural Biology ,Gene cluster ,MESH: Animals ,MESH: In Situ Hybridization, Fluorescence ,MESH: Contig Mapping ,Hox gene ,lcsh:QH301-705.5 ,[SDV.BDD]Life Sciences [q-bio]/Development Biology ,Bilateria ,MESH: Evolution, Molecular ,ComputingMilieux_MISCELLANEOUS ,In Situ Hybridization, Fluorescence ,Genetics ,Bacterial Artificial Chromosome Sequence ,0303 health sciences ,Deuterostome ,biology ,Agricultural and Biological Sciences(all) ,[SDV.BA]Life Sciences [q-bio]/Animal biology ,Chromosome Mapping ,MESH: Synteny ,Platynereis dumerilii, ParaHox, genome evolution, Xlox, Cdx, Gsx ,Larva ,Multigene Family ,Protostome ,General Agricultural and Biological Sciences ,ParaHox Gene ,Research Article ,Biotechnology ,MESH: Gene Expression ,MESH: Polychaeta ,Molecular Sequence Data ,MESH: Sequence Alignment ,ParaHox ,Synteny ,General Biochemistry, Genetics and Molecular Biology ,Evolution, Molecular ,QH301 ,03 medical and health sciences ,MESH: Homeodomain Proteins ,Animals ,Amino Acid Sequence ,Bacterial Artificial Chromosome Library ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Homeodomain Proteins ,MESH: Molecular Sequence Data ,Biochemistry, Genetics and Molecular Biology(all) ,[SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology ,Polychaeta ,Cell Biology ,biology.organism_classification ,lcsh:Biology (General) ,MESH: Multigene Family ,MESH: Chromosome Mapping ,Bacterial Artificial Chromosome ,MESH: Larva ,Sequence Alignment ,030217 neurology & neurosurgery ,Developmental Biology - Abstract
Background The ParaHox gene cluster is the evolutionary sister to the Hox cluster. Whilst the role of the Hox cluster in patterning the anterior-posterior axis of bilaterian animals is well established, and the organisation of vertebrate Hox clusters is intimately linked to gene regulation, much less is known about the more recently discovered ParaHox cluster. ParaHox gene clustering, and its relationship to expression, has only been described in deuterostomes. Conventional protostome models (Drosophila melanogaster and Caenorhabditis elegans) are secondarily derived with respect to ParaHox genes, suffering gene loss and cluster break-up. Results We provide the first evidence for ParaHox gene clustering from a less-derived protostome animal, the annelid Platynereis dumerilii. Clustering of these genes is thus not a sole preserve of the deuterostome lineage within Bilateria. This protostome ParaHox cluster is not entirely intact however, with Pdu-Cdx being on the opposite end of the same chromosome arm from Pdu-Gsx and Pdu-Xlox. From the genomic sequence around the P. dumerilii ParaHox genes the neighbouring genes are identified, compared with other taxa, and the ancestral arrangement deduced. Conclusion We relate the organisation of the ParaHox genes to their expression, and from comparisons with other taxa hypothesise that a relatively complex pattern of ParaHox gene expression existed in the protostome-deuterostome ancestor, which was secondarily simplified along several invertebrate lineages. Detailed comparisons of the gene content around the ParaHox genes enables the reconstruction of the genome surrounding the ParaHox cluster of the protostome-deuterostome ancestor, which existed over 550 million years ago.
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