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Greibe E, Nexo E. Development of a Sensitive ELISA for Gastric Intrinsic Factor and Detection of Intrinsic Factor Immunoreactivity in Human Serum. Nutrients 2022; 14:nu14194043. [PMID: 36235695 PMCID: PMC9572238 DOI: 10.3390/nu14194043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/24/2022] [Accepted: 09/24/2022] [Indexed: 11/16/2022] Open
Abstract
Gastric Intrinsic Factor (IF) is produced by the parietal cells of the stomach and secreted into the gastrointestinal tract where it ensures the active absorption of vitamin B12. We hypothesized that a small amount of IF ends up in the circulation and can be measured in serum. The aim of this study was to develop an assay for measuring human IF and to demonstrate its presence in serum. We designed a sensitive ELISA for measurement of human IF using a commercial monoclonal antibody and an in-house polyclonal antibody as capture and detecting antibody, respectively. Imprecision, accuracy, and linearity of the assay were examined. We established a reference interval based on serum samples from 240 healthy donors, and explored the daily IF fluctuations in 20 healthy subjects. Employing a prototype IF ELISA and size exclusion chromatography experiments, we demonstrated the presence of IF in human serum. In its final design, the IF ELISA has a measurement range of 0.2 to 50 pmol/L. The intra-assay and total imprecision were 7.9% and 15%, respectively. The 95% reference interval (18–65 years) was 1.7–11.6 pmol/L. No diurnal fluctuation or notable sex differences were observed. Our results suggest that the assay is capable of detecting and quantifying human IF in the circulation and may prove useful in the characterization of patients with impaired IF production.
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Affiliation(s)
- Eva Greibe
- Department of Clinical Biochemistry, Aarhus University Hospital, 8200 Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, 8000 Aarhus, Denmark
- Correspondence:
| | - Ebba Nexo
- Department of Clinical Biochemistry, Aarhus University Hospital, 8200 Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, 8000 Aarhus, Denmark
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2
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Koslová A, Trefil P, Mucksová J, Krchlíková V, Plachý J, Krijt J, Reinišová M, Kučerová D, Geryk J, Kalina J, Šenigl F, Elleder D, Kožich V, Hejnar J. Knock-Out of Retrovirus Receptor Gene Tva in the Chicken Confers Resistance to Avian Leukosis Virus Subgroups A and K and Affects Cobalamin (Vitamin B 12)-Dependent Level of Methylmalonic Acid. Viruses 2021; 13:v13122504. [PMID: 34960774 PMCID: PMC8708277 DOI: 10.3390/v13122504] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 01/18/2023] Open
Abstract
The chicken Tva cell surface protein, a member of the low-density lipoprotein receptor family, has been identified as an entry receptor for avian leukosis virus of classic subgroup A and newly emerging subgroup K. Because both viruses represent an important concern for the poultry industry, we introduced a frame-shifting deletion into the chicken tva locus with the aim of knocking-out Tva expression and creating a virus-resistant chicken line. The tva knock-out was prepared by CRISPR/Cas9 gene editing in chicken primordial germ cells and orthotopic transplantation of edited cells into the testes of sterilized recipient roosters. The resulting tva −/− chickens tested fully resistant to avian leukosis virus subgroups A and K, both in in vitro and in vivo assays, in contrast to their susceptible tva +/+ and tva +/− siblings. We also found a specific disorder of the cobalamin/vitamin B12 metabolism in the tva knock-out chickens, which is in accordance with the recently recognized physiological function of Tva as a receptor for cobalamin in complex with transcobalamin transporter. Last but not least, we bring a new example of the de novo resistance created by CRISPR/Cas9 editing of pathogen dependence genes in farm animals and, furthermore, a new example of gene editing in chicken.
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Affiliation(s)
- Anna Koslová
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (A.K.); (V.K.); (J.P.); (M.R.); (D.K.); (J.G.); (F.Š.); (D.E.)
| | - Pavel Trefil
- BIOPHARM, Research Institute of Biopharmacy and Veterinary Drugs, Pohoří-Chotouň 90, 254 49 Jílové u Prahy, Czech Republic; (P.T.); (J.M.); (J.K.)
| | - Jitka Mucksová
- BIOPHARM, Research Institute of Biopharmacy and Veterinary Drugs, Pohoří-Chotouň 90, 254 49 Jílové u Prahy, Czech Republic; (P.T.); (J.M.); (J.K.)
| | - Veronika Krchlíková
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (A.K.); (V.K.); (J.P.); (M.R.); (D.K.); (J.G.); (F.Š.); (D.E.)
| | - Jiří Plachý
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (A.K.); (V.K.); (J.P.); (M.R.); (D.K.); (J.G.); (F.Š.); (D.E.)
| | - Jakub Krijt
- Department of Pediatrics and Inherited Metabolic Disorders, Charles University, First Faculty of Medicine and General University Hospital in Prague, 128 08 Prague, Czech Republic; (J.K.); (V.K.)
| | - Markéta Reinišová
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (A.K.); (V.K.); (J.P.); (M.R.); (D.K.); (J.G.); (F.Š.); (D.E.)
| | - Dana Kučerová
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (A.K.); (V.K.); (J.P.); (M.R.); (D.K.); (J.G.); (F.Š.); (D.E.)
| | - Josef Geryk
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (A.K.); (V.K.); (J.P.); (M.R.); (D.K.); (J.G.); (F.Š.); (D.E.)
| | - Jiří Kalina
- BIOPHARM, Research Institute of Biopharmacy and Veterinary Drugs, Pohoří-Chotouň 90, 254 49 Jílové u Prahy, Czech Republic; (P.T.); (J.M.); (J.K.)
| | - Filip Šenigl
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (A.K.); (V.K.); (J.P.); (M.R.); (D.K.); (J.G.); (F.Š.); (D.E.)
| | - Daniel Elleder
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (A.K.); (V.K.); (J.P.); (M.R.); (D.K.); (J.G.); (F.Š.); (D.E.)
| | - Viktor Kožich
- Department of Pediatrics and Inherited Metabolic Disorders, Charles University, First Faculty of Medicine and General University Hospital in Prague, 128 08 Prague, Czech Republic; (J.K.); (V.K.)
| | - Jiří Hejnar
- Institute of Molecular Genetics, Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (A.K.); (V.K.); (J.P.); (M.R.); (D.K.); (J.G.); (F.Š.); (D.E.)
- Correspondence:
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3
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Ansaloni F, Gerdol M, Torboli V, Fornaini NR, Greco S, Giulianini PG, Coscia MR, Miccoli A, Santovito G, Buonocore F, Scapigliati G, Pallavicini A. Cold Adaptation in Antarctic Notothenioids: Comparative Transcriptomics Reveals Novel Insights in the Peculiar Role of Gills and Highlights Signatures of Cobalamin Deficiency. Int J Mol Sci 2021; 22:ijms22041812. [PMID: 33670421 PMCID: PMC7918649 DOI: 10.3390/ijms22041812] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 01/13/2023] Open
Abstract
Far from being devoid of life, Antarctic waters are home to Cryonotothenioidea, which represent one of the fascinating cases of evolutionary adaptation to extreme environmental conditions in vertebrates. Thanks to a series of unique morphological and physiological peculiarities, which include the paradigmatic case of loss of hemoglobin in the family Channichthyidae, these fish survive and thrive at sub-zero temperatures. While some of the distinctive features of such adaptations have been known for decades, our knowledge of their genetic and molecular bases is still limited. We generated a reference de novo assembly of the icefish Chionodraco hamatus transcriptome and used this resource for a large-scale comparative analysis among five red-blooded Cryonotothenioidea, the sub-Antarctic notothenioid Eleginops maclovinus and seven temperate teleost species. Our investigation targeted the gills, a tissue of primary importance for gaseous exchange, osmoregulation, ammonia excretion, and its role in fish immunity. One hundred and twenty genes were identified as significantly up-regulated in Antarctic species and surprisingly shared by red- and white-blooded notothenioids, unveiling several previously unreported molecular players that might have contributed to the evolutionary success of Cryonotothenioidea in Antarctica. In particular, we detected cobalamin deficiency signatures and discussed the possible biological implications of this condition concerning hematological alterations and the heavy parasitic loads typically observed in all Cryonotothenioidea.
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Affiliation(s)
- Federico Ansaloni
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.A.); (V.T.); (N.R.F.); (S.G.); (P.G.G.); (A.P.)
- International School for Advanced Studies, 34136 Trieste, Italy
| | - Marco Gerdol
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.A.); (V.T.); (N.R.F.); (S.G.); (P.G.G.); (A.P.)
- Correspondence:
| | - Valentina Torboli
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.A.); (V.T.); (N.R.F.); (S.G.); (P.G.G.); (A.P.)
| | - Nicola Reinaldo Fornaini
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.A.); (V.T.); (N.R.F.); (S.G.); (P.G.G.); (A.P.)
- Department of Cell Biology, Charles University, 12800 Prague, Czech Republic
| | - Samuele Greco
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.A.); (V.T.); (N.R.F.); (S.G.); (P.G.G.); (A.P.)
| | - Piero Giulio Giulianini
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.A.); (V.T.); (N.R.F.); (S.G.); (P.G.G.); (A.P.)
| | - Maria Rosaria Coscia
- Institute of Biochemistry and Cell Biology, National Research Council of Italy, 80131 Naples, Italy;
| | - Andrea Miccoli
- Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia, 01100 Viterbo, Italy; (A.M.); (F.B.); (G.S.)
| | | | - Francesco Buonocore
- Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia, 01100 Viterbo, Italy; (A.M.); (F.B.); (G.S.)
| | - Giuseppe Scapigliati
- Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia, 01100 Viterbo, Italy; (A.M.); (F.B.); (G.S.)
| | - Alberto Pallavicini
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.A.); (V.T.); (N.R.F.); (S.G.); (P.G.G.); (A.P.)
- Anton Dohrn Zoological Station, 80122 Naples, Italy
- National Institute of Oceanography and Experimental Geophysics, 34010 Trieste, Italy
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Rzepka Z, Rok J, Kowalska J, Banach K, Hermanowicz JM, Beberok A, Sieklucka B, Gryko D, Wrześniok D. Astrogliosis in an Experimental Model of Hypovitaminosis B12: A Cellular Basis of Neurological Disorders due to Cobalamin Deficiency. Cells 2020; 9:cells9102261. [PMID: 33050187 PMCID: PMC7600008 DOI: 10.3390/cells9102261] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/17/2022] Open
Abstract
Cobalamin deficiency affects human physiology with sequelae ranging from mild fatigue to severe neuropsychiatric abnormalities. The cellular and molecular aspects of the nervous system disorders associated with hypovitaminosis B12 remain largely unknown. Growing evidence indicates that astrogliosis is an underlying component of a wide range of neuropathologies. Previously, we developed an in vitro model of cobalamin deficiency in normal human astrocytes (NHA) by culturing the cells with c-lactam of hydroxycobalamin (c-lactam OH-Cbl). We revealed a non-apoptotic activation of caspases (3/7, 8, 9) in cobalamin-deficient NHA, which may suggest astrogliosis. The aim of the current study was to experimentally verify this hypothesis. We indicated an increase in the cellular expression of two astrogliosis markers: glial fibrillary acidic protein and vimentin in cobalamin-deficient NHA using Western blot analysis and immunocytochemistry with confocal laser scanning microscopy. In the next step of the study, we revealed c-lactam OH-Cbl as a potential non-toxic vitamin B12 antagonist in an in vivo model using zebrafish embryos. We believe that the presented results will contribute to a better understanding of the cellular mechanism underlying neurologic pathology due to cobalamin deficiency and will serve as a foundation for further studies.
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Affiliation(s)
- Zuzanna Rzepka
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, Jagiellońska 4, 41-200 Sosnowiec, Poland; (Z.R.); (J.R.); (J.K.); (K.B.); (A.B.)
| | - Jakub Rok
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, Jagiellońska 4, 41-200 Sosnowiec, Poland; (Z.R.); (J.R.); (J.K.); (K.B.); (A.B.)
| | - Justyna Kowalska
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, Jagiellońska 4, 41-200 Sosnowiec, Poland; (Z.R.); (J.R.); (J.K.); (K.B.); (A.B.)
| | - Klaudia Banach
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, Jagiellońska 4, 41-200 Sosnowiec, Poland; (Z.R.); (J.R.); (J.K.); (K.B.); (A.B.)
| | - Justyna Magdalena Hermanowicz
- Department of Pharmacodynamics, Medical University of Bialystok, Mickiewicza 2C, 15-222 Bialystok, Poland; (J.M.H.); (B.S.)
| | - Artur Beberok
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, Jagiellońska 4, 41-200 Sosnowiec, Poland; (Z.R.); (J.R.); (J.K.); (K.B.); (A.B.)
| | - Beata Sieklucka
- Department of Pharmacodynamics, Medical University of Bialystok, Mickiewicza 2C, 15-222 Bialystok, Poland; (J.M.H.); (B.S.)
| | - Dorota Gryko
- Institute of Organic Chemistry, Polish Academy of Science, Kasprzaka 44/52, 01-224 Warsaw, Poland;
| | - Dorota Wrześniok
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, Jagiellońska 4, 41-200 Sosnowiec, Poland; (Z.R.); (J.R.); (J.K.); (K.B.); (A.B.)
- Correspondence: ; Tel.: +48-3-2364-1050
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5
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Turakhia Y, Chen HI, Marcovitz A, Bejerano G. A fully-automated method discovers loss of mouse-lethal and human-monogenic disease genes in 58 mammals. Nucleic Acids Res 2020; 48:e91. [PMID: 32614390 PMCID: PMC7498332 DOI: 10.1093/nar/gkaa550] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/23/2020] [Accepted: 06/23/2020] [Indexed: 01/20/2023] Open
Abstract
Gene losses provide an insightful route for studying the morphological and physiological adaptations of species, but their discovery is challenging. Existing genome annotation tools focus on annotating intact genes and do not attempt to distinguish nonfunctional genes from genes missing annotation due to sequencing and assembly artifacts. Previous attempts to annotate gene losses have required significant manual curation, which hampers their scalability for the ever-increasing deluge of newly sequenced genomes. Using extreme sequence erosion (amino acid deletions and substitutions) and sister species support as an unambiguous signature of loss, we developed an automated approach for detecting high-confidence gene loss events across a species tree. Our approach relies solely on gene annotation in a single reference genome, raw assemblies for the remaining species to analyze, and the associated phylogenetic tree for all organisms involved. Using human as reference, we discovered over 400 unique human ortholog erosion events across 58 mammals. This includes dozens of clade-specific losses of genes that result in early mouse lethality or are associated with severe human congenital diseases. Our discoveries yield intriguing potential for translational medical genetics and evolutionary biology, and our approach is readily applicable to large-scale genome sequencing efforts across the tree of life.
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Affiliation(s)
- Yatish Turakhia
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Heidi I Chen
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - Amir Marcovitz
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - Gill Bejerano
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
- Department of Computer Science, Stanford University, Stanford, CA 94305, USA
- Department of Biomedical Data Science, Stanford University, Stanford, CA 94305, USA
- Department of Pediatrics, Stanford University, Stanford, CA 94305, USA
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Sloan JL, Achilly NP, Arnold ML, Catlett JL, Blake T, Bishop K, Jones M, Harper U, English MA, Anderson S, Trivedi NS, Elkahloun A, Hoffmann V, Brooks BP, Sood R, Venditti CP. The vitamin B12 processing enzyme, mmachc, is essential for zebrafish survival, growth and retinal morphology. Hum Mol Genet 2020; 29:2109-2123. [PMID: 32186706 PMCID: PMC7399538 DOI: 10.1093/hmg/ddaa044] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/10/2020] [Accepted: 03/11/2020] [Indexed: 12/16/2022] Open
Abstract
Cobalamin C (cblC) deficiency, the most common inborn error of intracellular cobalamin metabolism, is caused by mutations in MMACHC, a gene responsible for the processing and intracellular trafficking of vitamin B12. This recessive disorder is characterized by a failure to metabolize cobalamin into adenosyl- and methylcobalamin, which results in the biochemical perturbations of methylmalonic acidemia, hyperhomocysteinemia and hypomethioninemia caused by the impaired activity of the downstream enzymes, methylmalonyl-CoA mutase and methionine synthase. Cobalamin C deficiency can be accompanied by a wide spectrum of clinical manifestations, including progressive blindness, and, in mice, manifests with very early embryonic lethality. Because zebrafish harbor a full complement of cobalamin metabolic enzymes, we used genome editing to study the loss of mmachc function and to develop the first viable animal model of cblC deficiency. mmachc mutants survived the embryonic period but perished in early juvenile life. The mutants displayed the metabolic and clinical features of cblC deficiency including methylmalonic acidemia, severe growth retardation and lethality. Morphologic and metabolic parameters improved when the mutants were raised in water supplemented with small molecules used to treat patients, including hydroxocobalamin, methylcobalamin, methionine and betaine. Furthermore, mmachc mutants bred to express rod and/or cone fluorescent reporters, manifested a retinopathy and thin optic nerves (ON). Expression analysis using whole eye mRNA revealed the dysregulation of genes involved in phototransduction and cholesterol metabolism. Zebrafish with mmachc deficiency recapitulate the several of the phenotypic and biochemical features of the human disorder, including ocular pathology, and show a response to established treatments.
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Affiliation(s)
- Jennifer L Sloan
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, 20892 USA
| | - Nathan P Achilly
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, 20892 USA
| | - Madeline L Arnold
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, 20892 USA
| | - Jerrel L Catlett
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, 20892 USA
| | - Trevor Blake
- Zebrafish Core Facility, Translational and Functional Genomics Branch, National Human Genome Research Institute, Bethesda, MD, 20892 USA
| | - Kevin Bishop
- Zebrafish Core Facility, Translational and Functional Genomics Branch, National Human Genome Research Institute, Bethesda, MD, 20892 USA
| | - Marypat Jones
- Genomics Core, Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, MD, 20892 USA
| | - Ursula Harper
- Genomics Core, Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, MD, 20892 USA
| | - Milton A English
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, Bethesda, MD, 20892 USA
| | - Stacie Anderson
- Flow Cytometry, National Human Genome Research Institute, Bethesda, MD, 20892 USA
| | - Niraj S Trivedi
- Social Behavioral Research Branch, National Human Genome Research Institute, Bethesda, MD, 20892 USA
| | - Abdel Elkahloun
- Microarray Core, National Human Genome Research Institute, Bethesda, MD, 20892 USA
| | - Victoria Hoffmann
- Diagnostic and Research Services Branch, Division of Veterinary Resources, Office of the Director, National Institutes of Health, Bethesda, MD, 20892 USA
| | - Brian P Brooks
- Office of the Clinical Director, National Eye Institute, Bethesda, MD, 20892 USA
| | - Raman Sood
- Zebrafish Core Facility, Translational and Functional Genomics Branch, National Human Genome Research Institute, Bethesda, MD, 20892 USA
| | - Charles P Venditti
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, 20892 USA
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Benoit CR, Stanton AE, Tartanian AC, Motzer AR, McGaughey DM, Bond SR, Brody LC. Functional and phylogenetic characterization of noncanonical vitamin B 12-binding proteins in zebrafish suggests involvement in cobalamin transport. J Biol Chem 2018; 293:17606-17621. [PMID: 30237171 PMCID: PMC6231144 DOI: 10.1074/jbc.ra118.005323] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/13/2018] [Indexed: 12/19/2022] Open
Abstract
In humans, transport of food-derived cobalamin (vitamin B12) from the digestive system into the bloodstream involves three paralogous proteins: transcobalamin (TC), haptocorrin (HC), and intrinsic factor (IF). Each of these proteins contains two domains, an α-domain and a β-domain, which together form a cleft in which cobalamin binds. Zebrafish (Danio rerio) are thought to possess only a single cobalamin transport protein, referred to as Tcn2, which is a transcobalamin homolog. Here, we used CRISPR/Cas9 mutagenesis to create null alleles of tcn2 in zebrafish. Fish homozygous for tcn2-null alleles were viable and exhibited no obvious developmentally or behaviorally abnormal phenotypes. For this reason, we hypothesized that previously unidentified cobalamin-carrier proteins encoded in the zebrafish genome may provide an additional pathway for cobalamin transport. We identified genes predicted to code for two such proteins, Tcn-beta-a (Tcnba) and Tcn-beta-b (Tcnbb), which differ from all previously characterized cobalamin transport proteins as they lack the α-domain. These β-domain-only proteins are representative of an undescribed class of cobalamin-carrier proteins that are highly conserved throughout the ray-finned fishes. We observed that the genes encoding the three cobalamin transport homologs, tcn2, tcnba, and tcnbb, are expressed in unique spatial and temporal patterns in the developing zebrafish. Moreover, exogenously expressed recombinant Tcnba and Tcnbb bound cobalamin with high affinity, comparable with binding by full-length Tcn2. Taken together, our results suggest that this noncanonical protein structure has evolved to fully function as a cobalamin-carrier protein, thereby allowing for a compensatory cobalamin transport mechanism in the tcn2-/- zebrafish.
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Affiliation(s)
- Courtney R Benoit
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Abigail E Stanton
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Aileen C Tartanian
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Andrew R Motzer
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - David M McGaughey
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Stephen R Bond
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Lawrence C Brody
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
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8
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Lawrence AD, Nemoto-Smith E, Deery E, Baker JA, Schroeder S, Brown DG, Tullet JMA, Howard MJ, Brown IR, Smith AG, Boshoff HI, Barry CE, Warren MJ. Construction of Fluorescent Analogs to Follow the Uptake and Distribution of Cobalamin (Vitamin B 12) in Bacteria, Worms, and Plants. Cell Chem Biol 2018; 25:941-951.e6. [PMID: 29779954 DOI: 10.1016/j.chembiol.2018.04.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 01/18/2018] [Accepted: 04/11/2018] [Indexed: 12/25/2022]
Abstract
Vitamin B12 is made by only certain prokaryotes yet is required by a number of eukaryotes such as mammals, fish, birds, worms, and Protista, including algae. There is still much to learn about how this nutrient is trafficked across the domains of life. Herein, we describe ways to make a number of different corrin analogs with fluorescent groups attached to the main tetrapyrrole-derived ring. A further range of analogs were also constructed by attaching similar fluorescent groups to the ribose ring of cobalamin, thereby generating a range of complete and incomplete corrinoids to follow uptake in bacteria, worms, and plants. By using these fluorescent derivatives we were able to demonstrate that Mycobacterium tuberculosis is able to acquire both cobyric acid and cobalamin analogs, that Caenorhabditis elegans takes up only the complete corrinoid, and that seedlings of higher plants such as Lepidium sativum are also able to transport B12.
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Affiliation(s)
- Andrew D Lawrence
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Emi Nemoto-Smith
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK; National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20850, USA
| | - Evelyne Deery
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Joseph A Baker
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Susanne Schroeder
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - David G Brown
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | | | - Mark J Howard
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Ian R Brown
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| | - Helena I Boshoff
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20850, USA
| | - Clifton E Barry
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20850, USA
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK.
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Lie KK, Tørresen OK, Solbakken MH, Rønnestad I, Tooming-Klunderud A, Nederbragt AJ, Jentoft S, Sæle Ø. Loss of stomach, loss of appetite? Sequencing of the ballan wrasse (Labrus bergylta) genome and intestinal transcriptomic profiling illuminate the evolution of loss of stomach function in fish. BMC Genomics 2018; 19:186. [PMID: 29510660 PMCID: PMC5840709 DOI: 10.1186/s12864-018-4570-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 02/28/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The ballan wrasse (Labrus bergylta) belongs to a large teleost family containing more than 600 species showing several unique evolutionary traits such as lack of stomach and hermaphroditism. Agastric fish are found throughout the teleost phylogeny, in quite diverse and unrelated lineages, indicating stomach loss has occurred independently multiple times in the course of evolution. By assembling the ballan wrasse genome and transcriptome we aimed to determine the genetic basis for its digestive system function and appetite regulation. Among other, this knowledge will aid the formulation of aquaculture diets that meet the nutritional needs of agastric species. RESULTS Long and short read sequencing technologies were combined to generate a ballan wrasse genome of 805 Mbp. Analysis of the genome and transcriptome assemblies confirmed the absence of genes that code for proteins involved in gastric function. The gene coding for the appetite stimulating protein ghrelin was also absent in wrasse. Gene synteny mapping identified several appetite-controlling genes and their paralogs previously undescribed in fish. Transcriptome profiling along the length of the intestine found a declining expression gradient from the anterior to the posterior, and a distinct expression profile in the hind gut. CONCLUSIONS We showed gene loss has occurred for all known genes related to stomach function in the ballan wrasse, while the remaining functions of the digestive tract appear intact. The results also show appetite control in ballan wrasse has undergone substantial changes. The loss of ghrelin suggests that other genes, such as motilin, may play a ghrelin like role. The wrasse genome offers novel insight in to the evolutionary traits of this large family. As the stomach plays a major role in protein digestion, the lack of genes related to stomach digestion in wrasse suggests it requires formulated diets with higher levels of readily digestible protein than those for gastric species.
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Affiliation(s)
- Kai K. Lie
- Institute of Marine Research, P.O. Box. 1870, Nordnes, 5817 Bergen, NO Norway
| | - Ole K. Tørresen
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, NO Norway
| | - Monica Hongrø Solbakken
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, NO Norway
| | - Ivar Rønnestad
- Department of Biology, University of Bergen, P.O. Box 7803, 5020 Bergen, NO Norway
| | - Ave Tooming-Klunderud
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, NO Norway
| | - Alexander J. Nederbragt
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, NO Norway
- Biomedical Informatics Research Group, Department of Informatics, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, Norway
| | - Sissel Jentoft
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, 0316 Oslo, NO Norway
| | - Øystein Sæle
- Institute of Marine Research, P.O. Box. 1870, Nordnes, 5817 Bergen, NO Norway
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10
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Velkova A, Diaz JEL, Pangilinan F, Molloy AM, Mills JL, Shane B, Sanchez E, Cunningham C, McNulty H, Cropp CD, Bailey-Wilson JE, Wilson AF, Brody LC. The FUT2 secretor variant p.Trp154Ter influences serum vitamin B12 concentration via holo-haptocorrin, but not holo-transcobalamin, and is associated with haptocorrin glycosylation. Hum Mol Genet 2017; 26:4975-4988. [PMID: 29040465 PMCID: PMC5886113 DOI: 10.1093/hmg/ddx369] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 11/14/2022] Open
Abstract
Vitamin B12 deficiency is common in older individuals. Circulating vitamin B12 concentration can be used to diagnose deficiency, but this test has substantial false positive and false negative rates. We conducted genome-wide association studies (GWAS) in which we resolved total serum vitamin B12 into the fractions bound to transcobalamin and haptocorrin: two carrier proteins with very different biological properties. We replicated reported associations between total circulating vitamin B12 concentrations and a common null variant in FUT2. This allele determines the secretor phenotype in which blood group antigens are found in non-blood body fluids. Vitamin B12 bound to haptocorrin (holoHC) remained highly associated with FUT2 rs601338 (p.Trp154Ter). Transcobalamin bound vitamin B12 (holoTC) was not influenced by this variant. HoloTC is the bioactive the form of the vitamin and is taken up by all tissues. In contrast, holoHC is only taken up by the liver. Using holoHC from individuals with known FUT2 genotypes, we demonstrated that FUT2 rs601338 genotype influences the glycosylation of haptocorrin. We then developed an experimental model demonstrating that holoHC is transported into cultured hepatic cells (HepG2) via the asialoglycoprotein receptor (ASGR). Our data challenge current published hypotheses on the influence of genetic variation on this clinically important measure and are consistent with a model in which FUT2 rs601338 influences holoHC by altering haptocorrin glycosylation, whereas B12 bound to non-glycosylated transcobalamin (i.e. holoTC) is not affected. Our findings explain some of the observed disparity between use of total B12 or holoTC as first-line clinical tests of vitamin B12 status.
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Affiliation(s)
- Aneliya Velkova
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Jennifer E L Diaz
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Faith Pangilinan
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Anne M Molloy
- Department of Clinical Medicine, School of Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - James L Mills
- Division of Intramural Population Health Research, Eunice Kennedy Shriver NICHD, Bethesda, MD 20852, USA
| | - Barry Shane
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA 94720, USA
| | - Erica Sanchez
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | | | - Helene McNulty
- Northern Ireland Centre for Food and Health, University of Ulster, Coleraine BT52 1SA, Northern Ireland
| | - Cheryl D Cropp
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD 21224, USA
| | - Joan E Bailey-Wilson
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD 21224, USA
| | - Alexander F Wilson
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD 21224, USA
| | - Lawrence C Brody
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
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11
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Gunter HM, Schneider RF, Karner I, Sturmbauer C, Meyer A. Molecular investigation of genetic assimilation during the rapid adaptive radiations of East African cichlid fishes. Mol Ecol 2017; 26:6634-6653. [PMID: 29098748 DOI: 10.1111/mec.14405] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 08/06/2017] [Accepted: 08/24/2017] [Indexed: 12/19/2022]
Abstract
Adaptive radiations are characterized by adaptive diversification intertwined with rapid speciation within a lineage resulting in many ecologically specialized, phenotypically diverse species. It has been proposed that adaptive radiations can originate from ancestral lineages with pronounced phenotypic plasticity in adaptive traits, facilitating ecologically driven phenotypic diversification that is ultimately fixed through genetic assimilation of gene regulatory regions. This study aimed to investigate how phenotypic plasticity is reflected in gene expression patterns in the trophic apparatus of several lineages of East African cichlid fishes, and whether the observed patterns support genetic assimilation. This investigation used a split brood experimental design to compare adaptive plasticity in species from within and outside of adaptive radiations. The plastic response was induced in the crushing pharyngeal jaws through feeding individuals either a hard or soft diet. We find that nonradiating, basal lineages show higher levels of adaptive morphological plasticity than the derived, radiated lineages, suggesting that these differences have become partially genetically fixed during the formation of the adaptive radiations. Two candidate genes that may have undergone genetic assimilation, gif and alas1, were identified, in addition to alterations in the wiring of LPJ patterning networks. Taken together, our results suggest that genetic assimilation may have dampened the inducibility of plasticity related genes during the adaptive radiations of East African cichlids, flattening the reaction norms and canalizing their feeding phenotypes, driving adaptation to progressively more narrow ecological niches.
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Affiliation(s)
- Helen M Gunter
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Germany.,Zukunftskolleg, University of Konstanz, Konstanz, Germany
| | - Ralf F Schneider
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Germany.,International Max Planck Research School for Organismal Biology, University of Konstanz, Konstanz, Germany
| | | | | | - Axel Meyer
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Germany.,International Max Planck Research School for Organismal Biology, University of Konstanz, Konstanz, Germany.,Radcliffe Institute for Advanced Study, Harvard University, Cambridge, MA, USA
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12
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Lopes-Marques M, Ruivo R, Delgado I, Wilson JM, Aluru N, Castro LFC. Basal Gnathostomes provide unique insights into the evolution of vitamin B12 binders. Genome Biol Evol 2014; 7:457-64. [PMID: 25552533 PMCID: PMC4350170 DOI: 10.1093/gbe/evu289] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The uptake and transport of vitamin B12 (cobalamin; Cbl) in mammals involves a refined system with three evolutionarily related transporters: transcobalamin 1 (Tcn1), transcobalamin 2 (Tcn2), and the gastric intrinsic factor (Gif). Teleosts have a single documented binder with intermediate features to the human counterparts. Consequently, it has been proposed that the expansion of Cbl binders occurred after the separation of Actinopterygians. Here, we demonstrate that the diversification of this gene family took place earlier in gnathostome ancestry. Our data indicates the presence of single copy orthologs of the Sarcopterygii/Tetrapoda duplicates Tcn1 and Gif, and Tcn2, in Chondrichthyes. In addition, a highly divergent Cbl binder was found in the Elasmobranchii. We unveil a complex scenario forged by genome, tandem duplications and lineage-specific gene loss. Our findings suggest that from an ancestral transporter, exhibiting large spectrum and high affinity binding, highly specific Cbl transporters emerged through gene duplication and mutations at the binding pocket.
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Affiliation(s)
- Mónica Lopes-Marques
- CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, CIMAR Associate Laboratory, UPorto-University of Porto, Portugal ICBAS-Institute of Biomedical Sciences Abel Salazar, UPorto-University of Porto, Portugal
| | - Raquel Ruivo
- CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, CIMAR Associate Laboratory, UPorto-University of Porto, Portugal
| | - Inês Delgado
- CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, CIMAR Associate Laboratory, UPorto-University of Porto, Portugal
| | - Jonathan M Wilson
- CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, CIMAR Associate Laboratory, UPorto-University of Porto, Portugal Department of Biology, Wilfred Laurier University-Waterloo, Ontario, Canada
| | | | - L Filipe C Castro
- CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, CIMAR Associate Laboratory, UPorto-University of Porto, Portugal Department of Biology, Faculty of Sciences, UPorto-University of Porto, Portugal
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13
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Schneider RF, Li Y, Meyer A, Gunter HM. Regulatory gene networks that shape the development of adaptive phenotypic plasticity in a cichlid fish. Mol Ecol 2014; 23:4511-26. [PMID: 25041245 DOI: 10.1111/mec.12851] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 06/14/2014] [Accepted: 06/25/2014] [Indexed: 01/07/2023]
Abstract
Phenotypic plasticity is the ability of organisms with a given genotype to develop different phenotypes according to environmental stimuli, resulting in individuals that are better adapted to local conditions. In spite of their ecological importance, the developmental regulatory networks underlying plastic phenotypes often remain uncharacterized. We examined the regulatory basis of diet-induced plasticity in the lower pharyngeal jaw (LPJ) of the cichlid fish Astatoreochromis alluaudi, a model species in the study of adaptive plasticity. Through raising juvenile A. alluaudi on either a hard or soft diet (hard-shelled or pulverized snails) for between 1 and 8 months, we gained insight into the temporal regulation of 19 previously identified candidate genes during the early stages of plasticity development. Plasticity in LPJ morphology was first detected between 3 and 5 months of diet treatment. The candidate genes, belonging to various functional categories, displayed dynamic expression patterns that consistently preceded the onset of morphological divergence and putatively contribute to the initiation of the plastic phenotypes. Within functional categories, we observed striking co-expression, and transcription factor binding site analysis was used to examine the prospective basis of their coregulation. We propose a regulatory network of LPJ plasticity in cichlids, presenting evidence for regulatory crosstalk between bone and muscle tissues, which putatively facilitates the development of this highly integrated trait. Through incorporating a developmental time-course into a phenotypic plasticity study, we have identified an interconnected, environmentally responsive regulatory network that shapes the development of plasticity in a key innovation of East African cichlids.
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Affiliation(s)
- Ralf F Schneider
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätstrasse 10, 78457, Konstanz, Germany; International Max Planck Research School for Organismal Biology, University of Konstanz, Universitätsstr 10, 78457, Konstanz, Germany
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14
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Furger E, Frei DC, Schibli R, Fischer E, Prota AE. Structural basis for universal corrinoid recognition by the cobalamin transport protein haptocorrin. J Biol Chem 2013; 288:25466-25476. [PMID: 23846701 PMCID: PMC3757208 DOI: 10.1074/jbc.m113.483271] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 07/08/2013] [Indexed: 12/25/2022] Open
Abstract
Cobalamin (Cbl; vitamin B12) is an essential micronutrient synthesized only by bacteria. Mammals have developed a sophisticated uptake system to capture the vitamin from the diet. Cbl transport is mediated by three transport proteins: transcobalamin, intrinsic factor, and haptocorrin (HC). All three proteins have a similar overall structure but a different selectivity for corrinoids. Here, we present the crystal structures of human HC in complex with cyanocobalamin and cobinamide at 2.35 and 3.0 Å resolution, respectively. The structures reveal that many of the interactions with the corrin ring are conserved among the human Cbl transporters. However, the non-conserved residues Asn-120, Arg-357, and Asn-373 form distinct interactions allowing for stabilization of corrinoids other than Cbl. A central binding motif forms interactions with the e- and f-side chains of the corrin ring and is conserved in corrinoid-binding proteins of other species. In addition, the α- and β-domains of HC form several unique interdomain contacts and have a higher shape complementarity than those of intrinsic factor and transcobalamin. The stabilization of ligands by all of these interactions is reflected in higher melting temperatures of the protein-ligand complexes. Our structural analysis offers fundamental insights into the unique binding behavior of HC and completes the picture of Cbl interaction with its three transport proteins.
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Affiliation(s)
| | - Dominik C Frei
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, CH-5232 Villigen PSI and
| | - Roger Schibli
- From the Center for Radiopharmaceutical Sciences and; the Institute of Pharmaceutical Sciences, Eidgenössische Technische Hochschule (ETH) Zürich, CH-8093 Zürich, Switzerland
| | | | - Andrea E Prota
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, CH-5232 Villigen PSI and.
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15
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Proinsias KÓ, Giedyk M, Banach Ł, Rutkowska-Zbik D, Gryko D. Selectively Modified Cobyrinic Acid Derivatives. ASIAN J ORG CHEM 2013. [DOI: 10.1002/ajoc.201300051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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16
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Greibe E, Miller JW, Foutouhi SH, Green R, Nexo E. Metformin increases liver accumulation of vitamin B12 - an experimental study in rats. Biochimie 2013; 95:1062-5. [PMID: 23402786 DOI: 10.1016/j.biochi.2013.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Accepted: 02/01/2013] [Indexed: 12/20/2022]
Abstract
AIMS/HYPOTHESIS Patients treated with metformin exhibit low levels of plasma vitamin B12 (B12), and are considered at risk for developing B12 deficiency. In this study, we investigated the effect of metformin treatment on B12 uptake and distribution in rats. METHODS Sprague Dawley rats (n = 18) were divided into two groups and given daily subcutaneous injections with metformin or saline (control) for three weeks. Following this, the animals received an oral dose of radio-labeled B12 ((57)[Co]-B12), and urine and feces were collected for 24 h. Plasma, bowel content, liver, and kidneys were collected and analyzed for B12, unsaturated B12-binding capacity, and (57)[Co]-B12. RESULTS Three weeks of metformin treatment reduced plasma B12 by 22% or 289 [47-383] pmol/L (median and [range]) (p = 0.001), while no effect was observed on unsaturated B12-binding capacity. Compared with controls, the amount of B12 in the liver was 36% (p = 0.007) higher in metformin-treated rats, while the B12 content in the kidney was 34% (p = 0.013) lower. No difference in the total amount of absorbed (57)[Co]-B12 present in the tissues and organs studied was found, suggesting that metformin has no decreasing effect on the B12 absorption. CONCLUSIONS/INTERPRETATION These results show that metformin treatment increases liver accumulation of B12, thereby resulting in decreases in circulating B12 and kidney accumulation of the vitamin. Our data questions whether the low plasma B12 observed in patients treated with metformin reflects impaired B12 status, and rather suggests altered tissue distribution and metabolism of the vitamin.
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Affiliation(s)
- E Greibe
- Department of Clinical Biochemistry, Aarhus University Hospital, 8000 Aarhus, Denmark.
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17
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18
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Tanner SM, Sturm AC, Baack EC, Liyanarachchi S, de la Chapelle A. Inherited cobalamin malabsorption. Mutations in three genes reveal functional and ethnic patterns. Orphanet J Rare Dis 2012; 7:56. [PMID: 22929189 PMCID: PMC3462684 DOI: 10.1186/1750-1172-7-56] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 08/23/2012] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Inherited malabsorption of cobalamin (Cbl) causes hematological and neurological abnormalities that can be fatal. Three genes have been implicated in Cbl malabsorption; yet, only about 10% of ~400-500 reported cases have been molecularly studied to date. Recessive mutations in CUBN or AMN cause Imerslund-Gräsbeck Syndrome (IGS), while recessive mutations in GIF cause Intrinsic Factor Deficiency (IFD). IGS and IFD differ in that IGS usually presents with proteinuria, which is not observed in IFD. The genetic heterogeneity and numerous differential diagnoses make clinical assessment difficult. METHODS We present a large genetic screening study of 154 families or patients with suspected hereditary Cbl malabsorption. Patients and their families have been accrued over a period spanning >12 years. Systematic genetic testing of the three genes CUBN, AMN, and GIF was accomplished using a combination of single strand conformation polymorphism and DNA and RNA sequencing. In addition, six genes that were contenders for a role in inherited Cbl malabsorption were studied in a subset of these patients. RESULTS Our results revealed population-specific mutations, mutational hotspots, and functionally distinct regions in the three causal genes. We identified mutations in 126/154 unrelated cases (82%). Fifty-three of 126 cases (42%) were mutated in CUBN, 45/126 (36%) were mutated in AMN, and 28/126 (22%) had mutations in GIF. We found 26 undescribed mutations in CUBN, 19 in AMN, and 7 in GIF for a total of 52 novel defects described herein. We excluded six other candidate genes as culprits and concluded that additional genes might be involved. CONCLUSIONS Cbl malabsorption is found worldwide and genetically complex. However, our results indicate that population-specific founder mutations are quite common. Consequently, targeted genetic testing has become feasible if ethnic ancestry is considered. These results will facilitate clinical and molecular genetic testing of Cbl malabsorption. Early diagnosis improves the lifelong care required by these patients and prevents potential neurological long-term complications. This study provides the first comprehensive overview of the genetics that underlies the inherited Cbl malabsorption phenotype.
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Affiliation(s)
- Stephan M Tanner
- Human Cancer Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
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19
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Greibe E, Fedosov S, Sorensen BS, Højrup P, Poulsen SS, Nexo E. A single rainbow trout cobalamin-binding protein stands in for three human binders. J Biol Chem 2012; 287:33917-25. [PMID: 22872637 DOI: 10.1074/jbc.m112.398016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cobalamin uptake and transport in mammals are mediated by three cobalamin-binding proteins: haptocorrin, intrinsic factor, and transcobalamin. The nature of cobalamin-binding proteins in lower vertebrates remains to be elucidated. The aim of this study was to characterize the cobalamin-binding proteins of the rainbow trout (Oncorhynchus mykiss) and to compare their properties with those of the three human cobalamin-binding proteins. High cobalamin-binding capacity was found in trout stomach (210 pmol/g), roe (400 pmol/g), roe fluid (390 nmol/liter), and plasma (2500 nmol/liter). In all cases, it appeared to be the same protein based on analysis of partial sequences and immunological responses. The trout cobalamin-binding protein was purified from roe fluid, sequenced, and further characterized. Like haptocorrin, the trout cobalamin-binding protein was stable at low pH and had a high binding affinity for the cobalamin analog cobinamide. Like haptocorrin and transcobalamin, the trout cobalamin-binding protein was present in plasma and recognized ligands with altered nucleotide moiety. Like intrinsic factors, the trout cobalamin-binding protein was present in the stomach and resisted degradation by trypsin and chymotrypsin. It also resembled intrinsic factor in the composition of conserved residues in the primary cobalamin-binding site in the C terminus. The trout cobalamin-binding protein was glycosylated and displayed spectral properties comparable with those of haptocorrin and intrinsic factor. In conclusion, only one soluble cobalamin-binding protein was identified in the rainbow trout, a protein that structurally behaves like an intermediate between the three human cobalamin-binding proteins.
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Affiliation(s)
- Eva Greibe
- Department of Clinical Biochemistry, Aarhus University Hospital, 8000 Aarhus, Denmark.
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