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Ryazansky SS, Chen C, Potters M, Naumenko AN, Lukyanchikova V, Masri RA, Brusentsov II, Karagodin DA, Yurchenko AA, Dos Anjos VL, Haba Y, Rose NH, Hoffman J, Guo R, Menna T, Kelley M, Ferrill E, Schultz KE, Qi Y, Sharma A, Deschamps S, Llaca V, Mao C, Murphy TD, Baricheva EM, Emrich S, Fritz ML, Benoit JB, Sharakhov IV, McBride CS, Tu Z, Sharakhova MV. The chromosome-scale genome assembly for the West Nile vector Culex quinquefasciatus uncovers patterns of genome evolution in mosquitoes. BMC Biol 2024; 22:16. [PMID: 38273363 PMCID: PMC10809549 DOI: 10.1186/s12915-024-01825-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 01/11/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Understanding genome organization and evolution is important for species involved in transmission of human diseases, such as mosquitoes. Anophelinae and Culicinae subfamilies of mosquitoes show striking differences in genome sizes, sex chromosome arrangements, behavior, and ability to transmit pathogens. However, the genomic basis of these differences is not fully understood. METHODS In this study, we used a combination of advanced genome technologies such as Oxford Nanopore Technology sequencing, Hi-C scaffolding, Bionano, and cytogenetic mapping to develop an improved chromosome-scale genome assembly for the West Nile vector Culex quinquefasciatus. RESULTS We then used this assembly to annotate odorant receptors, odorant binding proteins, and transposable elements. A genomic region containing male-specific sequences on chromosome 1 and a polymorphic inversion on chromosome 3 were identified in the Cx. quinquefasciatus genome. In addition, the genome of Cx. quinquefasciatus was compared with the genomes of other mosquitoes such as malaria vectors An. coluzzi and An. albimanus, and the vector of arboviruses Ae. aegypti. Our work confirms significant expansion of the two chemosensory gene families in Cx. quinquefasciatus, as well as a significant increase and relocation of the transposable elements in both Cx. quinquefasciatus and Ae. aegypti relative to the Anophelines. Phylogenetic analysis clarifies the divergence time between the mosquito species. Our study provides new insights into chromosomal evolution in mosquitoes and finds that the X chromosome of Anophelinae and the sex-determining chromosome 1 of Culicinae have a significantly higher rate of evolution than autosomes. CONCLUSION The improved Cx. quinquefasciatus genome assembly uncovered new details of mosquito genome evolution and has the potential to speed up the development of novel vector control strategies.
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Affiliation(s)
- Sergei S Ryazansky
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA, USA
- Department of Molecular Genetics of Cell, NRC "Kurchatov Institute", Moscow, Russia
| | - Chujia Chen
- Genetics, Bioinformatics, Computational Biology Program, Virginia Polytechnic and State University, Blacksburg, VA, USA
| | - Mark Potters
- Department of Biochemistry, Virginia Polytechnic and State University, Blacksburg, USA
| | - Anastasia N Naumenko
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA, USA
- Department of Entomology, University of Maryland, College Park, MD, USA
| | - Varvara Lukyanchikova
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA, USA
- Group of Genomic Mechanisms of Development, Institute of Cytology and Genetics, Novosibirsk, Russia
- Laboratory of Structural and Functional Genomics, Novosibirsk State University, Novosibirsk, Russia
| | - Reem A Masri
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA, USA
| | - Ilya I Brusentsov
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA, USA
- Laboratory of Cell Differentiation Mechanisms, Institute of Cytology and Genetics, Novosibirsk, Russia
| | - Dmitriy A Karagodin
- Laboratory of Cell Differentiation Mechanisms, Institute of Cytology and Genetics, Novosibirsk, Russia
| | - Andrey A Yurchenko
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA, USA
| | - Vitor L Dos Anjos
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Yuki Haba
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Noah H Rose
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Jinna Hoffman
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Rong Guo
- Department of Entomology, University of Maryland, College Park, MD, USA
| | - Theresa Menna
- Department of Entomology, University of Maryland, College Park, MD, USA
| | - Melissa Kelley
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, USA
| | - Emily Ferrill
- County of San Diego Vector Control Program, San Diego, CA, USA
| | - Karen E Schultz
- Mosquito and Vector Management District of Santa Barbara County, Santa Barbara, CA, USA
| | - Yumin Qi
- Department of Biochemistry, Virginia Polytechnic and State University, Blacksburg, USA
| | - Atashi Sharma
- Department of Biochemistry, Virginia Polytechnic and State University, Blacksburg, USA
| | | | | | - Chunhong Mao
- Biocomplexity Institute & Initiative University of Virginia, Charlottesville, VA, USA
| | - Terence D Murphy
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Elina M Baricheva
- Laboratory of Cell Differentiation Mechanisms, Institute of Cytology and Genetics, Novosibirsk, Russia
| | - Scott Emrich
- Department of Electrical Engineering & Computer Science, the University of Tennessee, Knoxville, TN, USA
| | - Megan L Fritz
- Department of Entomology, University of Maryland, College Park, MD, USA
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, USA
| | - Igor V Sharakhov
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA, USA
- Fralin Life Sciences Institute, Virginia Polytechnic and State University, Blacksburg, VA, USA
- Department of Genetics and Cell Biology, Tomsk State University, Tomsk, Russia
| | - Carolyn S McBride
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Zhijian Tu
- Genetics, Bioinformatics, Computational Biology Program, Virginia Polytechnic and State University, Blacksburg, VA, USA
- Department of Biochemistry, Virginia Polytechnic and State University, Blacksburg, USA
- Fralin Life Sciences Institute, Virginia Polytechnic and State University, Blacksburg, VA, USA
| | - Maria V Sharakhova
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA, USA.
- Laboratory of Cell Differentiation Mechanisms, Institute of Cytology and Genetics, Novosibirsk, Russia.
- Fralin Life Sciences Institute, Virginia Polytechnic and State University, Blacksburg, VA, USA.
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Biedler JK, Aryan A, Qi Y, Wang A, Martinson EO, Hartman DA, Yang F, Sharma A, Morton KS, Potters M, Chen C, Dobson SL, Ebel GD, Kading RC, Paulson S, Xue RD, Strand MR, Tu Z. On the Origin and Evolution of the Mosquito Male-determining Factor Nix. Mol Biol Evol 2024; 41:msad276. [PMID: 38128148 PMCID: PMC10798136 DOI: 10.1093/molbev/msad276] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/02/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023] Open
Abstract
The mosquito family Culicidae is divided into 2 subfamilies named the Culicinae and Anophelinae. Nix, the dominant male-determining factor, has only been found in the culicines Aedes aegypti and Aedes albopictus, 2 important arboviral vectors that belong to the subgenus Stegomyia. Here we performed sex-specific whole-genome sequencing and RNAseq of divergent mosquito species and explored additional male-inclusive datasets to investigate the distribution of Nix. Except for the Culex genus, Nix homologs were found in all species surveyed from the Culicinae subfamily, including 12 additional species from 3 highly divergent tribes comprising 4 genera, suggesting Nix originated at least 133 to 165 million years ago (MYA). Heterologous expression of 1 of 3 divergent Nix open reading frames (ORFs) in Ae. aegypti resulted in partial masculinization of genetic females as evidenced by morphology and doublesex splicing. Phylogenetic analysis suggests Nix is related to femaleless (fle), a recently described intermediate sex-determining factor found exclusively in anopheline mosquitoes. Nix from all species has a conserved structure, including 3 RNA-recognition motifs (RRMs), as does fle. However, Nix has evolved at a much faster rate than fle. The RRM3 of both Nix and fle are distantly related to the single RRM of a widely distributed and conserved splicing factor transformer-2 (tra2). The RRM3-based phylogenetic analysis suggests this domain in Nix and fle may have evolved from tra2 or a tra2-related gene in a common ancestor of mosquitoes. Our results provide insights into the evolution of sex determination in mosquitoes and will inform broad applications of mosquito-control strategies based on manipulating sex ratios toward nonbiting males.
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Affiliation(s)
- James K Biedler
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Azadeh Aryan
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Yumin Qi
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Aihua Wang
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Ellen O Martinson
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Daniel A Hartman
- Center for Vector-borne Infectious Diseases, Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Fan Yang
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA
| | - Atashi Sharma
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Katherine S Morton
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Mark Potters
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Chujia Chen
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Genetics Bioinformatics and Computational Biology PhD program, Virginia Tech, Blacksburg, VA 24061, USA
| | - Stephen L Dobson
- Department of Entomology, University of Kentucky, Lexington, KY 40503, USA
- MosquitoMate, Inc., Lexington, KY 40502, USA
| | - Gregory D Ebel
- Center for Vector-borne Infectious Diseases, Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Rebekah C Kading
- Center for Vector-borne Infectious Diseases, Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Sally Paulson
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA
| | - Rui-De Xue
- Anastasia Mosquito Control District, St. Augustine, FL 32092, USA
| | - Michael R Strand
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Zhijian Tu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Genetics Bioinformatics and Computational Biology PhD program, Virginia Tech, Blacksburg, VA 24061, USA
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Chen C, Compton A, Nikolouli K, Wang A, Aryan A, Sharma A, Qi Y, Dellinger C, Hempel M, Potters M, Augustinos A, Severson DW, Bourtzis K, Tu Z. Marker-assisted mapping enables forward genetic analysis in Aedes aegypti, an arboviral vector with vast recombination deserts. Genetics 2022; 222:iyac140. [PMID: 36083009 PMCID: PMC9630976 DOI: 10.1093/genetics/iyac140] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 08/29/2022] [Indexed: 11/14/2022] Open
Abstract
Aedes aegypti is a major vector of arboviruses that cause dengue, chikungunya, yellow fever, and Zika. Although recent success in reverse genetics has facilitated rapid progress in basic and applied research, integration of forward genetics with modern technologies remains challenging in this important species, as up to 47% of its chromosome is refractory to genetic mapping due to extremely low rate of recombination. Here, we report the development of a marker-assisted mapping strategy to readily screen for and genotype only the rare but informative recombinants, drastically increasing both the resolution and signal-to-noise ratio. Using marker-assisted mapping, we mapped a transgene that was inserted in a >100-Mb recombination desert and a sex-linked spontaneous red-eye (re) mutation just outside the region. We subsequently determined, by CRISPR/Cas9-mediated knockout, that cardinal is the causal gene of re, which is the first forward genetic identification of a causal gene in Ae. aegypti. The identification of the causal gene of the sex-linked re mutation provides the molecular foundation for using gene editing to develop versatile and stable genetic sexing methods. To facilitate genome-wide forward genetics in Ae. aegypti, we generated and compiled a number of lines with markers throughout the genome. Thus, by overcoming the challenges presented by the vast recombination deserts and the scarcity of markers, we have shown that effective forward genetic analysis is increasingly feasible in this important arboviral vector species.
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Affiliation(s)
- Chujia Chen
- Genetics Bioinformatics and Computational Biology Program, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Austin Compton
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Katerina Nikolouli
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, IAEA Laboratories, 2444 Seibersdorf, Austria
| | - Aihua Wang
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Azadeh Aryan
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Atashi Sharma
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Yumin Qi
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Camden Dellinger
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Melanie Hempel
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Mark Potters
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Antonios Augustinos
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, IAEA Laboratories, 2444 Seibersdorf, Austria
| | - David W Severson
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, IAEA Laboratories, 2444 Seibersdorf, Austria
| | - Zhijian Tu
- Genetics Bioinformatics and Computational Biology Program, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
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Bun J, Bouchaud JP, Majumdar SN, Potters M. Instanton approach to large N Harish-Chandra-Itzykson-Zuber integrals. Phys Rev Lett 2014; 113:070201. [PMID: 25170689 DOI: 10.1103/physrevlett.113.070201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Indexed: 06/03/2023]
Abstract
We reconsider the large N asymptotics of Harish-Chandra-Itzykson-Zuber integrals. We provide, using Dyson's Brownian motion and the method of instantons, an alternative, transparent derivation of the Matytsin formalism for the unitary case. Our method is easily generalized to the orthogonal and symplectic ensembles. We obtain an explicit solution of Matytsin's equations in the case of Wigner matrices, as well as a general expansion method in the dilute limit, when the spectrum of eigenvalues spreads over very wide regions.
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Affiliation(s)
- J Bun
- Capital Fund Management, 23-25, rue de l'Université, 75007 Paris, France and CNRS, LPTMS, Batiment 100, Université d'Orsay, 91405 Orsay Cedex, France and DeVinci Finance Lab, Pôle Universitaire Léonard de Vinci, 92916 Paris La Défense, France
| | - J P Bouchaud
- Capital Fund Management, 23-25, rue de l'Université, 75007 Paris, France
| | - S N Majumdar
- CNRS, LPTMS, Batiment 100, Université d'Orsay, 91405 Orsay Cedex, France
| | - M Potters
- Capital Fund Management, 23-25, rue de l'Université, 75007 Paris, France
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Abstract
We investigate quantitatively the so-called "leverage effect," which corresponds to a negative correlation between past returns and future volatility. For individual stocks this correlation is moderate and decays over 50 days, while for stock indices it is much stronger but decays faster. For individual stocks the magnitude of this correlation has a universal value that can be rationalized in terms of a new "retarded" model which interpolates between a purely additive and a purely multiplicative stochastic process. For stock indices a specific amplification phenomenon seems to be necessary to account for the observed amplitude of the effect.
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Affiliation(s)
- J P Bouchaud
- Service de Physique de l'Etat Condensé, Centre d'études de Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France
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Poppema S, Potters M, Emmens R, Visser L, van den Berg A. Immune reactions in classical Hodgkin's lymphoma. Semin Hematol 1999; 36:253-9. [PMID: 10462325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
The immune reaction in classical Hodgkin's lymphoma (HL) can be separated into an inflammatory response in the involved tissues and a generalized immune response in the patient. The local immune reaction in HL is by far the most prominent among all tumors, with the exception of so called T-cell-rich B-cell lymphoma, a subtype of large-cell B-cell lymphoma. The general immune response in patients with HL is best described as an acquired cellular immune deficiency, most likely a result of the presence of tumor, although some data in the literature suggest a preexisting immune deficiency. The cellular origin of Reed-Sternberg (RS) cells in classical and nodular lymphocyte-predominant HL is discussed elsewhere. RS cells and their mononuclear variants can be considered as clones of neoplastic B cells that, by secreting potent cytokines/chemokines, not only cause the symptoms of HL but also promote their own growth and evade immune surveillance. The characteristic histologic features of HL--the prominent inflammatory response, the influx of eosinophils, and the presence of fibrosis and sclerosis--may also result from the expression of a range of surface molecules and the production of cytokines and chemokines by RS cells.
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Affiliation(s)
- S Poppema
- Department of Pathology and Laboratory Medicine, University Hospital Groningen, The Netherlands
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Dantuma NP, Potters M, De Winther MP, Tensen CP, Kooiman FP, Bogerd J, Van der Horst DJ. An insect homolog of the vertebrate very low density lipoprotein receptor mediates endocytosis of lipophorins. J Lipid Res 1999; 40:973-8. [PMID: 10224168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
A novel member of the low density lipoprotein (LDL) receptor family was identified, which is expressed in locust oocytes, fat body, brain, and midgut. This receptor appeared to be a homolog of the mammalian very low density lipoprotein receptor as it contains eight cysteine-rich repeats in its putative ligand-binding domain. When transiently expressed in COS-7 or stably expressed in LDL receptor-deficient CHO cells, the receptor mediates endocytic uptake of high density lipophorin (HDLp), an abundant lipoprotein in the circulatory compartment of insects. Moreover, in the latter cell line, we demonstrated that an excess of unlabeled HDLp competed with fluorescent labeled HDLp for uptake whereas an excess of human LDL did not affect uptake. Expression of the receptor mRNA in fat body cells is down-regulated during adult development, which is consistent with the previously reported down-regulation of receptor-mediated endocytosis of lipophorins in fat body tissue (Dantuma, N. P., M.A.P. Pijnenburg, J. H. B. Diederen, and D. J. Van der Horst. 1997. J. Lipid Res. 38: 254-265). The expression of this receptor in various tissues that internalize circulating lipophorins and its capability to mediate endocytosis of HDLp indicate that this novel member of the LDL receptor family may function as an endocytic lipophorin receptor in vivo.
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Affiliation(s)
- N P Dantuma
- Biochemical Physiology Research Group, Department of Experimental Zoology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Abstract
BACKGROUND The nodular sclerosis and mixed cellularity subtypes of Hodgkin's disease are histologically characterised by a small population of neoplastic cells, the so-called Reed-Sternberg cells and their mononuclear variants (RS cells) and an extensive admixture of other cell types including lymphocytes, plasma cells, eosinophils, and histiocytes. The nature of this infiltrate is largely known, but the mechanisms and functional effects are not. The small lymphocytes immediately surrounding the RS cells are mostly CD4+ T cells that express early activation markers. The absence of prominent specific cytotoxic T cell or natural killer (NK) cell populations seems to argue against a Th1-type response, whereas the sometimes prominent admixture of plasma cells and eosinophils is suggestive of a Th2-type response. Enrichment of the CD4 T-cell population may result from selective influx of CD4 T cells or from selective depletion of CD8 and NK cells. RESULTS AND DISCUSSION The T cells surrounding RS cells have an immuno-phenotype and cytokine production capability consistent with a Th2-type response. RS cells express several members of the TNF receptor family such as the FAS ligand (CD95L) that may induce apoptosis of activated, FAS expressing, CD8+ T cells and NK cells. The RS cells also produce TGF beta and interleukin-10 that may downmodulate the Th1 response. In addition, the Reed-Sternberg cells produce the chemokine TARC that could lead to the specific attraction of a Th2 T-cell subset. CONCLUSION RS cells have several mechanisms that may allow it to escape an effective immune response. The relative contributions of each of these and other potential mechanisms are not yet known.
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Affiliation(s)
- S Poppema
- Department of Pathology, University Hospital Groningen, The Netherlands.
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Gennari A, Potters M, Seinen W, Pieters R. Organotin-induced apoptosis as observed in vitro is not relevant for induction of thymus atrophy at antiproliferative doses. Toxicol Appl Pharmacol 1997; 147:259-66. [PMID: 9439721 DOI: 10.1006/taap.1997.8265] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The organotin compounds di-n-butyltin dichloride (DBTC) and tri-n-butyltin chloride (TBTC) selectively cause thymus atrophy. Previously, DBTC and TBTC were shown to inhibit proliferation of immature thymocytes, but other studies demonstrated that TBTC but not DBTC increased apoptosis in vitro and also in vivo. In this study, we examined whether apoptosis is increased in vitro by DBTC and TBTC at various concentrations and periods of incubation and whether apoptosis is involved in the induction of thymus atrophy at selective antiproliferative doses. In vitro, DBTC or TBTC at a concentration of 3 microM significantly increased DNA fragmentation in freshly isolated rat thymocytes after preincubation for 10 min followed by a 22-hr culture period. After continuous exposure for 22 hr, apoptosis was observed to be optimum at 1 microM TBTC and 0.3 microM DBTC and lower or absent at higher concentrations. Apparently, apoptosis induced by organotins in vitro depends on both duration and concentration of exposure. Selective antiproliferative doses of DBTC nor TBTC increased apoptosis on day 1 or 2 after single oral exposure. In contrast, the corticosteroid dexamethasone caused a depletion of both small and large thymocytes and a marked increase of apoptosis on both days 1 and 2 after dosing. Thus, although apoptosis is involved in the in vitro cytotoxic effects of both organotin compounds, it seems not involved in thymus atrophy at a dose that selectively inhibits immature thymocyte proliferation.
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Affiliation(s)
- A Gennari
- Research Institute of Toxicology, Utrecht University, The Netherlands
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Berghuis J, Haanappel IJM, Potters M, Loopstra BO, MacGillavry CH, Veenendaal AL. New calculations of atomic scattering factors. ACTA ACUST UNITED AC 1955. [DOI: 10.1107/s0365110x55001497] [Citation(s) in RCA: 207] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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