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Lee J, Wang J, Ally R, Trzaska S, Hickey J, Mujica A, Miloscio L, Mastaitis J, Morse B, Smith J, Atanasio A, Chiao E, Chen H, Latuszek A, Hu Y, Valenzuela D, Romano C, Zambrowicz B, Auerbach W. Production of large, defined genome modifications in rats by targeting rat embryonic stem cells. Stem Cell Reports 2022; 18:394-409. [PMID: 36525967 PMCID: PMC9860120 DOI: 10.1016/j.stemcr.2022.11.012] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 12/23/2022] Open
Abstract
Rats were more frequently used than mice to model human disease before mouse embryonic stem cells (mESCs) revolutionized genetic engineering in mice. Rat ESCs (rESCs) were first reported over 10 years ago, yet they are not as frequently used as mESCs. CRISPR-based gene editing in zygotes is widely used in rats but is limited by the difficulty of inserting or replacing DNA sequences larger than about 10 kb. We report here the generation of germline-competent rESC lines from several rat strains. These rESC lines maintain their potential for germline transmission after serial targeting with bacterial artificial chromosome (BAC)-based targeting vectors, and CRISPR-Cas9 cutting can increase targeting efficiency. Using these methods, we have successfully replaced entire rat genes spanning up to 101 kb with the human ortholog.
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Affiliation(s)
- Jeffrey Lee
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA.
| | | | - Roxanne Ally
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Sean Trzaska
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | - Alejo Mujica
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | - Brian Morse
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Janell Smith
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | - Eric Chiao
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Henry Chen
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | - Ying Hu
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
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Morris M, Shaw A, Lambert M, Perry HH, Lowenstein E, Valenzuela D, Velazquez-Ulloa NA. Developmental nicotine exposure affects larval brain size and the adult dopaminergic system of Drosophila melanogaster. BMC Dev Biol 2018; 18:13. [PMID: 29898654 PMCID: PMC6001141 DOI: 10.1186/s12861-018-0172-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 05/21/2018] [Indexed: 01/15/2023]
Abstract
BACKGROUND Pregnant women may be exposed to nicotine if they smoke or use tobacco products, nicotine replacement therapy, or via e-cigarettes. Prenatal nicotine exposure has been shown to have deleterious effects on the nervous system in mammals including changes in brain size and in the dopaminergic system. The genetic and molecular mechanisms for these changes are not well understood. A Drosophila melanogaster model for these effects of nicotine exposure could contribute to faster identification of genes and molecular pathways underlying these effects. The purpose of this study was to determine if developmental nicotine exposure affects the nervous system of Drosophila melanogaster, focusing on changes to brain size and the dopaminergic system at two developmental stages. RESULTS We reared flies on control or nicotine food from egg to 3rd instar larvae or from egg to adult and determined effectiveness of the nicotine treatment. We used immunohistochemistry to visualize the whole brain and dopaminergic neurons, using tyrosine hydroxylase as the marker. We measured brain area, tyrosine hydroxylase fluorescence, and counted the number of dopaminergic neurons in brain clusters. We detected an increase in larval brain hemisphere area, a decrease in tyrosine hydroxylase fluorescence in adult central brains, and a decrease in the number of neurons in the PPM3 adult dopaminergic cluster. We tested involvement of Dα7, one of the nicotinic acetylcholine receptor subunits, and found it was involved in eclosion, as previously described, but not involved in brain size. CONCLUSIONS We conclude that developmental nicotine exposure in Drosophila melanogaster affects brain size and the dopaminergic system. Prenatal nicotine exposure in mammals has also been shown to have effects on brain size and in the dopaminergic system. This study further establishes Drosophila melanogaster as model organism to study the effects of developmental nicotine exposure. The genetic and molecular tools available for Drosophila research will allow elucidation of the mechanisms underlying the effects of nicotine exposure during development.
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Affiliation(s)
- Melanie Morris
- School of Medicine, University of Washington, Seattle, USA
| | - Ariel Shaw
- Biochemistry, Cell and Molecular Biology Program, Lewis & Clark College, Portland, USA
| | | | | | - Eve Lowenstein
- Biology Department, Lewis & Clark College, Portland, USA
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Luu K, Chang B, Valenzuela D, Anderson D. Primary versus secondary tracheoesophageal puncture for voice rehabilitation in laryngectomy patients: A systematic review. Clin Otolaryngol 2018; 43:1250-1259. [DOI: 10.1111/coa.13138] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2018] [Indexed: 11/30/2022]
Affiliation(s)
- K. Luu
- Division of Otolaryngology - Head & Neck Surgery; Department of Surgery; University of British Columbia; Vancouver BC Canada
| | - B.A. Chang
- Division of Otolaryngology - Head & Neck Surgery; Department of Surgery; University of British Columbia; Vancouver BC Canada
| | - D. Valenzuela
- Division of Otolaryngology - Head & Neck Surgery; Department of Surgery; University of British Columbia; Vancouver BC Canada
| | - D. Anderson
- Division of Otolaryngology - Head & Neck Surgery; Department of Surgery; University of British Columbia; Vancouver BC Canada
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Valenzuela D, Moya F, Luco M, Tapia JL. [The role of pulmonary hypertension on bronchopulmonary dysplasia]. ACTA ACUST UNITED AC 2018; 88:699-706. [PMID: 29546917 DOI: 10.4067/s0370-41062017000600699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/26/2017] [Indexed: 11/17/2022]
Abstract
50 years ago, Northway described Broncopulmonary Dysplasia (BPD) in preterm infants exposed to mechanical ventilation. Since then, their survival has increased, nevertheless a "new BPD" has appeared and its incidence has not diminished. One of the characteristics of this pathology is the the abnormal vascular remodeling, which in its most severe expression is known as Pulmonary Hyper tension (PH); with an incidence of 17% in patients with BPD, which is proportional to the severity of the disease (33% in severe BPD), and as mortality factor (up to 48% 2-year mortality in PH-BPD). Thereby, it is important to know the diagnostic methods and therapeutic alternatives, topics discus sed in this review. Considering the high mortality in BPD associated PH, screening strategies in at risk population become important. The gold standard is cardiac catheterization; however, transtho-rathic echocardiography is a useful tool for the screening and diagnosis of PH in displasic patients, using cuantitive measures and cualitative changes in the evaluation. Seric type-B natriuretic peptide has shown to be useful for follow-up; regarding images, CT scan is used in severe cases. In terms of therapy; inhaled Nitric Oxide as a pulmonary vasodilator, phosphodiesterase inhibitors -sildenafil-, endotelin antagonists -bosentan-, and prostacyclin analogues -iloprost-, have been proposed. Their use, dosis and treatment lenght still lack support of high quality evidence, but diverse clinical expe riences have been described. Interdisciplinary care is also important, highlighting to optimize nu trition. Therefore, the challenge is to effectively prevent BPD and its complications. A PH screening protocol should be associated with risk stratification and treatment guidelines.
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Affiliation(s)
- D Valenzuela
- Facultad de Medicina, Pontificia Universidad Católica de Chile, Chile
| | - F Moya
- Facultad de Medicina, Pontificia Universidad Católica de Chile, Chile
| | - M Luco
- Departamento Neonatología, Pontificia Universidad Católica de Chile, Chile
| | - J L Tapia
- Departamento Neonatología, Pontificia Universidad Católica de Chile, Chile
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Atanasio A, Decman V, White D, Ramos M, Ikiz B, Lee HC, Siao CJ, Brydges S, LaRosa E, Bai Y, Fury W, Burfeind P, Zamfirova R, Warshaw G, Orengo J, Oyejide A, Fralish M, Auerbach W, Poueymirou W, Freudenberg J, Gong G, Zambrowicz B, Valenzuela D, Yancopoulos G, Murphy A, Thurston G, Lai KMV. C9orf72 ablation causes immune dysregulation characterized by leukocyte expansion, autoantibody production, and glomerulonephropathy in mice. Sci Rep 2016; 6:23204. [PMID: 26979938 PMCID: PMC4793236 DOI: 10.1038/srep23204] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 03/02/2016] [Indexed: 12/12/2022] Open
Abstract
The expansion of a hexanucleotide (GGGGCC) repeat in C9ORF72 is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Both the function of C9ORF72 and the mechanism by which the repeat expansion drives neuropathology are unknown. To examine whether C9ORF72 haploinsufficiency induces neurological disease, we created a C9orf72-deficient mouse line. Null mice developed a robust immune phenotype characterized by myeloid expansion, T cell activation, and increased plasma cells. Mice also presented with elevated autoantibodies and evidence of immune-mediated glomerulonephropathy. Collectively, our data suggest that C9orf72 regulates immune homeostasis and an autoimmune response reminiscent of systemic lupus erythematosus (SLE) occurs in its absence. We further imply that haploinsufficiency is unlikely to be the causative factor in C9ALS/FTD pathology.
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Affiliation(s)
| | - Vilma Decman
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY USA
| | - Derek White
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY USA
| | - Meg Ramos
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY USA
| | - Burcin Ikiz
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY USA
| | | | | | | | | | - Yu Bai
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY USA
| | - Wen Fury
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY USA
| | | | | | | | - Jamie Orengo
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY USA
| | | | | | | | | | | | - Guochun Gong
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY USA
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Kaloff C, Anastassiadis K, Ayadi A, Baldock R, Beig J, Birling MC, Bradley A, Brown S, Bürger A, Bushell W, Chiani F, Collins F, Doe B, Eppig J, Finnell R, Fletcher C, Flicek P, Fray M, Friedel R, Gambadoro A, Gates H, Hansen J, Herault Y, Hicks G, Hörlein A, Hrabé de Angelis M, Iyer V, de Jong P, Koscielny G, Kühn R, Liu P, Lloyd K, Lopez R, Marschall S, Martínez S, McKerlie C, Meehan T, von Melchner H, Moore M, Murray S, Nagy A, Nutter L, Pavlovic G, Pombero A, Prosser H, Ramirez-Solis R, Ringwald M, Rosen B, Rosenthal N, Rossant J, Ruiz Noppinger P, Ryder E, Skarnes W, Schick J, Schnütgen F, Schofield P, Seisenberger C, Selloum M, Smedley D, Simpson E, Stewart A, Teboul L, Tocchini Valentini G, Valenzuela D, West A, Wurst W. Genome wide conditional mouse knockout resources. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.ddmod.2017.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Valenzuela D, Zitko P, Matamala J, Lillo P. Potential risk of an outbreak of guillain-barre syndrome? Epidemiological analysis of 4,796 hospital discharged cases in Chile. J Neurol Sci 2015. [DOI: 10.1016/j.jns.2015.08.1206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Segovia-Miranda F, Serrano F, Dyrda A, Ampuero E, Retamal C, Bravo-Zehnder M, Parodi J, Zamorano P, Valenzuela D, Massardo L, van Zundert B, Inestrosa NC, González A. Pathogenicity of Lupus Anti-Ribosomal P Antibodies: Role of Cross-Reacting Neuronal Surface P Antigen in Glutamatergic Transmission and Plasticity in a Mouse Model. Arthritis Rheumatol 2015; 67:1598-610. [DOI: 10.1002/art.39081] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 02/12/2015] [Indexed: 12/25/2022]
Affiliation(s)
| | - Felipe Serrano
- Pontificia Universidad Católica de Chile; Santiago Chile
| | | | | | | | | | | | - Pedro Zamorano
- Pontificia Universidad Católica de Chile; Santiago Chile
| | | | | | | | - Nibaldo C. Inestrosa
- Pontificia Universidad Católica de Chile, Santiago, Chile, and Universidad de Magallanes; Punta Arenas Chile
| | - Alfonso González
- Pontificia Universidad Católica de Chile, Santiago, Chile, and Universidad de Magallanes; Punta Arenas Chile
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Miao H, Gale N, Guo H, Qian J, Petty A, Kaspar J, Murphy A, Valenzuela D, Yancopoulos G, Hambardzumyan D, Lathia J, Rich J, Lee J, Wang B. CS-21 * EphA2 PROMOTES INFILTRATIVE INVASION OF GLIOMA STEM CELLS IN VIVO THROUGH CROSSTALK WITH Akt AND REGULATES STEM PROPERTIES. Neuro Oncol 2014. [DOI: 10.1093/neuonc/nou242.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
Abstract. From November 1994 to March 1997, I studied the ecology of the White-nosed coati (Nasua narica; Procyonidae) in the central portion of its geographical range, in the tropical dry forests of the Chamela-Cuixmala Biosphere Reserve (CCBR), Jalisco, Mexico. I present here information about density, group size, diet diversity and feeding habits, ectoparasite load, mortality factors and reproduction. Average density estimates was 42.94 ± 16.88 ind. / km² (mean ± 95 % confidence interval) and average group size was 6.1 ± 0.49 (n = 142). Fecal analysis, demonstrated a trophic niche breadth of 2.674 with 85.11 % of the diet consisting of fruit and arthropods: two resources whose spatio-temporal availability is strongly affected by seasonality. The results are compared with available data and discussed in the context of seasonality effects on the ecology of this species.Resumen. De noviembre de 1994 a marzo de 1997, estudié aspectos de la ecología del coatí (Nasua narica; Procyonidae) en la porción media de su distribución geográfica, en la selva baja caducifolia de la Reserva de la Biosfera de Chamela Cuixmala, Jalisco, México. Presento aquí información sobre su densidad, el tamaño de sus grupos, la diversidad de su dieta y sus hábitos alimentarios, la carga de ectoparásitos, algunos factores de mortalidad y algunos aspectos reproductivos. El promedio de estimaciones de densidad fue 42.94 ± 16.88 ind. / km² (media ± intervalo de confianza al 95%), y el tamaño promedio de grupo fue de 6.1 ± 0.49 (n= 142). El análisis de heces fecales demostró una diversidad trófica de 2.674, y que el 85.11 % de la dieta consiste de frutas y artrópodos: dos recursos cuya disponibilidad espacio-temporal es fuertemente afectada por la estacionalidad climática. Los resultados se discuten en el contexto del los efectos de un ambiente estacional en la ecología de esta especie.Key words: tropical dry forest; climatic seasonality; Jalisco, México; Carnivore; Nasua narica
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Wang LH, Xue Y, Liu X, Luo F, Kelly L, Huang T, Valenzuela D, Papdopoulos N, Graham N, Murphy A. FRI0020 Preclinical development of sarilumab, the first fully human monoclonal antibody (MAB) against IL-6r alpha: utilization and value of double humanized animal model. Ann Rheum Dis 2014. [DOI: 10.1136/annrheumdis-2013-eular.1148] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Bradley A, Anastassiadis K, Ayadi A, Battey JF, Bell C, Birling MC, Bottomley J, Brown SD, Bürger A, Bult CJ, Bushell W, Collins FS, Desaintes C, Doe B, Economides A, Eppig JT, Finnell RH, Fletcher C, Fray M, Frendewey D, Friedel RH, Grosveld FG, Hansen J, Hérault Y, Hicks G, Hörlein A, Houghton R, Hrabé de Angelis M, Huylebroeck D, Iyer V, de Jong PJ, Kadin JA, Kaloff C, Kennedy K, Koutsourakis M, Kent Lloyd KC, Marschall S, Mason J, McKerlie C, McLeod MP, von Melchner H, Moore M, Mujica AO, Nagy A, Nefedov M, Nutter LM, Pavlovic G, Peterson JL, Pollock J, Ramirez-Solis R, Rancourt DE, Raspa M, Remacle JE, Ringwald M, Rosen B, Rosenthal N, Rossant J, Ruiz Noppinger P, Ryder E, Schick JZ, Schnütgen F, Schofield P, Seisenberger C, Selloum M, Simpson EM, Skarnes WC, Smedley D, Stanford WL, Francis Stewart A, Stone K, Swan K, Tadepally H, Teboul L, Tocchini-Valentini GP, Valenzuela D, West AP, Yamamura KI, Yoshinaga Y, Wurst W. The mammalian gene function resource: the International Knockout Mouse Consortium. Mamm Genome 2012; 23:580-6. [PMID: 22968824 PMCID: PMC3463800 DOI: 10.1007/s00335-012-9422-2] [Citation(s) in RCA: 234] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 07/20/2012] [Indexed: 11/16/2022]
Abstract
In 2007, the International Knockout Mouse Consortium (IKMC) made the ambitious promise to generate mutations in virtually every protein-coding gene of the mouse genome in a concerted worldwide action. Now, 5 years later, the IKMC members have developed high-throughput gene trapping and, in particular, gene-targeting pipelines and generated more than 17,400 mutant murine embryonic stem (ES) cell clones and more than 1,700 mutant mouse strains, most of them conditional. A common IKMC web portal (www.knockoutmouse.org) has been established, allowing easy access to this unparalleled biological resource. The IKMC materials considerably enhance functional gene annotation of the mammalian genome and will have a major impact on future biomedical research.
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Affiliation(s)
- Allan Bradley
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | | | - Abdelkader Ayadi
- Institut Clinique de la Souris and Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France
| | - James F. Battey
- National Institute on Deafness and Other Communication Disorders (NIH), Bethesda, MD 20892 USA
| | - Cindy Bell
- Genome Canada, Ottawa, ON K2P 1P1 Canada
| | - Marie-Christine Birling
- Institut Clinique de la Souris and Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France
| | - Joanna Bottomley
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | - Steve D. Brown
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD UK
| | - Antje Bürger
- Institute of Developmental Genetics, Helmholtz Zentrum München, Technische Universität München, 85764 Neuherberg, Germany
| | | | - Wendy Bushell
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | | | - Christian Desaintes
- Infectious Diseases and Public Health, European Commission, DG Research & Innovation, 1049 Brussels, Belgium
| | - Brendan Doe
- Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche (CNR), Monterotondo-Scalo, 00015 Rome, Italy
| | - Aris Economides
- Velocigene Division, Regeneron Pharmaceuticals Inc., Tarrytown, NY 10591 USA
| | | | - Richard H. Finnell
- The Texas A&M Institute for Genomic Medicine, College Station, TX 77843-4485 USA
- University of Texas at Austin, Austin, TX 78712 USA
| | | | - Martin Fray
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD UK
| | - David Frendewey
- Velocigene Division, Regeneron Pharmaceuticals Inc., Tarrytown, NY 10591 USA
| | - Roland H. Friedel
- Institute of Developmental Genetics, Helmholtz Zentrum München, Technische Universität München, 85764 Neuherberg, Germany
- Icahn Medical Institute, The Mount Sinai Hospital, New York, NY 10029 USA
| | - Frank G. Grosveld
- Department of Cell Biology, Center of Biomedical Genetics, Erasmus University Medical Center, 3015 GE Rotterdam, The Netherlands
| | - Jens Hansen
- Institute of Developmental Genetics, Helmholtz Zentrum München, Technische Universität München, 85764 Neuherberg, Germany
| | - Yann Hérault
- Institut Clinique de la Souris and Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France
| | - Geoffrey Hicks
- Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, MB R3E OV9 Canada
| | - Andreas Hörlein
- Institute of Developmental Genetics, Helmholtz Zentrum München, Technische Universität München, 85764 Neuherberg, Germany
| | - Richard Houghton
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | | | - Danny Huylebroeck
- Department of Development and Regeneration, Faculty of Medicine, University of Leuven (KU Leuven), 3000 Leuven, Belgium
| | - Vivek Iyer
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | - Pieter J. de Jong
- Children’s Hospital Oakland Research Institute (CHORI), Oakland, CA 94609 USA
| | | | - Cornelia Kaloff
- Institute of Developmental Genetics, Helmholtz Zentrum München, Technische Universität München, 85764 Neuherberg, Germany
| | - Karen Kennedy
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | - Manousos Koutsourakis
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | - K. C. Kent Lloyd
- Mouse Biology Program, School of Veterinary Medicine, University of California, Davis, CA 95616 USA
| | - Susan Marschall
- Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Jeremy Mason
- The Jackson Laboratory, Bar Harbor, ME 04609 USA
| | - Colin McKerlie
- Research Institute, The Hospital for Sick Children, SickKids Foundation, Toronto, ON M5G2L3 Canada
| | - Michael P. McLeod
- The Texas A&M Institute for Genomic Medicine, College Station, TX 77843-4485 USA
| | - Harald von Melchner
- Department of Molecular Haematology, University of Frankfurt Medical School, 60590 Frankfurt am Main, Germany
| | - Mark Moore
- National Institutes of Health, Bethesda, MD 20205 USA
| | - Alejandro O. Mujica
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
- Velocigene Division, Regeneron Pharmaceuticals Inc., Tarrytown, NY 10591 USA
| | - Andras Nagy
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Joseph and Wolf Lebovic Health Complex, Toronto, ON M5G 1X5 Canada
| | - Mikhail Nefedov
- Children’s Hospital Oakland Research Institute (CHORI), Oakland, CA 94609 USA
| | - Lauryl M. Nutter
- Research Institute, The Hospital for Sick Children, SickKids Foundation, Toronto, ON M5G2L3 Canada
| | - Guillaume Pavlovic
- Institut Clinique de la Souris and Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France
| | | | - Jonathan Pollock
- Division of Basic Neuroscience and Research, National Institute of Drug Abuse (NIDA), Bethesda, MD 20892-0001 USA
| | - Ramiro Ramirez-Solis
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | - Derrick E. Rancourt
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 1N4 Canada
| | - Marcello Raspa
- Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche (CNR), Monterotondo-Scalo, 00015 Rome, Italy
| | - Jacques E. Remacle
- Infectious Diseases and Public Health, European Commission, DG Research & Innovation, 1049 Brussels, Belgium
| | | | - Barry Rosen
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | - Nadia Rosenthal
- European Molecular Biology Laboratory (EMBL), Monterotondo, 00015 Rome, Italy
| | - Janet Rossant
- Research Institute, The Hospital for Sick Children, SickKids Foundation, Toronto, ON M5G2L3 Canada
| | - Patricia Ruiz Noppinger
- Centre for Cardiovascular Research, Department of Vertebrate Genomics, Charité, 10115 Berlin, Germany
| | - Ed Ryder
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | - Joel Zupicich Schick
- Institute of Developmental Genetics, Helmholtz Zentrum München, Technische Universität München, 85764 Neuherberg, Germany
| | - Frank Schnütgen
- Department of Molecular Haematology, University of Frankfurt Medical School, 60590 Frankfurt am Main, Germany
| | - Paul Schofield
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG UK
| | - Claudia Seisenberger
- Institute of Developmental Genetics, Helmholtz Zentrum München, Technische Universität München, 85764 Neuherberg, Germany
| | - Mohammed Selloum
- Institut Clinique de la Souris and Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France
| | - Elizabeth M. Simpson
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics at the Child & Family Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4 Canada
| | - William C. Skarnes
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | - Damian Smedley
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
- European Bioinformatics Institute (EBI), Hinxton, Cambridge, CB10 1ST UK
| | | | - A. Francis Stewart
- Biotechnology Center (BIOTEC) of the Technische Universität Dresden, 01307 Dresden, Germany
| | - Kevin Stone
- The Jackson Laboratory, Bar Harbor, ME 04609 USA
| | - Kate Swan
- Genome Canada, Ottawa, ON K2P 1P1 Canada
| | | | - Lydia Teboul
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD UK
| | | | - David Valenzuela
- Velocigene Division, Regeneron Pharmaceuticals Inc., Tarrytown, NY 10591 USA
| | - Anthony P. West
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH UK
| | - Ken-ichi Yamamura
- Division of Developmental Genetics, Center for Animal Resources and Development, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, 860-0811 Japan
| | - Yuko Yoshinaga
- Children’s Hospital Oakland Research Institute (CHORI), Oakland, CA 94609 USA
| | - Wolfgang Wurst
- Institute of Developmental Genetics, Helmholtz Zentrum München, Technische Universität München, 85764 Neuherberg, Germany
- Max-Planck-Institute of Psychiatry, 80804 Munich, Germany
- Deutsches Zentrum fuer Neurodegenerative Erkrankungen e.V. (DZNE) Site Munich, 80336 Munich, Germany
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Willinger T, Rongvaux A, Takizawa H, Yancopoulos G, Valenzuela D, Murphy A, Auerbach W, Eynon E, Stevens S, Manz M, Flavell R. Human IL-3/GM-CSF knock-in mice support human alveolar macrophage development and human immune responses in the lung (161.5). The Journal of Immunology 2011. [DOI: 10.4049/jimmunol.186.supp.161.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Mice with a functional human immune system have the potential to allow in vivo studies of human infectious diseases and to enable vaccine testing. To this end, mice need to fully support the development of human immune cells, allow infection with human pathogens, and be capable of mounting effective human immune responses. A major limitation of humanized mice is the poor development and function of human myeloid cells and the absence of human immune responses at mucosal surfaces such as the lung. To overcome this, we generated human IL-3/GM-CSF knock-in (hIL-3/GM-CSF KI) mice. These mice faithfully expressed human GM-CSF and IL-3 and developed pulmonary alveolar proteinosis due to elimination of mouse GM-CSF. We demonstrate that hIL-3/GM-CSF KI mice engrafted with human CD34+ hematopoietic cells had improved human myeloid cell reconstitution in the lung. In particular, hIL-3/GM-CSF KI mice supported the development of human alveolar macrophages that partially rescued the PAP syndrome. Moreover, human alveolar macrophages mounted correlates of a human innate immune response against influenza virus. hIL-3/GM-CSF KI mice represent a unique mouse model which permits the study of human mucosal immune responses to lung pathogens.
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Affiliation(s)
- Tim Willinger
- 1Immunobiology, Yale University School of Medicine, New Haven, CT
| | - Anthony Rongvaux
- 1Immunobiology, Yale University School of Medicine, New Haven, CT
| | - Hitoshi Takizawa
- 2University Hospital Zurich, Division of Hematology, Zurich, Switzerland
| | | | | | | | | | - Elizabeth Eynon
- 1Immunobiology, Yale University School of Medicine, New Haven, CT
| | | | - Markus Manz
- 2University Hospital Zurich, Division of Hematology, Zurich, Switzerland
- 4Institute for Research in Biomedicine, Bellinzona, Switzerland
| | - Richard Flavell
- 1Immunobiology, Yale University School of Medicine, New Haven, CT
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15
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Kincaid E, Che J, Welsh R, Karow M, Murphy A, Valenzuela D, Yancopoulo G, Rock K. The role of immunoproteasomes in antigen presentation and thymic selection (100.7). The Journal of Immunology 2011. [DOI: 10.4049/jimmunol.186.supp.100.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Proteasomes, multisubunit complexes that degrade cellular proteins, are instrumental in forming epitopes for MHC class I antigen presentation. An alternate set of catalytic proteasome beta subunits are induced by IFN-gamma and expressed constitutively in dendritic cells, T-cells and B-cells. Immunoproteasomes containing these inducible subunits have increased chymotryptic and tryptic activities and decreased caspase-like activity, and are hypothesized to produce more peptides suitable for binding to MHC class I. To date mutant mice lacking one or two of the immunoproteasome subunits have been generated and have revealed some changes in MHC class I antigen presentation. However, the overall role of the immunoproteasome is unclear because mice that completely lack all three subunits have not been produced up until now. We have generated mice that completely lack immunoproteasomes. These animals have reduced presentation of MHC class I-presented peptides, and the peptides that are presented appear to be substantially different than those on cells from wild type mice. Moreover, the phenotype of these animals is distinct from mice lacking any individual immunoproteasome subunit. The loss of immunoproteasomes also affects T cell development in the thymus. The phenotype of these animals will be discussed.
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Affiliation(s)
- Eleanor Kincaid
- 1Pathology, University of Massachusetts Medical School, Worcester, MA
| | - Jenny Che
- 1Pathology, University of Massachusetts Medical School, Worcester, MA
| | - Raymond Welsh
- 1Pathology, University of Massachusetts Medical School, Worcester, MA
| | | | - Andrew Murphy
- 2Regeneron Pharmaceuticals Incorporated, Tarrytown, NY
| | | | | | - Kenneth Rock
- 1Pathology, University of Massachusetts Medical School, Worcester, MA
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16
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Weigmann B, Lehr HA, Yancopoulos G, Valenzuela D, Murphy A, Stevens S, Schmidt J, Galle PR, Rose-John S, Neurath MF. The transcription factor NFATc2 controls IL-6-dependent T cell activation in experimental colitis. ACTA ACUST UNITED AC 2008; 205:2099-110. [PMID: 18710929 PMCID: PMC2526204 DOI: 10.1084/jem.20072484] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The nuclear factor of activated T cells (NFAT) family of transcription factors controls calcium signaling in T lymphocytes. In this study, we have identified a crucial regulatory role of the transcription factor NFATc2 in T cell–dependent experimental colitis. Similar to ulcerative colitis in humans, the expression of NFATc2 was up-regulated in oxazolone-induced chronic intestinal inflammation. Furthermore, NFATc2 deficiency suppressed colitis induced by oxazolone administration. This finding was associated with enhanced T cell apoptosis in the lamina propria and strikingly reduced production of IL-6, -13, and -17 by mucosal T lymphocytes. Further studies using knockout mice showed that IL-6, rather than IL-23 and -17, are essential for oxazolone colitis induction. Administration of hyper-IL-6 blocked the protective effects of NFATc2 deficiency in experimental colitis, suggesting that IL-6 signal transduction plays a major pathogenic role in vivo. Finally, adoptive transfer of IL-6 and wild-type T cells demonstrated that oxazolone colitis is critically dependent on IL-6 production by T cells. Collectively, these results define a unique regulatory role for NFATc2 in colitis by controlling mucosal T cell activation in an IL-6–dependent manner. NFATc2 in T cells thus emerges as a potentially new therapeutic target for inflammatory bowel diseases.
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Affiliation(s)
- Benno Weigmann
- Institute of Molecular Medicine, Johanes Gutenberg Univeristy, 55131 Mainz, Germany
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17
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Lombard DB, Alt FW, Cheng HL, Bunkenborg J, Streeper RS, Mostoslavsky R, Kim J, Yancopoulos G, Valenzuela D, Murphy A, Yang Y, Chen Y, Hirschey MD, Bronson RT, Haigis M, Guarente LP, Farese RV, Weissman S, Verdin E, Schwer B. Mammalian Sir2 homolog SIRT3 regulates global mitochondrial lysine acetylation. Mol Cell Biol 2007; 27:8807-14. [PMID: 17923681 PMCID: PMC2169418 DOI: 10.1128/mcb.01636-07] [Citation(s) in RCA: 949] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Accepted: 09/30/2007] [Indexed: 12/12/2022] Open
Abstract
Homologs of the Saccharomyces cerevisiae Sir2 protein, sirtuins, promote longevity in many organisms. Studies of the sirtuin SIRT3 have so far been limited to cell culture systems. Here, we investigate the localization and function of SIRT3 in vivo. We show that endogenous mouse SIRT3 is a soluble mitochondrial protein. To address the function and relevance of SIRT3 in the regulation of energy metabolism, we generated and phenotypically characterized SIRT3 knockout mice. SIRT3-deficient animals exhibit striking mitochondrial protein hyperacetylation, suggesting that SIRT3 is a major mitochondrial deacetylase. In contrast, no mitochondrial hyperacetylation was detectable in mice lacking the two other mitochondrial sirtuins, SIRT4 and SIRT5. Surprisingly, despite this biochemical phenotype, SIRT3-deficient mice are metabolically unremarkable under basal conditions and show normal adaptive thermogenesis, a process previously suggested to involve SIRT3. Overall, our results extend the recent finding of lysine acetylation of mitochondrial proteins and demonstrate that SIRT3 has evolved to control reversible lysine acetylation in this organelle.
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Affiliation(s)
- David B Lombard
- Howard Hughes Medical Institute, The Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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18
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Wortley KE, Garcia K, Okamoto H, Thabet K, Anderson KD, Shen V, Herman JP, Valenzuela D, Yancopoulos GD, Tschöp MH, Murphy A, Sleeman MW. Peptide YY regulates bone turnover in rodents. Gastroenterology 2007; 133:1534-43. [PMID: 17920065 DOI: 10.1053/j.gastro.2007.08.024] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2007] [Accepted: 07/12/2007] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Peptide YY (PYY) and pancreatic polypeptide (PPY) are members of the neuropeptide Y peptide family. The neuropeptide Y receptor signaling pathway has been implicated in a number of physiologic processes, including the regulation of energy balance and bone mass. To investigate the contribution of endogenous PYY and PPY to these processes, we generated both Pyy- and Ppy-deficient mice. METHODS Pyy(-/-) and Ppy(-/-) mice and their respective wild-type littermates were studied from 8 weeks to 9 months of age. Food intake, metabolic parameters, and locomotor activity were monitored using indirect calorimetry. Body composition and bone parameters were analyzed using dual energy x-ray absorptiometry, histomorphometry, and vertebral compression testing. RESULTS Studies in these mice showed an osteopenic phenotype specific to the Pyy-deficient line, which included a reduction in trabecular bone mass and a functional deficit in bone strength. Furthermore, female Pyy(-/-) mice showed a greater sensitivity to ovariectomy-induced bone loss compared with wild-type littermates. No food intake or metabolic phenotype was apparent in male or female Pyy(-/-) mice on standard chow. However, female Pyy(-/-) mice on a high-fat diet showed a greater propensity to gain body weight and adiposity. No metabolic or osteopenic phenotype was observed in Ppy-deficient mice. CONCLUSIONS These results indicate that endogenous PYY plays a critical role in regulating bone mass. In comparison, its role in regulating body weight is minor and is confined to situations of high-fat feeding.
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19
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Pilecka I, Patrignani C, Pescini R, Curchod ML, Perrin D, Xue Y, Yasenchak J, Clark A, Magnone MC, Zaratin P, Valenzuela D, Rommel C, van Huijsduijnen RH. Protein-tyrosine Phosphatase H1 Controls Growth Hormone Receptor Signaling and Systemic Growth. J Biol Chem 2007; 282:35405-15. [DOI: 10.1074/jbc.m705814200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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20
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Todorovic V, Frendewey D, Gutstein DE, Chen Y, Freyer L, Finnegan E, Liu F, Murphy A, Valenzuela D, Yancopoulos G, Rifkin DB. Long form of latent TGF-beta binding protein 1 (Ltbp1L) is essential for cardiac outflow tract septation and remodeling. Development 2007; 134:3723-32. [PMID: 17804598 DOI: 10.1242/dev.008599] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Latent TGF-beta binding protein 1 (LTBP1) is a member of the LTBP/fibrillin family of extracellular proteins. Due to the usage of different promoters, LTBP1 exists in two major forms, long (L) and short (S), each expressed in a temporally and spatially unique fashion. Both LTBP1 molecules covalently interact with latent TGF-beta and regulate its function, presumably via interaction with the extracellular matrix (ECM). To explore the in vivo role of Ltbp1 in mouse development, at the time when only the L isoform is expressed, we mutated the Ltbp1L locus by gene targeting. Ltbp1L-null animals die shortly after birth from defects in heart development, consisting of the improper septation of the cardiac outflow tract (OFT) and remodeling of the associated vessels. These cardiac anomalies present as persistent truncus arteriosus (PTA) and interrupted aortic arch (IAA), which are associated with the faulty function of cardiac neural crest cells (CNCCs). The lack of Ltbp1L in the ECM of the septating OFT and associated vessels results in altered gene expression and function of CNCCs and decreased Tgf-beta activity in the OFT. This phenotype reveals a crucial role for Ltbp1L and matrix as extracellular regulators of Tgf-beta activity in heart organogenesis.
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Affiliation(s)
- Vesna Todorovic
- Cell Biology Department, NYU School of Medicine, New York, NY 10016, USA.
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21
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Thai TH, Calado DP, Casola S, Ansel KM, Xiao C, Xue Y, Murphy A, Frendewey D, Valenzuela D, Kutok JL, Schmidt-Supprian M, Rajewsky N, Yancopoulos G, Rao A, Rajewsky K. Regulation of the germinal center response by microRNA-155. Science 2007; 316:604-8. [PMID: 17463289 DOI: 10.1126/science.1141229] [Citation(s) in RCA: 1164] [Impact Index Per Article: 68.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
MicroRNAs are small RNA species involved in biological control at multiple levels. Using genetic deletion and transgenic approaches, we show that the evolutionarily conserved microRNA-155 (miR-155) has an important role in the mammalian immune system, specifically in regulating T helper cell differentiation and the germinal center reaction to produce an optimal T cell-dependent antibody response. miR-155 exerts this control, at least in part, by regulating cytokine production. These results also suggest that individual microRNAs can exert critical control over mammalian differentiation processes in vivo.
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Affiliation(s)
- To-Ha Thai
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, MA 02115, USA
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22
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23
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Mostoslavsky R, Chua KF, Lombard DB, Pang WW, Fischer MR, Gellon L, Liu P, Mostoslavsky G, Franco S, Murphy MM, Mills KD, Patel P, Hsu JT, Hong AL, Ford E, Cheng HL, Kennedy C, Nunez N, Bronson R, Frendewey D, Auerbach W, Valenzuela D, Karow M, Hottiger MO, Hursting S, Barrett JC, Guarente L, Mulligan R, Demple B, Yancopoulos GD, Alt FW. Genomic instability and aging-like phenotype in the absence of mammalian SIRT6. Cell 2006; 124:315-29. [PMID: 16439206 DOI: 10.1016/j.cell.2005.11.044] [Citation(s) in RCA: 1151] [Impact Index Per Article: 63.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 09/19/2005] [Accepted: 11/03/2005] [Indexed: 10/25/2022]
Abstract
The Sir2 histone deacetylase functions as a chromatin silencer to regulate recombination, genomic stability, and aging in budding yeast. Seven mammalian Sir2 homologs have been identified (SIRT1-SIRT7), and it has been speculated that some may have similar functions to Sir2. Here, we demonstrate that SIRT6 is a nuclear, chromatin-associated protein that promotes resistance to DNA damage and suppresses genomic instability in mouse cells, in association with a role in base excision repair (BER). SIRT6-deficient mice are small and at 2-3 weeks of age develop abnormalities that include profound lymphopenia, loss of subcutaneous fat, lordokyphosis, and severe metabolic defects, eventually dying at about 4 weeks. We conclude that one function of SIRT6 is to promote normal DNA repair, and that SIRT6 loss leads to abnormalities in mice that overlap with aging-associated degenerative processes.
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Affiliation(s)
- Raul Mostoslavsky
- Howard Hughes Medical Institute, The Children's Hospital, CBR Institute for Biomedical Research, Harvard University Medical School, Boston, MA 02115, USA
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24
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Wortley KE, Anderson KD, Yasenchak J, Murphy A, Valenzuela D, Diano S, Yancopoulos GD, Wiegand SJ, Sleeman MW. Agouti-related protein-deficient mice display an age-related lean phenotype. Cell Metab 2005; 2:421-7. [PMID: 16330327 DOI: 10.1016/j.cmet.2005.11.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2005] [Revised: 08/12/2005] [Accepted: 11/11/2005] [Indexed: 10/25/2022]
Abstract
Endogenous modulators of the central melanocortin system, such as the agouti-related protein (AgRP), should hold a pivotal position in the regulation of energy intake and expenditure. Despite this, AgRP-deficient mice were recently reported to exhibit normal food intake, body weight gain, and energy expenditure. Here we demonstrate that 2- to 3-month-old Agrp null mice do in fact exhibit subtle changes in response to feeding challenges (fasting and MCR agonists) but, of more significance and magnitude, exhibit reduced body weight and adiposity after 6 months of age. This age-dependent lean phenotype is correlated with increased metabolic rate, body temperature, and locomotor activity and increased circulating thyroid hormone (T4 and T3) and BAT UCP-1 expression. These results provide further proof of the importance of the AgRP neuronal system in the regulation of energy homeostasis.
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25
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Valenzuela D, Ceballos G. Habitat Selection, Home Range, and Activity of the White-Nosed Coati (Nasua narica) in a Mexican Tropical Dry Forest. J Mammal 2000. [DOI: 10.1093/jmammal/81.3.810] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
From November of 1994 to June of 1996 an epizootic of mange, probably caused by the mite Notoedres cati, occurred in white-nosed coatis (Nasua narica) in the tropical dry forests of the Chamela-Cuixmala Biosphere Reserve in western Mexico. A monitoring scheme to determine the extent and severity of the epizootic within coatis was implemented. Trapping periods and transects were conducted for 2 yr. To control the spread of the disease, all captured infected coatis were either euthanized or treated with acaricides such as Butox and Ivomec-F, depending on the severity of their infection. Four other species of wild mammals and feral cats had skin conditions resembling mange. A more severe problem with the disease was predicted and later confirmed in the less isolated areas of the reserve, with a higher density of coatis. Our results indicate that epizootics may be more prone to occur in areas with greater fragmentation and less isolation from anthropogenic influence. Interestingly, although there was an apparently severe impact of the mange epizootic in the coati population, the long-term impact of the disease is unknown but appears to be negligible. So in order to understand the role of diseases in wildlife populations, long-term experimental studies are required.
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Affiliation(s)
- D Valenzuela
- Instituto de Ecología, Ciudad Universitaria, México, DF. CP
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28
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Mende U, Zagrovic B, Cohen A, Li Y, Valenzuela D, Fishman MC, Neer EJ. Effect of deletion of the major brain G-protein alpha subunit (alpha(o)) on coordination of G-protein subunits and on adenylyl cyclase activity. J Neurosci Res 1998; 54:263-72. [PMID: 9788285 DOI: 10.1002/(sici)1097-4547(19981015)54:2<263::aid-jnr14>3.0.co;2-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Heterotrimeric G-proteins, composed of alpha and betagamma subunits, transmit signals from cell-surface receptors to cellular effectors and ion channels. Cellular responses to receptor agonists depend on not only the type and amount of G-protein subunits expressed but also the ratio of alpha and betagamma subunits. Thus far, little is known about how the amounts of alpha and betagamma subunits are coordinated. Targeted disruption of the alpha(o) gene leads to loss of both isoforms of alpha(o), the most abundant alpha subunit in the brain. We demonstrate that loss of alpha(o) protein in the brain is accompanied by a reduction of beta protein to 32+/-2% (n = 4) of wild type. Sucrose density gradient experiments show that all of the betagamma remaining in the brains of alpha(o)-/- mice sediments as a heterotrimer (s20,w = 4.4 S, n = 2), with no detectable free alpha or betagamma subunits. Thus, the level of the remaining betagamma subunits matches that of the remaining alpha subunits. Protein levels of alpha subunits other than alpha(o) are unchanged, suggesting that they are controlled independently. Coordination of betagamma to alpha occurs posttranscriptionally because the mRNA level of the predominant beta1 subtype in the brains of alpha(o)-/- mice was unchanged. Adenylyl cyclase can be positively or negatively regulated by betagamma. Because the level of other alpha subunits is unchanged and alpha(o) itself has little or no effect on adenylyl cyclase, we could examine how a large change in the level of betagamma affects this enzyme. Surprisingly, we could not detect any difference in the adenylyl cyclase activity between brain membranes from wild-type and alpha(o)-/- mice. We propose that alpha(o) and its associated betagamma are sequestered in a distinct pool of membranes that does not contribute to the regulation of adenylyl cyclase.
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Affiliation(s)
- U Mende
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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29
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Valenzuela D, Han X, Mende U, Fankhauser C, Mashimo H, Huang P, Pfeffer J, Neer EJ, Fishman MC. G alpha(o) is necessary for muscarinic regulation of Ca2+ channels in mouse heart. Proc Natl Acad Sci U S A 1997; 94:1727-32. [PMID: 9050846 PMCID: PMC19984 DOI: 10.1073/pnas.94.5.1727] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Heterotrimeric G proteins, composed of G alpha and G betagamma subunits, transmit signals from cell surface receptors to cellular effector enzymes and ion channels. The G alpha(o) protein is the most abundant G alpha subtype in the nervous system, but it is also found in the heart. Its function is not completely known, although it is required for regulation of N-type Ca2+ channels in GH3 cells and also interacts with GAP43, a major protein in growth cones, suggesting a role in neuronal pathfinding. To analyze the function of G alpha(o), we have generated mice lacking both isoforms of G alpha(o) by homologous recombination. Surprisingly, the nervous system is grossly intact, despite the fact that G alpha(o) makes up 0.2-0.5% of brain particulate protein and 10% of the growth cone membrane. The G alpha(o)-/- mice do suffer tremors and occasional seizures, but there is no obvious histologic abnormality in the nervous system. In contrast, G alpha(o)-/- mice have a clear and specific defect in ion channel regulation in the heart. Normal muscarinic regulation of L-type calcium channels in ventricular myocytes is absent in the mutant mice. The L-type calcium channel responds normally to isoproterenol, but there is no evident muscarinic inhibition. Muscarinic regulation of atrial K+ channels is normal, as is the electrocardiogram. The levels of other G alpha subunits (G alpha(s), G alpha(q), and G alpha(i)) are unchanged in the hearts of G alpha(o)-/- mice, but the amount of G betagamma is decreased. Whichever subunit, G alpha(o) or G betagamma, carries the signal forward, these studies show that muscarinic inhibition of L-type Ca2+ channels requires coupling of the muscarinic receptor to G alpha(o). Other cardiac G alpha subunits cannot substitute.
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Affiliation(s)
- D Valenzuela
- Laboratory of Developmental Biology and Cardiovascular Research Center, Massachusetts General Hospital, Charlestown 02129, USA
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30
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Schmidt CJ, Zubiaur M, Valenzuela D, Neer EJ, Dräger UC. G(O), a guanine nucleotide binding protein, is expressed during neurite extension in the embryonic mouse. J Neurosci Res 1994; 38:182-7. [PMID: 8078103 DOI: 10.1002/jnr.490380208] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The developmental pattern of expression of the G protein alpha o subunit and GAP43 were compared by immunohistochemical staining of mouse embryos. Staining for alpha o and GAP43 was identical and detected throughout the developing nervous system, and the antigens first appeared in neurons at the beginning of neuronal differentiation. GAP43 and alpha o were not detected in regions containing only neuroblasts. These observations suggest that alpha o and GAP43 may not be required for the decision to pass from neuroblast to differentiated neuron, but may play a role in signal transduction during early neuronal development.
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Affiliation(s)
- C J Schmidt
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115
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31
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Strittmatter SM, Valenzuela D, Fishman MC. An amino-terminal domain of the growth-associated protein GAP-43 mediates its effects on filopodial formation and cell spreading. J Cell Sci 1994; 107 ( Pt 1):195-204. [PMID: 8175908 DOI: 10.1242/jcs.107.1.195] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [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: 11/20/2022] Open
Abstract
GAP-43 is a neuronal protein that is believed to be important to neuronal growth and nerve terminal plasticity. It is enriched on the inner surface of growth cone membranes, a localization that may depend upon palmitoylation of Cys3 and Cys4. It is a major substrate for protein kinase C, which phosphorylates Ser41. Isolated GAP-43 can bind to actin and to calmodulin, and can activate the heterotrimeric GTP-binding proteins, G(o) and Gi. A peptide consisting of the GAP-43 sequence 39–55 binds calmodulin, and an amino-terminal GAP-43 (1–10) peptide activates G(o), suggesting that these stretches may be functional domains of the intact protein. When expressed in non-neuronal cells, GAP-43 enhances filopodial extension and has effects upon cell spreading. We have examined the effects of various GAP-43 domains upon this assay, by expression of GAP-43, GAP-43 mutant proteins, and GAP-43-CAT fusion proteins in COS-7 cells. We find that the amino terminus (Met-Leu-Cys-Cys-Met-Arg-Arg-Thr-Lys-Gln) is an important contributor to these effects on cell shape. A GAP-43 protein mutant in Cys3 and Cys4 does not bind to the membrane, and is inactive. Mutants in Arg6 or Lys9 also are inactive, although they remain localized to particulate fractions; Arg7 mutants are active. A chimeric gene consisting of GAP-43 (1–10) fused to chloramphenicol acetyl transferase (CAT) also causes cell shape changes. As for GAP-43, the effects of this fusion protein are abolished by mutations of Cys3, Cys4, Arg6 or Lys9, but not by mutation of Arg7. Therefore, the cell surface activity of transfected GAP-43 depends upon its amino terminus, although other domains may regulate it in this regard. Since the amino-terminal domain includes the peptide stretch known to be capable of activating G(o) and Gi, we examined the effect of GAP-43 on a Gi-regulated second messenger system, the inhibition of cAMP production in A431 cells. A431 cells stably transfected with GAP-43 spread less well than do controls. In addition, they evidence decreased levels of forskolin-stimulated cAMP, consistent with chronic stimulation of Gi. Stimulation of adenylate cyclase by isoproterenol reverses the GAP-43-induced changes in cell shape. This suggests that G protein stimulation is involved in GAP-43 effects upon cell shape.
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Affiliation(s)
- S M Strittmatter
- Developmental Biology Laboratory, Massachusetts General Hospital, Charlestown
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32
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Abstract
The addition of palmitate to cysteine residues enhances the hydrophobicity of proteins, and consequently their membrane association. Here we have investigated whether this type of fatty acylation also regulates protein-protein interactions. GAP-43 is a neuronal protein that increases guanine nucleotide exchange by heterotrimeric G proteins. Two cysteine residues near the N-terminus of GAP-43 are subject to palmitoylation, and are necessary for membrane binding as well as for G(o) activation. N-terminal peptides, which include these cysteines, stimulate G(o). Monopalmitoylation reduces, and dipalmitoylation abolishes the activity of the peptides. The activity of GAP-43 protein purified from brain also is reversibly blocked by palmitoylation. This suggests that palmitoylation controls a cycle of GAP-43 between an acylated, membrane-bound reservoir of inactive GAP-43, and a depalmitoylated, active pool of protein.
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Affiliation(s)
- Y Sudo
- Developmental Biology Laboratory, Massachusetts General Hospital, Charlestown
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33
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Strittmatter SM, Valenzuela D, Sudo Y, Linder ME, Fishman MC. An intracellular guanine nucleotide release protein for G0. GAP-43 stimulates isolated alpha subunits by a novel mechanism. J Biol Chem 1991; 266:22465-71. [PMID: 1834672] [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: 12/29/2022] Open
Abstract
G protein-coupled membrane receptors activate G proteins by enhancing guanine nucleotide exchange. G0 is a major component of the growing regions (growth cones) of neurons. GAP-43 is a neuronal protein associated with the cytosolic face of the growth cone plasma membrane and stimulates binding of guanosine 5'-3-O-(thio)triphosphate (GTP gamma S) to Go (Strittmatter, S. M., Valenzuela, D., Kennedy, T. E., Neer, E. J., and Fishman, M. C. (1990) Nature 344, 836-841). Here we have examined the mechanism by which GAP-43 affects G0. Like G protein-coupled receptors, GAP-43 enhances GDP release from G0, increases the initial rate of GTP gamma S binding, and increases the GTPase activity of Go, all without altering the intrinsic kappa cat for the GTPase. Unlike the case for receptors, however, the GAP-43 effect is not blocked by pertussis toxin, nor affected by the presence or absence of beta gamma or of phospholipids. There is specificity to the interaction, in that GAP-43 increases GTP gamma S binding to recombinant alpha o and alpha i1, but not to recombinant alpha s. Thus, GAP-43 is a guanine nucleotide release protein with a novel mechanism of action, potentially controlling membrane-associated G proteins from within the cell.
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Affiliation(s)
- S M Strittmatter
- Development Biology Laboratory, Massachusetts General Hospital-East, Charlestown 02129
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34
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Strittmatter S, Valenzuela D, Sudo Y, Linder M, Fishman M. An intracellular guanine nucleotide release protein for G0. GAP-43 stimulates isolated alpha subunits by a novel mechanism. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54595-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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35
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Abstract
The neuronal growth cone plays a crucial role in forming the complex brain architecture achieved during development, and similar nerve terminal mechanisms may operate to modify synaptic structure during adulthood. The growth cone leads the elongating axon towards appropriate synaptic targets by altering motility in response to a variety of extracellular signals. Independently of extrinsic clues, neurons manifest intrinsic control of their growth and form (Banker and Cowan, 1979). Hence, there must be intracellular proteins which control nerve cell shape, so-called 'plasticity' or 'growth' genes. GAP-43 may be such a molecule (Skene and Willard, 1981; Benowitz and Lewis, 1983). For example, GAP-43 is localized to the growth cone membrane (Meiri et al. 1986; Skene et al. 1986) and can enhance filopodial formation even in non-neuronal cells (Zuber et al. 1989a). It includes a small region at the amino terminus for membrane association and perhaps growth cone targeting (Zuber et al. 1989b, Liu et al. 1991). We have found that Go, a member of the G protein family that links receptors and second messengers, is the major non-cytoskeletal protein in the growth cone membrane (Strittmatter et al. 1990). Double staining immunohistochemistry for GAP-43 and Go shows that the distributions of the two proteins are quite similar. Purified GAP-43 regulates the activity of purified Go (Strittmatter et al. 1990), a surprising observation since GAP-43 is an intracellular protein. We have compared the mechanism of GAP-43 activation of Go with that of G protein-linked receptors.2+ interactions between Go and GAP-43 suggest that Go plays a pivotal role in growth cone function, coordinating the effects of both extracellular signals and intracellular growth proteins.
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36
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Affiliation(s)
- M C Fishman
- Developmental Biology Laboratory, Massachusetts General Hospital, Boston 02114
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37
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Abstract
G0, a GTP-binding protein that transduces information from transmembrane receptors, has been found to be a major component of the neuronal growth cone membrane. GAP-43, an intracellular growth cone protein closely associated with neuronal growth, stimulates GTP-gamma-S binding to G0. It does so through an amino-terminal domain homologous to G-linked transmembrane receptors. Thus, G0 in the growth cone may be regulated by intracellular as well as extracellular signals.
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Affiliation(s)
- S M Strittmatter
- Developmental Biology Laboratory, Massachusetts General Hospital, Boston
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38
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Sorvillo JM, McCormack ES, Yanez L, Valenzuela D, Reynolds FH. Preparation and characterization of monoclonal antibodies specific for human transforming growth factor alpha. Oncogene 1990; 5:377-86. [PMID: 1690379] [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: 12/28/2022]
Abstract
A series of monoclonal antibodies (mAbs) against transforming growth factor alpha (TGF alpha) have been produced. The generation of these reagents, as well as their biochemical and immunochemical characterization is described. TGF alpha peptides, mutant recombinant TGF alpha proteins and two-site immunoradiometric assays were used to identify the epitopes recognized by each antibody. This approach has allowed the specific localization of immunodominant domains on the molecule. Certain mAbs were found to be useful for selected procedures. mAb 134A-2B3 was used for immunoblotting both the precursor and mature forms of TGF alpha from conditioned media of tumor cells. One mAb 189-2130.1, which reacted with the carboxyl terminal seventeen amino acids, was able to block TGF alpha binding to the EGF receptor. mAb 213-4.4 was used for immunohistochemical detection of TGF alpha in fixed tumor cells. mAbs 137-178 and 134A-2B3 were used to develop a two-site immunoradiometric immunoassay which was sensitive to 1 ng ml-1 and detected TGF alpha from a variety of tumor cells. A series of mAbs such as these could prove useful in studying the biochemical properties as well as the immunochemical localization of TGF alpha in normal tissues and tumors.
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Affiliation(s)
- J M Sorvillo
- Oncogene Science, Inc., Manhasset, New York 11030
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39
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Abstract
We show here, both in vivo and in vitro, that P22 repressor binds co-operatively to operator sites separated by an integral number of turns of the DNA helix. We measure this co-operativity in vivo using an assay in which repression of a promoter requires co-operative binding of P22 repressors to two separated (non-adjacent) operator sites. We report the isolation of mutant repressors that have high affinity for single operator sites, but are defective in co-operative binding. Six different mutants, all bearing single amino acid changes in the carboxyl domain, have been isolated. We purified the two mutants most deficient in co-operative binding, and found that they bind non-co-operatively in vitro to adjacent as well as to non-adjacent pairs of operator sites.
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Affiliation(s)
- D Valenzuela
- Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, MA 02138
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40
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Abstract
Replacement of the solvent-exposed residues of the DNA recognition helix of the 434 repressor with the corresponding residues of the P22 repressor generates a hybrid protein, 434R[alpha 3(P22R)], which binds specifically to P22 operators. We show here that a new DNA-binding specificity is generated by combining 434 and 434R[alpha 3(P22R)] repressor monomers to form a heterodimer. The heterodimer specifically recognizes a chimeric P22/434 operator that lacks two-fold rotational symmetry.
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Affiliation(s)
- M Hollis
- Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, MA 02138
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41
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Abstract
Human IFN-alpha 1 and IFN-alpha 2 differ in 28 of 166 amino acids and show very different specific antiviral activities on human and murine cells. We have identified, by hybrid scanning and site-directed mutagenesis, three residues in IFN-alpha 2, in positions 121, 125 and 132 which, when replaced individually or jointly by their IFN-alpha 1 counterparts, modify its activity on mouse cells by up to 400-fold. We argue that these residues are involved in direct contacts with the mouse interferon receptor.
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42
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Valenzuela D, Schulman LH. Identification of peptide sequences at the tRNA binding site of Escherichia coli methionyl-tRNA synthetase. Biochemistry 1986; 25:4555-61. [PMID: 3094575 DOI: 10.1021/bi00364a015] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Four different structural regions of Escherichia coli tRNAfMet have been covalently coupled to E. coli methionyl-tRNA synthetase (MetRS) by using a tRNA derivative carrying a lysine-reactive cross-linker. We have previously shown that this cross-linking occurs at the tRNA binding site of the enzyme and involves reaction of only a small number of the potentially available lysine residues in the protein [Schulman, L. H., Valenzuela, D., & Pelka, H. (1981) Biochemistry 20, 6018-6023; Valenzuela, D., Leon, O., & Schulman, L. H. (1984) Biochem. Biophys. Res. Commun. 119, 677-684]. In this work, four of the cross-linked peptides have been identified. The tRNA-protein cross-linked complex was digested with trypsin, and the peptides attached to the tRNA were separated from the bulk of the tryptic peptides by anion-exchange chromatography. The tRNA-bound peptides were released by cleavage of the disulfide bond of the cross-linker and separated by reverse-phase high-pressure liquid chromatography, yielding five major peaks. Amino acid analysis indicated that four of these peaks contained single peptides. Sequence analysis showed that the peptides were cross-linked to tRNAfMet through lysine residues 402, 439, 465, and 640 in the primary sequence of MetRS. Binding of the tRNA therefore involves interactions with the carboxyl-terminal half of MetRS, while X-ray crystallographic data have shown the ATP binding site to be located in the N-terminal domain of the protein [Zelwer, C., Risler, J. L., & Brunie, S. (1982) J. Mol. Biol. 155, 63-81].(ABSTRACT TRUNCATED AT 250 WORDS)
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43
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Abstract
The human alpha-interferon (IFN-alpha) gene family consists of at least 14 potentially functional non-allelic members; the amino acid sequences they encode differ from each other by up to approximately 20% of their residues. Human IFN-beta, which is encoded by a single gene, is distantly related to the IFN-alpha family; it differs in 67% of its residues from IFN-alpha 2. There is considerable evidence that IFN-alpha and -beta compete for the same receptors on their target cells. Comparison of 14 non-allelic human IFN-alpha sequences and the IFN-beta sequence has revealed that 37 of 166 residues are completely conserved and that several of these are arranged in clusters, for example at positions 29-33, 47-50 and 136-150. It is commonly held that evolutionary conservation of amino acids indicates that the residues in question are essential for function. To test this hypothesis in the case of IFNs, we have introduced single site-directed point mutations into the strictly conserved codons 48 and 49 of the IFN-alpha 2 gene which form part of the longest uninterrupted cluster (position 47-50). We report here that the mutant proteins, containing Tyr, Ser and Cys instead of Phe48, or His instead of Gln49, have biological activities indistinguishable from those of wild-type IFN-alpha. In addition, when Glu62, a residue conserved in all known alpha and beta IFNs of man, mouse and cattle, was replaced by Lys, antiviral activity remained unchanged.
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44
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Valenzuela D, Leon O, Schulman LH. Modification of specific lysine residues in E. coli methionyl-tRNA synthetase by crosslinking to E. coli formylmethionine tRNA. Biochem Biophys Res Commun 1984; 119:677-84. [PMID: 6424668 DOI: 10.1016/s0006-291x(84)80303-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A protein affinity labeling derivative of E. coli tRNAfMet has been prepared which carries an average of one reactive side chain per molecule, distributed over four structural regions. Each side chain contains a disulfide bond capable of reaction with cysteine residues and an N-hydroxysuccinimide ester group capable of coupling to lysine epsilon-amino groups in proteins. Reaction of the modified tRNA with E. coli methionyl-tRNA synthetase leads to crosslinking only by reaction with lysine residues in the protein. Examination of the tRNA present in the crosslinked complex reveals that the enzyme is coupled to side chains attached to the 5' terminal nucleotide, the dihydrouridine loop, the anticodon and the CCA sequence. Digestion of the crosslinked enzyme with trypsin followed by peptide mapping reveals that the major crosslinking reactions occur at four specific lysine residues, with minor reaction at two additional sites. Native methionyl-tRNA synthetase contains 90 lysine residues, 45 in unique sequences of the dimeric alpha 2 enzyme. Crosslinking of the protein to different regions in tRNAfMet thus occurs with the high degree of selectivity necessary for use in determining the peptide sequences which are near specific nucleotide sequences of tRNA bound to the protein.
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45
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Abstract
The mode of production of the brown pigments of Bacillus subtilis 168 L-4, pigments frequently used as phenotypic markers for sporulation in this organism, has been studied. A defined liquid medium which promoted maximal pigment formation was developed. Five brown components, which could be resolved by thin-layer chromatography, were produced in the culture broth. Removal of cells from the medium at the end of logarithmic growth did not alter the type or amount of the pigments formed, indicating that the cells excreted pigment precursors into the medium during growth. Pigment formation from the precursors was found to occur by an oxygen-requiring, base-dependent, Mn2+-requiring, nonenzymatic pathway. Pigment production was also stimulated by the presence of tyrosine and histidine in the medium. The increases in extracellular pH often associated with spore formation in B. subtilis might be the cause of the concomitant appearance of brown pigments.
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46
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Schulman LH, Valenzuela D, Pelka H. Reversible inactivation of Escherichia coli methionyl-tRNA synthetase by covalent attachment of formylmethionine tRNA to the tRNA binding site with a cleavable cross-linker. Biochemistry 1981; 20:6018-23. [PMID: 7030381 DOI: 10.1021/bi00524a015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Protein affinity labeling groups have been attached to single-stranded cytidine residues in four structural regions of tRNAfMet. Modification of the tRNA with an average of one cross-linking group per molecule is achieved with retention of 75% of the original methionine acceptor activity. Incubation of the modified tRNA with methionyl-tRNA synthetase (MetRS) results in covalent coupling of the protein and nucleic acid by reaction of N-hydroxysuccinimide ester groups attached to the tRNA with lysine residues in the enzyme. In the presence of excess MetRS, approximately 30% of the input tRNA can be covalently bound to protein, indicating that lysine residues are appropriately oriented for reaction with cross-linking groups attached to certain sites in the tRNA but not to others. The cross-linking reaction results in loss of aminoacylation activity of MetRS equal to the amount of covalently bound tRNA. Enzyme activity is restored by release of bound tRNA following cleavage of the disulfide bond of the cross-linker with a sulfhydryl reagent. The data indicate that cross-linking occurs at the tRNA binding site of the enzyme. In the presence of excess modified tRNAfMet, a maximum of 1 mol of tRNA is cross-linked per mol of MetRS, in keeping with the known anticooperative tRNA binding properties of the native dimeric synthetase. In addition, the coupling reaction is effectively inhibited by unmodified tRNAfMet, but not by noncognate tRNAs.
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47
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Chaudhuri A, Stringer EA, Valenzuela D, Maitra U. Characterization of eukaryotic initiation factor 2 containing two polypeptide chains of Mr = 48,000 and 38,000. J Biol Chem 1981; 256:3988-94. [PMID: 6908592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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48
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Stringer EA, Chaudhuri A, Valenzuela D, Maitra U. Rabbit reticulocyte initiation factor 2 contains two polypeptide chains of molecular weights 48,000 and 38,000. Proc Natl Acad Sci U S A 1980; 77:3356-9. [PMID: 6932024 PMCID: PMC349614 DOI: 10.1073/pnas.77.6.3356] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Eukaryotic initiation factor 2 (eIF-20) purified from rabbit reticulocyte lysates consists of equimolar amounts of two polypeptide chains of Mr 48,000 and 38,000. Determination of the molecular weight of the native factor gave a value which is consistent with a Mr of 86,000 indicating that the factor is composed of one Mr 48,000 and one Mr 38,000 polypeptide. The purified factor exhibited all the binding activities characteristic of eIF-2. The factor formed ternary complexes with Met-tRNAfMet and GTP; it bound GDP to form a binary complex; and it also possessed the property of binding a wide variety of RNA species, including reoviral mRNA, phage T3 mRNA, rRNAs, and tRNA. Furthermore, the ternary complex formed by purified eIF-2 interacted with the 40S ribosomal subunit in the presence of AUG codon to form a 40S initiation complex. These results indicate that all binding activities attributed to eIF-2 are contained in the 48,000- and 38,000-dalton polypeptides.
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49
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Perretta M, Valladares L, Garrido F, Valenzuela D, Ludwig U. Hormonal control of gene expression: differential activation of rat bone marrow RNA polymerases by erythropoietin and testosterone. Arch Biol Med Exp 1979; 12:309-18. [PMID: 95387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hormones play a role in the regulation of gene expression by inducing changes in enzyme patterns in target cells mediated by the synthesis of specific RNA molecules. Erythropoiesis has been used as a system for studying the molecular mechanism of regulation of gene action by means of two hormones: erythropoietin and testosterone. Experiments designed to correlate the biochemical action of both hormones on rat marrow cells are herein reported. Both factors seems to act at different biochemical and citological levels. Erythropoietin triggers the erythropoietic process acting on the erythropoietin sensitive cells (ESC), in which the hormone induces the synthesis of a high molecular weight RNA, which is the precursor of a functional 9 S messenger RNA. Testosterone seems to act on polychromatophilic erythroblasts, in which the synthesis of ribosomal RNA or its precursor is stimulated. The steroid enhances the nuclear ribonuclease activity, which could represent a control mechanism for the processing (maturation) of high molecular weight RNAs. The incorporation of 3H-GTP and 3H-UTP into RNA by isolated rat bone marrow nuclei is stimulated by erythropoietin and testosterone. Using alpha-amanitine and different ionic strength conditions it was found that erythropoietin enhances preferentially RNA polymerase II activity while testosterone increases RNA polymerase I activity. It is postulated that erythropoietin and testosterone act synergically to create the biochemical machinery for hemoglobin synthesis, the macromolecule that characterizes the erythropoietic process.
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50
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Adhya S, Sarkar P, Valenzuela D, Maitra U. Termination of transcription by Escherichia coli RNA polymerase: influence of secondary structure of RNA transcripts on rho-independent and rho-dependent termination. Proc Natl Acad Sci U S A 1979; 76:1613-7. [PMID: 156360 PMCID: PMC383440 DOI: 10.1073/pnas.76.4.1613] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The effect of RNA secondary structure on rho-independent and rho-dependent termination of transcription of T3 DNA by Escherichia coli RNA polymerase has been studied by incorporating, into nascent transcripts, base analogs that lead to altered base-pairing properties. A guanine --> hypoxanthine substitution, with attendant weakening of secondary structure, abolished the rho-independent termination at 20% of the genome; in contrast, replacement of cytosine with 5-bromocytosine, which forms stronger pairs with guanine, enhanced termination at this site. rho-Independent termination was not altered by replacing uracil with 5-bromouracil. There are two major rho-dependent termination sites on the T3 DNA-at 8 and 15%. The termination activity of rho in this system also depended on RNA secondary structure. The incorporation of 5-bromouracil instead of uracil into RNA did not alter the site specificity of rho action but rho was rendered inactive when cytosine was replaced by 5-bromocytosine. In contrast, replacement of GTP with ITP in the reaction increased rho-dependent inhibition of RNA synthesis, caused production of heterogeneous-sized transcripts, and stimulated rho-mediated ATP hydrolysis. The rho-associated ATPase activity, in the presence of isolated T3 RNA, was also stimulated by inosine substitution. Furthermore, the temperature-sensitive rho isolated from rho 15 mutant of E. coli, which does not terminate transcription in the presence of the common rNTPs, was active when GTP was replaced with ITP. These results suggest that strongly paired G.C-rich regions in RNA stem-loop structures or RNA.DNA hybrids are essential for rho-independent termination, whereas rho-dependent termination requires weakly paired cytosine residues for its action.
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