DOCSLIB.ORG

DNA Sequence Analysis of Spontaneous Mutagenesis in Saccharomyces Cerevisiae

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
DNA Sequence Analysis of Spontaneous Mutagenesis in Saccharomyces Cerevisiae Copyright 1998 by the Genetics Society of America DNA Sequence Analysis of Spontaneous Mutagenesis in Saccharomyces cerevisiae Bernard A. Kunz, Karthikeyan Ramachandran and Edward J. Vonarx School of Biological and Chemical Sciences, Deakin University, Geelong, Victoria, 3217, Australia ABSTRACT To help elucidate the mechanisms involved in spontaneous mutagenesis, DNA sequencing has been applied to characterize the types of mutation whose rates are increased or decreased in mutator or antimutator strains, respectively. Increased spontaneous mutation rates point to malfunctions in genes that normally act to reduce spontaneous mutation, whereas decreased rates are associated with defects in genes whose products are necessary for spontaneous mutagenesis. In this article, we survey and discuss the mutational speci®cities conferred by mutator and antimutator genes in the budding yeast Saccharomyces cerevisiae. The implications of selected aspects of the data are considered with respect to the mechanisms of spontaneous mutagenesis. PONTANEOUS mutations play a fundamental role in the production of single and multiple base pair alter- S in evolution and have been implicated in aging, ations (Ripley and Glickman 1983; Kunkel 1990). In- carcinogenesis, and human genetic disease (Harmon sertions of transposable elements generally constitute 1981; Kirkwood 1989; Cooper and Krawczak 1990; larger sequence changes in DNA. Although transposon Arber 1991; Drake 1991a; Loeb 1991, 1994; Win- movement can be a relatively infrequent event, transpo- tersberger 1991; Caskey et al. 1992; Strauss 1992). sition rates may be increased by the presence of DNA They are thought to originate as a consequence of intra- damage, including that which occurs spontaneously cellular events, including the formation of DNA lesions, (Bradshaw and McEntee 1989; Kunz et al. 1990, the occurrence of DNA synthesis errors during replica- 1994a). tion, repair and recombination, and the movement of Two general strategies have been used in attempts transposable elements (Sargentini and Smith 1985; to better understand the mechanisms responsible for Smith and Sargentini 1985; Ramel 1989; Loeb and spontaneous mutagenesis. The ®rst is to characterize Cheng 1990; Drake 1991b; Kunkel 1992; Smith 1992; strains that have enhanced spontaneous mutation rates. Amariglio and Rechavi 1993; Ames et al. 1993; Lin- The rationale for this route is that mutator phenotypes dahl 1993). are expected to result from defects in genes whose prod- DNA lesions can arise naturally through intracellular ucts act to minimize genetic instability. Indeed, as ex- metabolism or the intrinsic instability of DNA. For exam- pected, such studies have revealed that spontaneous ple, there is evidence consistent with spontaneous alkyl- mutations can arise through failure of DNA repair or ation, deamination, and loss of DNA bases, as well as processes that maintain the accuracy of DNA replica- Loeb their modi®cation by reactive oxygen species ( and tion (Haynes and Kunz 1981; Sargentini and Smith Preston Ames Lindahl Fried- 1986; et al. 1993; 1993; 1985; Kramer et al. 1989a; Rebeck and Samson 1991; berg et al. 1995). Because a substantial fraction of en- Michaels and Miller 1992; Smith 1992; Xiao and dogenous DNA damage may involve the alteration or Samson 1993; Kunz et al. 1994a and references therein). loss of nucleotide bases, many spontaneous mutations The second approach is to isolate antimutator mutants may be generated during replication past miscoding or with the aim to identify genes whose functions are re- noninstructional lesions. The accuracy of DNA synthesis quired for spontaneous mutagenesis. A number of these on undamaged templates is attributed in large measure mutants have been recovered, mainly in prokaryotic to DNA polymerase (pol)-mediated nucleotide selection systems, and where characterized, they have been found and proofreading of replication errors, as well as to to have alterations primarily in genes that encode DNA postreplicative mismatch correction of errors that es- polymerases (Sargentini and Smith 1985; Morrison cape proofreading (Loeb and Cheng 1990; Kunkel et al. 1989; Smith 1992; Drake 1993 and references 1992; Goodman et al. 1993; Modrich 1994). The topog- therein; Fijalkowska et al. 1993). raphy of the DNA molecule itself also is an important Early studies of spontaneous mutagenesis in mutator factor, however, and roles have been proposed for DNA and antimutator strains relied on genetic analysis of secondary structures and misaligned template primers reversion, suppression, or forward mutation (for re- views, see Lawrence 1982; Sargentini and Smith 1985; Friedberg et al. 1995). Because of technological Corresponding author: B. A. Kunz, School of Biological and Chemi- cal Sciences, Deakin University, Geelong, Victoria, 3217 Australia. restrictions, the systems used did not identify the DNA E-mail: [email protected] sequence alterations involved, or they were unable to Genetics 148: 1491±1505 (April, 1998) 1492 B. A. Kunz, K. Ramachandran and E. J. Vonarx detect all types of mutation that occurred. These limita- large number of samples. In this case, however, geno- tions were overcome by applying DNA sequencing tech- typic and phenotypic reversion to wild type are assumed niques to examine forward mutations in prokaryotic to involve the same sequence change, but this may not and then eukaryotic organisms (Friedberg et al. 1995). necessarily be so. For example, intragenic suppression The resulting data on the types of DNA sequence may be indistinguishable phenotypically from locus re- changes that occur, the rates at which they arise, their version. Reversion systems will notbe considered further site speci®city, and how these parameters are in¯uenced in this review. by mutator and antimutator alleles have yielded insights Mutational spectra derived from different assay sys- into processes that act to maintain genetic stability and tems should be compared with caution because of the ensure accurate transmission of the hereditary material. inherent characteristics of the systems. Ideally an assay In this article, we review the modulation of spontane- system should involve a target gene large enough to ous mutagenesis in mutator and antimutator strains of allow all possible types of mutation to occur and be the budding yeast Saccharomyces cerevisiae, as revealed recovered. While a larger target gene should be more by DNA sequence analysis. First, we discuss brie¯y the representative of the genome, practical dif®culties in selected aspects of systems used in the analysis of muta- sequencing could negate this advantage. Multiple se- genesis. Next, sequence changes arising spontaneously quencing sessions may be required to identify mutations in a wild-type background are considered to establish in a large target. Even if a mutation is identi®ed near the types of mutations that do occur and provide a basis the sequencing primer, the entire target has to be se- for comparison. We then survey the effects of eliminat- quenced to verify that there are no additional alter- ing genes whose inactivation leads to a mutator or anti- ations. Another desirable feature is a wide variety of mutator phenotype on the magnitude and speci®city of sequence contexts, which helps maximize detection of spontaneous mutagenesis. Finally, we focus on a select sequence-speci®c effects. The proportion of intronic number of ®ndings with implications for the mecha- sequences in the assay system, however, should be low nisms of spontaneous mutagenesis in eukaryotic cells. because many intronic mutations may not produce phe- Assay systems: In vivo mutagenesis assay systems can notypic changes. If nondetectable mutations are not be based on the characterization of forward or reverse randomly distributed with respect to class or location mutations on a target gene (assay gene). Sequence anal- throughout the target gene, then mutational speci®city yses using forward systems have been reported for the will be biased and the mutational data will not be repre- CAN1, LYS2, SUP4-o, and URA3 genes. Commonly used sentative of the true spectrum. Thus, if possible, the reversion systems are based on ade2, his7, hom3,orlys2 ability of the system to detect all possible substitutions alleles. Mutant strains are usually constructed by delet- at all positions within the target should be characterized. ing part or all of the gene, disrupting the gene sequence If this requirement is not met, the interpretation of by inserting additional DNA into the gene, or by intro- the spectral data should acknowledge this limitation. ducing point mutations into the gene. Deletion of a Irrespective of the size or sequence content of the assay signi®cant portion or all of the gene is the preferable target, a statistically signi®cant number of mutants must method because this usually results in complete loss of be examined to construct a meaningful spectrum. Small the gene's function. In contrast, disruptions and point data sets increase the probability that spectral features mutations may result in partial retention or alteration of are caused by chance. gene function, and different point mutations especially Spontaneous DNA sequence alterations: To date, mu- may produce different phenotypic effects. Assay genes tations that occur spontaneously in wild-type cells have can be located on a chromosome or a centromeric plas- been characterized using the yeast centromere plasmid- mid. This type of plasmid mimics chromosome behavior borne SUP4-o
Load more

Recommended publications
  • The Counsyl Foresight™ Carrier Screen
    The Counsyl Foresight™ Carrier Screen 180 Kimball Way | South San Francisco, CA 94080 www.counsyl.com | [email protected] | (888) COUNSYL The Counsyl Foresight Carrier Screen - Disease Reference Book 11-beta-hydroxylase-deficient Congenital Adrenal Hyperplasia .................................................................................................................................................................................... 8 21-hydroxylase-deficient Congenital Adrenal Hyperplasia ...........................................................................................................................................................................................10 6-pyruvoyl-tetrahydropterin Synthase Deficiency ..........................................................................................................................................................................................................12 ABCC8-related Hyperinsulinism........................................................................................................................................................................................................................................ 14 Adenosine Deaminase Deficiency .................................................................................................................................................................................................................................... 16 Alpha Thalassemia.............................................................................................................................................................................................................................................................
    [Show full text]
  • Oral Ambroxol Increases Brain Glucocerebrosidase Activity in a Nonhuman Primate
    Received: 17 November 2016 | Revised: 24 January 2017 | Accepted: 12 February 2017 DOI 10.1002/syn.21967 SHORT COMMUNICATION Oral ambroxol increases brain glucocerebrosidase activity in a nonhuman primate Anna Migdalska-Richards1 | Wai Kin D. Ko2 | Qin Li2,3 | Erwan Bezard2,3,4,5 | Anthony H. V. Schapira1 1Department of Clinical Neurosciences, Institute of Neurology, University College Abstract London, NW3 2PF, United Kingdom Mutations in the glucocerebrosidase 1 (GBA1) gene are related to both Parkinson disease (PD) and 2Motac Neuroscience, Manchester, United Gaucher disease (GD). In both cases, the condition is associated with deficiency of glucocerebrosi- Kingdom dase (GCase), the enzyme encoded by GBA1. Ambroxol is a small molecule chaperone that has 3 Institute of Laboratory Animal Sciences, been shown in mice to cross the blood-brain barrier, increase GCase activity and reduce alpha- China Academy of Medical Sciences, Beijing synuclein protein levels. In this study, we analyze the effect of ambroxol treatment on GCase City, People’s Republic of China activity in healthy nonhuman primates. We show that daily administration of ambroxol results in 4University de Bordeaux, Institut des Maladies Neurodeg en eratives, UMR 5293, increased brain GCase activity. Our work further indicates that ambroxol should be investigated as Bordeaux F-33000, France a novel therapy for both PD and neuronopathic GD in humans. 5CNRS, Institut des Maladies Neurodeg en eratives, UMR 5293, Bordeaux F-33000, France KEYWORDS Correspondence ambroxol, glucocerebrosidase,
    [Show full text]
  • Assessment of a Targeted Gene Panel for Identification of Genes Associated with Movement Disorders
    Supplementary Online Content Montaut S, Tranchant C, Drouot N, et al; French Parkinson’s and Movement Disorders Consortium. Assessment of a targeted gene panel for identification of genes associated with movement disorders. JAMA Neurol. Published online June 18, 2018. doi:10.1001/jamaneurol.2018.1478 eMethods. Supplemental methods. eTable 1. Name, phenotype and inheritance of the genes included in the panel. eTable 2. Probable pathogenic variants identified in a cohort of 23 patients with cerebellar ataxia using WES analysis. eTable 3. Negative cases in a cohort of 23 patients with cerebellar ataxia studied using WES analysis. eTable 4. Variants of unknown significance (VUSs) identified in the cohort. eFigure 1. Examples of pedigrees of cases with identified causative variants. eFigure 2. Pedigrees suggesting mendelian inheritance in negative cases. eFigure 3. Examples of pedigrees of cases with identified VUSs. eResults. Supplemental results. This supplementary material has been provided by the authors to give readers additional information about their work. © 2018 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/26/2021 eMethods. Supplemental methods Patients selection In the multicentric, prospective study, patients were selected from 25 French, 1 Luxembourg and 1 Algerian tertiary MDs centers between September 2014 and July 2016. Inclusion criteria were patients (1) who had developed one or several chronic MDs (2) with an age of onset below 40 years and/or presence of a family history of MDs. Patients suffering from essential tremor, tic or Gilles de la Tourette syndrome, pure cerebellar ataxia or with clinical/paraclinical findings suggestive of an acquired cause were excluded.
    [Show full text]
  • Sphingolipids and Cell Signaling: Relationship Between Health and Disease in the Central Nervous System
    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 6 April 2021 doi:10.20944/preprints202104.0161.v1 Review Sphingolipids and cell signaling: Relationship between health and disease in the central nervous system Andrés Felipe Leal1, Diego A. Suarez1,2, Olga Yaneth Echeverri-Peña1, Sonia Luz Albarracín3, Carlos Javier Alméciga-Díaz1*, Angela Johana Espejo-Mojica1* 1 Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá D.C., 110231, Colombia; [email protected] (A.F.L.), [email protected] (D.A.S.), [email protected] (O.Y.E.P.) 2 Faculty of Medicine, Universidad Nacional de Colombia, Bogotá D.C., Colombia; [email protected] (D.A.S.) 3 Nutrition and Biochemistry Department, Faculty of Science, Pontificia Universidad Javeriana, Bogotá D.C., Colombia; [email protected] (S.L.A.) * Correspondence: [email protected]; Tel.: +57-1-3208320 (Ext 4140) (C.J.A-D.). [email protected]; Tel.: +57-1-3208320 (Ext 4099) (A.J.E.M.) Abstract Sphingolipids are lipids derived from an 18-carbons unsaturated amino alcohol, the sphingosine. Ceramide, sphingomyelins, sphingosine-1-phosphates, gangliosides and globosides, are part of this group of lipids that participate in important cellular roles such as structural part of plasmatic and organelle membranes maintaining their function and integrity, cell signaling response, cell growth, cell cycle, cell death, inflammation, cell migration and differentiation, autophagy, angiogenesis, immune system. The metabolism of these lipids involves a broad and complex network of reactions that convert one lipid into others through different specialized enzymes. Impairment of sphingolipids metabolism has been associated with several disorders, from several lysosomal storage diseases, known as sphingolipidoses, to polygenic diseases such as diabetes and Parkinson and Alzheimer diseases.
    [Show full text]
  • GM2 Gangliosidoses: Clinical Features, Pathophysiological Aspects, and Current Therapies
    International Journal of Molecular Sciences Review GM2 Gangliosidoses: Clinical Features, Pathophysiological Aspects, and Current Therapies Andrés Felipe Leal 1 , Eliana Benincore-Flórez 1, Daniela Solano-Galarza 1, Rafael Guillermo Garzón Jaramillo 1 , Olga Yaneth Echeverri-Peña 1, Diego A. Suarez 1,2, Carlos Javier Alméciga-Díaz 1,* and Angela Johana Espejo-Mojica 1,* 1 Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia; [email protected] (A.F.L.); [email protected] (E.B.-F.); [email protected] (D.S.-G.); [email protected] (R.G.G.J.); [email protected] (O.Y.E.-P.); [email protected] (D.A.S.) 2 Faculty of Medicine, Universidad Nacional de Colombia, Bogotá 110231, Colombia * Correspondence: [email protected] (C.J.A.-D.); [email protected] (A.J.E.-M.); Tel.: +57-1-3208320 (ext. 4140) (C.J.A.-D.); +57-1-3208320 (ext. 4099) (A.J.E.-M.) Received: 6 July 2020; Accepted: 7 August 2020; Published: 27 August 2020 Abstract: GM2 gangliosidoses are a group of pathologies characterized by GM2 ganglioside accumulation into the lysosome due to mutations on the genes encoding for the β-hexosaminidases subunits or the GM2 activator protein. Three GM2 gangliosidoses have been described: Tay–Sachs disease, Sandhoff disease, and the AB variant. Central nervous system dysfunction is the main characteristic of GM2 gangliosidoses patients that include neurodevelopment alterations, neuroinflammation, and neuronal apoptosis. Currently, there is not approved therapy for GM2 gangliosidoses, but different therapeutic strategies have been studied including hematopoietic stem cell transplantation, enzyme replacement therapy, substrate reduction therapy, pharmacological chaperones, and gene therapy.
    [Show full text]
  • Diagnostic Methods for Lysosomal Storage Disease
    Reports of Biochemistry & Molecular Biology Vol.7, No.2, Jan 2019 Review article www.RBMB.net Diagnostic methods for Lysosomal Storage Disease Armin Mokhtariye1,3, Lida Hagh-Nazari1, Abdol-Reza Varasteh2, Fatemeh Keyfi*3 Abstract Lysosomal storage disorders (LSD) are a class of metabolic disturbance in which manifested by the accumulation of large molecules (complex lipids, glycoproteins, glycosaminoglycans, etc.) in lysosomes. LSDs have a wide range of clinical symptoms that may contain organ dysfunction, neurological and skeletal disorders. The first stage of diagnosis is clinically suspected by a physician. Next stage is enzyme activity assays including Fluorometry and MS/MS methods. These methods usually placed in newborn program screening. The second laboratory diagnostic stage is molecular examination (RFLP-PCR and ARMS-PCR, Mutations Scanning Methods, DNA sequencing, MLPA and NGS methods) that is confirmation of the enzyme assays. In this article, routine diagnostic methods for LSDs were discussed. The gold standard for enzyme activity assay and molecular diagnosis is TMS and NGS, respectively. Keywords: Diagnostic methods, Enzyme activity, Lysosomal storage disease, Molecular assay. Introduction Pompe disease is a rare and neuromuscular The last operators in the endocytic process are disorder due to a lack or decrease of the acid alpha lysosomes that cleavage the large molecules into glucosidase (GAA) that leads to a deposit of simpler component (1). Hydrolytic enzymes are glycogen in lysosomes of many tissues, particularly proprietary for multiple substrates in the lysosomes- heart and skeletal muscle (6, 7). This enzyme is which are activated in the acidic pH (between 4.5 coded by GAA gene, located on chromosome 17 and 5.0) in the organelles' intracellular (1).
    [Show full text]
  • Molecular Therapy for Lysosomal Storage Diseases
    Chapter 24 Molecular Therapy for Lysosomal Storage Diseases Daisuke Tsuji and Kohji Itoh Additional information is available at the end of the chapter http://dx.doi.org/10.5772/54074 1. Introduction Lysosomes are organella involving the catabolism of biomolecules extracellularly and intra‐ cellularly incorporated, which contain more than 60 distinct acidic hydrolases (lysosomal enzymes) and their co-factors. Lysosomal storage diseases (LSDs) are caused by germ-line gene mutations encoding lysosomal enzymes, their activator proteins, integral membrane proteins, cholesterol transporters and proteins concerning intracellular trafficking of lysoso‐ mal enzymes [1,2]. The LSDs associate with excessive accumulation of natural substrates, in‐ cluding glycoconjugates (glycosphingolipids, oligosaccharides derived from glycoproteins, and glycosaminoglycans from proteoglycans) as well as heterogeneous manifestations in both visceral and nervous systems [1,2]. LSDs comprise greater than 40 diseases, of which incidence is about 1 per 100 thousand births, and recognized as so-called ‘Orphan diseases’. In the biosynthesis of lysosomal matrix enzymes, newly synthesized enzymes are N-glyco‐ sylated in the endoplasmic reticulum (ER) and then phosphorylated in the Golgi apparatus on the 6 position of the terminal mannose residues (M6P) via two step reactions catalyzed by Golgi-localized phosphotransferase and uncovering enzyme necessary to expose the ter‐ minal M6P residues [3,4]. The M6P-carrying enzymes then bind the cation-dependent man‐ nose 6-phosphate receptor (CD-M6PR) at physiological pH in the Golgi. The enzyme– receptor complex is then transported to late-endosomes where the M6P-carrying enzymes dissociate from the receptor at acidic pH, while the CD-M6PR then traffics back to the Golgi as a shuttle.
    [Show full text]
  • Protein Network Analyses of Pulmonary Endothelial Cells In
    www.nature.com/scientificreports OPEN Protein network analyses of pulmonary endothelial cells in chronic thromboembolic pulmonary hypertension Sarath Babu Nukala1,8,9*, Olga Tura‑Ceide3,4,5,9, Giancarlo Aldini1, Valérie F. E. D. Smolders2,3, Isabel Blanco3,4, Victor I. Peinado3,4, Manuel Castell6, Joan Albert Barber3,4, Alessandra Altomare1, Giovanna Baron1, Marina Carini1, Marta Cascante2,7,9 & Alfonsina D’Amato1,9* Chronic thromboembolic pulmonary hypertension (CTEPH) is a vascular disease characterized by the presence of organized thromboembolic material in pulmonary arteries leading to increased vascular resistance, heart failure and death. Dysfunction of endothelial cells is involved in CTEPH. The present study describes for the frst time the molecular processes underlying endothelial dysfunction in the development of the CTEPH. The advanced analytical approach and the protein network analyses of patient derived CTEPH endothelial cells allowed the quantitation of 3258 proteins. The 673 diferentially regulated proteins were associated with functional and disease protein network modules. The protein network analyses resulted in the characterization of dysregulated pathways associated with endothelial dysfunction, such as mitochondrial dysfunction, oxidative phosphorylation, sirtuin signaling, infammatory response, oxidative stress and fatty acid metabolism related pathways. In addition, the quantifcation of advanced oxidation protein products, total protein carbonyl content, and intracellular reactive oxygen species resulted increased
    [Show full text]
  • DNA Repair Mechanisms and the Bypass of DNA Damage in Saccharomyces Cerevisiae
    YEASTBOOK GENOME ORGANIZATION & INTEGRITY DNA Repair Mechanisms and the Bypass of DNA Damage in Saccharomyces cerevisiae Serge Boiteux* and Sue Jinks-Robertson†,1 *Centre National de la Recherche Scientifique UPR4301 Centre de Biophysique Moléculaire, 45071 Orléans cedex 02, France, and yDepartment of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710 ABSTRACT DNA repair mechanisms are critical for maintaining the integrity of genomic DNA, and their loss is associated with cancer predisposition syndromes. Studies in Saccharomyces cerevisiae have played a central role in elucidating the highly conserved mech- anisms that promote eukaryotic genome stability. This review will focus on repair mechanisms that involve excision of a single strand from duplex DNA with the intact, complementary strand serving as a template to fill the resulting gap. These mechanisms are of two general types: those that remove damage from DNA and those that repair errors made during DNA synthesis. The major DNA-damage repair pathways are base excision repair and nucleotide excision repair, which, in the most simple terms, are distinguished by the extent of single-strand DNA removed together with the lesion. Mistakes made by DNA polymerases are corrected by the mismatch repair pathway, which also corrects mismatches generated when single strands of non-identical duplexes are exchanged during homologous recombination. In addition to the true repair pathways, the postreplication repair pathway allows lesions or structural aberrations that block replicative DNA polymerases to be tolerated. There are two bypass mechanisms: an error-free mechanism that involves a switch to an undamaged template for synthesis past the lesion and an error-prone mechanism that utilizes specialized translesion synthesis DNA polymerases to directly synthesize DNA across the lesion.
    [Show full text]
  • The Unique Phenotype of Lipid-Laden Macrophages
    International Journal of Molecular Sciences Review The Unique Phenotype of Lipid-Laden Macrophages Marco van Eijk * and Johannes M. F. G. Aerts * Leiden Institute of Chemistry, Leiden University, 2333 CC Leiden, The Netherlands * Correspondence: [email protected] (M.v.E.); [email protected] (J.M.F.G.A.) Abstract: Macrophages are key multi-talented cells of the innate immune system and are equipped with receptors involved in damage and pathogen recognition with connected immune response guiding signaling systems. In addition, macrophages have various systems that are involved in the uptake of extracellular and intracellular cargo. The lysosomes in macrophages play a central role in the digestion of all sorts of macromolecules and the entry of nutrients to the cytosol, and, thus, the regulation of endocytic processes and autophagy. Simplistically viewed, two macrophage phenotype extremes exist. On one end of the spectrum, the classically activated pro-inflammatory M1 cells are present, and, on the other end, alternatively activated anti-inflammatory M2 cells. A unique macrophage population arises when lipid accumulation occurs, either caused by flaws in the catabolic machinery, which is observed in lysosomal storage disorders, or as a result of an acquired condition, which is found in multiple sclerosis, obesity, and cardiovascular disease. The accompanying overload causes a unique metabolic activation phenotype, which is discussed here, and, consequently, a unifying phenotype is proposed. Keywords: adipose tissue; foam cell; Gaucher disease; GPNMB; macrophage; multiple sclerosis; obesity; TREM-2 Citation: van Eijk, M.; Aerts, J.M.F.G. The Unique Phenotype of Lipid-Laden Macrophages.
    [Show full text]
  • An Intrinsic Mechanism of Secreted Protein Aging and Turnover
    An intrinsic mechanism of secreted protein aging and turnover Won Ho Yanga,b, Peter V. Aziza,b, Douglas M. Heithoffc, Michael J. Mahanc, Jeffrey W. Smithb, and Jamey D. Martha,b,c,1 aCenter for Nanomedicine, University of California, Santa Barbara, CA 93106; bSanford–Burnham–Prebys Medical Discovery Institute, La Jolla, CA 92037; and cDepartment of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106 Edited by Kevin P. Campbell, University of Iowa Carver College of Medicine, Iowa City, IA, and approved September 23, 2015 (received for review August 4, 2015) The composition and functions of the secreted proteome are con- activity levels that change in disease (9). We investigated whether trolled by the life spans of different proteins. However, unlike the normal activities of circulating glycosidases may hydrolyze intracellular protein fate, intrinsic factors determining secreted pro- N-glycan linkages attached to secreted proteins, thereby generat- tein aging and turnover have not been identified and characterized. ing multivalent ligands of endocytic lectin receptors in contribut- Almost all secreted proteins are posttranslationally modified with the ing to a mechanism of secreted protein aging and turnover. covalent attachment of N-glycans. We have discovered an intrinsic Results mechanism of secreted protein aging and turnover linked to the stepwise elimination of saccharides attached to the termini of N-Glycan Remodeling in the Aging of Secreted Proteins. Most se- N-glycans. Endogenous glycosidases, including neuraminidase 1 (Neu1), creted proteins are modified with N-glycans before entry into cir- neuraminidase 3 (Neu3), beta-galactosidase 1 (Glb1), and hexosamini- culatory systems. We isolated secreted proteins among platelet-poor dase B (HexB), possess hydrolytic activities that temporally remodel plasma following i.v.
    [Show full text]
  • An Unusual Splicing Mutation in the HEXB Gene Is Associated with Dramatically Different Phenotypes in Patients from Different Racial Backgrounds
    An unusual splicing mutation in the HEXB gene is associated with dramatically different phenotypes in patients from different racial backgrounds. B McInnes, … , S Tsuji, D J Mahuran J Clin Invest. 1992;90(2):306-314. https://doi.org/10.1172/JCI115863. Research Article Sandhoff disease is caused by mutations affecting the beta subunit of lysosomal beta-hexosaminidase (EC 3.2.1.52) and displays a wide spectrum of clinical phenotypes. We report a 57-year-old patient with a very mild phenotype, although residual hexosaminidase A activity in his cultured fibroblasts was less than 3% of normal activity, a level observed in juvenile onset patients. Northern and Western blot analyses confirmed a similar low level of beta subunit-mRNA and mature beta-protein, respectively. Two mutations of the HEXB gene were identified in this patient, a partial 5' gene deletion (a null allele), and a C----T transition 8 nucleotides downstream from the intron 10/exon 11 junction affecting the splicing of the beta subunit-mRNA. In their homozygous forms, the 5' deletion has been previously shown to result in a severe infantile phenotype, and the C----T transition in a juvenile phenotype. The genotype and the low level of residual hexosaminidase A activity would be expected to produce a juvenile Sandhoff phenotype in this patient, as well as in four of his six clinically normal siblings. The biochemical basis of his mild phenotype is uncertain, but may result from genetic variations in the RNA splicing machinery. Find the latest version: https://jci.me/115863/pdf An Unusual Splicing Mutation in the HEXB Gene Is Associated with Dramatically Different Phenotypes in Patients From Different Racial Backgrounds Beth McInnes, * Michel Potier,t1 Nobuaki Wakamatsu,11 Serge B.
    [Show full text]