DOCSLIB.ORG

Recessive Mutations in the INS Gene Result in Neonatal Diabetes Through Reduced Insulin Biosynthesis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Recessive Mutations in the INS Gene Result in Neonatal Diabetes Through Reduced Insulin Biosynthesis Recessive mutations in the INS gene result in neonatal diabetes through reduced insulin biosynthesis Intza Garina,b,c,1, Emma L. Edghilld,1, Ildem Akermanb,e,f,1, Oscar Rubio-Cabezasd,g,1, Itxaso Ricaa, Jonathan M. Locked, Miguel Angel Maestrob,e,f, Adnan Alshaikhh, Ruveyde Bundaki, Gabriel del Castilloj, Asma Deebk, Dorothee Deissl, Juan M. Fernandezm, Koumudi Godbolen, Khalid Hussaino, Michele O’Connellp, Thomasz Klupaq, Stanislava Kolouskovar, Fauzia Mohsins, Kusiel Perlmant, Zdenek Sumnikr, Jose M. Rialu, Estibaliz Ugartev, Thiruvengadam Vasanthiw, Neonatal Diabetes International Group2, Karen Johnstoned, Sarah E. Flanagand, Rosa Martíneza,b,c, Carlos Castañob,e,f, Ann-Marie Patchd, Eduardo Fernández-Rebolloa,b,c, Klemens Railel, Noel Morgand, Lorna W. Harriesd, Luis Castañoa,b,c, Sian Ellardd, Jorge Ferrerb,e,f, Guiomar Perez de Nanclaresa,b,c,3, and Andrew T. Hattersleyd,3 aEndocrinology and Diabetes Research Group, Hospital de Cruces, Barakaldo, 48903 Spain; bCentro de Investigación Biomédica en Red en Diabetes y Metabolismo; cCentro de Investigación Biomédica en Red en Enfermedades Raras, Instituto de Salud Carlos III, 48903 Spain; dInstitute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, United Kingdom; eHospital Clínic de Barcelona, Spain; fInstitut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain; gDepartment of Endocrinology, Hospital Infantil Universitario Niño Jesús, Madrid, Spain; hKing Abdulaziz Medical City, National Guard Health Affairs, Jeddah, Kingdom of Saudi Arabia; iDepartment of Pediatric Endocrinology, Istanbul University Hospital, Istanbul, Turkey; jDepartment of Neonatology, Hospital Infantil Los Angeles, San Juan de Pasto, Columbia; kImperial College London Diabetes Centre, Abu Dhabi, United Arab Emirates; lDepartment of Pediatric Diabetology and Endocrinology, Charité Campus, Virchow Children’s Hospital, Berlin, Germany; mDepartment of Pediatric Endocrinology, Hospital Universitario San Cecilio, Granada, 18012 Spain; nDeenanath Mangehskar Hospital and Research Center, Erandawane, Pune, India; oGreat Ormond Street Hospital for Children NHS Trust, London, United Kingdom; pRoyal Children’s Hospital, Melbourne, Australia; qDepartment of Metabolic Disease, Jagiellonian University Medical College, Krakow, Poland; rDepartment of Pediatrics, Second Faculty of Medicine, Charles University, Prague, Czech Republic; sPediatric Diabetic Team, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders, Dhaka, Bangladesh; tDivision of Endocrinology, Hospital for Sick Children, Toronto, Canada; uDepartment of Pediatric Endocrinology, Hospital Nuestra Señora de la Candelaria, Tenerife, 38010 Spain; vDepartment of Endocrinology, Hospital de Basurto, Bilbao, 48013 Spain; and wKanchi Kamakoti Childs Trust Hospital, Chennai, India MEDICAL SCIENCES Edited by Donald F. Steiner, University of Chicago, and approved December 22, 2009 (received for review September 15, 2009) Heterozygous coding mutations in the INS gene that encodes pre- chromosome 6q24 are the most common cause of TNDM (13), proinsulin were recently shown to be an important cause of perma- followed by mutations in the KCNJ11 and ABCC8 genes (14). nent neonatal diabetes. These dominantly acting mutations prevent Despite these advances, the etiology of neonatal diabetes is still normal folding of proinsulin, which leads to beta-cell death through not known in at least 30% of patients with PNDM, suggesting endoplasmic reticulum stress and apoptosis. We now report 10 dif- other genetic causes are still to be found (9). INS ferent recessive mutations in 15 probands with neonatal diabe- Insulin is secreted from islet beta cells of the pancreas. Insuffi- tes. Functional studies showed that recessive mutations resulted in cient secretion of insulin results in hyperglycemia and diabetes, diabetes because of decreased insulin biosynthesis through distinct whereas excessive secretion results in hypoglycemia. Insulin bio- mechanisms, including gene deletion, lack of the translation initia- synthesis and secretion are therefore tightly regulated to maintain tion signal, and altered mRNA stability because of the disruption of a polyadenylation signal. A subset of recessive mutations caused blood glucose levels within a narrow physiological range. Extensive cis INS abnormal INS transcription, including the deletion of the C1 and studies have dissected an array of sequence elements in the E1 cis regulatory elements, or three different single base-pair sub- promoter region and their cognate DNA binding factors, which stitutions in a CC dinucleotide sequence located between E1 and A1 together ensure the cellular specificity and rate of INS transcription elements. In keeping with an earlier and more severe beta-cell (15–22). In addition, insulin biosynthesis is strongly dependent on defect, patients with recessive INS mutations had a lower birth posttranscriptional regulatory mechanisms, including the modu- weight (−3.2 SD score vs. −2.0 SD score) and were diagnosed earlier lation of translation and stability (23–25). The latter is largely (median 1 week vs. 10 weeks) compared to those with dominant INS mediated through sequences located in the untranslated regions of mutations. Mutations in the insulin gene can therefore result in INS transcripts (26–28). neonatal diabetes as a result of two contrasting pathogenic mech- anisms. Moreover, the recessively inherited mutations provide a genetic demonstration of the essential role of multiple sequence Author contributions: O.R.-C., K.R., N.M., L.W.H., L.C., S.E., J.F., G.P.d.N., and A.T.H. de- elements that regulate the biosynthesis of insulin in man. signed research; I.G., E.L.E., I.A., O.R.-C., I.R., J.M.L., M.A.M., A.A., R.B., G.d.C., A.D., D.D., J.M.F., K.G., K.H., M.O., T.K., S.K., F.M., K.P., Z.S., J.M.R., E.U., T.V., N.D.I.G., K.J., S.E.F., R. gene regulation | genetic testing | gene expression regulation | RNA M., C.C., A.-M.P., E.F.-R., and K.R. performed research; I.G., I.A., O.R.-C., L.W.H., S.E., J.F., and G.P.d.N. analyzed data; and E.L.E., O.R.-C., J.F., G.P.d.N., and A.T.H. wrote the paper. instability | promoter regions The authors declare no conflict of interest. This article is a PNAS Direct Submission. eonatal diabetes is diagnosed within the first 6 months of life Freely available online through the PNAS open access option. N(1, 2) and there are two main clinical subtypes: the persistent, 1 I.G., E.L.E., I.A., and O.R.-C. contributed equally to this work. permanent neonatal diabetes (PNDM) and the remitting and 2Members of the Neonatal Diabetes International Group: Firdevs Bas, Faculty of Medicine, frequently relapsing, transient neonatal diabetes (TNDM). Istanbul University, Istanbul, Turkey; Ondrej Cinek, Motol University Hospital, Czech Re- Recently there have been considerable advances in the under- public; Maciek Malecki, Department of Metabolic Disease, Jagiellonian University Med- standing of the genetics of neonatal diabetes (3). Most patients ical College, Krakow, Poland; and Marianna Rachmiel, Division of Endocrinology, Hospital for Sick Children, Toronto, Canada. with PNDM have activating mutations in KCNJ11 or ABCC8, the 3To whom correspondence may be addressed. E-mail: [email protected] or genes encoding the potassium ATP-sensitive (KATP) channel [email protected]. – subunits Kir6.2 (4) and SUR1 (5 7), or heterozygous mutations in This article contains supporting information online at www.pnas.org/cgi/content/full/ the preproinsulin (INS) gene (8–12). In contrast, abnormalities in 0910533107/DCSupplemental. www.pnas.org/cgi/doi/10.1073/pnas.0910533107 PNAS Early Edition | 1of6 Downloaded by guest on September 24, 2021 Heterozygous missense mutations in the coding region of the important for the INS promoter activity in transient transfection INS gene have recently been described as a cause of neonatal studies (15, 18, 33–35). The c.-331(C > G, C > A) and c.-332C > G diabetes (8–12). Most of the reported mutations are predicted to mutations were located between the E1 and A1 elements (Fig. 3A). disrupt the folding of the proinsulin molecule. The resulting This sequence is conserved among a subset of mammalian species misfolded protein accumulates in the endoplasmic reticulum (Fig. 3A) and mutagenesis of multiple bases neighboring this (ER), resulting in ER stress and beta-cell apoptosis (29, 30). An dinucleotide impairs INS promoter activity (36). We constructed alternative potential genetic mechanism would be reduced insulin promoter fragments carrying the point mutations c.-331(C > insulin secretion because of a disruption of the INS coding G, C > A) and c.-332C > G. The point mutations induced up to 90% sequence, as seen in the double Ins1 and Ins2 knockout mouse reduction in transcriptional activity, while a control mutation, c.- (31), or of the sequences that regulate insulin biosynthesis. 339G > A, did not alter the transcriptional activity in pancreatic However, as yet this has not been demonstrated in humans. beta-cell lines (Fig. 3B). Thus, the CC dinucleotide that is mutated We now report recessively acting mutations within the INS gene in eight unrelated probands with neonatal diabetes forms part of an in a series of patients with neonatal diabetes. In contrast to the essential positive cis regulatory sequence of the INS promoter. previously described dominant mutations, these mutations reduce Mutated or absent translational start site. The two point mutations insulin
Load more

Recommended publications
  • An Atlas of Gene Regulatory Elements in Adult Mouse Cerebrum Yang Eric Li1*, Sebastian Preissl2*, Xiaomeng Hou2, Ziyang Zhang1
    bioRxiv preprint doi: https://doi.org/10.1101/2020.05.10.087585; this version posted May 11, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 An Atlas of Gene Regulatory Elements in Adult Mouse Cerebrum 2 3 Yang Eric Li1*, Sebastian Preissl2*, Xiaomeng Hou2, Ziyang Zhang1, Kai Zhang1, Rongxin 4 Fang1, Yunjiang Qiu1, Olivier Poirion2, Bin Li1, Hanqing Liu3, Xinxin Wang2, Jee Yun Han2, 5 Jacinta Lucero4, Yiming Yan1, Samantha Kuan1, David Gorkin2, Michael Nunn3, Eran A. 6 Mukamel5, M. Margarita Behrens4, Joseph Ecker3,6 and Bing Ren1,2,7 7 8 *these authors contributed equally 9 10 1Ludwig Institute for Cancer Research, 9500 Gilman Drive, La Jolla, CA 92093, USA 11 2Center for Epigenomics, Department of Cellular and Molecular Medicine, University of 12 California, San Diego, School of Medicine, La Jolla, CA, USA. 13 3Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, 14 92037, USA. 15 4Computational Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, 16 CA 92037, USA 17 5Department of Cognitive Science, University of California, San Diego, La Jolla, CA 18 92037, USA. 19 6Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA, 20 92037, USA. 21 7Institute of Genomic Medicine, Moores Cancer Center, University of California San 22 Diego, School of Medicine, La Jolla, CA, USA. 23 24 Correspondence: Bing Ren ([email protected]) 1 bioRxiv preprint doi: https://doi.org/10.1101/2020.05.10.087585; this version posted May 11, 2020.
    [Show full text]
  • Evolution of Genomic Expression
    C H A P T E R 5 Evolution of Genomic Expression Bernardo Lemos, Christian R. Landry, Pierre Fontanillas, Susan P. Renn, Rob Kulathinal, Kyle M. Brown, and Daniel L. Hartl Introduction Genomic regulation is key to cellular differentiation, tissue morphogenesis, and development. Increasing evidence indicates that evolutionary diversity of phenotypes—from cellular to organismic—may also be, in large part, the result of variation in the regulation of genomic expression. In this chapter we explore the complexity of gene regulation from the perspective of single genes and whole genomes. The first part describes the major factors affecting gene expression levels, from rates of gene transcrip- tion—as mediated by promoter–enhancer interactions and chromatin mod- ifications—to rates of mRNA degradation. This description underscores the multiple levels at which genomic expression can be regulated as well as the complexity and variety of mechanisms used. We then briefly describe the major experimental and computational biology techniques for analyzing gene expression variation and its underlying causes. The final section reviews our understanding of the role of regulatory variation in evolution, including the molecular evolution and population genetics of noncoding DNA, as well as the inheritance and phenotypic evolution of levels of mRNA abundance. The Complex Regulation of Genomic Expression The regulation of gene expression is a complex and dynamic process. It is not a simple matter to turn a gene on and off, let alone precisely regulate its level of expression. Regulation can be accomplished through various mech- anisms at nearly every step of the process of gene expression. Furthermore, each mechanism may require a variety of elements, including DNA sequences, RNA molecules, and proteins, acting in combination to deter- 2 Chapter Five Evolution of Genomic Expression 3 mine the final amount, timing, and location of functional gene product.
    [Show full text]
  • In Response to DNA Damage and C&Sol
    Oncogene (2009) 28, 3235–3245 & 2009 Macmillan Publishers Limited All rights reserved 0950-9232/09 $32.00 www.nature.com/onc ORIGINAL ARTICLE C/EBPa expression is partially regulated by C/EBPb in response to DNA damage and C/EBPa-deficient fibroblasts display an impaired G1 checkpoint R Ranjan1, EA Thompson1, K Yoon2 and RC Smart1 1Cell Signaling and Cancer Group, Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC, USA and 2National Cancer Center, Division of Common Cancers, Lung Cancer Branch, Goyang-si, Gyeonggi-do, South Korea We observed that CCAAT/enhancer-binding protein involved in homo- or hetero-dimerization (Ramji and (C/EBP)a is highly inducible in primary fibroblasts by Foka, 2002). The N-terminal region contains transcrip- DNA-damaging agents that induce strand breaks, alky- tion activation and regulatory domains that interact late and crosslink DNA as well as those that produce with basal transcription apparatus and transcription bulky DNA lesions. Fibroblasts deficient in C/EBPa co-activators. There are six members of the C/EBP family À/À (C/EBPa ) display an impaired G1 checkpoint as and C/EBPs have important functions in fundamental evidenced by an inappropriate entry into the S-phase in cellular processes, including proliferation, apoptosis, response to DNA damage, and these cells also display an differentiation, inflammation, senescence and energy enhanced G1/S transition in response to mitogens. The metabolism (Ramji and Foka, 2002; Johnson, 2005). induction of C/EBPa by DNA
    [Show full text]
  • Molecular Basis of the Function of Transcriptional Enhancers
    cells Review Molecular Basis of the Function of Transcriptional Enhancers 1,2, 1, 1,3, Airat N. Ibragimov y, Oleg V. Bylino y and Yulii V. Shidlovskii * 1 Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia; [email protected] (A.N.I.); [email protected] (O.V.B.) 2 Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia 3 I.M. Sechenov First Moscow State Medical University, 8, bldg. 2 Trubetskaya St., 119048 Moscow, Russia * Correspondence: [email protected]; Tel.: +7-4991354096 These authors contributed equally to this study. y Received: 30 May 2020; Accepted: 3 July 2020; Published: 5 July 2020 Abstract: Transcriptional enhancers are major genomic elements that control gene activity in eukaryotes. Recent studies provided deeper insight into the temporal and spatial organization of transcription in the nucleus, the role of non-coding RNAs in the process, and the epigenetic control of gene expression. Thus, multiple molecular details of enhancer functioning were revealed. Here, we describe the recent data and models of molecular organization of enhancer-driven transcription. Keywords: enhancer; promoter; chromatin; transcriptional bursting; transcription factories; enhancer RNA; epigenetic marks 1. Introduction Gene transcription is precisely organized in time and space. The process requires the participation of hundreds of molecules, which form an extensive interaction network. Substantial progress was achieved recently in our understanding of the molecular processes that take place in the cell nucleus (e.g., see [1–9]).
    [Show full text]
  • Transcription in Eukaryotes
    Transcription in eukaryotes Chromatin structure and its effects on transcription RNA polymerases Promoters General Transcription Factors Activators and Repressors Enhancers and ( Silencers ) Order of events leading to transcription initiation in eukaryotes at a specific promoter CRC … and chemical DNA modifications The order of steps on the pathway to transcription initiation appears to be different for different promoters Acção concertada de: -Activadores/ repressores ( proteínas auxiliares acessórias) -Proteínas de remodelação da cromatina -Capacidade de ligação dos factores gerais da transcrição Chromatin Remodeling Complexes (CRC) or Nucleosome remodeling factors ATPase/Helicase activity and DNA binding protein motifs Histone acetylation is one of the Histone histone chemical modifications acetylation characteristic of actively transcribed chromatin Interaction with other histones and with DNA Lys + HAT- histone acetyltransferase HDAC- histone deacetylase DNA chemical modifications affecting transcription initiation in eukaryotes How DNA methylation may help turning off genes? The binding of gene regulatory proteins and the general transcription machinery near an active promoter may prevent DNA methylation by excluding de novo methylases . If most of these proteins dissociate from the DNA, however, as generally occurs when a cell no longer produces the required activator proteins , the DNA becomes methylated , which enables other proteins to bind, and these shut down the gene completely by further altering chromatin structure . DNA
    [Show full text]
  • Minireview Mcbindall—A Better Name for CCAAT/Enhancer Binding
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Cell, Vol. 107, 259–261, November 2, 2001, Copyright 2001 by Cell Press McBindall—A Better Name for Minireview CCAAT/Enhancer Binding Proteins? Steven L. McKnight1 code a heterodimeric transcription factor, as well as Department of Biochemistry recognition that the Myc proto-oncogene encodes a UT Southwestern Medical Center transcription factor. Such studies also provided a frame- 5323 Harry Hines Boulevard work and powerful battery of reagents useful for the Dallas, Texas 75390 biological study of C/EBP itself. Finally, biochemical studies of C/EBP helped dispel the myth, anticipated from earlier work on bacterial gene expression, that C/EBP-related transcription factors regulate the bal- eukaryotic transcription factors must have exquisite ance between cell proliferation and mitotic growth ar- binding specificity. This shift of thinking led to the under- rest during terminal differentiation. Three new studies standing that eukaryotic genes employ complex en- give evidence that this regulation is mediated by pro- hancers that integrate the instruction of multiple tran- tein:protein interactions completely distinct from the scription factors acting in a combinatorial manner role of C/EBPs in gene expression. (Thompson and McKnight, 1992). The previous issue of Cell and the most recent issue In the mid-1980s Barbara Graves and Peter Johnson of Molecular Cell present three exciting papers relevant were postdoctoral fellows in my laboratory at the Carne- to the function of various members of the C/EBP family gie Embryology Department. Barbara and Peter were of transcription factors.
    [Show full text]
  • Cross-Species Regulatory Sequence Activity Prediction
    bioRxiv preprint doi: https://doi.org/10.1101/660563; this version posted September 25, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. Cross-species regulatory sequence activity prediction David R. Kelley Calico Life Sciences South San Francisco, CA [email protected] September 25, 2019 Abstract Machine learning algorithms trained to predict the regulatory activity of nucleic acid sequences have revealed principles of gene regulation and guided genetic variation analysis. While the human genome has been extensively annotated and studied, model organisms have been less explored. Model organism genomes offer both additional training sequences and unique annotations describing tissue and cell states unavailable in humans. Here, we develop a strategy to train deep convolutional neural networks simultaneously on multiple genomes and apply it to learn sequence predictors for large compendia of human and mouse data. Training on both genomes improves gene expression prediction accuracy on held out sequences. We further demonstrate a novel and powerful transfer learning approach to use mouse regulatory models to analyze human genetic variants associated with molecular phenotypes and disease. Together these techniques unleash thousands of non-human epigenetic and transcriptional profiles toward more effective investigation of how gene regulation affects human disease. Introduction Predicting the behavior of any nucleic acid sequence in any environment is a primary objective of gene regulation research. In recent years, machine learning approaches to directly tackle this problem have achieved significant accuracy gains predicting transcription factor (TF) binding, chromatin features, and gene expression from input DNA sequence (1{7).
    [Show full text]
  • Transcriptional Regulation of INSR, the Insulin Receptor Gene
    G C A T T A C G G C A T genes Review Transcriptional Regulation of INSR, the Insulin Receptor Gene Sandhya Payankaulam 1, Ana-Maria Raicu 2 and David N. Arnosti 1,2,* 1 Department of Biochemistry and Molecular Biology, Michigan State University, 603 Wilson Rd. 413 Biochemistry, East Lansing, MI 48824, USA; [email protected] 2 Cell and Molecular Biology Program, Michigan State University, 603 Wilson Rd. 413 Biochemistry, East Lansing, MI 48824, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-(517)-432-5504 Received: 28 October 2019; Accepted: 23 November 2019; Published: 29 November 2019 Abstract: The insulin receptor gene encodes an evolutionarily conserved signaling protein with a wide spectrum of functions in metazoan development. The insulin signaling pathway plays key roles in processes such as metabolic regulation, growth control, and neuronal function. Misregulation of the pathway features in diabetes, cancer, and neurodegenerative diseases, making it an important target for clinical interventions. While much attention has been focused on differential pathway activation through ligand availability, sensitization of overall signaling may also be mediated by differential expression of the insulin receptor itself. Although first characterized as a “housekeeping” gene with stable expression, comparative studies have shown that expression levels of the human INSR mRNA differ by tissue and in response to environmental signals. Our recent analysis of the transcriptional controls affecting expression of the Drosophila insulin receptor gene indicates that a remarkable amount of DNA is dedicated to encoding sophisticated feedback and feed forward signals. The human INSR gene is likely to contain a similar level of transcriptional complexity; here, we summarize over three decades of molecular biology and genetic research that points to a still incompletely understood regulatory control system.
    [Show full text]
  • Section 2: ß-Cell Genes: Functional Aspects
    Section 2: ␤-Cell Genes: Functional Aspects Regulation of pdx-1 Gene Expression Danielle Melloul, Sonya Marshak, and Erol Cerasi The homeodomain-containing transcription factor pan- tion of the endoderm, it is crucial for the development creatic duodenal homeobox 1 (PDX-1) plays a key role of endocrine and exocrine cell types (2,6). Differentiation in pancreas development and in ␤-cell function. Up- and maintenance of the ␤-cell phenotype also require stream sequences of the gene up to about ؊6 kb show PDX-1. In mice, ␤-cell–selective disruption of pdx-1 led to islet-specific activity in transgenic mice. Attempts to the development of diabetes with increasing age and was identify functional regulatory elements involved in the associated with reduced insulin and GLUT2 expression controlled expression of the pdx-1 gene led to the (7). Indeed, mice heterozygous for pdx-1 were found to be ␤ identification of distinct distal -cell–specific enhanc- glucose intolerant (7,8). In transgenic mice expressing ers in human and rat genes. Three additional sequences, ؅ an antisense ribozyme specific for mouse pdx-1 in the conserved between the mouse and the human 5 -flank- ␤ ing regions, two of which are also found in the chicken -cells, the expression of the endogenous gene was de- gene, conferred ␤-cell–specific expression on a reporter creased and followed by impaired glucose tolerance and gene, albeit to different extents. A number of transcrip- elevated glycated hemoglobin levels (9). Impaired expres- tion factors binding to and modulating the transcrip- sion of PDX-1 as a consequence of hyperglycemia or tional activity of the regulatory elements were increased lipid concentrations (10) is associated with identified, such as hepatocyte nuclear factor (HNF)-3␤, diabetes.
    [Show full text]
  • Identification of the Regulatory Sequence of Anaerobically Expressed Locus Aeg-46.5 MUHYEON Choet and WILLIAM S
    JOURNAL OF BACTERIOLOGY, Feb. 1993, p. 1165-1172 Vol. 175, No. 4 0021-9193/93/041165-08$02.00/0 Copyright X 1993, American Society for Microbiology Identification of the Regulatory Sequence of Anaerobically Expressed Locus aeg-46.5 MUHYEON CHOEt AND WILLIAM S. REZNIKOFF* Department ofBiochemistry, University of Wisconsin, 420 Henry Mall, Madison, Wisconsin 53706 Received 1 September 1992/Accepted 14 December 1992 A newly identified anaerobically expressed locus, aeg-46.5, which is located at min 46.5 on Escherichia coli linkage map, was cloned and analyzed. The phenotype of this gene was studied by using a lacZ operon fusion. aeg-46.5 is induced anaerobically in the presence of nitrate in wild-type and narL cells. It is repressed by the narL gene product, as it showed derepressed anaerobic expression in narL mutant cells. We postulate that aeg-46.5 is subject to multiple regulatory systems, activation as a result of anaerobiosis, narL-independent nitrate-dependent activation, and narL-mediated repression. The regulatory region of aeg-46.5 was identified. A 304-bp DNA sequence which includes the regulatory elements was obtained, and the 5' end of aeg-46.5 mRNA was identified. It was verified that the anaerobic regulation of aeg-46.5 expression is controlled on the transcriptional level. Computer analysis predicted possible control sites for the NarL and FNR proteins. The proposed NarL site was found in a perfect-symmetry element. The aeg-46.5 regulatory elements are adjacent to, but divergent from, those of the eco gene. Escherichia coli produces energy by breaking down a was discovered that aeg-46.5 is repressed by NarL.
    [Show full text]
  • Cis-Regulatory Code of Stress-Responsive Transcription in Arabidopsis Thaliana
    Cis-regulatory code of stress-responsive transcription in Arabidopsis thaliana Cheng Zoua, Kelian Suna, Joshua D. Mackalusoa,b,c, Alexander E. Seddona, Rong Jinb, Michael F. Thomashowd,e, and Shin-Han Shiua,1 Departments of aPlant Biology, bComputer Science and Engineering, cBiochemistry and Molecular Biology, and eCrop and Soil Sciences, and dDepartment of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 Edited by Philip Benfey, Duke University, Durham, NC, and approved July 19, 2011 (received for review March 3, 2011) Environmental stress leads to dramatic transcriptional reprogram- essential for stress-responsive transcription (e.g., refs. 3 and 4). ming, which is central to plant survival. Although substantial The importance of a few CRE combinations has also been dem- knowledge has accumulated on how a few plant cis-regulatory onstrated (17–19), indicating that stress-responsive genes are elements (CREs) function in stress regulation, many more CREs re- regulated by multiple transcription factors. In addition, the roles of main to be discovered. In addition, the plant stress cis-regulatory plant CRE copy number and location in transcriptional regulation code, i.e., how CREs work independently and/or in concert to spec- of plant stress have also been studied for a few CREs (5, 20–22). ify stress-responsive transcription, is mostly unknown. On the basis Although these pioneering studies have clearly demonstrated the of gene expression patterns under multiple stresses, we identified existence of stress cis-regulatory codes in plants, there are few a large number of putative CREs (pCREs) in Arabidopsis thaliana examples and a global description of CRE-based stress regulatory with characteristics of authentic cis-elements.
    [Show full text]
  • Epigenetics: Core Misconcept
    OPINION OPINION Epigenetics: Core misconcept Mark Ptashne1 cific genes, and encourage (activate) or dis- Ludwig Professor of Molecular Biology, Memorial Sloan–Kettering Cancer Center, New courage (repress) transcription into mRNA York, NY 10021 of those genes (2–4). The process is started by transcrip- tion factors, contributed mainly by the A recent issue of PNAS opened with an 50 years a compelling answer has emerged mother, found in the fertilized egg. In the unfortunate Core Concepts article titled from studies in a wide array of organisms. first cell division these transcription fac- “Epigenetics” (1). The author, a science Curiously, the article ignores this body of tors are distributed asymmetrically to the writer, began promisingly enough: knowledge, and substitutes for it misguided daughter cells. Then, and in subsequent musings presented as facts. cell generations, new patterns of gene ex- Despite the fact that every cell in a human body Let me begin with a very brief overview pression arise in two ways: as a matter of contains the same genetic material, not every cell of what drives development, a process that course (some transcription factors activat- looks or behaves the same….How does each cell retain its unique properties when, in its DNA- unfolds with essentially no changes in DNA ing expression of genes encoding other containing nucleus, it has the same master set of sequence. Development of an organism regulatory proteins, etc.), and in response genes as every other cell? from a fertilized egg is driven primarily by to signals sent by other cells. Signaling used the actions of regulatory proteins called in development affects expression of genes Indeed understanding this problem has transcription factors.
    [Show full text]