DOCSLIB.ORG

Eukaryotic Promoter Recognition James W

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Eukaryotic Promoter Recognition James W Downloaded from genome.cshlp.org on October 1, 2021 - Published by Cold Spring Harbor Laboratory Press REVIEW Eukaryotic Promoter Recognition James W. Fickett1,3 and Artemis G. Hatzigeorgiou2 1Bioinformatics, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406; 2Synaptic Ltd., 13671 Acharnai, Greece Computational analysis of polymerase II (Pol II) Another line of development in gene identifica- promoters may contribute to improved gene iden- tion is based on homology (e.g., Gish and States tification and to prediction of the expression con- 1993; Gelfand et al. 1996). If there is a close homo- text of genes. Before assessing the state of computa- log in the databases to one of the genes in the se- tional promoter recognition per se in the main body quence under analysis, sequence similarity will usu- of this review, we will provide a context by giving a ally group the exons for this gene correctly. Still, in brief overview of these two problems. many cases there is no close homolog and no guar- antee when there is some homolog that the en- coded protein lacks insertions/deletions. Partitioning a Genome into Genes Clearly, some means of recognizing the begin- Only recently has it become common to determine nings of genes, probably via the promoter, or the eukaryotic genomic sequences large enough to con- ends, probably by means of the polyadenylation sig- tain several genes. With these data comes a new nal or translation termination signal (e.g., Kondra- problem for gene finding programs: to partition a khin et al. 1994; Wahle and Keller 1996; Dalphin et set of exons correctly among several genes. al. 1997; Solovyev and Salamov 1997), would enable One line of development in eukaryotic gene a major advance. The promoter seems to be a much identification begins with coding region identifica- richer signal than the 38 processing signals, though, tion by statistical means and adds pattern recogni- as we shall see below, it is not easy to take advantage tion for sites of transcriptional, splicing, and trans- of the information in the promoter. lational control to produce algorithms capable of suggesting overall gene structure (for review, see Determining the Correct Protein Translation Gelfand 1995; Fickett 1996a). To date, most devel- opment effort has focused on integration of the Of course, the single most important goal in gene various kinds of pattern information in the rela- identification is to correctly deduce the protein tively simple case where a single complete gene is product(s) of the gene. After partitioning the ge- present in the input sequence. In this case, current nome into genes, the greatest difficulty in eukary- algorithms usually suggest a putative protein trans- otes is correctly determining the splicing structure. lation similar to that in the literature, though there Locating the correct initiation codon is also a diffi- is still significant room for improvement (Burset cult and important step in this case. If the transcrip- and Guigo 1996). The extension of these algorithms tion start site (TSS) is known, and there is no intron to deal with a sequence containing multiple or par- interrupting the 58-untranslated region, Kozak’s tial genes is just beginning (Burge and Karlin 1997; (1996) rules can probably locate the correct initia- http://gnomic.stanford.edu/∼chris/GENSCAN- tion codon in most cases. W.html). Because the signals that control the start In prokaryotes the problem is of a different and stop of transcription and translation, and the nature. Because splicing is normally absent, divid- location of splicing, are still not very well under- ing the genome into gene units is ordinarily stood, it is not uncommon for a gene-finding algo- straightforward. This does not make the correct de- rithm to confuse internal with initial and terminal duction of protein product trivial, however, for exons, thus wrongly partitioning the exons. The finding the correct initiation codon within an open problem is compounded by our incomplete under- reading frame (ORF) is difficult. In this case, pro- standing of alternative splicing control elements. moter location, though useful, does not provide the key information that it does for eukaryotes because 3Corresponding author. of the existence of multicistronic operons. Rather, E-MAIL [email protected]; FAX (610) 270-5580. for prokaryotes, the key need is reliable localization 7:861–878 ©1997 by Cold Spring Harbor Laboratory Press ISSN 1054-9803/97 $5.00 GENOME RESEARCH 861 Downloaded from genome.cshlp.org on October 1, 2021 - Published by Cold Spring Harbor Laboratory Press FICKETT AND HATZIGEORGIOU of the ribosome binding site (Shine and Dalgarno oped with one approach will almost certainly trans- 1974). fer in part to the other. Determination of Expression Context Eukaryotic Promoter Recognition Many experimental techniques are being developed In the rest of the paper we concentrate on the key for cataloging the expression context of genes problem of general eukaryotic promoter recogni- (e.g., Prashar and Weismann 1996 and references tion. First, we review a few salient points from re- therein). Development of computer algorithms to cent advances in biochemical understanding of predict expression context from genomic sequence transcription initiation, next, the core computa- has received much less attention but may represent tional resources and techniques are discussed, and an important opportunity. then currently available tools are described. To give Gene expression is regulated at many levels, in- some feeling for the current state of the art, the cluding chromatin packing (for review, see Kingston application of these tools to some recently deter- et al. 1996), transcription initiation (see below), mined promoter sequences is also described. Fi- polyadenylation (for review, see Wahle and Keller nally, we discuss prospects for the future. 1996), splicing (for review, see McKeown 1992), mRNA stability (e.g., Decker and Parker 1994), translation initiation (for review, see Kozak 1992), Eukaryotic Transcription Initiation and others. But it is generally thought that the single most important point of regulation is at tran- The biochemical mechanisms controlling transcrip- scription initiation. The initiation of transcription tion initiation in eukaryotes are currently under in- seems to be regulated in large part by coordinate tense investigation. Recent advances are reviewed binding of many proteins to the promoter and, for in, for example, Burley and Roeder (1996); Chao some genes, to one or more enhancers. Specific and Young (1996); Kaiser and Meisterernst (1996); combinations of binding sites, then, may provide Kornberg (1996); Novina and Roy (1996); Roeder the information necessary to suggest a particular ex- (1996); Stargell and Struhl (1996); Verrijzer and pression context, and it is here that computational Tjian (1996); Ptashne and Gann (1997); Smale work to date has focused. (1997). Here we will attempt to summarize the con- In most cases, researchers in this area have clusions most relevant to sequence analysis. taken the locations of transcriptional regulatory re- The so-called preinitiation complex (PIC) recog- gions (promoters and enhancers) as given and, in nizes the core promoter and initiates transcription. attempting to define those patterns in the DNA The PIC includes, besides Pol II, the general initia- (combinations of binding sites) that determine ex- tion factors (or general transcription factors, GTFs) pression context, have only attempted to give pat- TFIIA, TFIIB, TFIID, TFIIE, TFIIF, and TFIIH. Each of terns with sufficient information content to sort these may itself be a multiprotein complex. TFIID, regulatory regions into those that are active in a which consists of TATA-binding protein [TBP; the particular context and those that are not (e.g., Cla- so-called TATA box is ∼25 bp upstream of the tran- verie and Sauvaget 1985; Fondrat and Kalogeropou- scription start site (TSS) in metazoans] and several los 1994; Pedersen et al. 1996; Rosenblueth et al. TBP-associated factors (TAFs), is the only one of 1996). For this approach to be successful in the long these known to have site-specific DNA-binding abil- run, reliable algorithms must be developed for the ity (though several other GTFs are known to be in recognition of promoters and enhancers in general. close contact with the DNA; cf. Coulombe et al. Another approach to the problem is to attempt to 1994). TBP is one of the major determinants of this define patterns with very high information content, DNA-binding specificity, and the consensus se- capable of distinguishing regulatory regions active quence or position weight matrix (PWM) often used in a specific context from all the other DNA in the to recognize the TATA box (Bucher 1990) is prob- genome (e.g., Fickett 1996b; Tronche et al. 1997). ably characterizing the DNA-binding specificity of With this approach, one can imagine that general TBP (see Singer et al. 1990; Wiley et al. 1992). promoter recognition would eventually consist of Around the TSS there is a loosely conserved ini- separately recognizing a large number of specific tiator region (abbreviated Inr; for review, see Kauf- cases. It is too early to clearly define the benefits of mann et al. 1996; Smale 1997) that is one determi- either strategy, and in any case, techniques devel- nant of promoter strength and, in the absence of a 862 GENOME RESEARCH Downloaded from genome.cshlp.org on October 1, 2021 - Published by Cold Spring Harbor Laboratory Press EUKARYOTIC PROMOTER RECOGNITION TATA box, can determine the location of the TSS. To synergistically. There may be many such regions, some extent, the TATA box and the Inr are inter- and they may either enhance or repress expression changeable. For example, TFIID containing a mu- of the gene in particular circumstances (see Yuh and tated TBP defective in DNA binding cannot func- Davidson 1996 for an elegant example). Often these tion on TATA-only promoters, but supports tran- specific regulatory regions are active even if their scription from Inr-containing promoters (Martinez location of orientation is changed, in which case et al.
Load more

Recommended publications
  • Preinitiation Complex
    Science Highlight – June 2011 Transcription Starts Here: Structural Models of a “Minimal” Preinitiation Complex RNA polymerase II (pol II) plays a central role in the regulation of gene expression. Pol II is the enzyme responsible for synthesizing all the messenger RNA (mRNA) and most of the small nuclear RNA (snRNA) in eukaryotes. One of the key questions for transcription is how pol II decides where to start on the genomic DNA to specifically and precisely turn on a gene. This is achieved during transcription initiation by concerted actions of the core enzyme pol II and a myriad of transcription factors including five general transcription factors, known as TFIIB, -D, -E, -F, -H, which together form a giant transcription preinitiation complex on a promoter prior to transcription. One of the most prominent core promoter DNA elements is the TATA box, usually directing transcription of tissue-specific genes. TATA-box binding protein (TBP), a key component of TFIID, recognizes the TATA DNA sequence. Based on the previous crystallographic studies, the TATA box DNA is bent by nearly 90 degree through the binding of TBP (1). This striking structural feature is thought to serve as a physical landmark for the location of active genes on the genome. In addition, the location of the TATA box at least in part determines the transcription start site (TSS) in most eukaryotes, including humans. The distance between the TATA box and the TSS is conserved at around 30 base pairs. TBP does not contact pol II directly and the TATA-containing promoter must be directed to the core enzyme through another essential transcription factor TFIIB.
    [Show full text]
  • Identification of Promoter Regions in the Human Genome by Using a Retroviral Plasmid Library-Based Functional Reporter Gene Assa
    Downloaded from genome.cshlp.org on September 29, 2021 - Published by Cold Spring Harbor Laboratory Press Methods Identification of Promoter Regions in the Human Genome by Using a Retroviral Plasmid Library-Based Functional Reporter Gene Assay Shirin Khambata-Ford,1,5 Yueyi Liu,2 Christopher Gleason,1 Mark Dickson,3 Russ B. Altman,2 Serafim Batzoglou,4 and Richard M. Myers1,3,6 1Department of Genetics, 2Stanford Medical Informatics, 3Stanford Human Genome Center, Stanford University School of Medicine, Stanford, California 94305, USA; 4Department of Computer Science, Stanford University, Stanford, California 94305, USA Attempts to identify regulatory sequences in the human genome have involved experimental and computational methods such as cross-species sequence comparisons and the detection of transcription factor binding-site motifs in coexpressed genes. Although these strategies provide information on which genomic regions are likely to be involved in gene regulation, they do not give information on their functions. We have developed a functional selection for promoter regions in the human genome that uses a retroviral plasmid library-based system. This approach enriches for and detects promoter function of isolated DNA fragments in an in vitro cell culture assay. By using this method, we have discovered likely promoters of known and predicted genes, as well as many other putative promoter regions based on the presence of features such as CpG islands. Comparison of sequences of 858 plasmid clones selected by this assay with the human genome draft sequence indicates that a significantly higher percentage of sequences align to the 500-bp segment upstream of the transcription start sites of known genes than would be expected from random genomic sequences.
    [Show full text]
  • Molecular Biology and Applied Genetics
    MOLECULAR BIOLOGY AND APPLIED GENETICS FOR Medical Laboratory Technology Students Upgraded Lecture Note Series Mohammed Awole Adem Jimma University MOLECULAR BIOLOGY AND APPLIED GENETICS For Medical Laboratory Technician Students Lecture Note Series Mohammed Awole Adem Upgraded - 2006 In collaboration with The Carter Center (EPHTI) and The Federal Democratic Republic of Ethiopia Ministry of Education and Ministry of Health Jimma University PREFACE The problem faced today in the learning and teaching of Applied Genetics and Molecular Biology for laboratory technologists in universities, colleges andhealth institutions primarily from the unavailability of textbooks that focus on the needs of Ethiopian students. This lecture note has been prepared with the primary aim of alleviating the problems encountered in the teaching of Medical Applied Genetics and Molecular Biology course and in minimizing discrepancies prevailing among the different teaching and training health institutions. It can also be used in teaching any introductory course on medical Applied Genetics and Molecular Biology and as a reference material. This lecture note is specifically designed for medical laboratory technologists, and includes only those areas of molecular cell biology and Applied Genetics relevant to degree-level understanding of modern laboratory technology. Since genetics is prerequisite course to molecular biology, the lecture note starts with Genetics i followed by Molecular Biology. It provides students with molecular background to enable them to understand and critically analyze recent advances in laboratory sciences. Finally, it contains a glossary, which summarizes important terminologies used in the text. Each chapter begins by specific learning objectives and at the end of each chapter review questions are also included.
    [Show full text]
  • 1589622468 115 19.Pdf
    Journal of Global Antimicrobial Resistance 18 (2019) 168–176 Contents lists available at ScienceDirect Journal of Global Antimicrobial Resistance journal homepage: www.elsevier.com/locate/jgar Characterisation of drug resistance-associated mutations among clinical multidrug-resistant Mycobacterium tuberculosis isolates from Hebei Province, China a b b b b a,1, Qianlin Li , Yuling Wang , Yanan Li , Huixia Gao , Zhi Zhang , Fumin Feng *, b,1, Erhei Dai * a Department of Epidemiology and Statistics, North China University of Science and Technology, Tangshan 063210, Hebei, China b Department of Laboratory Medicine, The Fifth Affiliated Hospital of Shijiazhuang, North China University of Science and Technology, Shijiazhuang 050021, Hebei, China A R T I C L E I N F O A B S T R A C T Article history: Objectives: Multidrug-resistant tuberculosis (MDR-TB) is a major public-health problem in China. Received 15 November 2018 However, there is little information on the molecular characterisation of clinical MDR-TB isolates in Hebei Received in revised form 9 March 2019 Province. Accepted 14 March 2019 Methods: In this study, 123 MDR-TB isolates were identified in sputum cultures using traditional drug Available online 27 March 2019 susceptibility testing. The isolates were analysed for mutations in seven genes associated with resistance to antituberculous four drugs: katG and inhA promoter for isoniazid (INH); rpoB for rifampicin (RIF); gyrA Keywords: and gyrB for ofloxacin (OFLX); and rrs and eis promoter for kanamycin (KAN). All strains were genotyped Multidrug-resistant tuberculosis by spoligotyping and 15-loci MIRU-VNTR analysis. MDR-TB Results: A total of 39 distinct mutations were found at the seven loci in 114/123 (92.7%) MDR-TB isolates.
    [Show full text]
  • Long-Range Repression in the Drosophila Embryo HAINI N
    Proc. Natl. Acad. Sci. USA Vol. 93, pp. 9309-9314, September 1996 Colloquium Paper This paper was presented at a colloquium entitled "Biology of Developmental Transcription Control, " organized by Eric H. Davidson, Roy J. Britten, and Gary Felsenfeld, held October 26-28, 1995, at the National Academy of Sciences in Irvine, CA. Long-range repression in the Drosophila embryo HAINI N. CAI, DAVID N. ARNOSTI, AND MICHAEL LEVINE* Department of Biology, Center for Molecular Genetics, Pacific Hall, University of California at San Diego, La Jolla, CA 92093-0347 ABSTRACT Transcriptional repressors can be character- Short-range transcriptional repression appears to account ized by their range of action on promoters and enhancers. for enhancer autonomy in a modular promoter. Repressors Short-range repressors interact over distances of50-150 bp to bound to a given enhancer do not interfere with the activators inhibit, or quench, either upstream activators or the basal contained within neighboring enhancers. For example, the transcription complex. In contrast, long-range repressors act posterior border of eve stripe 3 is established by the gap over several kilobases to silence basal promoters. We describe repressor knirps (kni; ref. 7), which is a member of the nuclear recent progress in characterizing the functional properties of receptor superfamily, and is expressed in the presumptive one such long-range element in the Drosophila embryo and abdomen in early embryos (8). There are at least five kni- discuss the contrasting types of gene regulation that are made binding sites in the stripe 3 enhancer, two of which map within possible by short- and long-range repressors.
    [Show full text]
  • Polymerase II Into the Preinitiation Complex OSVALDO FLORES*, HUA Lu*, MARIE Killeentt, JACK Greenblattt, ZACHARY F
    Proc. NatI. Acad. Sci. USA Vol. 88, pp. 9999-10003, November 1991 Biochemistry The small subunit of transcription factor IIF recruits RNA polymerase II into the preinitiation complex OSVALDO FLORES*, HUA Lu*, MARIE KILLEENtt, JACK GREENBLATTt, ZACHARY F. BURTON§, AND DANNY REINBERG*¶ *Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854; tBanting and Best Department of Medical Research, and tDepartment of Molecular and Medical Genetics, University of Toronto, Toronto, ON M5S lA1, Canada; and §Department of Biochemistry, Michigan State University, East Lansing, MI 48823 Communicated by Nicholas R. Cozzarelli, August 16, 1991 ABSTRACT We found that transcription factor IIF me- experiments also suggested that RNA polymerase II bound diates the association of RNA polymerase H with promoter directly to the DA complex followed by association offactors sequences containing transcription factors HD, BB, and HA IIB and IIE (14, 26). However, direct association of RNA (DAB complex). The resulting DNA-protein complex con- polymerase II with a IID/IIA DNA-protein complex (DA tained RNA polymerase H and the two subunits oftranscription complex) has not been confirmed (27, 28). Gel shift assays factor HF (RAP 30 and RAP 74). Cloned human RAP 30 was have been successfully used to resolve complexes formed by sufficient for the recruitment ofRNA polymerase H to the DAB the general factors and RNA polymerase II at specific complex. This ability of RAP 30 to recruit RNA polymerase to promoter regions (28, 29). Using this method, Buratowski et a promoter is also a characteristic of a factors in prokaryotes.
    [Show full text]
  • E-Box- and MEF-2-Independent Muscle-Specific Expression
    MOLECULAR AND CELLULAR BIOLOGY, Aug. 1994, p. 5474-5486 Vol. 14, No. 8 0270-7306/94/$04.00+0 Copyright © 1994, American Society for Microbiology E-Box- and MEF-2-Independent Muscle-Specific Expression, Positive Autoregulation, and Cross-Activation of the Chicken MyoD (CMD1) Promoter Reveal an Indirect Regulatory Pathway CLAUDE A. DECHESNE,t QIN WEI, JUANITA ELDRIDGE, LEILA GANNOUN-ZAKI,t PHILIPPE MILLASSEAU,t LYDIE BOUGUELERET,§ DOMINIQUE CATERINA,§ AND BRUCE M. PATERSON* Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892 Received 15 February 1994/Returned for modification 17 March 1994/Accepted 23 May 1994 Members of the MyoD family of gene-regulatory proteins (MyoD, myogenin, myf5, and MRF4) have all been shown not only to regulate the transcription of numerous muscle-specific genes but also to positively autoregulate and cross activate each other's transcription. In the case of muscle-specific genes, this transcriptional regulation can often be correlated with the presence of a DNA consensus in the regulatory region CANNTG, known as an E box. Little is known about the regulatory interactions of the myogenic factors themselves; however, these interactions are thought to be important for the activation and maintenance of the muscle phenotype. We have identified the minimal region in the chicken MyoD (CMDI) promoter necessary for muscle-specific transcription in primary cultures of embryonic chicken skeletal muscle. The CMD1 promoter is silent in primary chick fibroblast cultures and in muscle cell cultures treated with the thymidine analog bromodeoxyuridine. However, CMD1 and chicken myogenin, as well as, to a lesser degree, chicken MyfS and MRF4, expressed in trans can activate transcription from the minimal CMD1 promoter in these primary fibroblast cultures.
    [Show full text]
  • Saccharomyces Cerevisiae Promoter Engineering Before and During the Synthetic Biology Era
    biology Review Saccharomyces cerevisiae Promoter Engineering before and during the Synthetic Biology Era Xiaofan Feng and Mario Andrea Marchisio * School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Tianjin 300072, China; [email protected] * Correspondence: [email protected] or [email protected] Simple Summary: Promoters are DNA sequences where the process of transcription starts. They can work constitutively or be controlled by environmental signals of different types. The quantity of proteins and RNA present in yeast genetic circuits highly depends on promoter strength. Hence, they have been deeply studied and modified over, at least, the last forty years, especially since the year 2000 when Synthetic Biology was born. Here, we present how promoter engineering changed over these four decades and discuss its possible future directions due to novel computational methods and technology. Abstract: Synthetic gene circuits are made of DNA sequences, referred to as transcription units, that communicate by exchanging proteins or RNA molecules. Proteins are, mostly, transcription factors that bind promoter sequences to modulate the expression of other molecules. Promoters are, therefore, key components in genetic circuits. In this review, we focus our attention on the construction of artificial promoters for the yeast S. cerevisiae, a popular chassis for gene circuits. We describe the initial techniques and achievements in promoter engineering that predated the start of the Synthetic Biology epoch of about 20 years. We present the main applications of synthetic Citation: Feng, X.; Marchisio, M.A. promoters built via different methods and discuss the latest innovations in the wet-lab engineering Saccharomyces cerevisiae Promoter of novel promoter sequences.
    [Show full text]
  • Promoter-Mediated Diversification of Transcriptional Bursting Dynamics Following Gene Duplication
    Promoter-mediated diversification of transcriptional bursting dynamics following gene duplication Edward Tunnacliffea,b, Adam M. Corrigana,b,1, and Jonathan R. Chubba,b,2 aMedical Research Council Laboratory for Molecular Cell Biology, University College London, WC1E 6BT London, United Kingdom; and bDepartment of Cell and Developmental Biology, University College London, WC1E 6BT London, United Kingdom Edited by Joseph S. Takahashi, Howard Hughes Medical Institute and University of Texas Southwestern Medical Center, Dallas, TX, and approved July 6, 2018 (received for review January 21, 2018) During the evolution of gene families, functional diversification of is a broadly applicable evolutionary strategy, shared by species that proteins often follows gene duplication. However, many gene diverged more than 400 Mya (SI Appendix,TableS1)(7). families expand while preserving protein sequence. Why do cells Dictyostelium cells are highly motile, so may require lots of maintain multiple copies of the same gene? Here we have actin, perhaps beyond the production capacity of a single gene. addressed this question for an actin family with 17 genes encoding However, estimates of their actin content are of the same order an identical protein. The genes have divergent flanking regions as skeletal muscle, which derives its actin from only one gene and are scattered throughout the genome. Surprisingly, almost (8, 9). Divergent flanking sequences (10, 11) and different ge- nomic contexts of the act8 genes suggest different regulatory the entire family
    [Show full text]
  • TBP, a Universal Eukaryotic Transcription Factor?
    Downloaded from genesdev.cshlp.org on October 9, 2021 - Published by Cold Spring Harbor Laboratory Press REVIEW TBP, a universal eukaryotic transcription factor? Nouria Hernandez Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11742 In eukaryotes, transcription is carried out by three dif- cDNAs from several other species, including Drosophila ferent RNA polymerases, RNA polymerases I, II, and III, (Hoey et al. 1990; Muhich et al. 1990) and humans (Ho- each of which is dedicated to the transcription of differ- ffman et al. 1990b; Kao et al. 1990; Peterson et al. 1990). ent sets of genes. The genes in each class contain char- Like the yeast protein, the Drosophila and human TBPs acteristic promoters, which often consist of two types of are small proteins of 38 kD, a surprising result because elements: the basal promoter elements and the modula- the molecular mass of the mammalian TATA box-bind- tor promoter elements. The basal promoter elements are ing factor TFIID was known to be -750 kD (Nakajima et sufficient to determine RNA polymerase specificity and al. 1988; Conaway et al. 1990, 1991). In addition, like direct low levels of transcription, whereas the modulator TFIID, these TBPs could mediate basal RNA polymerase elements enhance or reduce the basal levels of transcrip- II transcription, but unlike TFIID, they could not re- tion. None of the RNA polymerases can recognize its spond to transcriptional activators (Hoey et al. 1990; Ho- target promoters directly. Instead, basal promoter ele- ffman et al. 1990b; Peterson et al. 1990; Pugh and Tjian ments are first recognized by specific transcription fac- 1990; Smale et al.
    [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 The order of steps on the pathway to transcription initiation appears to be different for different promoters AlteraçãoAlteração estruturaestrutura cromatinacromatina Actividade génica ACETILAÇÃO DE HISTONAS COMPLEXOS DE REMODELAÇÃO DA CROMATINA (CRC) LysLys+ menor ligação do DNA às histonas nos nucleossomas Acção concertada de: -Activadores/ repressores ( proteínas auxiliares acessórias) -Proteínas de remodelação da cromatina -Capacidade de ligação dos factores gerais da transcrição Histone Histone acetylation is characteristic acetylation of actively transcribed chromatin Interaction with other histones and with DNA HAT- histone acetyltransferase HDAC- histone deacetylase Chromatin Remodeling Complexes (CRC) or Nucleosome remodeling factors ATPase/Helicase activity and DNA binding protein motifs Local alterations in chromatin structure directed by eucaryotic gene activator proteins Histone acetylation and nucleossome remodeling generally render the DNA package in chromatin more acessible to other proteins in the cell, including those required for transcription initiation. Specific patterns of histone modification directly aid in the assembly of the general transcription factors at the promoter. Enzymes that increase, even transiently, the acessibility of DNA
    [Show full text]
  • Transcriptional Regulation of the Human Osteopontin Promoter: Functional Analysis and DNA-Protein Interactions
    Oncogene (2000) 19, 5801 ± 5809 ã 2000 Macmillan Publishers Ltd All rights reserved 0950 ± 9232/00 $15.00 www.nature.com/onc Transcriptional regulation of the human osteopontin promoter: functional analysis and DNA-protein interactions Dongyan Wang1, Shunsuke Yamamoto3, Naoki Hijiya3, Etty N Benveniste2 and Candece L Gladson*,1 1Department of Pathology, Division of Neuropathology, The University of Alabama at Birmingham, LHRB 567, 701 19th Street South, Birmingham, Alabama, AL 35294, USA; 2Department of Cell Biology, The University of Alabama at Birmingham, Birmingham, Alabama, AL 35294, USA; 3Department of Pathology, Oita Medical University, Hasama-machi, Oita 879-55, Japan Synthesis of cell attachment proteins and cytokines, such requires integrin-mediated attachment and migration as osteopontin (OPN), can promote tumor cell remodel- of the tumor cells to the extracellular matrix. Although ing of the extracellular matrix into an environment that migration can occur on the existing matrix of the promotes tumor cell attachment and migration. We normal brain (reviewed in Gladson, 1999), the tumor investigated the transcriptional regulation of OPN in the cells can actively remodel their extracellular matrix U-251MG and U-87MG human malignant astrocytoma through the synthesis of matrix proteins and cell cell lines. Deletion and mutagenesis analyses of the OPN attachment proteins that promote cell attachment and promoter region identi®ed a proximal promoter element migration. Malignant astrocytoma cells in vivo exhibit (724 to 794 relative to the transcription initiation site) upregulation of at least two such proteins, vitronectin that is essential for maintaining high levels of OPN (Gladson and Cheresh, 1991; Gladson et al., 1995) and expression in the tumor cells.
    [Show full text]