DOCSLIB.ORG

Gre Biochemistry Test Practice Book

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gre Biochemistry Test Practice Book GRE ® Biochemistry, Cell and Molecular Biology Test Practice Book This practice book contains ◾ one actual, full-length GRE® Biochemistry, Cell and Molecular Biology Test ◾ test-taking strategies Become familiar with ◾ test structure and content ◾ test instructions and answering procedures Compare your practice test results with the performance of those who took the test at a GRE administration. www.ets.org/gre Table of Contents Overview ..................................................................................................................................................3 Test Content ............................................................................................................................................3 Preparing for the Test ...............................................................................................................................5 Test-Taking Strategies ..............................................................................................................................5 What Your Scores Mean ..........................................................................................................................6 Taking the Practice Test ..........................................................................................................................6 Scoring the Practice Test .........................................................................................................................6 Evaluating Your Performance ..................................................................................................................7 Practice Test .............................................................................................................................................9 Worksheet for Scoring the Practice Test ...............................................................................................58 Score Conversion Table .........................................................................................................................59 Answer Sheet .........................................................................................................................................60 Test takers with disabilities or health-related needs who need test preparation materials in an alternate format should contact the ETS Office of Disability Services [email protected] . For additional information, visit www.ets.org/gre/disabilities. Copyright © 2016 by Educational Testing Service. All rights reserved. ETS, the ETS logo, GRADUATE RECORD EXAMINATIONS, and GRE are registered trademarks of Educational Testing Service (ETS) in the United States and other countries. MEASURING THE POWER OF LEARNING is a trademark of ETS. 007884-72507 GRE Biochemistry Test Practice Book • Dr01 4/17/08 ta • Dr02 5/7/08 ta • Dr03 5/20/08 ta • [NEW 108353] • CS6 • Dr01 5/1/15 jw • Dr02 6/1/15 jw • Dr03 6/11/15 jw • Dr03 int1 6/15/15 jw • Dr04 6/22/15 jw • [New Job] 007884-113203 Drft01 3/22/16 ew • PDF-ACC Drft01 3/28/16 ew Overview The three subscore areas are interrelated. Because of these interrelationships, individual questions or sets of The GRE® Biochemistry, Cell and Molecular Biology questions may test more than one content area. Test consists of approximately 170 multiple-choice Therefore, the relative emphases of the three areas in questions, a number of which are grouped in sets the following content outline should not be considered toward the end of the test and based on descriptions of definitive. Likewise, the topics listed are not intended to laboratory situations, diagrams or experimental results. be all-inclusive but, rather, representative of the typical Testing time is 2 hours and 50 minutes; there are no undergraduate experience. separately-timed sections. This publication provides a comprehensive overview of the GRE Biochemistry, Cell and Molecular Biology I. Biochemistry (36%) Test to help you get ready for test day. It is designed to A. Chemical and Physical Foundations help you: Thermodynamics and kinetics • Understand what is being tested Redox states • Gain familiarity with the question types Water, pH, acid-base reactions and buffers • Review test-taking strategies Solutions and equilibria • Understand scoring Solute-solvent interactions • Practice taking the test Chemical interactions and bonding To learn more about the GRE Subject Tests, visit Chemical reaction mechanisms www.ets.org/gre. B. Structural Biology: Structure, Assembly, Organization, and Dynamics Small molecules Test Content Macromolecules (e.g., nucleic acids, The content of the test is organized into three major polysaccharides, polypeptides, complex areas: biochemistry, cell biology, and molecular biology lipids) and genetics. In addition to the total score, a subscore Supramolecular complexes (e.g., membranes, in each of these subfield areas is reported. Because these ribosomes, multienzyme complexes) three disciplines are basic to the study of all organisms, Macromolecular structure and function test questions encompass both eukaryotes and C. Catalysis and Binding prokaryotes. Throughout the test, there is an emphasis Enzyme reaction mechanisms and kinetics on questions requiring problem-solving skills (including Ligand-protein interaction (e.g., receptors, mathematical calculations that do not require the use of substrates and effectors, transport proteins, a calculator) as well as content knowledge. While only antigen-antibody interactions) two content areas in the following outline specifically Interplay between structure and function mention methodology, questions on methodology and data interpretation are included in all sections. D. Major Metabolic Pathways Because of the diversity of undergraduate curricula, Carbon, nitrogen, and sulfur assimilation few test takers will have encountered all of the topics in Anabolism the content outline. Consequently, no test taker should Catabolism expect to be able to answer all questions on the edition Synthesis and degradation of macromolecules of the test he or she takes. E. Bioenergetics Energy transformations at the substrate level Electron transport Proton and chemical gradients Energy coupling (e.g., phosphorylation, transport) GRE Biochemistry, Cell and Molecular Biology Test Practice Book 3 | Page F. Regulation and Integration of Metabolism D. Protein, Processing, Targeting, and Turnover Covalent modification of enzymes Translocation across membranes Allosteric regulation Posttranslational modification Compartmentation Intracellular trafficking Hormones Secretion and endocytosis G. Methods Protein turnover (e.g., proteosomes, Biophysical approaches (e.g., spectroscopy, lysosomes, damaged protein response) x-ray crystallography, mass spectroscopy) E. Cell Division, Differentiation and Development Isotopes Cell cycle, mitosis, and cytokinesis Separation techniques (e.g., centrifugation, Meiosis and gametogenesis chromatography, electrophoresis) Fertilization and early embryonic Immunotechniques development (including positional Macromolecular structure information, homeotic genes, tissue- specific expression, nuclear and cytoplasmic II. Cell Biology (28%) interactions, growth factors and induction, environment, stem cells and polarity) Methods of importance to cellular biology, such Stem cells (embryonic and adult, roles in as fluorescence probes (e.g., FRAP, FRET, GFP), development) imaging, cell sorting, and proteomics will be covered as appropriate within the context of the III. Molecular Biology and Genetics (36%) content below. A. Genetic Foundations A. Cellular Compartments of Prokaryotes and Mendelian and non-Mendelian inheritance Eukaryotes: Organization, Dynamics and Transformation, transduction, and Functions conjugation Cellular membrane systems (e.g., structure, Recombination and complementation function, transport across membranes, water Mutational analysis regulation) Genetic mapping and linkage analysis Nucleus (e.g., envelope, matrix, nuclear transport) B. Chromatin and Chromosomes Mitochondria and chloroplasts (e.g. general Karyotypes and genetic diagnostics function, biogenesis and evolution) Translocations, inversions, deletions, and duplications B. Cell Surface and Communication (in context of Aneuploidy and polyploidy development and adult organisms) Structure Extracellular matrix (including cell walls) Epigenetics Cell adhesion and junctions Signal transduction C. Genomics Receptor function Genome structure Excitable membrane systems Physical mapping Repeated DNA and gene families C. Cytoskeleton, Motility, and Shape Gene identification Regulation of assembly and disassembly of Transposable elements filament systems Bioinformatics Motor function, regulation, and diversity Molecular evolution Muscle function Cell motility 4 | Page GRE Biochemistry, Cell and Molecular Biology Test Practice Book D. Genome Maintenance Preparing for the Test DNA replication DNA damage and repair GRE Subject Test questions are designed to measure DNA modification skills and knowledge gained over a long period of time. DNA recombination and gene conversion Although you might increase your scores to some extent through preparation a few weeks or months before you E. Gene Expression take the test, last minute cramming is unlikely to be of The genetic code further help. The following information may be helpful. Transcription/transcriptional profiling RNA processing • A general review of your college courses is Translation probably the best preparation for the test. However, the test covers a broad range
Load more

Recommended publications
  • METACYC ID Description A0AR23 GO:0004842 (Ubiquitin-Protein Ligase
    Electronic Supplementary Material (ESI) for Integrative Biology This journal is © The Royal Society of Chemistry 2012 Heat Stress Responsive Zostera marina Genes, Southern Population (α=0.
    [Show full text]
  • Copyright by Young-Sam Lee 2010
    Copyright by Young-Sam Lee 2010 The Dissertation Committee for Young-Sam Lee Certifies that this is the approved version of the following dissertation: Structural and Functional Studies of the Human Mitochondrial DNA Polymerase Committee: Whitney Yin, Supervisor Ian Molineux Kenneth Johnson Tanya Paull Jon Robertus Structural and Functional Studies of the Human Mitochondrial DNA Polymerase by Young-Sam Lee, B.S, M.S. Dissertation Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy The University of Texas at Austin August, 2010 Dedication For my wife, In-Sook Jung. Acknowledgements I would like to appreciate Dr. Whitney Yin for giving me chance to working in her lab and mentoring me through my graduate program. Not only the scientific insights, also the warmness that she gave me and my family encouraged me to pursue my Ph. D. degree in the foreign country. I also would like to thank “a guru of molecular biology” Dr. Ian Molineux and “a guru of enzyme kinetics” Dr. Kenneth Johnson. Without their critical advice, I would not be accomplished my publication. I hope to be a respectable expert in my research field like them. I also should remember friendship and generosity given by many current and former Yin lab members: Hey-Ryung Chang, Qingchao “Eric” Meng, Xu Yang, Jeff Knight, Dr. Michio Matsunaga, Dr. He “River” Quan, Taewung Lee, Xin “Ella” Wang, Jamila Momand, and Max Shay. Most of all, I really appreciate my parents for their endless love and support, and my wife, In-Sook Jung, and my son, Jason Seung-Hyeon Lee who always stand by me with patients during my graduate carrier.
    [Show full text]
  • Introduction of Human Telomerase Reverse Transcriptase to Normal Human Fibroblasts Enhances DNA Repair Capacity
    Vol. 10, 2551–2560, April 1, 2004 Clinical Cancer Research 2551 Introduction of Human Telomerase Reverse Transcriptase to Normal Human Fibroblasts Enhances DNA Repair Capacity Ki-Hyuk Shin,1 Mo K. Kang,1 Erica Dicterow,1 INTRODUCTION Ayako Kameta,1 Marcel A. Baluda,1 and Telomerase, which consists of the catalytic protein subunit, No-Hee Park1,2 human telomerase reverse transcriptase (hTERT), the RNA component of telomerase (hTR), and several associated pro- 1School of Dentistry and 2Jonsson Comprehensive Cancer Center, University of California, Los Angeles, California teins, has been primarily associated with maintaining the integ- rity of cellular DNA telomeres in normal cells (1, 2). Telomer- ase activity is correlated with the expression of hTERT, but not ABSTRACT with that of hTR (3, 4). Purpose: From numerous reports on proteins involved The involvement of DNA repair proteins in telomere main- in DNA repair and telomere maintenance that physically tenance has been well documented (5–8). In eukaryotic cells, associate with human telomerase reverse transcriptase nonhomologous end-joining requires a DNA ligase and the (hTERT), we inferred that hTERT/telomerase might play a DNA-activated protein kinase, which is recruited to the DNA role in DNA repair. We investigated this possibility in nor- ends by the DNA-binding protein Ku. Ku binds to hTERT mal human oral fibroblasts (NHOF) with and without ec- without the need for telomeric DNA or hTR (9), binds the topic expression of hTERT/telomerase. telomere repeat-binding proteins TRF1 (10) and TRF2 (11), and Experimental Design: To study the effect of hTERT/ is thought to regulate the access of telomerase to telomere DNA telomerase on DNA repair, we examined the mutation fre- ends (12, 13).
    [Show full text]
  • Indications for a Central Role of Hexokinase Activity in Natural Variation of Heat Acclimation in Arabidopsis Thaliana
    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 14 June 2020 doi:10.20944/preprints202006.0169.v1 Article Indications for a central role of hexokinase activity in natural variation of heat acclimation in Arabidopsis thaliana Vasil Atanasov §, Lisa Fürtauer § and Thomas Nägele * LMU Munich, Plant Evolutionary Cell Biology, Großhaderner Str. 2-4, 82152 Planegg, Germany § Authors contributed equally * Correspondence: [email protected] Abstract: Diurnal and seasonal changes of abiotic environmental factors shape plant performance and distribution. Changes of growth temperature and light intensity may vary significantly on a diurnal, but also on a weekly or seasonal scale. Hence, acclimation to a changing temperature and light regime is essential for plant survival and propagation. In the present study, we analyzed photosynthetic CO2 assimilation and metabolic regulation of the central carbohydrate metabolism in two natural accessions of Arabidopsis thaliana originating from Russia and south Italy during exposure to heat and a combination of heat and high light. Our findings indicate that it is hardly possible to predict photosynthetic capacities to fix CO2 under combined stress from single stress experiments. Further, capacities of hexose phosphorylation were found to be significantly lower in the Italian than in the Russian accession which could explain an inverted sucrose-to-hexose ratio. Together with the finding of significantly stronger accumulation of anthocyanins under heat/high light these observations indicate a central role of hexokinase activity in stabilization of photosynthetic capacities within a changing environment. Keywords: photosynthesis; carbohydrate metabolism; hexokinase; heat acclimation; environmental changes; natural variation; high light; combined stress. 1. Introduction Changes of growth temperature and light intensity broadly affect plant molecular, physiological and developmental processes.
    [Show full text]
  • Intraprotein Radical Transfer During Photoactivation of DNA Photolyase
    letters to nature tri-NaCitrate and 20% PEG 3350, at a ®nal pH of 7.4 (PEG/Ion Screen, Hampton (Daresbury Laboratory, Warrington, 1992). Research, San Diego, California) within two weeks at 4 8C. Intact complex was veri®ed by 25. Evans P. R. in Proceedings of the CCP4 Study Weekend. Data Collection and Processing (eds Sawyer, L., SDS±polyacrylamide gel electrophoresis of washed crystals (see Supplementary Infor- Isaacs, N. & Bailey, S.) 114±122 (Daresbury Laboratory, 1993). mation). Data were collected from a single frozen crystal, cryoprotected in 28.5% PEG 26. Collaborative Computational Project Number 4. The CCP4 suite: programs for protein crystal- 4000 and 10% PEG 400, at beamline 9.6 at the SRS Daresbury, UK. lography. Acta Crystallogr. 50, 760±763 (1994). The data were processed using MOSFLM24 and merged using SCALA25 from the CCP4 27. Navaza, J. AMORE - An automated package for molecular replacement. Acta Cryst. A 50, 157±163 26 (1994). package (Table 1) The molecular replacement solution for a1-antitrypsin in the complex 27 28 28. Engh, R. et al. The S variant of human alpha 1-antitrypsin, structure and implications for function and was obtained using AMORE and the structure of cleaved a1-antitrypsin as the search model. Conventional molecular replacement searches failed to place a model of intact metabolism. Protein Eng. 2, 407±415 (1989). 29 29. Lee, S. L. New inhibitors of thrombin and other trypsin-like proteases: hydrogen bonding of an trypsin in the complex, although maps calculated with phases from a1-antitrypsin alone showed clear density for the ordered portion of trypsin (Fig.
    [Show full text]
  • • Glycolysis • Gluconeogenesis • Glycogen Synthesis
    Carbohydrate Metabolism! Wichit Suthammarak – Department of Biochemistry, Faculty of Medicine Siriraj Hospital – Aug 1st and 4th, 2014! • Glycolysis • Gluconeogenesis • Glycogen synthesis • Glycogenolysis • Pentose phosphate pathway • Metabolism of other hexoses Carbohydrate Digestion! Digestive enzymes! Polysaccharides/complex carbohydrates Salivary glands Amylase Pancreas Oligosaccharides/dextrins Dextrinase Membrane-bound Microvilli Brush border Maltose Sucrose Lactose Maltase Sucrase Lactase ‘Disaccharidase’ 2 glucose 1 glucose 1 glucose 1 fructose 1 galactose Lactose Intolerance! Cause & Pathophysiology! Normal lactose digestion Lactose intolerance Lactose Lactose Lactose Glucose Small Intestine Lactase lactase X Galactose Bacteria 1 glucose Large Fermentation 1 galactose Intestine gases, organic acid, Normal stools osmotically Lactase deficiency! active molecules • Primary lactase deficiency: อาการ! genetic defect, การสราง lactase ลด ลงเมออายมากขน, พบมากทสด! ปวดทอง, ถายเหลว, คลนไสอาเจยนภาย • Secondary lactase deficiency: หลงจากรบประทานอาหารทม lactose acquired/transient เชน small bowel เปนปรมาณมาก เชนนม! injury, gastroenteritis, inflammatory bowel disease! Absorption of Hexoses! Site: duodenum! Intestinal lumen Enterocytes Membrane Transporter! Blood SGLT1: sodium-glucose transporter Na+" Na+" •! Presents at the apical membrane ! of enterocytes! SGLT1 Glucose" Glucose" •! Co-transports Na+ and glucose/! Galactose" Galactose" galactose! GLUT2 Fructose" Fructose" GLUT5 GLUT5 •! Transports fructose from the ! intestinal lumen into enterocytes!
    [Show full text]
  • A Mutation in DNA Polymerase Α Rescues WEE1KO Sensitivity to HU
    International Journal of Molecular Sciences Article A Mutation in DNA Polymerase α Rescues WEE1KO Sensitivity to HU Thomas Eekhout 1,2 , José Antonio Pedroza-Garcia 1,2 , Pooneh Kalhorzadeh 1,2, Geert De Jaeger 1,2 and Lieven De Veylder 1,2,* 1 Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium; [email protected] (T.E.); [email protected] (J.A.P.-G.); [email protected] (P.K.); [email protected] (G.D.J.) 2 Center for Plant Systems Biology, VIB, 9052 Gent, Belgium * Correspondence: [email protected] Abstract: During DNA replication, the WEE1 kinase is responsible for safeguarding genomic integrity by phosphorylating and thus inhibiting cyclin-dependent kinases (CDKs), which are the driving force of the cell cycle. Consequentially, wee1 mutant plants fail to respond properly to problems arising during DNA replication and are hypersensitive to replication stress. Here, we report the identification of the pola-2 mutant, mutated in the catalytic subunit of DNA polymerase α, as a suppressor mutant of wee1. The mutated protein appears to be less stable, causing a loss of interaction with its subunits and resulting in a prolonged S-phase. Keywords: replication stress; DNA damage; cell cycle checkpoint Citation: Eekhout, T.; Pedroza- 1. Introduction Garcia, J.A.; Kalhorzadeh, P.; De Jaeger, G.; De Veylder, L. A Mutation DNA replication is a highly complex process that ensures the chromosomes are in DNA Polymerase α Rescues correctly replicated to be passed onto the daughter cells during mitosis. Replication starts WEE1KO Sensitivity to HU. Int.
    [Show full text]
  • METABOLIC EVOLUTION in GALDIERIA SULPHURARIA By
    METABOLIC EVOLUTION IN GALDIERIA SULPHURARIA By CHAD M. TERNES Bachelor of Science in Botany Oklahoma State University Stillwater, Oklahoma 2009 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY May, 2015 METABOLIC EVOLUTION IN GALDIERIA SUPHURARIA Dissertation Approved: Dr. Gerald Schoenknecht Dissertation Adviser Dr. David Meinke Dr. Andrew Doust Dr. Patricia Canaan ii Name: CHAD M. TERNES Date of Degree: MAY, 2015 Title of Study: METABOLIC EVOLUTION IN GALDIERIA SULPHURARIA Major Field: PLANT SCIENCE Abstract: The thermoacidophilic, unicellular, red alga Galdieria sulphuraria possesses characteristics, including salt and heavy metal tolerance, unsurpassed by any other alga. Like most plastid bearing eukaryotes, G. sulphuraria can grow photoautotrophically. Additionally, it can also grow solely as a heterotroph, which results in the cessation of photosynthetic pigment biosynthesis. The ability to grow heterotrophically is likely correlated with G. sulphuraria ’s broad capacity for carbon metabolism, which rivals that of fungi. Annotation of the metabolic pathways encoded by the genome of G. sulphuraria revealed several pathways that are uncharacteristic for plants and algae, even red algae. Phylogenetic analyses of the enzymes underlying the metabolic pathways suggest multiple instances of horizontal gene transfer, in addition to endosymbiotic gene transfer and conservation through ancestry. Although some metabolic pathways as a whole appear to be retained through ancestry, genes encoding individual enzymes within a pathway were substituted by genes that were acquired horizontally from other domains of life. Thus, metabolic pathways in G. sulphuraria appear to be composed of a ‘metabolic patchwork’, underscored by a mosaic of genes resulting from multiple evolutionary processes.
    [Show full text]
  • PURIFIED THERMOSTABLE NUCLEIC ACID POLYMERASE ENZYME from $I(TERMOTOGA MARITIMA)
    Europäisches Patentamt *EP000544789B1* (19) European Patent Office Office européen des brevets (11) EP 0 544 789 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.7: C12N 15/54, C12N 9/12 of the grant of the patent: 05.03.2003 Bulletin 2003/10 (86) International application number: PCT/US91/05753 (21) Application number: 91915802.2 (87) International publication number: (22) Date of filing: 13.08.1991 WO 92/003556 (05.03.1992 Gazette 1992/06) (54) PURIFIED THERMOSTABLE NUCLEIC ACID POLYMERASE ENZYME FROM $i(TERMOTOGA MARITIMA) GEREINIGTES THERMOSTABILES NUKLEINSÄURE-POLYMERASEENZYM AUS THERMOTOGA MARITIMA ENZYME D’ACIDE NUCLEIQUE THERMOSTABLE PURIFIEE PROVENANT DE L’EUBACTERIE $i(THERMOTOGA MARITIMA) (84) Designated Contracting States: (74) Representative: Poredda, Andreas et al AT BE CH DE DK ES FR GB GR IT LI LU NL SE Roche Diagnostics GmbH, Patentabteilung, (30) Priority: 13.08.1990 US 567244 Sandhofer Strasse 116 68305 Mannheim (DE) (43) Date of publication of application: 09.06.1993 Bulletin 1993/23 (56) References cited: • CHEMICAL ABSTRACTS, vol. 105, no. 5, 04 (73) Proprietor: F. HOFFMANN-LA ROCHE AG August 1986, Columbus, OH (US); R. HUBER et 4002 Basel (CH) al., p. 386, AN 38901u • JOURNAL OF BIOLOGICAL CHEMISTRY, vol. (72) Inventors: 264, no. 11, 15 April 1989, American Society for • GELFAND, David, H. Biochemistry & Molecular Biology Inc., Oakland, CA 94611 (US) Baltimore, MD (US); F.C. LAWYER et al., pp. • LAWYER, Frances, C. 6427-6437 Oakland, CA 94611 (US) • STOFFEL, Susanne El Cerrito, CA 94530 (US) Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted.
    [Show full text]
  • Telomeres.Pdf
    Telomeres Secondary article Elizabeth H Blackburn, University of California, San Francisco, California, USA Article Contents . Introduction Telomeres are specialized DNA–protein structures that occur at the ends of eukaryotic . The Replication Paradox chromosomes. A special ribonucleoprotein enzyme called telomerase is required for the . Structure of Telomeres synthesis and maintenance of telomeric DNA. Synthesis of Telomeric DNA by Telomerase . Functions of Telomeres Introduction . Telomere Homeostasis . Alternatives to Telomerase-generated Telomeric DNA Telomeres are the specialized chromosomal DNA–protein . Evolution of Telomeres and Telomerase structures that comprise the terminal regions of eukaryotic chromosomes. As discovered through studies of maize and somes. One critical part of this protective function is to fruitfly chromosomes in the 1930s, they are required to provide a means by which the linear chromosomal DNA protect and stabilize the genetic material carried by can be replicated completely, without the loss of terminal eukaryotic chromosomes. Telomeres are dynamic struc- DNA nucleotides from the 5’ end of each strand of this tures, with their terminal DNA being constantly built up DNA. This is necessary to prevent progressive loss of and degraded as dividing cells replicate their chromo- terminal DNA sequences in successive cycles of chromo- somes. One strand of the telomeric DNA is synthesized by somal replication. a specialized ribonucleoprotein reverse transcriptase called telomerase. Telomerase is required for both
    [Show full text]
  • Cell Type–Dependent Effects of Polo-Like Kinase 1 Inhibition Compared with Targeted Polo Box Interference in Cancer Cell Lines
    3189 Cell type–dependent effects of Polo-like kinase 1 inhibition compared with targeted polo box interference in cancer cell lines Jenny Fink, Karl Sanders, Alexandra Rippl, certain cell lines but highly contrasting effects in others. Sylvia Finkernagel, Thomas L. Beckers, This may point to subtle differences in the molecular and Mathias Schmidt machinery of mitosis regulation in cancer cells. [Mol Cancer Ther 2007;6(12):3189–97] Nycomed GmbH, Konstanz, Germany Introduction Abstract Polo-like kinase 1 (Plk1) has been identified as key player Multiple critical roles within mitosis have been assigned for G2-M transition and mitotic progression in both normal to Polo-like kinase 1 (Plk1), making it an attractive and tumor cells (1). Multiple roles have been assigned to candidate for mitotic targeting of cancer cells. Plk1 Plk1 at the entry into M phase, mitotic spindle formation, contains two domains amenable for targeted interference: condensation and separation of chromosomes, exit from a kinase domain responsible for the enzymatic function mitosis by activation of the anaphase-promoting complex, and a polo box domain necessary for substrate recogni- and in cytokinesis (reviewed in ref. 2). Moreover, recent tion and subcellular localization. Here, we compare two reports implicated an involvement of Plk1 in the resump- approaches for targeted interference with Plk1 function, tion of cell cycle reentry after checkpoint activation through either by a Plk1 small-molecule enzyme inhibitor or by DNA-damaging agents (3). It is therefore not surprising inducible overexpression of the polo box in human cancer that targeted interference with Plk1, primarily by anti- cell lines.
    [Show full text]
  • Saccharomyces Rrm3p, a 5 to 3 DNA Helicase That Promotes Replication
    Downloaded from genesdev.cshlp.org on September 24, 2021 - Published by Cold Spring Harbor Laboratory Press Saccharomyces Rrm3p, a 5؅ to 3؅ DNA helicase that promotes replication fork progression through telomeric and subtelomeric DNA Andreas S. Ivessa,1 Jin-Qiu Zhou,1,2 Vince P. Schulz, Ellen K. Monson, and Virginia A. Zakian3 Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544-1014, USA In wild-type Saccharomyces cerevisiae, replication forks slowed during their passage through telomeric ؅ C1–3A/TG1–3 tracts. This slowing was greatly exacerbated in the absence of RRM3, shown here to encode a 5 ,to 3؅ DNA helicase. Rrm3p-dependent fork progression was seen at a modified Chromosome VII-L telomere at the natural X-bearing Chromosome III-L telomere, and at Y؅-bearing telomeres. Loss of Rrm3p also resulted in replication fork pausing at specific sites in subtelomeric DNA, such as at inactive replication origins, and at internal tracts of C1–3A/TG1–3 DNA. The ATPase/helicase activity of Rrm3p was required for its role in telomeric and subtelomeric DNA replication. Because Rrm3p was telomere-associated in vivo, it likely has a direct role in telomere replication. [Key Words: Telomere; helicase; telomerase; replication; RRM3; yeast] Received February 7, 2002; revised version accepted April 10, 2002. Telomeres are the natural ends of eukaryotic chromo- Because conventional DNA polymerases cannot repli- somes. In most organisms, the very ends of chromo- cate the very ends of linear DNA molecules, special somes consist of simple repeated sequences. For ex- mechanisms are required to prevent the loss of terminal ample, Saccharomyces cerevisiae chromosomes end in DNA.
    [Show full text]