2 Introduction Regulation of gene expression allows cells to adapt to environmental changes and is responsible for the distinct activities of the differentiated cell types that make up complex organisms. Transcription is the first step in gene expression, and the initial level at which gene expression is regulated. RNAs in eukaryotic cells are then modified and processed in various ways.
3 Transcription in Prokaryotes RNA polymerase catalyzes polymerization of ribonucleoside 5 - triphosphates (NTPs) as directed by a DNA template, always in the 5 to 3 direction. Transcription initiates de novo (no preformed primer required) at specific sites this is a major step at which regulation of transcription occurs.
4 Transcription in Prokaryotes Bacterial RNA polymerase has five types of subunits. The σ subunit is weakly bound and can be separated from the others. It is required to identify the correct sites for transcription initiation. Most bacteria have several different σ s that direct RNA polymerase to different start sites under different conditions.
5 Transcription in Prokaryotes The promoter is the gene sequence to which RNA polymerase binds to initiate transcription. Promoters have six nucleotides and are located at 10 and 35 base pairs upstream of the transcription start site. Consensus sequences are the bases most frequently found in different promoters.
6 Transcription in Prokaryotes Experiments have shown the functional importance of the 10 and 35 promoter elements. The sites at which RNA polymerase binds to promoters have been directly identified by DNA footprinting. A DNA fragment is labeled at one end with a radioisotope or fluorescent dye. The labeled DNA is incubated with RNA polymerase and then partially digested with DNase. Regions of DNA where the protein binds are protected from DNase digestion, and can be identified by comparing to DNA with no bound protein.
7 Figure 7.3 DNA footprinting
8 Transcription in Prokaryotes Footprinting analysis has shown that the σ subunit binds specifically to sequences in both the 35 and 10 promoter regions, substantiating the importance of these sequences in promoter function. σ binds specifically to both the 35 and 10 sequences, leading to the initiation of transcription at the beginning of a gene. Initial binding is referred to as a closed-promoter complex because the DNA is not unwound. The polymerase then unwinds bases of DNA to form an open-promoter complex, allowing transcription. After addition of about ten nucleotides, σ is released from the polymerase. The polymerase continues elongation of the RNA chain.
9 Figure 7.4 Transcription by E. coli RNA polymerase (Part 1)
10 Figure 7.4 Transcription by E. coli RNA polymerase (Part 2)
11 Transcription in Prokaryotes During elongation, polymerase maintains an unwound region of about 15 base pairs. High-resolution structural analysis shows that the β and β subunits form a crab claw-like structure that grips the DNA template. An internal channel between these subunits contains the polymerase active site.
12 Transcription in Prokaryotes RNA synthesis continues until the polymerase encounters a termination signal. The most common signal is a symmetrical inverted repeat of a GC-rich sequence followed by seven A residues. Transcription of the GC-rich inverted repeat results in a segment of RNA that can form a stable stemloop structure. This disrupts its association with the DNA template and terminates transcription.
13 Figure 7.6 Transcription termination
14 Transcription in Prokaryotes Alternatively, transcription of some genes is terminated by a specific termination protein (Rho), which binds extended segments of single-stranded RNA. Most transcriptional regulation in bacteria operates at initiation. Studies of gene regulation in the 1950s used enzymes involved in lactose metabolism. The enzymes are only expressed when lactose is present.
15 Transcription in Prokaryotes β-galactosidase cleaves lactose into glucose and galactose. Lactose permease transports lactose into the cell. Transacetylase is thought to inactivate toxic thiogalactosides that are transported into the cell along with lactose.
16 Transcription in Prokaryotes Genes encoding these enzymes are expressed as a single unit, called an operon. Transcription of the operon is controlled by o (operator), adjacent to the transcription initiation site. The i gene (not physically linked to the operon), encodes a protein that binds to the operator.
17 Transcription in Prokaryotes Mutants that don t produce i gene product express the operon even when lactose is not available. This implies that the normal i gene product is a repressor, which blocks transcription when bound to o. In normal cells, lactose binds to the repressor, preventing it from binding to the operator, and the genes are expressed. The lactose operon illustrates the central principle of gene regulation: control of transcription is mediated by the interaction of regulatory proteins with specific DNA sequences.
18 Transcription in Prokaryotes Cis-acting control elements only affect the expression of linked genes on the same DNA molecule (e.g. the operator). Trans-acting factors can affect expression of genes located on other chromosomes (e.g. the repressor). The lac operon is an example of negative control binding of the repressor blocks transcription. An example of positive control in E. coli : Presence of glucose (the preferred energy source) represses expression of genes for enzymes that break down other sugars, such as the lac operon.
19 Transcription in Prokaryotes Low glucose levels activate adenylyl cyclase, which converts ATP to camp. camp then binds to catabolite activator protein (CAP). CAP then binds to its target DNA sequences, 60 bases upstream of the transcription start site in the lac operon.
20 Eukaryotic RNA Polymerases and General Transcription Factors Eukaryotic cells have three nuclear RNA polymerases that transcribe different classes of genes. They are complex enzymes, consisting of 12 to 17 different subunits each. They all have 9 conserved subunits, 5 of which are related to subunits of bacterial RNA polymerase.
21 Eukaryotic RNA Polymerases and General Transcription Factors RNA polymerase II is responsible for synthesis of mrna and it has been the focus of most transcription studies. Unlike prokaryotic RNA polymerase, it requires initiation factors that (in contrast to bacterial σ factors) are not associated with the polymerase.
22 Eukaryotic RNA Polymerases and General Transcription Factors General transcription factors are proteins involved in transcription from all polymerase II promoters. About 10% of the genes in the human genome encode transcription factors, emphasizing the importance of these proteins. Promoters contain several different regulatory sequence elements. Promoters of different genes contain different combinations of promoter elements, which appear to function together to bind general transcription factors.
23 Figure 7.11 Formation of a polymerase II preinitiation complex in vitro (Part 1)
24 Eukaryotic RNA Polymerases and General Transcription Factors Sequence elements include the TATA box which resembles the 10 sequence element of bacterial promoters. A minimum of five general transcription factors are required for initiation of transcription in vitro. The first step is binding of general transcription factor TFIID, composed of multiple subunits, including the TATAbinding protein (TBP) and 14 other polypeptides, called TBP-associated factors (TAFs).
25 Eukaryotic RNA Polymerases and General Transcription Factors Following recruitment of RNA polymerase II to the promoter, the binding of two additional factors (TFIIE and TFIIH) completes formation of the preinitiation complex.
26 Eukaryotic RNA Polymerases and General Transcription Factors Within a cell, additional factors are required to initiate transcription. These include Mediator, a large protein complex of more than 20 subunits; it interacts with both general transcription factors and RNA polymerase.
27 Eukaryotic RNA Polymerases and General Transcription Factors RNA polymerase I is devoted solely to transcription of rrna genes, which are present in tandem repeats. Transcription yields a large 45S pre-rrna, which is processed to yield the 28S, 18S, and 5.8S rrnas.
28 Eukaryotic RNA Polymerases and General Transcription Factors Promoters of rrna genes are recognized by two transcription factors, UBF (upstream binding factor) and SL1 (selectivity factor 1), which recruit polymerase I. SL1 transcription factor is composed of four subunits, one of which is TBP.
29 Eukaryotic RNA Polymerases and General Transcription Factors Genes for trnas, 5S rrna, and some of the small RNAs are transcribed by polymerase III. Promoters of 5S rrna and trna genes are downstream of the transcription initiation site. The promoter of the U6 snrna gene is upstream of the transcription start site and contains a TATA box.
30 Regulation of Transcription in Eukaryotes An important difference between transcriptional regulation in prokaryotes and eukaryotes results from the packaging of eukaryotic DNA into chromatin. Modifications of chromatin structure play key roles in the control of transcription in eukaryotic cells. Many cis-acting sequences regulate expression of eukaryotic genes. Some eukaryotic regulatory sequences have been identified by gene transfer assays.
31 Regulation of Transcription in Eukaryotes Regulatory sequences are ligated to a reporter gene that encodes an easily detectable enzyme, such as firefly luciferase. The regulatory sequence then directs expression of the reporter gene in cultured cells. Two cis-acting regulatory sequences were identified by studies of the promoter of the herpes simplex virus gene that encodes thymidine kinase.
32 Regulation of Transcription in Eukaryotes Some regulatory sequences are farther away called enhancers. They were first identified during studies of the promoter of another virus, SV40.
33 Regulation of Transcription in Eukaryotes Activity of enhancers doesn t depend on either their distance from, or orientation with respect to, the transcription initiation site.
34 Figure 7.20 Action of enhancers (Part 2)
35 Regulation of Transcription in Eukaryotes Enhancers, like promoters, function by binding transcription factors that then regulate RNA polymerase. DNA looping allows a transcription factor bound to a distant enhancer to interact with proteins associated with the RNA polymerase/mediator complex at the promoter.
36 Regulation of Transcription in Eukaryotes Example: an enhancer controls transcription of immunoglobulin genes in B lymphocytes. Gene transfer experiments show that the enhancer is active in lymphocytes, but not in other types of cells. This regulatory sequence is partly responsible for tissue-specific expression of the immunoglobulin genes. Enhancers usually contain multiple sequence elements that bind different transcriptional regulatory proteins. The immunoglobulin heavy-chain enhancer spans about 200 base pairs and contains at least nine distinct sequence elements that serve as proteinbinding sites.
37 Regulation of Transcription in Eukaryotes The immunoglobulin enhancer contains negative regulatory elements that inhibit transcription in inappropriate cell types; and positive regulatory elements that activate transcription in B lymphocytes. The overall activity reflects the combined action of the proteins associated with each of the sequence elements. Activity of any given enhancer is specific for the promoter of its appropriate target gene. This specificity is maintained in part by insulators or barrier elements, which divide chromosomes into independent domains and prevent enhancers from acting on promoters located in an adjacent domain.
38 Regulation of Transcription in Eukaryotes Transcription factor binding sites have been identified by DNA footprinting and electrophoretic-mobility shift assay (EMSA). Radiolabeled DNA fragments are incubated with a protein and then subjected to electrophoresis through a nondenaturing gel. Migration of a DNA fragment through the gel is slowed by a bound protein.
39 Regulation of Transcription in Eukaryotes Binding sites are usually short DNA sequences (6 10 base pairs) and they are degenerate the transcription factor will bind to the consensus sequence, but also to sequences that differ from the consensus at one or more positions. Transcription factor binding sites are shown as pictograms, representing the frequency of each base at all positions of known binding sites for a given factor.
40 Regulation of Transcription in Eukaryotes Chromatin immunoprecipitation identifies DNA regions that bind to transcription factors. Cells are treated with formaldehyde to cross-link transcription factors to the DNA sequences to which they were bound. Chromatin is extracted and fragmented. Fragments of DNA linked to a transcription factor can then be isolated by immunoprecipitation.
41 Regulation of Transcription in Eukaryotes One of the first transcription factors to be isolated was Sp1, in studies of virus SV40 DNA, by Tjian and colleagues. Sp1 binds to GC boxes in the SV40 promoter. This established the action of Sp1 and also suggested a method for purification of transcription factors.
42 Regulation of Transcription in Eukaryotes DNA-affinity chromatography: Double-stranded oligonucleotides with repeated GC box sequences are bound to agarose beads in a column. Cell extracts are passed through the column. Sp1 binds to the GC box with high affinity and is retained on the column.
43 Regulation of Transcription in Eukaryotes Transcriptional activators, like Sp1, bind to regulatory DNA sequences and stimulate transcription. These factors have two independent domains: one region binds DNA, the other stimulates transcription by interacting with other proteins, such as Mediator.
44 Regulation of Transcription in Eukaryotes Many different transcription factors have now been identified in eukaryotic cells. About 2000 are encoded in the human genome. They contain many distinct types of DNA-binding domains. The most common is the zinc finger domain, which binds zinc ions and folds into loops ( fingers ) that bind DNA. Steroid hormone receptors contain zinc fingers; they regulate gene transcription in response to hormones such as estrogen and testosterone.
45 Figure 7.28 Examples of DNA-binding domains (Part 2) Helix-turn-helix domain: one helix makes most of the contacts with DNA, the other helices lie across the complex to stabilize the interaction. They include homeodomain proteins, important in the regulation of gene expression during embryonic development.
46 Regulation of Transcription in Eukaryotes Homeodomain proteins were first discovered as developmental mutants in Drosophila. They result in development of flies in which one body part is transformed into another. In Antennapedia, legs rather than antennae grow from the head.1
Three types of RNA polymerase in eukaryotic nuclei Type Location RNA synthesized Effect of α-amanitin I Nucleolus Pre-rRNA for 18,.8 and 8S rrnas Insensitive II Nucleoplasm Pre-mRNA, some snrnas Sensitive
1 To know and explain: Regulation of Bacterial Gene Expression Constitutive ( house keeping) vs. Controllable genes OPERON structure and its role in gene regulation Regulation of Eukaryotic Gene Expression
REVIEW SESSION Wednesday, September 15 5:30 PM SHANTZ 242 E Gene Regulation Gene Regulation Gene expression can be turned on, turned off, turned up or turned down! For example, as test time approaches,
3.B.1 Gene Regulation Gene regulation results in differential gene expression, leading to cell specialization. We will focus on gene regulation in prokaryotes first. Gene regulation accounts for some of
Prokaryotic Regulation Control of transcription initiation can be: Positive control increases transcription when activators bind DNA Negative control reduces transcription when repressors bind to DNA regulatory
Welcome to Class 21! Introductory Biochemistry! Lecture 21: Outline and Objectives l Regulation of Gene Expression in Prokaryotes! l transcriptional regulation! l principles! l lac operon! l trp attenuation!
PROKARYOTE GENES: E. COLI LAC OPERON CHAPTER 13 CHAPTER 13 PROKARYOTE GENES: E. COLI LAC OPERON Figure 1. Electron micrograph of growing E. coli. Some show the constriction at the location where daughter
Topic 4 - #14 The Lactose Operon The Lactose Operon The lactose operon is an operon which is responsible for the transport and metabolism of the sugar lactose in E. coli. - Lactose is one of many organic
Bacterial DNA contains genes that encode for many different proteins (enzymes) so that many processes have the ability to occur -not all processes are carried out at any one time -what allows expression
m Eukaryotic mrna processing Newly made RNA is called primary transcript and is modified in three ways before leaving the nucleus: Cap structure a modified guanine base is added to the 5 end. Poly-A tail
CHAPTER 13.3 13.5: Prokaryotic Genetics 1. Most bacteria are not pathogenic. Identify several important roles they play in the ecosystem and human culture. 2. How do variations arise in bacteria considering
Gene Expression- Overview Differentiating cells Achieved through changes in gene expression All cells contain the same whole genome A typical differentiated cell only expresses ~50% of its total gene Overview
Name: AP Biology Mr. Croft Chapter 15 Active Reading Guide Regulation of Gene Expression The overview for Chapter 15 introduces the idea that while all cells of an organism have all genes in the genome,
Lecture 18 June 2 nd, 2016 Gene Expression Regulation Mutations From Gene to Protein Central Dogma Replication DNA RNA PROTEIN Transcription Translation RNA Viruses: genome is RNA Reverse Transcriptase
Gene regulation I Biochemistry 302 Bob Kelm February 25, 2005 Principles of gene regulation (cellular versus molecular level) Extracellular signals Chemical (e.g. hormones, growth factors) Environmental
Gene Expression Quiz Overall Expectation: - Demonstrate an understanding of concepts related to molecular genetics, and how genetic modification is applied in industry and agriculture Specific Expectation(s):
GENE REGULATION AND PROBLEMS OF DEVELOPMENT By Surinder Kaur DIET Ropar Surinder_1998@ yahoo.in Mob No 9988530775 GENE REGULATION Gene is a segment of DNA that codes for a unit of function (polypeptide,
Paper Module : 15 : 23 Development Team Principal Investigator : Prof. Neeta Sehgal Department of Zoology, University of Delhi Co-Principal Investigator : Prof. D.K. Singh Department of Zoology, University
16 CONTROL OF GENE EXPRESSION Chapter Outline 16.1 REGULATION OF GENE EXPRESSION IN PROKARYOTES The operon is the unit of transcription in prokaryotes The lac operon for lactose metabolism is transcribed
OpenStax-CNX module: m52697 1 15.2 Prokaryotic Transcription * Shannon McDermott Based on Prokaryotic Transcription by OpenStax This work is produced by OpenStax-CNX and licensed under the Creative Commons
1 Description of Module Subject Name?? Paper Name Module Name/Title XV- 04: 2 OPERONS OBJECTIVES To understand how gene is expressed and regulated in prokaryotic cell To understand the regulation of Lactose
Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Enduring understanding 3.B: Expression of genetic information involves cellular and molecular
Biology Biology 1 of 26 Fruit fly chromosome 12-5 Gene Regulation Mouse chromosomes Fruit fly embryo Mouse embryo Adult fruit fly Adult mouse 2 of 26 Gene Regulation: An Example Gene Regulation: An Example
Translation and Operons You Should Be Able To 1. Describe the three stages translation. including the movement of trna molecules through the ribosome. 2. Compare and contrast the roles of three different
Chapter 18 Regulation of Gene Expression Edited by Shawn Lester PowerPoint Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley
Complete all warm up questions Focus on operon functioning we will be creating operon models on Monday 1. What is the Central Dogma? 2. How does prokaryotic DNA compare to eukaryotic DNA? 3. How is DNA
Controlling Gene Expression Control Mechanisms Gene regulation involves turning on or off specific genes as required by the cell Determine when to make more proteins and when to stop making more Housekeeping
Transcription Transcription: DNA to RNA A) production of complementary strand of DNA B) RNA types C) transcription start/stop signals D) Initiation of eukaryotic gene expression E) transcription factors
APGRU6L2 Control of Prokaryotic (Bacterial) Genes 2007-2008 Bacterial metabolism Bacteria need to respond quickly to changes in their environment STOP u if they have enough of a product, need to stop production
REGULATION OF GENE EXPRESSION Bacterial Genetics Lac and Trp Operon Levels of Metabolic Control The amount of cellular products can be controlled by regulating: Enzyme activity: alters protein function
Chapter 18 Regulation of Gene Expression PowerPoint Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from
13.4 Gene Regulation and Expression THINK ABOUT IT Think of a library filled with how-to books. Would you ever need to use all of those books at the same time? Of course not. Now picture a tiny bacterium
Gene regulation II Biochemistry 302 Bob Kelm February 28, 2005 Catabolic operons: Regulation by multiple signals targeting different TFs Catabolite repression: Activity of lac operon is restricted when
Control of Prokaryotic (Bacterial) Gene Expression Figure 18.1 How can this fish s eyes see equally well in both air and water? Aka. Quatro ojas Regulation of Gene Expression: Prokaryotes and eukaryotes
Warm-Up Explain how a secondary messenger is activated, and how this affects gene expression. (LO 3.22) Yesterday s Picture The first cell on Earth (approx. 3.5 billion years ago) was simple and prokaryotic,
STO-143 Gene Switches Teacher Information Summary Kit contains How do bacteria turn on and turn off genes? Students model the action of the lac operon that regulates the expression of genes essential for
Regulation of gene Expression in Prokaryotes & Eukaryotes 1 The trp Operon Contains 5 genes coding for proteins (enzymes) required for the synthesis of the amino acid tryptophan. Also contains a promoter
Chapter 18: Control of Gene Expression 海洋生物研究所 曾令銘 海事大樓 426 室分機 : 5326 Differential Expression of Genes Prokaryotes and eukaryotes precisely regulate gene expression in response to environmental conditions
Regulation of Transcription in Eukaryotes Leucine zipper and helix-loop-helix proteins contain DNA-binding domains formed by dimerization of two polypeptide chains. Different members of each family can
Name Chapter 10 Reading Guide From DNA to Protein: Gene Expression Concept 10.1 Genetics Shows That Genes Code for Proteins 1. In most cases, genes code for and it is that determine. 2. Describe what Garrod
THINK ABOUT IT Think of a library filled with how-to books. Would you ever need to use all of those books at the same time? Of course not. Now picture a tiny bacterium that contains more than 4000 genes.
Villa et al. (2005) Structural dynamics of the lac repressor-dna complex revealed by a multiscale simulation. PNAS 102: 6783-6788. Background: The lac operon is a cluster of genes in the E. coli genome
Honors Biology Reading Guide Chapter 11 v Promoter a specific nucleotide sequence in DNA located near the start of a gene that is the binding site for RNA polymerase and the place where transcription begins
Chapter 12 Genes: Expression and Regulation 1 DNA Transcription or RNA Synthesis produces three types of RNA trna carries amino acids during protein synthesis rrna component of ribosomes mrna directs protein
Regulation of Gene Expression at the level of Transcription (examples are mostly bacterial) Diarmaid Hughes ICM/Microbiology VT2009 Regulation of Gene Expression at the level of Transcription (examples
Bacterial Genetics & Operons The Bacterial Genome Because bacteria have simple genomes, they are used most often in molecular genetics studies Most of what we know about bacterial genetics comes from the
1 GENE ACTIVITY Gene structure Transcription Transcript processing mrna transport mrna stability Translation Posttranslational modifications 2 DNA Promoter Gene A Gene B Termination Signal Transcription
Gene regulation II Biochemistry 302 February 27, 2006 Molecular basis of inhibition of RNAP by Lac repressor 35 promoter site 10 promoter site CRP/DNA complex 60 Lewis, M. et al. (1996) Science 271:1247
Why? Control of Expression in Prokaryotes How do prokaryotes use operons to control gene expression? Houses usually have a light source in every room, but it would be a waste of energy to leave every light
Chapter 18 Regulation of Gene Expression Differential gene expression Every somatic cell in an individual organism contains the same genetic information and replicated from the same original fertilized
GEETICS - CLUTCH CH.12 GEE REGULATIO I PROKARYOTES!! www.clutchprep.com GEETICS - CLUTCH CH.12 GEE REGULATIO I PROKARYOTES COCEPT: LAC OPERO An operon is a group of genes with similar functions that are
BME 5742 Biosystems Modeling and Control Lecture 24 Unregulated Gene Expression Model Dr. Zvi Roth (FAU) 1 The genetic material inside a cell, encoded in its DNA, governs the response of a cell to various
13.4 Gene Regulation and Expression Lesson Objectives Describe gene regulation in prokaryotes. Explain how most eukaryotic genes are regulated. Relate gene regulation to development in multicellular organisms.
Boolean models of gene regulatory networks Matthew Macauley Math 4500: Mathematical Modeling Clemson University Spring 2016 Gene expression Gene expression is a process that takes gene info and creates
Gene, genetic code and regulation of the gene expression, Regulating the Metabolism, The Lac- Operon system,catabolic repression, The Trp Operon system: regulating the biosynthesis of the tryptophan. Mitesh
GENES AND CHROMOSOMES III Lecture 5 BIOL 266/4 2014-15 Dr. S. Azam Biology Department Concordia University CELL NUCLEUS AND THE CONTROL OF GENE EXPRESSION OPERONS Introduction All cells in a multi-cellular
Alberts Johnson Lewis Raff Roberts Walter Molecular Biology of the Cell Fifth Edition Chapter 7 Control of Gene Expression Copyright Garland Science 2008 A neuron and a lymphocyte share the same genome
Alberts Johnson Lewis Raff Roberts Walter Molecular Biology of the Cell Fifth Edition Chapter 6 How Cells Read the Genome: From DNA to Protein Copyright Garland Science 2008 Figure 6-1 Molecular Biology
The Eukaryotic Genome and Its Expression Lecture Series 11 The Eukaryotic Genome and Its Expression A. The Eukaryotic Genome B. Repetitive Sequences (rem: teleomeres) C. The Structures of Protein-Coding
Organization of Genes Differs in Prokaryotic and Eukaryotic DNA Chapter 10 p.110-114 Arrangement of information in DNA----- requirements for RNA Common arrangement of protein-coding genes in prokaryotes=
Control of Gene Expression Mechanisms of Gene Control Gene Control in Eukaryotes Master Genes Gene Control In Prokaryotes Epigenetics Gene Expression The overall process by which information flows from
Regulation of Transcription in Eukaryotes Nelson Saibo email@example.com In eukaryotes gene expression is regulated at different levels 1 - Transcription 2 Post-transcriptional modifications 3 RNA transport
Ch. 18 Regula'on of Gene Expression BIOL 222 Overview: Conduc'ng the Gene'c Orchestra Prokaryotes and eukaryotes alter gene expression in response to their changing environment In mul@cellular eukaryotes
Prokaryotic Gene Expression (Learning Objectives) 1. Learn how bacteria respond to changes of metabolites in their environment: short-term and longer-term. 2. Compare and contrast transcriptional control
Chapter 17 From Gene to Protein DNA The information molecule Sequences of bases is a code DNA organized in to chromosomes Chromosomes are organized into genes What do the genes actually say??? Reflecting
Regulation and signaling Overview Cells need to regulate the amounts of different proteins they express, depending on cell development (skin vs liver cell) cell stage environmental conditions (food, temperature,
Control of Prokaryotic (Bacterial) Genes 20072008 Bacterial metabolism n Bacteria need to respond quickly to changes in their environment u if they have enough of a product, need to stop production n why?
Week 10! 10-24-2013! Annotated Bibliography! Sources of papers! 3 papers! Peer-reviewed scientific literature (no review articles)! No more than 2 from:! the same author! the same journal! 2 of the 3 must
THE EDIBLE OPERON David O. Freier Lynchburg College [BIOL 220W Cellular Diversity] You have the following resources available to you: Short bread cookies = DNA / genetic elements Fudge Mint cookies = RNA
11 Regulation of Gene Expression in Bacteria and Their Viruses WORKING WITH THE FIGURES 1. Compare the structure of IPTG shown in Figure 11-7 with the structure of galactose shown in Figure 11-5. Why is
Controllo dell espressione genica: procarioti 1. Operon Regolazione dell espressione nei procarioti 2. Regulation mostly on the transcriptional level. POSITIVE: energy saving, regulation of only one mrna
Chapter 9 DNA recognition by eukaryotic transcription factors TRANSCRIPTION 101 Eukaryotic RNA polymerases RNA polymerase RNA polymerase I RNA polymerase II RNA polymerase III RNA polymerase IV Function
Предсказание и анализ промотерных последовательностей Татьяна Татаринова Eukaryotic Transcription 2 Initiation Promoter: the DNA sequence that initially binds the RNA polymerase The structure of promoter-polymerase
Ch 10, 11 &14 Preview Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Why did the original one-gene, one-enzyme hypothesis have to be modified? a. Some
Chapter 10, 11, 14: Gene Expression, Regulation, and Development Exam Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Why did the original one-gene, one-enzyme
Unit Two: Molecular Genetics 5.5 Control Mechanisms 5.7 Key Differences 5.8 Genes and Chromosomes Control Mechanisms Not all genes need to be produced at all times. Example: alcohol dehydrogenase Methods
RNA Processing: Eukaryotic mrnas Eukaryotic mrnas have three main parts (Figure 13.8): 5! untranslated region (5! UTR), varies in length. The coding sequence specifies the amino acid sequence of the protein
UE Praktikum Bioinformatik WS 08/09 University of Vienna 7SK snrna 7SK was discovered as an abundant small nuclear RNA in the mid 70s but a possible function has only recently been suggested. Two independent
Prokaryotic Gene Expression (Learning Objectives) 1. Learn how bacteria respond to changes of metabolites in their environment: short-term and longer-term. 2. Compare and contrast transcriptional control
BIO 5099: Molecular Biology for Computer Scientists (et al) Lecture 18: Eukaryotic genes http://compbio.uchsc.edu/hunter/bio5099 Larry.Hunter@uchsc.edu Eukaryotic vs. Prokaryotic genes Like in prokaryotes,
Prokaryo'c Operon Model Ac'vity Differen'al Expression of Genes Prokaryotes and eukaryotes precisely regulate gene expression in response to environmental condi6ons In mul6cellular eukaryotes, gene expression
Functional Genomics Research Stream The Research Plan Tuning In Is A Good Idea Research Meeting: March 23, 2010 The Road to Publication Transcription Factors Protein that binds specific DNA sequences controlling