Textbook Question
Compare and contrast the items in each pair:
(a) enhancers and the E. coli CAP binding site
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Ch. 19 - Control of Gene Expression in Eukaryotes
Freeman8th EditionBiological ScienceISBN: 9780138276263
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Table of contents
- Ch. 1 - Biology: The Study of Life13
- Ch. 2 - Water and Carbon: The Chemical Basis of Life14
- Ch.3 - Protein Structure and Function10
- Ch.4 - Nucleic Acids and the RNA World10
- Ch. 5 - An Introduction to Carbohydrates10
- Ch. 6 - Lipids, Membranes, and the First Cells11
- Ch. 7 - Inside the Cell10
- Ch. 8 - Energy and Enzymes: An Introduction to Metabolism10
- Ch. 9 - Cellular Respiration and Fermentation11
- Ch. 10 - Photosynthesis12
- Ch. 11 - Cell-Cell Interactions12
- Ch. 12 - The Cell Cycle8
- Ch. 13 - Meiosis12
- Ch. 14 - Mendel and the Gene23
- Ch. 15 - DNA and the Gene: Synthesis and Repair15
- Ch. 16 - How Genes Work16
- Ch. 17 - Transcription, RNA Processing, and Translation16
- Ch. 18 - Control of Gene Expression in Bacteria16
- Ch. 19 - Control of Gene Expression in Eukaryotes12
- Ch. 20 - The Molecular Revolution: Biotechnology, Genomics, and New Frontiers15
- Ch. 21 - Genes, Development, and Evolution12
- Ch. 22 - Evolution by Natural Selection16
- Ch. 23 - Evolutionary Processes13
- Ch. 24 - Speciation15
- Ch. 25 - Phylogenies and the History of Life13
- Ch. 26 - Bacteria and Archaea15
- Ch. 27 - Diversification of Eukaryotes16
- Ch. 28 - Green Algae and Land Plants16
- Ch. 29 - Fungi18
- Ch. 30 - An Introduction to Animals9
- Ch. 31 - Protostome Animals15
- Ch. 32 - Deuterostome Animals17
- Ch. 33 - Viruses16
- Ch. 34 - Plant Form and Function16
- Ch. 35 - Water and Sugar Transport in Plants16
- Ch. 36 - Plant Nutrition13
- Ch. 37 - Plant Sensory Systems, Signals, and Responses16
- Ch. 38 - Flowering Plant Reproduction and Development16
- Ch. 39 - Animal Form and Function17
- Ch. 40 - Water and Electrolyte Balance in Animals16
- Ch. 41 - Animal Nutrition16
- Ch. 42 - Gas Exchange and Circulation16
- Ch. 43 - Animal Nervous Systems16
- Ch. 44 - Animal Sensory Systems16
- Ch. 45 - Animal Movement11
- Ch. 46 - Chemical Signals in Animals16
- Ch. 47 - Animal Reproduction and Development16
- Ch. 48 - The Immune System in Animals16
- Ch. 49 - An Introduction to Ecology15
- Ch. 50 - Behavioral Ecology16
- Ch. 51 - Population Ecology16
- Ch. 52 - Community Ecology20
- Ch. 53 - Ecosystems and Global Ecology17
- Ch. 54 - Biodiversity and Conservation Ecology18
Chapter 19, Problem 6
Imagine discovering a loss-of-function mutation in a eukaryotic gene. You determine the gene's nucleotide sequence from the start site for transcription to the termination point of transcription and find no differences from the wild-type sequence. Explain where you think the mutation might be and how the mutation might be acting.
Verified step by step guidance1
Consider the possibility that the mutation is located in a regulatory region rather than within the coding sequence itself. Regulatory regions include promoters, enhancers, and silencers, which control the expression of the gene.
Examine the promoter region, which is upstream of the transcription start site. A mutation here could affect the binding of transcription factors or RNA polymerase, leading to reduced or abolished transcription.
Investigate the enhancer regions, which can be located far from the gene they regulate. A mutation in an enhancer could disrupt the binding of activator proteins, reducing the gene's expression levels.
Consider the possibility of a mutation in the splice sites or intronic regions. Such mutations could lead to improper splicing of the pre-mRNA, resulting in a non-functional protein product.
Explore the potential for epigenetic changes, such as DNA methylation or histone modification, which could silence the gene without altering the nucleotide sequence. These changes can affect chromatin structure and gene accessibility.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Gene Expression Regulation
Gene expression regulation involves controlling the timing, location, and amount of a gene's product being produced. In eukaryotes, this regulation can occur at multiple levels, including transcription, RNA processing, and translation. Mutations affecting regulatory elements, such as promoters or enhancers, can lead to loss-of-function by altering the gene's expression without changing the coding sequence.
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Introduction to Regulation of Gene Expression
Non-coding Regions
Non-coding regions of DNA, such as introns, promoters, and enhancers, play crucial roles in gene regulation. Mutations in these areas can affect gene function by disrupting the normal regulatory processes, even if the coding sequence remains unchanged. These mutations can impact transcription factor binding, RNA splicing, or other regulatory mechanisms, leading to altered gene expression.
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Post-transcriptional Modifications
Post-transcriptional modifications include processes like RNA splicing, editing, and transport, which are essential for producing functional mRNA. Mutations affecting these processes can result in loss-of-function by producing defective mRNA or preventing its proper translation. Such mutations might not alter the nucleotide sequence but can disrupt the normal maturation and function of the mRNA.
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Related Practice
Textbook Question
Compare and contrast the items in each pair:
(b) promoter-proximal elements and the operator of the lac operon
Textbook Question
Compare and contrast the items in each pair:
(c) general transcription factors and sigma.
Textbook Question
The following statements are about the control of chromatin condensation. Select True or False for each.
T/F Reducing histone acetylase activity is likely to decrease gene transcription.
T/F Mutations that reduce the number of positively charged amino acids on histones should promote open chromatin.
T/F Chromatin remodeling complexes add chemical groups to histones.
T/F Adding an inhibitor of DNA methylation is likely to reduce gene transcription.
Textbook Question
Predict how a mutation that caused continuous production of active p53 would affect the cell.
Textbook Question
In the follow-up work to the experiment shown in Figure 19.6, the researchers used a technique that allowed them to see if two DNA sequences are in close physical proximity (association). They applied this method to examine how often an enhancer and the core promoter of the Hnf4a regulatory gene were near each other. A logical prediction is that compared with rats born to mothers fed a healthy diet, the Hnf4a gene in rats born to mothers fed a protein-poor diet would
a. Show no difference in how often the promoter and enhancer associated
b. Never show any promoter–enhancer association
c. Show a lower frequency of promoter–enhancer association
d. Show a higher frequency of promoter–enhancer association