Textbook Question
Explain the features of the Initiator (Inr) elements, BREs, DPEs, and MTEs of focused promoters.
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Ch. 16 - Regulation of Gene Expression in Eukaryotes
Klug10th EditionEssentials of GeneticsISBN: 9780135588789
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Table of contents
- Ch. 1 - Introduction to Genetics16
- Ch. 2 - Mitosis and Meiosis28
- Ch. 3 - Mendelian Genetics37
- Ch. 4 - Modification of Mendelian Ratios53
- Ch. 5 - Sex Determination and Sex Chromosomes32
- Ch. 6 - Chromosome Mutations: Variation in Number and Arrangement37
- Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes36
- Ch. 8 - Genetic Analysis and Mapping in Bacteria and Bacteriophages24
- Ch. 9 - DNA Structure and Analysis38
- Ch. 10 - DNA Replication29
- Ch. 11 - Chromosome Structure and DNA Sequence Organization22
- Ch. 12 - The Genetic Code and Transcription36
- Ch. 13 - Translation and Proteins27
- Ch. 14 - Gene Mutation, DNA Repair, and Transposition34
- Ch. 15 - Regulation of Gene Expression in Bacteria22
- Ch. 16 - Regulation of Gene Expression in Eukaryotes37
- Ch. 17 - Recombinant DNA Technology27
- Ch. 18 - Genomics, Bioinformatics, and Proteomics30
- Ch. 19 - The Genetics of Cancer21
- Ch. 20 - Quantitative Genetics and Multifactorial Traits37
- Ch. 21 - Population and Evolutionary Genetics45
Chapter 16, Problem 14
Explain how the use of alternative promoters and alternative polyadenylation signals produces mRNAs with different - and -ends.
Verified step by step guidance1
Understand that alternative promoters are different DNA sequences located upstream of a gene that can initiate transcription at different start sites, leading to mRNAs with variable 5'-ends.
Recognize that the choice of an alternative promoter affects which exon is included at the 5'-end of the mRNA, thus producing transcripts with different 5' untranslated regions (5' UTRs) or even different coding sequences.
Know that alternative polyadenylation signals are different sequences within the gene that signal where the mRNA should be cleaved and a poly(A) tail added, resulting in mRNAs with different 3'-ends.
Realize that the use of alternative polyadenylation sites can change the length of the 3' untranslated region (3' UTR) or even affect the coding sequence if polyadenylation occurs within an exon.
Combine these concepts to explain that by using different promoters and polyadenylation signals, a single gene can produce multiple mRNA isoforms that differ at their 5' and 3' ends, which can influence mRNA stability, localization, and translation efficiency.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Alternative Promoters
Alternative promoters are different DNA sequences upstream of a gene that can initiate transcription at distinct start sites. Using alternative promoters results in mRNAs with varied 5' ends, which can affect the untranslated region and potentially influence mRNA stability and translation efficiency.
Recommended video:
Guided course
01:57
Alternative DNA Forms
Alternative Polyadenylation Signals
Alternative polyadenylation involves the use of different polyadenylation (polyA) sites within the same gene, leading to mRNAs with variable 3' ends. This process can change the length of the 3' untranslated region, impacting mRNA stability, localization, and translation regulation.
Recommended video:
Guided course
01:57Alternative DNA Forms
mRNA End Processing and Regulation
The 5' and 3' ends of mRNA are critical for its function, including stability, export, and translation. Alternative promoter usage and polyadenylation modify these ends, allowing a single gene to produce multiple mRNA isoforms with distinct regulatory properties and functional outcomes.
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Guided course
08:39mRNA Processing