Domanda del libro di testo
The regulation of mRNA decay relies heavily upon deadenylases and decapping enzymes. Explain how these classes of enzymes are critical to initiating mRNA decay.
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Ch. 18 - Post-transcriptional Regulation in Eukaryotes
Klug12th EditionConcepts of GeneticsISBN: 9780135564776
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TOC.tableOfContents
- Ch. 1 - Introduction to Genetics17
- Ch. 2 - Mitosis and Meiosis36
- Ch. 3 - Mendelian Genetics51
- Ch. 4 - Extensions of Mendelian Genetics74
- Ch. 5 - Chromosome Mapping in Eukaryotes51
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages46
- Ch. 7 - Sex Determination and Sex Chromosomes33
- Ch. 8 - Chromosome Mutations: Variation in Number and Arrangement40
- Ch. 9 - Extranuclear Inheritance31
- Ch. 10 - DNA Structure and Analysis43
- Ch. 11 - DNA Replication and Recombination44
- Ch. 12 - DNA Organization in Chromosomes30
- Ch. 13 - The Genetic Code and Transcription54
- Ch. 14 - Translation and Proteins47
- Ch. 15 - Gene Mutation, DNA Repair, and Transposition41
- Ch. 16 - Regulation of Gene Expression in Bacteria29
- Ch. 17 - Transcriptional Regulation in Eukaryotes41
- Ch. 18 - Post-transcriptional Regulation in Eukaryotes33
- Ch. 19 - Epigenetics33
- Ch. 20 - Recombinant DNA Technology44
- Ch. 21 - Genomic Analysis36
- Ch. 22 - Applications of Genetic Engineering and Biotechnology36
- Ch. 23 - Developmental Genetics37
- Ch. 24 - Cancer Genetics34
- Ch. 25 - Quantitative Genetics and Multifactorial Traits54
- Ch. 26 - Population and Evolutionary Genetics45
Klug12th EditionConcepts of GeneticsISBN: 9780135564776Non è quello che usi tu?Cambia libro di testo
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Klug 12th EditionCh. 18 - Post-transcriptional Regulation in EukaryotesProblema 8
Klug 12th EditionCh. 18 - Post-transcriptional Regulation in EukaryotesProblema 8Capitolo 18, Problema 8
Nonsense-mediated decay is an mRNA surveillance pathway that eliminates mRNAs with premature stop codons. How does the cell distinguish between normal mRNAs and those with a premature stop?
Guida verificata passo dopo passo1
Understand that nonsense-mediated decay (NMD) is a quality control mechanism that targets mRNAs containing premature stop codons (also called nonsense codons) to prevent the production of truncated, potentially harmful proteins.
Recognize that during normal mRNA processing, exon junction complexes (EJCs) are deposited upstream of exon-exon junctions after splicing; these EJCs serve as markers for the cell to monitor mRNA integrity.
Learn that during the first round of translation, the ribosome removes EJCs as it moves along the mRNA; if the ribosome encounters a stop codon before the last EJC is removed, this indicates a premature stop codon.
Understand that the presence of an EJC downstream of a stop codon signals to the NMD machinery that the stop codon is premature, triggering the degradation of that mRNA.
Summarize that the cell distinguishes normal mRNAs from those with premature stops by checking whether translation terminates upstream of EJCs, using the position of stop codons relative to EJCs as a key indicator.
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Nonsense-Mediated Decay (NMD) Pathway
NMD is a cellular quality control mechanism that detects and degrades mRNAs containing premature stop codons to prevent the production of truncated, potentially harmful proteins. It ensures only properly processed mRNAs are translated, maintaining protein integrity.
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09:49
Point Mutations
Premature Stop Codons and Translation Termination
Premature stop codons are nonsense mutations that cause early termination of translation. The cell distinguishes these from normal stop codons by their position relative to downstream exon-exon junctions, which affects the recruitment of NMD factors.
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01:55Translation Termination
Exon Junction Complex (EJC) and mRNA Surveillance
The EJC is a protein complex deposited near exon-exon junctions after splicing. During translation, if a stop codon is detected upstream of an EJC, it signals that the stop is premature, triggering NMD to degrade the faulty mRNA.
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08:26Functional Genomics
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