Table of contents

1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

13. Gene Regulation in Eukaryotes

Epigenetics, Chromatin Modifications, and Regulation

Genetics

13. Gene Regulation in Eukaryotes

Epigenetics, Chromatin Modifications, and Regulation

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2:08 minutes

Problem 1d

Textbook Question

How do we know that microRNAs negatively regulate target mRNAs?

Verified step by step guidance

Understand that microRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression by binding to complementary sequences on target mRNAs, leading to their degradation or translational repression.

Review experimental approaches such as reporter assays where a reporter gene is fused to the target mRNA sequence; observe that the presence of specific miRNAs reduces reporter gene expression, indicating negative regulation.

Examine loss-of-function and gain-of-function experiments: knocking down or deleting a miRNA leads to increased levels of its target mRNA or protein, while overexpressing the miRNA decreases target expression.

Consider biochemical methods like RNA immunoprecipitation to show physical association between miRNAs and their target mRNAs within the RNA-induced silencing complex (RISC), supporting direct regulation.

Analyze genome-wide studies such as microarray or RNA sequencing data that reveal inverse correlations between miRNA levels and their predicted target mRNAs, reinforcing the concept of negative regulation.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

MicroRNA (miRNA) Function

MicroRNAs are small non-coding RNA molecules that regulate gene expression by binding to complementary sequences on target mRNAs, leading to mRNA degradation or inhibition of translation. This posttranscriptional regulation reduces the production of specific proteins.

Experimental Evidence for miRNA Regulation

Researchers use techniques such as reporter assays, loss- and gain-of-function experiments, and RNA immunoprecipitation to demonstrate that miRNAs bind target mRNAs and reduce their expression. Observing decreased protein levels or mRNA stability upon miRNA activity confirms their negative regulatory role.

Mechanisms of Posttranscriptional Gene Regulation

Posttranscriptional regulation involves controlling mRNA stability, localization, and translation after transcription. miRNAs contribute by guiding RNA-induced silencing complexes (RISCs) to target mRNAs, which results in mRNA cleavage or translational repression, thereby fine-tuning gene expression.