What is epigenetics?
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By mastering this deck, learners will understand how epigenetic modifications regulate gene expression without altering DNA sequence, enabling insights into development, disease mechanisms, and potential therapeutic strategies. This knowledge enhances their ability to interpret gene regulation in health and disease contexts effectively.
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| # | Front | Back | Hint |
|---|---|---|---|
| 1 | What is epigenetics? |
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Study chemical modifications and structural changes to DNA and histones that influence gene accessibility.
Epigenetics refers to heritable changes in gene expression that do not involve alterations to the underlying DNA sequence, often mediated by chemical modifications of DNA or histones. |
| Think 'above' or 'on top of' DNA |
| 2 | Name two common chemical modifications of histones involved in gene regulation. | Histone acetylation and histone methylation are two common modifications that influence chromatin structure and gene expression. | Consider modifications that loosen or tighten DNA-histone interactions |
| 3 | How does histone acetylation generally affect gene expression? | Histone acetylation neutralizes positive charges on histones, reducing their affinity for DNA, leading to a more open chromatin structure and increased gene transcription. | Acetyl groups add 'space' for transcription factors |
| 4 | What enzyme is primarily responsible for adding acetyl groups to histones? | Histone acetyltransferases (HATs). | Think 'HATs' as 'Histone Acetyl Transferases' |
| 5 | What is DNA methylation, and where does it typically occur? | DNA methylation involves the addition of methyl groups to cytosine bases, primarily at CpG dinucleotides, leading to gene silencing. | CpG sites are like 'methylation hotspots' |
| 6 | How does DNA methylation influence gene expression? | Methylation of promoter regions typically results in gene silencing by preventing transcription factor binding and recruiting repressive proteins. | Think 'methylation means 'mute' the gene |
| 7 | What are CpG islands? | CpG islands are regions with a high frequency of CpG sites, often located near gene promoters and subject to methylation regulation. | CpG islands are the 'control hubs' of gene regulation |
| 8 | Describe chromatin remodeling and its purpose. | Chromatin remodeling involves structural changes to nucleosomes and chromatin fibers, making DNA more or less accessible for transcription, replication, or repair. | Think of chromatin as 'packaging' that needs to be adjusted |
| 9 | Name two types of ATP-dependent chromatin remodeling complexes. | SWI/SNF and ISWI complexes. | Recall 'SWI/SNF' as 'Switch' or 'Slide' complexes |
| 10 | What is the role of histone variants in chromatin structure? | Histone variants replace canonical histones in nucleosomes, influencing chromatin dynamics and gene regulation, often associated with specialized functions like DNA repair or transcription activation. | Variants add 'special features' to nucleosomes |
| 11 | How does methylation of histones affect gene expression? | Histone methylation can either activate or repress gene expression depending on the specific amino acid and methylation state; for example, H3K4me3 is associated with active transcription, while H3K27me3 is linked to repression. | Think 'H3' as the histone tail with different 'marks' |
| 12 | What is the significance of the epigenetic marks being reversible? | Reversibility allows dynamic regulation of gene expression in response to environmental cues, developmental stages, and cellular needs, providing flexibility in gene regulation. | Reversible modifications are like 'on/off switches' |
| 13 | Explain the concept of imprinting in epigenetics. | Genomic imprinting is an epigenetic phenomenon where only one allele of a gene is expressed depending on its parental origin, regulated by DNA methylation and histone modifications. | Imprinting is like a 'parental stamp' on genes |
| 14 | How do non-coding RNAs participate in epigenetic regulation? | Non-coding RNAs, such as XIST and siRNAs, can recruit chromatin-modifying complexes to specific genomic regions, influencing DNA methylation and histone modifications to regulate gene expression. | RNAs act as 'guides' or 'scouts' in epigenetic marks |
| 15 | What is X-chromosome inactivation and how is it maintained epigenetically? | X-chromosome inactivation is the process where one X chromosome is silenced in female mammals, maintained through DNA methylation, histone modifications, and the expression of XIST RNA. | X-inactivation is 'turning off' one X to balance gene dosage |
| 16 | Describe the concept of 'epigenetic memory'. | Epigenetic memory refers to the heritable maintenance of specific epigenetic marks through cell divisions, ensuring consistent gene expression patterns in daughter cells. | Memory in epigenetics is like a 'bookmark' that persists |
| 17 | What role do environmental factors play in epigenetics? | Environmental factors such as diet, stress, and toxins can influence epigenetic marks, thereby affecting gene expression and potentially contributing to disease or developmental changes. | Environment can 'write' or 'erase' epigenetic marks |
| 18 | Provide an example of an epigenetic drug used in medicine. | Histone deacetylase inhibitors (HDAC inhibitors), such as vorinostat, are used in cancer therapy to reactivate silenced tumor suppressor genes. | Drugs that 'unblock' gene expression |
| 19 | Why is understanding chromatin remodeling important for gene therapy? | Because chromatin structure influences gene accessibility, manipulating remodeling complexes can enhance or suppress gene expression, improving gene therapy effectiveness. | Remodeling opens or closes the 'door' to genes |
| 20 | What is the relationship between epigenetics and aging? | Epigenetic alterations, such as changes in DNA methylation and histone modifications, accumulate with age and are associated with age-related decline in gene regulation and increased disease risk. | Aging involves 'epigenetic drift' |
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