Epigenomics and DNA Methylation Quiz

Epigenomics

• The study of heritable changes in gene expression that do not involve alterations to the underlying DNA sequence.
• Focuses on mechanisms that regulate gene activity without changing the genetic code.
• Epigenetic modifications are influenced by environmental factors and lifestyle choices.
• Plays a key role in development, health, and disease.

DNA Methylation

• A crucial epigenetic mechanism involving the addition of a methyl group to a cytosine base in DNA.
• Primarily occurs at CpG dinucleotides – cytosine followed by guanine.
• Methylation patterns are established during development and can be altered by various factors, such as environmental exposures or dietary changes.
• Can either silence or activate gene expression depending on the location and density of methylation.

Post-Translational Modification

• Modifications to proteins after translation that can alter their structure, function, and interactions.
• Plays a significant role in regulating gene expression and cellular processes.

Chromatin Remodeling

• Dynamic process involving changes in the structure of chromatin, the complex of DNA and proteins that package DNA within the nucleus.
• Allows for access to DNA by regulatory proteins, influencing gene expression.
• Includes processes like nucleosome repositioning and modification of histone proteins.

Histone Modification

• Chemical modifications to histone proteins that alter their interactions with DNA and influence gene expression.
• Common types of histone modifications include acetylation, methylation, phosphorylation, ubiquitination, SUMOylation, ADP ribosylation, and deamination.

SUMOylation

• The attachment of a small ubiquitin-like modifier (SUMO) protein to a target protein.
• Can alter protein interactions, subcellular localization, and stability.
• Involved in various cellular processes, including DNA repair, transcription, and stress response.

Acetylation

• The addition of an acetyl group to a lysine residue on a histone protein.
• Typically associated with increased gene transcription.
• Acetylated histones are more accessible to transcription factors, allowing for easier gene expression.

Methylation

• The addition of a methyl group to a lysine or arginine residue on a histone protein.
• Can either promote or repress gene transcription depending on the location and number of methyl groups.
• Methylation patterns are dynamic and can be influenced by various factors.

Phosphorylation

• The addition of a phosphate group to a serine, threonine, or tyrosine residue on a histone protein.
• Plays a role in regulating chromatin structure and gene expression.
• Can influence the recruitment of other regulatory proteins to chromatin.

Ubiquitination

• The attachment of ubiquitin, a small protein, to a target protein.
• Can lead to protein degradation, alter protein interactions, or change protein localization.
• Plays a crucial role in a wide range of cellular processes.

ADP Ribosylation

• The addition of ADP-ribose to a target protein.
• Can alter protein function, stability, and interactions.
• Involved in processes like DNA repair, signal transduction, and immune response.

Deamination

• The removal of an amine group from a cytosine base in DNA, converting it to uracil.
• Can lead to mutations and contribute to genome instability.

Methods in Epigenomics

• A variety of techniques are used to study epigenetic modifications.

ChIP Assay

• Chromatin Immunoprecipitation (ChIP) assay is a widely used technique to analyze protein-DNA interactions.
• Allows for the identification of specific DNA regions bound by a particular protein, like histone modifications.

Histone Modification Assay

• Methods used to analyze and quantify specific modifications on histone proteins.
• Includes techniques like Western blotting, mass spectrometry, and immuno-fluorescence microscopy.
• Provide insights into the dynamics of histone modifications and their impact on gene expression.

Test your understanding of epigenomics, focusing on gene expression changes that do not involve the DNA sequence. This quiz covers key mechanisms like DNA methylation and post-translational modifications and their impact on health and disease.