DNA methylation

Definition

DNA methylation is a biochemical process involving the addition of a methyl group to the DNA molecule, typically at the cytosine base in a CpG dinucleotide context. This modification plays a crucial role in regulating gene expression, often leading to gene silencing, and is a key mechanism of epigenetic regulation alongside histone modifications.

5 Must Know Facts For Your Next Test

1. DNA methylation usually occurs at cytosine residues followed by guanine (CpG), where the addition of a methyl group can inhibit transcription factors from binding to DNA.
2. This modification is essential for normal development and differentiation, as it helps regulate the expression of genes during cellular processes.
3. Aberrant DNA methylation patterns have been linked to various diseases, including cancer, where hypermethylation can lead to tumor suppressor gene silencing.
4. Methylation patterns can be influenced by environmental factors such as diet, toxins, and stress, highlighting the interaction between genetics and lifestyle.
5. DNA methylation is heritable and can be passed from one generation to another, affecting traits and predispositions without changing the actual DNA sequence.

Review Questions

• How does DNA methylation influence gene expression and what are the potential consequences of altered methylation patterns?
  • DNA methylation primarily influences gene expression by adding a methyl group to cytosines in CpG sites, which can block transcription factors from accessing the DNA and thus silence gene expression. Altered methylation patterns can lead to significant consequences, such as the activation of oncogenes or the silencing of tumor suppressor genes, contributing to the development of diseases like cancer. Understanding these patterns helps explain how environmental factors can affect genetic regulation.
• Discuss the relationship between DNA methylation and histone modifications in the context of epigenetic regulation.
  • DNA methylation and histone modifications work together as key mechanisms of epigenetic regulation. While DNA methylation directly modifies the DNA itself, histone modifications alter the structure of chromatin, influencing how tightly or loosely DNA is packaged. This interaction can create a synergistic effect on gene expression; for example, methylated DNA may attract proteins that also modify histones, leading to further repression of transcription. Together, they establish a dynamic regulatory landscape that impacts cellular function.
• Evaluate the implications of DNA methylation in the context of disease prevention and therapeutic strategies.
  • Understanding DNA methylation has significant implications for disease prevention and therapeutic strategies. By identifying specific methylation patterns associated with diseases like cancer, researchers can develop targeted therapies that either reverse aberrant methylation or restore normal patterns. Additionally, lifestyle interventions that influence methylation may provide preventative measures against disease onset. This evolving field illustrates how manipulating epigenetic marks can potentially lead to innovative treatments that address both genetic predispositions and environmental influences on health.

Related terms

Epigenetics: The study of heritable changes in gene expression that do not involve alterations to the underlying DNA sequence.

Histone modifications: Chemical changes to histone proteins that can affect chromatin structure and gene expression, including acetylation and phosphorylation.

CpG islands: Regions of the genome with a high frequency of CpG sites, often found near gene promoters, and are typically associated with regulatory elements that are sensitive to methylation.