Dna methylation

DNA Methylation is a biological process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter, DNA methylation typically acts to repress gene transcription.

Overview

DNA methylation is a crucial part of normal organismal development and cellular differentiation in higher organisms. DNA methylation stably alters the gene expression pattern in cells such that cells can "remember where they have been" or decrease gene expression. DNA methylation is typically removed during zygote formation and re-established through successive cell divisions during development.

Mechanism

DNA methylation involves the addition of a methyl group to the cytosine or adenine DNA nucleotides. In mammals, DNA methylation is found in CpG sites where a cytosine DNA nucleotide is located next to a guanine nucleotide in the linear sequence of bases along its length.

Function

DNA methylation influences gene expression by inhibiting the binding of transcription factors and other proteins to DNA. Besides its role in regulating gene expression, DNA methylation also serves as a cellular defense mechanism against the proliferation of transposable elements and preserving the integrity of the genome.

Diseases associated with DNA Methylation

Abnormal DNA methylation patterns are thought to be involved in oncogenesis. Hypermethylation of tumor suppressor genes or hypomethylation of oncogenes can lead to unregulated growth and division of cells, which is a common feature of cancer.

See also

• Epigenetics
• Histone methylation
• Methyltransferase
• DNA methyltransferase

References

Dna methylation Resources
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