hemi-methylated DNA-binding

Definition

Target type: molecularfunction

Binding to double-stranded hemi-methylated DNA at replication foci (one strand methylated, while the other strand is unmethylated). Methylation of cytosine or adenine in DNA is an important mechanism for establishing stable heritable epigenetic marks. [GOC:imk, GOC:sp, PMID:18772889]

Hemi-methylated DNA-binding involves the recognition of DNA sequences where only one strand of the double helix is methylated. This type of binding is crucial for various cellular processes, including:

**1. DNA Replication and Repair:**

- During DNA replication, hemi-methylated DNA serves as a template for the newly synthesized strand, ensuring that methylation patterns are faithfully inherited.
- DNA repair mechanisms often utilize hemi-methylated DNA as a signal to identify and repair damaged bases.

**2. Gene Regulation:**

- Hemi-methylated DNA can act as a signal for gene silencing or activation depending on the context and specific proteins involved.
- Some proteins bind specifically to hemi-methylated DNA, recruiting other factors that modulate gene expression.

**3. Development and Differentiation:**

- Hemi-methylation patterns are often dynamic during development, playing a role in cell fate determination and differentiation.
- Changes in hemi-methylation levels can influence the expression of genes involved in cell growth, proliferation, and differentiation.

**4. Immune Response:**

- Hemi-methylation patterns can be recognized by the immune system, contributing to the regulation of immune responses.
- Some immune cells can distinguish between hemi-methylated and fully methylated DNA, triggering specific immune responses.

**Molecular Mechanisms:**

The molecular mechanisms underlying hemi-methylated DNA-binding vary depending on the protein involved. Some proteins recognize specific DNA sequences in conjunction with methylation status, while others utilize a combination of DNA sequence and methylation recognition.

**Examples of Hemi-Methylated DNA-Binding Proteins:**

- **DNMT1:** DNA methyltransferase 1, responsible for maintaining methylation patterns during replication. It recognizes hemi-methylated DNA to direct methylation of the newly synthesized strand.
- **TET enzymes:** Ten-eleven translocation enzymes, involved in DNA demethylation. They can oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in hemi-methylated DNA, initiating the demethylation process.
- **Transcription factors:** Some transcription factors, such as the Polycomb group proteins, can specifically bind to hemi-methylated DNA, influencing gene expression.

**Overall, hemi-methylated DNA-binding plays a vital role in various cellular processes by providing a dynamic and reversible mechanism for regulating DNA methylation, gene expression, and cellular responses.**'
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Proteins (1)

Compounds (2)