Induced DNA demethylation by targeting Ten-Eleven Translocation 2 to the human ICAM-1 promoter

Area of Science:

• Epigenetics
• Molecular Biology
• Genomics

Background:

• Active DNA demethylation is crucial in mammalian development, with Ten-Eleven Translocation (TET) dioxygenases initiating 5-methylcytosine (5-mC) oxidation.
• Aberrant DNA methylation, including tumor suppressor gene silencing via hypermethylation in cancer, is linked to various diseases.
• Current epigenetic drugs lack specificity, causing genome-wide effects.

Purpose of the Study:

• To engineer designer DNA-binding domains fused to TET dioxygenases (TET1, TET2, TET3) for targeted DNA demethylation.
• To assess the impact of targeted TET fusions on specific CpG methylation and gene expression of epigenetically silenced genes (ICAM-1, EpCAM).

Main Methods:

• Fusion of designer DNA-binding domains with TET1, TET2, and TET3 dioxygenases.
• Targeting of epigenetically silenced genes (ICAM-1, EpCAM) for demethylation.
• Assessment of CpG methylation status and gene expression levels at targeted loci.

Main Results:

• Targeted demethylation of CpG sites was observed in the promoters of targeted genes using TET2 and, to a lesser extent, TET1, but not TET3.
• Re-activation of ICAM-1 gene transcription was observed following targeted demethylation.
• Demonstrated successful induction of targeted DNA demethylation and subsequent gene re-expression.

Conclusions:

• Developed a novel Epigenetic Editing approach for targeted DNA demethylation.
• This method facilitates the re-activation of silenced gene expression.
• Provides a powerful tool for studying epigenetic mechanisms and gene regulation.