Light-Activation of DNA-Methyltransferases

Area of Science:

• Epigenetics and Molecular Biology
• Cancer Research
• Synthetic Biology

Background:

• 5-Methylcytosine (5mC) is a crucial epigenetic mark in mammals, regulated by DNA methyltransferases (DNMTs).
• Dysregulation of DNA methylation is linked to cancer development.
• Current methods lack spatiotemporal control over DNMT activity in vivo, hindering functional studies.

Purpose of the Study:

• To develop a method for light-controlled DNA methyltransferase (DNMT) activity in vivo.
• To investigate the roles of DNMTs and the impact of cancer-related mutations on de novo DNA methylation.
• To explore early transcriptome alterations induced by controlled DNA methylation.

Main Methods:

• Genetically encoding a photocaged cysteine residue in DNMTs to enable light-inducible catalytic activity.
• Using a programmable transcription activator-like effector (TALE) domain for targeted DNA methylation.
• Monitoring de novo DNA methylation and associated transcriptome changes upon light activation.

Main Results:

• Demonstrated light-activated, spatiotemporal control of DNMT catalysis in vivo.
• Provided insights into how cancer-associated DNMT mutations affect de novo methylation.
• Achieved localized and tunable cytosine methylation at specific genomic loci (pericentromeric satellite-3 DNA).
• Observed early transcriptome alterations following DNMT-mediated methylation.

Conclusions:

• The developed light-controlled system allows precise dissection of DNA methylation dynamics and its downstream effects.
• This technology facilitates the study of normal and aberrant epigenetic processes in various biological contexts, including cancer.
• Sets a foundation for investigating the kinetics and order of chromatin events triggered by DNA methylation.