Harnessing Methyltransferase-Guided Targeting for Sequence-Specific Proximity Labeling of DNA.

Area of Science:

• Chemical Biology
• Genomics
• Epigenetics

Background:

• Methyltransferase (MTase)-based DNA labeling is crucial for site-specific genomic and epigenetic analysis.
• Expanding the capabilities of MTases as programmable molecular guides is essential for advancing DNA modification techniques.

Purpose of the Study:

• To introduce a novel MTase-directed proximity labeling approach for sequence-specific DNA modification.
• To enable DNA labeling beyond the natural catalytic transfer site of MTases.

Main Methods:

• Developed a new strategy termed GLOW (Guided Labeling Outside the natural site With MTases).
• Utilized newly designed S-adenosyl-L-methionine (SAM) analogues.
• Employed single-molecule fluorescence imaging and gel-based restriction enzyme assays to confirm labeling.

Main Results:

• Demonstrated sequence-specific DNA labeling adjacent to, rather than within, the canonical MTase recognition site.
• Confirmed labeling accuracy using advanced imaging and enzymatic assays.
• Achieved enhanced ligand stability and avoided interference from endogenous DNA methylation.

Conclusions:

• Established MTase-guided proximity labeling as a novel enzymatic targeting mode.
• Broadened the potential of MTase-based methods for complex genomic contexts.
• Enriched the chemical biology toolkit for advanced sequence-specific DNA modification.