6mA-Sniper: Quantifying 6mA sites in eukaryotes at single-nucleotide resolution

Area of Science:

• Epigenetics
• Molecular Biology
• Genomics

Background:

• N6-methyldeoxyadenine (6mA) is a key epigenetic regulator in prokaryotes, but its role in eukaryotes remains largely unknown.
• Previous studies have debated the prevalence and functional significance of 6mA in eukaryotic genomes.

Purpose of the Study:

• To develop a high-resolution method for quantifying 6mA sites in eukaryotes.
• To investigate the dynamics and regulatory mechanisms of 6mA modification in Caenorhabditis elegans.

Main Methods:

• Development and application of 6mA-Sniper for single-nucleotide resolution mapping of 6mA.
• Verification of identified 6mA sites using restriction endonuclease digestion (Mnl I).
• Analysis of 6mA profiles in Caenorhabditis elegans under different conditions (infection, gene deletion).

Main Results:

• 6mA-Sniper successfully mapped 2034 6mA sites in Caenorhabditis elegans.
• 6mA levels increased post-Pseudomonas aeruginosa infection and decreased upon METL-9 deletion.
• Identified a specific DNA motif ([GC]GAG) enriched for 6mA sites, suggesting active regulation by METL-9.
• Regions with infection-induced 6mA sites showed enrichment of up-regulated genes, potentially involving cross-talk with H3K27me3.

Conclusions:

• 6mA-Sniper is a feasible and effective tool for eukaryotic 6mA site quantification.
• 6mA modification plays a significant, previously underappreciated role in eukaryotic gene regulation.
• The 6mA profile is actively shaped by methyltransferases and can be influenced by environmental factors and other epigenetic modifications.