Universal Enrichment and Sequencing of DNA Modifications Using a Click-Coupled IgG-Protein A/G System.

Area of Science:

• Molecular Biology
• Epigenetics
• Biochemistry

Background:

• Nucleic acid enrichment is crucial for studying epigenetic modifications and disease biomarkers.
• Current enrichment methods lack specificity, versatility, and are costly.

Purpose of the Study:

• To develop a universal, cost-efficient, and versatile strategy for nucleic acid enrichment.
• To enable specific capture and genome-wide mapping of DNA modifications.

Main Methods:

• Developed "Click-IP-Seq" using Protein A/G and DBCO-modified IgG for targeted nucleic acid capture.
• Utilized copper-free strain-promoted azide-alkyne cycloaddition (SPAAC) click chemistry.
• Applied the method to enrich 8-oxo-7,8-dihydroguanine (8-oxo-dG) and 5-hydroxymethylcytosine (5hmC).

Main Results:

• Successfully enriched 8-oxo-dG and 5hmC in model DNA systems.
• Mapped the genome-wide distribution of 8-oxo-dG in cultured cells and human tissues.
• Conducted comprehensive profiling of 8-oxo-dG in human colorectal carcinoma tissues.

Conclusions:

• Click-IP-Seq provides a cost-effective and modular alternative to biotin-streptavidin systems for DNA enrichment.
• The method is applicable for fundamental epigenetic research and next-generation molecular diagnostics.
• Enables novel insights into DNA damage and repair mechanisms through precise mapping of oxidative lesions.