Single-Molecule Nanopore Sequencing of the CpG Island from the Promoter of O6-Methylguanine-DNA Methyltransferase Provides Insights into the Mechanism of De Novo Methylation of G/C-Rich Regions.

• Tác giả: Adelya I Genatullina, Elizaveta S Gromova, Daniil P Malyshev, Galina V Pavlova, Alexander V Sergeev, Maria I Zvereva
• Ngôn ngữ: eng
• Ký hiệu phân loại: 133.5266 Astrology
• Thông tin xuất bản: Switzerland : Epigenomes , 2025
• Bộ sưu tập: NCBI
• ID: 243702

Tóm tắt

BACKGROUND: The methylation of cytosine residues at CpG sites within the O6-methylguanine-DNA methyltransferase ( OBJECTIVES: Our study explores the impact of potential G-quadruplex-forming sequences (PQS) in the METHODS: Nanopore sequencing was employed to analyze the methylation of 94 clinically significant CpG sites in the human MGMTp using an in vitro de novo methylation system. Circular dichroism spectroscopy was used to identify G4 structures within the MGMTp CpG island. Interactions between the catalytic domain of Dnmt3a and the PQS from the MGMTp were examined by biolayer interferometry. RESULTS: Guanine-rich DNA strands of the PQSs in the MGMTp were hypomethylated, while the complementary cytosine-rich strands were methylated by DNA methyltransferase Dnmt3a with higher efficiency. The accuracy of detecting modified bases in the PQS was significantly lower compared to surrounding sequences. Single-stranded guanine-rich DNA sequences from the MGMTp exhibited strong binding to Dnmt3a-CD, with an affinity approximately 10 times higher than their cytosine-rich complements ( CONCLUSIONS: The obtained data indicate the role of PQSs in establishing de novo methylation of the