Live‐Cell Imaging of DNA Methylation Based on Synthetic‐Molecule/Protein Hybrid Probe

Abstract The epigenetic modification of DNA involves the conversion of cytosine to 5‐methylcytosine, also known as DNA methylation. DNA methylation is important in modulating gene expression and thus, regulating genome and cellular functions. Recent studies have shown that aberrations in DNA methylation are associated with various epigenetic disorders or diseases including cancer. This stimulates great interest in the development of methods that can detect and visualize DNA methylation. For instance, fluorescent proteins (FPs) in conjugation with methyl‐CpG‐binding domain (MBD) have been employed for live‐cell imaging of DNA methylation. However, the FP‐based approach showed fluorescence signals for both the DNA‐bound and ‐unbound states and thus differentiation between these states is difficult. Synthetic‐molecule/protein hybrid probes can provide an alternative to overcome this restriction. In this article, we discuss the synthetic‐molecule/protein hybrid probe that we developed recently for live‐cell imaging of DNA methylation, which exhibited fluorescence enhancement only after binding to methylated DNA.