Modular DNA-Incorporated Aggregation-Induced Emission Probe for Sensitive Detection and Imaging of DNA Methyltransferase.

Abstract

DNA adenine methylation (Dam) MTase serves a very important epigenetic process that transfers a methyl group on an adenine residue including N6-methyladenosine (m6A). A variety of evidence have demonstrated that m6A methylation plays a significant role in modulating genes in human disease and development. Hence, a modular DNA-incorporated AIEgen probe (TPE-Py-DNA) was specifically developed for detection and imaging of Dam MTase. TPE-Py-DNA consisted of two modules: a "turn-on" fluorescent AIEgen (TPE-Py) and a DNA sequence (Alk-DNA) involved in specific recognition of the targeted strand. The TPE-Py-DNA probe was dispersed and almost nonfluorescent in an aqueous environment. On the contrary, the TPE-Py-DNA molecule was digested based on the target-recycling strategy in assistance with exonuclease III (Exo III) when Dam MTase was presented, finally releasing aggregated AIEgens to produce a remarkably increased fluorescence signal. Therefore, the detection limit toward Dam MTase was as low as 3.1 × 10-5 U mL-1, and the fluorescent signal could be used to detect Dam MTase activities in real samples and screen its inhibitors. More importantly, the Dam MTase expression was visualized in E. coli cells via CLMS imaging and confirmed in E. coli cell-bearing tissues. In this vein, our results demonstrated that the TPE-Py-DNA probe is a potent tool for the Dam MTase detection and imaging as well as offers an efficient biosensing platform for further investigation of disease pathway and carcinogenesis.