DNA-templated silver nanoclusters for DNA methylation detection

Abstract

DNA methylation entails the covalent addition of a methyl group to C-5 position of cytosine by a family of DNA methyltransferase enzymes and has a significant role in gene regulation. Epigenetic changes such as DNA methylation of CpG islands located in the promoter region of some tumor suppressor genes are very common in human diseases such as cancer. Detection of aberrant methylation pattern could serve as an excellent diagnostic approach. It is key to develop methods for the direct and simple detection of methylated DNA or of methyltransferase activity without using antibodies, chemical modification, labeling and enzymatic treatments. In this study, we employ DNA-templated silver nanoclusters for detection of DNA methylation. This method entails use of cytosine rich DNA sequence as an effective template. By monitoring changes in fluorescence intensity, DNA methylation and DNA methyltransferase activity is detected. Upon DNA methylation, the fluorescence intensity of DNA templated Ag/NCs is decreased in a linear range when the concentration of methylated DNA is increased.