Locus-specific rewriting of DNA methylation in mammalian cells.

DNA methylation is the most abundant epigenetic modification on the human genome and plays a critical role in gene regulation, development, and is altered in many diseases. Since its discovery over a century ago, advancements in our understanding of DNA methylation have enabled the development of programmable epigenome editors for manipulating DNA methylation at target genomic loci for use in fundamental research and clinical applications. In this review, we describe major findings in the field of DNA methylation biology and how these findings have been utilized to build DNA methylation-based epigenome editors. We further discuss the usage of epigenome editors in fundamental biology and emerging clinical applications.