TALEored Epigenetics : A DNA-Binding Scaffold for Programmable Epigenome Editing and Analysis

Abstract

Epigenetic modification of the cytosine 5-position is an important regulator of gene expression with essential roles in genome stability, development and disease. Besides 5-methylcytosine (mC), the oxidized mC derivatives 5 hydroxymethyl-, 5-formyl- and 5-carboxylcytosine (hmC, fC and caC) have recently been discovered. These are intermediates of an active demethylation pathway, but may also represent new epigenetic marks with individual biological roles. This increase in chemical complexity of DNA-encoded information has created a pressing need for new approaches that allow to read and edit this information. Transcription-activator-like effectors (TALEs) are DNA-binding domains with programmable sequence selectivity that offer the direct reading of epigenetic cytosine-modifications but also enable guiding enzymatic editing domains to genomic loci of choice. Here we review recent advances in employing TALEs for these applications.