ABSTRACT
Epigenetic regulation centers on the chromatin structure and the effects of remodeling and modifying enzymes upon it. Chromatin can be altered at the DNA and protein levels (e.g., via DNAmethylation and histone modifications). Changes in DNA methylation can have profound effects on gene expression. The histone octamer, forming the core of the nucleosome, is subject to transformation by two types of enzymes: remodelers and modifiers. Remodelers are classified as ATP-dependent proteins that alter DNA-histone interactions by repositioning histones, making regulatory cis elements on a DNA sequence more accessible to transcription factors; whereas modifiers are defined as ATP-independent proteins that perform posttranslational covalent modifications on amino-terminus
tails of histones. This can either facilitate or hinder the binding of regulatory proteins on DNA and thus affect transcriptional activity.
