Chromatin modifications by CARM1/PRMT4 and p300/KAT3B in the regulation of gene expression, probed by specific small molecule inhibitiors

Abstract

Chromatin is the complex nucleoprotein structure of DNA wrapped around the histones. This structure undergoes several hierarchical and distinct organizational states, aided by not only histones, but also nonhistone proteins and small RNAs, finally resulting into the compact entity packed into the tiny confines of the nucleus. The higher order chromatin is a deterrent to the essential cellular processes like transcription, replication and repair. Hence, there exists a dynamicity wherein based on the signals, the chromatin undergoes decompaction, thereby exposing the DNA for the above mentioned processes. Once the requirement is met, the chromatin once again compacts (Kouzarides, 2007). This is probably, the reason for chromatin being considered as a ‘relay platform of different signals’. However, this dynamicity is not a global phenomena, rather is a local process involving only certain chromatin territories. The eukaryotic genome is arranged into several chromatin territories interspersed with empty spaces, leading to a three dimensional fluid representation of chromatin. Thus, any cellular process is an event recognized by specific chromatin territories (Meaburn and Misteli, 2007) which interact with other regions if essential by processes called gene looping and thereby lead to gene expression.