Chromatin higher order structure and possible therapeutic target

Abstract

Canonical form of chromatin structure was unveiled by James Watson and Francis Crick which unravels the better understanding of their structural and functional significance. Experimental observations disclose that non-canonical DNA structures like hairpin, cruciform, Z-DNA, multi-stranded structures such as DNA triplex, G-quadruplex, i-motif forms by depending on specific sequence. Non-canonical structure specifically G-quadruplex stability depends on various factors such as base sequence, ions, super helical stress, and ligands, which ultimately regulates different processes like replication, transcription, translation, and recombination. However, chromatin higher order structure also modifies the gene expression level by modulating nucleosome and also recruited different chromatin remodeler protein to the transcription site to maintain an epigenetic landscape in the genome. Though G-quadruplex regulates multiple cellular processes, but their presence accelerated the mutagenicity and genome instability. The present review is an overview of higher order chromatin structure particularly focussed on G- quadruplex, which is summarized from recent literature, demonstrated the structural form and stability through some specific binding ligand and their role in cellular level. This would provide a mechanistic view to derive the structure-function relation of these non-canonical forms of DNA and their identification as potential therapeutic targets for diverse genetic diseases and cancer.