A Histone Cycle: a Systematic Overview on Histone (Octamer Protein) Replication

Abstract

Genetic information plays an important role in each individual for their differentiation. DNA replication is a highly conserved process that accurately copies the genetic information from one generation to the next. The processes of chromatin disassembly and reassembly during DNA replication also have to be precisely regulated to ensure that the genetic material is compactly packaged to fit into the nucleus while also maintaining the epigenetic information that is carried by the histone proteins bound to the DNA, through cell divisions. So, for the synthesis of genome or gene a group of eight proteins collectively known as octamer proteins or histones plays a crucial role. Colloid of chromosomes is converts into the double stranded DNA structure with intermediate structure of histone proteins. As eukaryotic replication disrupts each nucleosome as the fork passes, followed by incorporation of newly synthesized histones into nucleosomes in the daughter genomes. For the cellular machinery to access the DNA, the chromatin must be unwound and the DNA cleared of histone proteins. In this review, we focus on the process of replication-coupled nucleosome assembly to understand how characteristic steady-state nucleosome landscapes are attained. Recent studies have begun to elucidate mechanisms involved in histone transfer during replication and maturation of the nucleosome landscape after disruption by replication. A fuller understanding of replication-coupled nucleosome assembly will be needed to explain how epigenetic information is replicated at every cell division. We also give details about regulation of histone in human and the DNA Damage Response.