Phosphorylation of histone H2A.X as a DNA-associated biomarker (Review)

Abstract

The complex genomic structure of eukaryotic cells is primarily achieved by the binding of DNA to histones. Different members of the histone families form a complex with genomic DNA and, as a nucleosome, constitute the functional unit of chromatin. In addition to their structural functionality, histones are also involved in other molecular mechanisms, such as DNA damage recognition and repair. A very important factor of DNA damage management is the histone H2A.X. The phosphorylation of H2A.X initiates various processes of the DNA repair systems and plays significant roles in cellular regu- lation. The H2A.X phosphorylation status represents a central sum parameter for genome integrity and allows conclusions to be drawn about DNA-associated processes in cells and tissues. As a biomarker for DNA damage and genotoxicity, as well as a clinical marker for radiotherapy outcome, drug efficacy and tissue regeneration, the H2A.X phosphorylation status repre- sents an effective biomarker for current and future biomedical applications. The present brief review article provides an over- view of the various molecular functions and cellular events in which the phosphorylation of histone H2A.X can occur.