Epigenetic alterations have come to prominence in biomedical research. In particular, hypermethylation of CpG islands located in the promoter regions of tumor-suppressor genes is now firmly established as an important mechanism for gene inactivation in cancer.
Discovery of histone variants using highly specific antibodies has led to the emerging notion that alterations in histone modifications and further changes in chromatin structure are induced by exchange of histone variants. Covalent histone modifications and the incorporation of histone variants bring about changes in chromatin structure that in turn alter the gene expression.
Forming the major protein component of chromatin, histones are essential to the structure and organization of chromosomes, forming the nucleosome around which DNA is packaged and wrapped.
