Histones

• Basic chromosomal protein molecules around which the DNA in the cell nucleus is arranged. Thus the DNA is tightly packed (packaging form of the DNA). This results in nucleosomes that are strung together like pearls on a necklace. An important enzyme that determines the packaging properties of histones is topoisomerase. Numerous studies show that the acetylation of histones correlates with transcriptional activation and the deacetylation of histones with transcriptional repression. The opposing activities of two classes of enzymes, histone acetyltransferases (HAT) and histone deacetylases (HDAC) control the extent of histone acetylation.
• Today, a number of drugs are available, so-called HDAC inhibitors, which allow to intervene in the "histone code" and to influence epigenetic gene regulation. Although these substances modulate the expression of 2-5% of all genes, they are surprisingly not associated with significant side effects in vivo and are already used therapeutically in cutaneous T-cell lymphomas (see Vorinostat).

Anti-histone antibodies can be detected in about 30% of patients with systemic lupus erythematosus. Almost all patients with drug-induced lupus erythematosus have anti-histone antibodies.