Rett and ICF syndromes: methylation moves into medicine

Epigenetics and airways disease

Epigenetics is the term used to describe heritable changes in gene expression that are not coded in the DNA sequence itself but by post-translational modifications in DNA and histone proteins. These modifications include histone acetylation, methylation, ubiquitination, sumoylation and phosphorylation. Epigenetic regulation is not only critical for generating diversity of cell types during mammalian development, but it is also important for maintaining the stability and integrity of the expression profiles of different cell types. Until recently, the study of human disease has focused on genetic mechanisms rather than on non-coding events. However, it is becoming increasingly clear that disruption of epigenetic processes can lead to several major pathologies, including cancer, syndromes involving chromosomal instabilities, and mental retardation. Furthermore, the expression and activity of enzymes that regulate these epigenetic modifications have been reported to be abnormal in the airways of patients with respiratory disease. The development of new diagnostic tools might reveal other diseases that are caused by epigenetic alterations. These changes, despite being heritable and stably maintained, are also potentially reversible and there is scope for the development of 'epigenetic therapies' for disease.

Dimethyl sulfoxide stimulates the catalytic activity of de novo DNA methyltransferase 3a (Dnmt3a) in vitro

Mammalian DNA methyltransferase Dnmt3a is required for de novo methylation of CpG dinucleotides in genomic DNA. While DNA methyltransferase inhibitors have been extensively utilized both in vitro and in vivo, no stimulator of catalytic activity has been identified thus far. Here we show that the methyltransfer activity of Dnmt3a is stimulated by the addition of dimethyl sulfoxide (DMSO) to the reaction solution in vitro. Enzymatic analysis of initial reaction velocity suggests that the DMSO stimulation effect depends on the interaction between DMSO and the reaction substrates (DNA and AdoMet), but not the enzyme itself.