Expression pattern of DNA-methyltransferases and its health implication (short review)

Epigenetics is heritable and reversible alterations of gene expression without direct alteration of DNA sequences. One example of epigenetic factors is DNA methylation, which prevents certain genes from being expressed. Another example is histone modifications. In addition, miRNAs can silence genes at transcriptional and posttranscriptional level. DNA methylation is regulated by DNA methyltransferases (DNMT1, DNMT3a, and DNMT3b). Aberrant DNMTs expression is the dominant mechanism for the genome instability which associates with a wide range of diseases such as a cancer, autoimmune diseases, mental disorders. In this article we reviewed the major mechanisms of changes of DNA methylation regulated by DNMTs and the role of this changes in pathogenesis of various diseases. In addition we briefly reviewed epigenetic agents, such as inhibitors of DNA methyltransferases or HDAC (histone deacetylase) targeting oncology, hematology, immunology, and neurologic disease indications, and which are in various phases of study or have been clinically tested and approved by FDA (Food and Drug Administration).