DNA methylation is involved in the regulation of many cellular processes, including chromosome stability, chromatin structure, X chromosome inactivation, embryonic development, and transcription. About 1% of the genome consists of 500-2000 bp CpG-rich areas or islands. About half of all CpG islands correspond to transcription start sites and promoters of expressed genes. Methylation of CpG islands is an important mechanism for gene silencing and inactivation of defined tumor suppressor genes in human cancers.
The discovery that differences between genomes cannot fully explain phenotypic differences between species or even between individuals has spurred the sequencing of “methylomes” data sets consisting of the location of every methylated cytosine in an organism’s genomic DNA. Advances in methylated DNA mapping, together with increased access to high resolution DNA sequencing, has made possible the large number of recently published methylomes in species ranging from rice to sea squirts, and in the presence of diverse environmental signals. Recent research suggests that Hydroxymethylationhas an important part to play in regulation of gene expression.
Merck offers antibodies to proteins involved in DNA methylation with demonstrated performance in a variety of applications. The DNA-methyltransferase enzymes (DNMT1, DNMT3a and DNMT3b) maintain normal patterns of DNA methylation. MECP2, MBD1, MBD2, MBD3, MBD4, and Kaiso each possess a MBD and act as methylation-sensitive transcriptional repressors.
5-hydroxymethylcytosine and TET
5-hydroxymethylcytosine (5hmC) is generated from 5mC by the family of Ten-Eleven Translocation (TET1-3) enzymes and may also play a critical role in epigenetic gene regulation. 5hmC residues are found in active genes and are emerging as regulators of gene activation and cellular differentiation during embryonic development and brain maturation. Relatively high levels of 5hmC have been detected in the brain, especially in certain areas, such as the hippocampus, that are required for cognitive functioning. 5hmC and TET enzymes may also be involved in tumorigenesis, and are therefore key targets for epigenetics research, to fully elucidate the dynamic changes in the epigenome involved in development and disease.