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Epigenetics

“Epigenetics” is literally translated to “on” or “upon” “genetics”.  In general terms, it is a regulatory system that is layered over the genomic DNA sequence that we learn about in basic biology.  More specifically, epigenetics refers to functionally relevant modifications to the genome that do not involve a change in the DNA sequence.

Epigenetic alterations, including DNA methylation and histone deacetylation, are among the most common molecular alterations in human cancer (1).  DNA methyla­tion in particular is known to be a pivotal regulator of multiple cellular processes, including devel­opment and tumorigenesis (2).

While cancer is the best-characterized disease in which epigenetics plays a pivotal role, epigenetic alterations have been implicated in a vast array of human diseases including obesity (3), schizophrenia (4), cardiovascular disease (5) and antibiotic resistance (6).  The ability to selectively manipulate the enzymes that control this epigenetic regulation would unlock a new era in personalized medicine.

  1. Jones PA, Baylin SB. The fundamental role of epigenetic events in cancer. Nat Rev Genet. 2002; 3:415-428.
  2. Wolffe AP, Matzke MA. Epigenetics: Regulation through repression.  Science.. 1999; 286(5439):481-486.
  3. Wang X, Zhu H, Snieder H, Su S, Munn D, Harshfield G, Maria BL, Dong Y, Treiber F, Gutin B, Shi H. Obesity related methylation changes in DNA of peripheral blood leukocytes. BMC Med. 2010; 8:87-93.
  4. Roth TL, Lubin FD, Sodhi M, Kleinman JE. Epigenetic mechanisms in schizophrenia. Biochim Biophys Acta. 2009; 1790(9): 869-877.
  5. Kim M, Long TI, Arakawa K, Wang R, Yu MC, Laird PW. DNA methylation as a biomarker for cardiovascular disease.  PLoS ONE. 2010; 5(3): e9692.
  6. Kaminska KH, Purta E, Hansen LH, Bujnicki JM, Vester B, Long KS. Insights into the structure, function and evolution of the radical-SAM 23S rRNA methylatransferase Cfr that confers antibiotic resistance in bacteria. Nucleic Acids Res. 2010; 38(5): 1652-1663.

Illustration of the genome and the associated epigenetic modifications.

Illustration of the genome and the associated epigenetic modifications.

Source – NIH Roadmap Epigenomics Mapping Consortium