Maxillofacial Plastic and Reconstructive Surgery

Korean Association of Maxillofacial Plastic and Reconstructive Surgeons (대한악안면성형재건외과학회)
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UNDERSTANDING OF EPIGENETICS AND DNA METHYLATION

후생유전학 (Epigenetics)과 DNA methylation의 이해

  • Oh, Jung-Hwan (Dept. of Oral & Maxillofacial Surgery, Kyung-Hee University Dental School) ;
  • Kwon, Young-Dae (Dept. of Oral & Maxillofacial Surgery, Kyung-Hee University Dental School) ;
  • Yoon, Byung-Wook (Dept. of Oral & Maxillofacial Surgery, Kyung-Hee University Dental School) ;
  • Choi, Byung-Jun (Dept. of Oral & Maxillofacial Surgery, Kyung-Hee University Dental School)
  • 오정환 (경희대학교 치의학전문대학원 구강악안면외과학교실) ;
  • 권용대 (경희대학교 치의학전문대학원 구강악안면외과학교실) ;
  • 윤병욱 (경희대학교 치의학전문대학원 구강악안면외과학교실) ;
  • 최병준 (경희대학교 치의학전문대학원 구강악안면외과학교실)
  • Published : 2008.05.30
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Abstract

Epigenetic is usually referring to heritable traits that do not involve changes to the underlying DNA sequence. DNA methylation is known to serve as cellular memory. and is one of the most important mechanism of epigenetic. DNA methylation is a covalent modification in which the target molecules for methylation in mammalian DNA are cytosine bases in CpG dinucleotides. The 5' position of cytosine is methylated in a reaction catalyzed by DNA methyltransferases; DNMTl, DNMT3a, and DNMT3b. There are two different regions in the context of DNA methylation: CpG poor regions and CpG islands. The intergenic and the intronic region is considered to be CpG poor, and CpG islands are discrete CpG-rich regions which are often found in promoter regions. Normally, CpG poor regions are usually methylated whereas CpG islands are generally hypomethylated. DNA methylation is involved in various biological processes such as tissue-specific gene expression, genomic imprinting, and X chromosome inactivation. In general. cancer cells are characterized by global genomic hypomethylation and focal hypermethylation of CpG islands, which are generally unmethylated in normal cells. Gene silencing by CpG hypermethylation at the promotors of tumor suppressor genes is probably the most common mechanism of tumor suppressor inactivation in cancer.

DNA 메틸화는 histone modification과 함께 DNA의 염기서열이 유지되면서 유전기능이 변화되고 자손까지 전달 될 수 있는 후생 유전의 중요한 한 부분이다. DNA 메틸화는 크로마틴의 구조를 변경시키는 과정을 통하여 유전자와 repetitive sequence의 표현을 억제시킬 수 있다. DNA 메틸화는 X-불활성화, 유전체 각인, 유전자 발현조절, 암 생성 등에 중요한 역할을 하는 것으로 밝혀졌고, DNA 메틸화 표지자 (DNA methylation marker)들은 종양의 진단과 치료에 대한 반응을 예측하는 지표로 활용되고 있다. 지금까지 많은 연구 성과에도 불구하고 DNA메틸화, 메틸화에 의한 gene silencing, DNA 메틸화의 표적부위 등에 대한 명확한 기전이 아직도 밝혀지지 않고 있어 향후 더 많은 기초적 연구가 필요할 것이다. 최근에는 후생 유전적 변화는 가역적이기 때문에 종양억제유전자를 억압하는 후생 유전적 변화를 제거한다면 그 종양억제유전자를 다시 활성화시킬 수 있다는 개념의 후생유전 치료법 연구로 DNA 메틸화 억제제와 histone deacetyaltion에 관여하는 HDAC의 억제제들이 항암제로서 개발되어 사용되고 있는데 향후 더 많은 약제 개발과 임상적 연구가 진행되어야 할 것이다.

Keywords

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