BMRI BioMed Research International 2314-6141 2314-6133 Hindawi Publishing Corporation 10.1155/2014/784706 784706 Review Article Dynamic Alu Methylation during Normal Development, Aging, and Tumorigenesis http://orcid.org/0000-0003-0439-6164 Luo Yanting luoyt@big.ac.cn 1 Lu Xuemei luxm@big.ac.cn 1 http://orcid.org/0000-0001-5739-1653 Xie Hehuang davidxie@vt.edu 1, 2, 3 Lee Yeon-Su 1 Beijing Institute of Genomics Chinese Academy of Sciences Beijing 100101 China cas.cn 2 Epigenomics and Computational Biology Lab, Virginia Bioinformatics Institute Virginia Tech Blacksburg, VA 24060 USA vt.edu 3 Department of Biological Sciences Virginia Tech Blacksburg, VA 24060 USA vt.edu 2014 27 8 2014 2014 10 04 2014 16 08 2014 27 8 2014 2014 Copyright © 2014 Yanting Luo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

DNA methylation primarily occurs on CpG dinucleotides and plays an important role in transcriptional regulations during tissue development and cell differentiation. Over 25% of CpG dinucleotides in the human genome reside within Alu elements, the most abundant human repeats. The methylation of Alu elements is an important mechanism to suppress Alu transcription and subsequent retrotransposition. Decades of studies revealed that Alu methylation is highly dynamic during early development and aging. Recently, many environmental factors were shown to have a great impact on Alu methylation. In addition, aberrant Alu methylation has been documented to be an early event in many tumors and Alu methylation levels have been associated with tumor aggressiveness. The assessment of the Alu methylation has become an important approach for early diagnosis and/or prognosis of cancer. This review focuses on the dynamic Alu methylation during development, aging, and tumor genesis. The cause and consequence of Alu methylation changes will be discussed.

 http://dx.doi.org/10.13039/501100001809 National Natural Science Foundation of China 81270633 http://dx.doi.org/10.13039/501100001809 National Natural Science Foundation of China 91131903