Song Fei, Smith Joseph F, Kimura Makoto T, Morrow Arlene D, Matsuyama Tomoki, Nagase Hiroki, Held William A
Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA.
Proc Natl Acad Sci U S A. 2005 Mar 1;102(9):3336-41. doi: 10.1073/pnas.0408436102. Epub 2005 Feb 22.
Early studies proposed that DNA methylation could have a role in regulating gene expression during development [Riggs, A.D. (1975) Cytogenet. Cell Genet. 14, 9-25]. However, some studies of DNA methylation in known tissue-specific genes during development do not support a major role for DNA methylation. In the results presented here, tissue-specific differentially methylated regions (TDMs) were first identified, and then expression of genes associated with these regions correlated with methylation status. Restriction landmark genomic scanning (RLGS) was used in conjunction with virtual RLGS to identify 150 TDMs [Matsuyama, T., Kimura, M.T., Koike, K., Abe, T., Nakao, T., Asami, T., Ebisuzaki, T., Held, W.A., Yoshida, S. & Nagase, H. (2003) Nucleic Acids Res. 31, 4490-4496]. Analysis of 14 TDMs by methylation-specific PCR and by bisulfite genomic sequencing confirms that the regions identified by RLGS are differentially methylated in a tissue-specific manner. The results indicate that 5% or more of the CpG islands are TDMs, disputing the general notion that all CpG islands are unmethylated. Some of the TDMs are within 5' promoter CpG islands of genes, which exhibit a tissue-specific expression pattern that is consistent with methylation status and a role in tissue differentiation.
早期研究表明，DNA甲基化可能在发育过程中对基因表达具有调控作用[里格斯，A.D.（1975年）《细胞遗传学与细胞遗传学》14卷，第9 - 25页]。然而，一些关于发育过程中已知组织特异性基因的DNA甲基化研究并不支持DNA甲基化起主要作用。在本文给出的结果中，首先鉴定出组织特异性差异甲基化区域（TDMs），然后将与这些区域相关的基因表达与甲基化状态进行关联。限制酶切位点基因组扫描（RLGS）与虚拟RLGS结合使用，以鉴定150个TDMs[松山，T.，木村，M.T.，小池，K.，阿部，T.，中尾，T.，浅见，T.，海老崎，T.，赫尔德，W.A.，吉田，S.和长濑，H.（2003年）《核酸研究》31卷，第4490 - 4496页]。通过甲基化特异性PCR和亚硫酸氢盐基因组测序对14个TDMs进行分析，证实了RLGS鉴定出的区域以组织特异性方式存在差异甲基化。结果表明，5%或更多的CpG岛是TDMs，这与所有CpG岛均未甲基化的普遍观念相矛盾。一些TDMs位于基因的5'启动子CpG岛内，这些基因呈现出与甲基化状态一致的组织特异性表达模式，并在组织分化中发挥作用。
