Ioudinkova Elena, Verbovaia Lilia, Kadulin Sergey, Goldman Igor, Razin Sergey V
Laboratory of Structural and Functional Organization of Chromosomes, Institute of Gene Biology RAS, 119334 Moscow, Russia.
J Cell Biochem. 2004 May 1;92(1):99-103. doi: 10.1002/jcb.20023.
It is demonstrated that a heterologous (chicken) CpG island containing five Sp1 canonical recognition sequences becomes highly methylated in the genome of transgenic mice bearing one or several copies of the transgene. Similar levels of methylation of the chicken CpG island were observed in different tissues of transgenic mice except the brain where the level of methylation of this chicken CpG-rich fragment was significantly lower than in other tissues. Analysis of susceptibility of the "transgenic" CpG island to Hpa II and Msp I restriction nucleases revealed an unusual methylation pattern interfering with the action of both of these enzymes. A conclusion has been drawn that heterologous CpG island per se does not contain all necessary signals permitting to maintain its own non-methylated status in the genome of transgenic animals.
已证明，含有五个Sp1典型识别序列的异源（鸡）CpG岛在携带一个或多个转基因拷贝的转基因小鼠基因组中高度甲基化。在转基因小鼠的不同组织中观察到鸡CpG岛的甲基化水平相似，但在大脑中，这个富含鸡CpG的片段的甲基化水平明显低于其他组织。对“转基因”CpG岛对Hpa II和Msp I限制性核酸酶的敏感性分析揭示了一种异常的甲基化模式，这种模式干扰了这两种酶的作用。得出的结论是，异源CpG岛本身并不包含在转基因动物基因组中维持其自身非甲基化状态所需的所有信号。
