Reboulleau C P, Williams J, Randolph V A, Shapiro H S
Biochim Biophys Acta. 1983 Jun 24;740(2):145-51. doi: 10.1016/0167-4781(83)90071-4.
The extent of single-strand nicks in DNA from murine erythroleukemia cells induced to differentiate to hemoglobin synthesis in the presence of the hypomethylating agent ethionine was estimated and compared to those levels in uninduced cells and from cells induced to differentiate upon exposure to dimethylsulfoxide or butyrate ion. Although ethionine has been shown to cause more extensive hypomethylation in the DNA of induced cells than that caused by dimethylsulfoxide or butyrate ion, the frequency of detected single-strand breaks in the DNA of uninduced, control cells was not significantly different from that of cells exposed to any of these inducing chemicals. This data indicates that no correlation exists between DNA hypomethylation and DNA single-strand breaks and that unmethylated CpG loci likely do not operate as specific endonuclease recognition sites or as potential origins of transcription in these mammalian cells.
对在存在低甲基化剂乙硫氨酸的情况下诱导分化为血红蛋白合成的小鼠红白血病细胞DNA中的单链切口程度进行了估计，并与未诱导细胞以及暴露于二甲基亚砜或丁酸盐离子后诱导分化的细胞中的水平进行了比较。尽管已表明乙硫氨酸在诱导细胞的DNA中引起的低甲基化比二甲基亚砜或丁酸盐离子引起的更广泛，但未诱导的对照细胞DNA中检测到的单链断裂频率与暴露于任何这些诱导化学物质的细胞的频率没有显著差异。该数据表明DNA低甲基化与DNA单链断裂之间不存在相关性，并且未甲基化的CpG位点在这些哺乳动物细胞中可能不作为特定的内切核酸酶识别位点或潜在的转录起始点起作用。
