Hypomethylating drugs efficiently decrease cytosine methylation in telomeric DNA and activate telomerase without affecting telomere lengths in tobacco cells
Hypomethylating drugs efficiently decrease cytosine methylation in telomeric DNA and activate telomerase without affecting telomere lengths in tobacco cells
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DOI：
10.1007/s11103-011-9816-7
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发表时间：
2011-11-01
影响因子：
5.1
通讯作者：
Fajkus, Jiri
中科院分区：
文献类型：
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作者：
Majerova, Eva;Fojtova, Miloslava;Fajkus, Jiri
端粒稳态在多个水平上受到调节，包括端粒和亚端粒的局部染色质结构。最近的报道表明，抑制性染色质标记的减少，如亚端粒区域的胞嘧啶甲基化水平的降低，导致小鼠细胞中的端粒延长。在这里，我们表明，相当一部分的胞嘧啶甲基化不仅在亚端粒，但也在烟草BY-2细胞的端粒DNA。药物诱导的低甲基化（表现在亚端粒，端粒和全球DNA水平）导致端粒酶的激活。然而，与小鼠细胞相比，5-甲基胞嘧啶水平的降低和端粒酶的上调不会导致端粒长度的任何变化。这些结果表明，在植物细胞中的端粒酶活性的调节的多层次的过程中的表观遗传机制的参与，并在同一时间，他们表明，端粒酶活性的变化可以被其他因素支配端粒长度的稳定性。
Telomere homeostasis is regulated at multiple levels, including the local chromatin structure of telomeres and subtelomeres. Recent reports demonstrated that a decrease in repressive chromatin marks, such as levels of cytosine methylation in subtelomeric regions, results in telomere elongation in mouse cells. Here we show that a considerable fraction of cytosines is methylated not only in subtelomeric, but also in telomeric DNA of tobacco BY-2 cells. Drug-induced hypomethylation (demonstrated at subtelomeric, telomeric, and global DNA levels) results in activation of telomerase. However, in contrast to mouse cells, the decrease in 5-methylcytosine levels and upregulation of telomerase do not result in any changes of telomere lengths. These results demonstrate the involvement of epigenetic mechanisms in the multilevel process of regulation of telomerase activity in plant cells and, at the same time, they indicate that changes in telomerase activity can be overridden by other factors governing telomere length stability.