tRNA genes protect a reporter gene from epigenetic silencing in mouse cells
tRNA genes protect a reporter gene from epigenetic silencing in mouse cells
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DOI：
10.4161/cc.10.16.17092
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发表时间：
2011-08-15
期刊：
影响因子：
4.3
通讯作者：
Larionov, Vladimir
中科院分区：
文献类型：
--
作者：
Ebersole, Thomas;Kim, Jung-Hyun;Larionov, Vladimir
tRNA基因在酵母中具有染色质屏障元件的功能，这是一个公认的事实。然而，到目前为止，没有实验证据表明tRNA和其他pol - iii转录基因在哺乳动物中表现出屏障活性。本研究利用最近开发的报告基因试验来测试一组pol - iii转录基因和具有可变启动子和基因间区域的基因簇，以防止小鼠细胞中异染色质介导的报告基因沉默的能力。结果表明，小鼠tRNA基因的功能拷贝是有效的屏障元件。tRNA基因的数量及其取向影响屏障功能。此外，中间区域和侧翼区域的DNA序列组成影响tRNA基因的屏障活性。当tRNA基因的中间和侧翼区域被富含at的序列取代时，屏障活性维持的时间要长得多，这表明DNA甲基化在功能屏障的建立中起负作用。因此，我们的研究结果表明，tRNA基因是哺乳动物细胞中染色质结构域结构建立和维持的基本要素。
It is a well-established fact that the tRNA genes in yeast can function as chromatin barrier elements. However, so far there is no experimental evidence that tRNA and other Pol-III-transcribed genes exhibit barrier activity in mammals. This study utilizes a recently developed reporter gene assay to test a set of Pol-III-transcribed genes and gene clusters with variable promoter and intergenic regions for their ability to prevent heterochromatin-mediated reporter gene silencing in mouse cells. The results show that functional copies of mouse tRNA genes are effective barrier elements. The number of tRNA genes as well as their orientation influence barrier function. Furthermore, the DNA sequence composition of intervening and flanking regions affects barrier activity of tRNA genes. Barrier activity was maintained for much longer time when the intervening and flanking regions of tRNA genes were replaced by AT-rich sequences, suggesting a negative role of DNA methylation in the establishment of a functional barrier. Thus, our results suggest that tRNA genes are essential elements in establishment and maintenance of chromatin domain architecture in mammalian cells.