Wang Xiufang, Ma Zhihong, Kong Xianglong, Lv Zhanjun
Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, Hebei Province, China.
Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, Hebei Province, China; Clinical Laboratory, The Second Hospital of Tangshan, 21 North Jianshe Road, Tangshan, Hebei Province, China.
Int J Biochem Cell Biol. 2016 Oct;79:24-32. doi: 10.1016/j.biocel.2016.08.004. Epub 2016 Aug 3.
The study of the interaction between RNA and DNA sequences in activating genes has important significance for understanding the mechanisms of RNA-mediated activation. Here, we used in vitro chromatin reconstitution approach to observe whether RNAs increase DNase I digestion, plasmid transfection to observe whether RNAs promote gene expression, and bioinformatics analysis to predict the binding ability of RNAs to centromere DNA (constitutive heterochromatin). Synthetic RNAs (23nt) that were complementary to mouse albumin gene and total liver RNA increased DNase I digestion sensitivity of mouse albumin gene, suggesting that RNAs can increase chromatin accessibility. Transcribed sense-antisense tandem Alu elements activated an enhanced green fluorescent protein reporter gene after stable transfection. Bioinformatics analysis showed that the binding strength of RNA population to centromere DNAs is significantly lower than that of their flanking sequences, which suggests that the centromere is not easily affected by RNAs produced from other transcribed regions and may be the reason why centromeres consist of constitutive heterochromatin. The results in this paper illustrate that RNAs complementary to DNA sequences play roles in activating genes. Since RNA is mainly produced from the cell's own DNA, the work presented in this paper suggests that RNAs transcribed from DNA create feedback that activates DNA transcription.
研究RNA与DNA序列在激活基因过程中的相互作用，对于理解RNA介导的激活机制具有重要意义。在此，我们采用体外染色质重构方法来观察RNA是否会增加DNA酶I消化，通过质粒转染来观察RNA是否促进基因表达，并利用生物信息学分析来预测RNA与着丝粒DNA（组成型异染色质）的结合能力。与小鼠白蛋白基因互补的合成RNA（23nt）以及肝脏总RNA增加了小鼠白蛋白基因对DNA酶I消化的敏感性，这表明RNA能够增加染色质的可及性。转录的正义-反义串联Alu元件在稳定转染后激活了增强型绿色荧光蛋白报告基因。生物信息学分析表明，RNA群体对着丝粒DNA的结合强度显著低于其侧翼序列，这表明着丝粒不易受到其他转录区域产生的RNA的影响，这可能是着丝粒由组成型异染色质构成的原因。本文的结果表明，与DNA序列互补的RNA在激活基因中发挥作用。由于RNA主要由细胞自身的DNA产生，本文所展示的工作表明，由DNA转录产生的RNA会产生反馈从而激活DNA转录。
