Inhibition of Dicing of Guanosine-Rich shRNAs by Quadruplex-Binding Compounds
Inhibition of Dicing of Guanosine-Rich shRNAs by Quadruplex-Binding Compounds
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DOI：
10.1002/cbic.200800271
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发表时间：
2008-11-03
期刊：
影响因子：
3.2
通讯作者：
Hartig, Joerg S.
中科院分区：
文献类型：
--
作者：
Henn, Anja;Joachimi, Astrid;Hartig, Joerg S.
RNA干扰由小发夹前体触发，所述小发夹前体被核酸内切酶切割器加工以产生活性物质，如siRNA和miRNA。为了调节RNAi介导的基因表达抑制，我们设想了一种策略，该策略依赖于通过直接RNA-小分子相互作用对shRNA前体加工的序列特异性抑制。在这里，我们提出了在这个方向上的第一步，通过增加shRNAs与guanosinerich序列，易于折叠成四链结构。添加选择性结合到这样的四链体序列的小分子应该允许特异性抑制含有合适的富含G的元件的shRNA的切割。在试图找到防止切割加工的化合物时，我们已经检查了四链体结合化合物对含有G-四链体的shRNA的切割加工的影响。尽管已知与四链体结合的各种小分子抑制了shRNA的体外切割，但与缺乏富含鸟嘌呤的元件的对照序列相比，只有两种物质类别，即某些四氮杂卟啉和双喹啉化合物，显示出对富含G的shRNA的选择性抑制。富含G的shRNA在哺乳动物细胞培养物中显示出对基因表达的有效敲低，但该效果不受添加相应四链体结合化合物的影响。
RNA interference is triggered by small hairpin precursors that are processed by the endonuclease dicer to yield active species such as siRNAs and miRNAs. To regulate the RNAi-mediated suppression of gene expression, we imagined a strategy that relies on the sequence-specific inhibition of shRNA precursor processing by immediate RNA-small molecule interactions. Here, we present a first step in this direction by augmenting shRNAs with guanosinerich sequences that are prone to fold into four-stranded structures. The addition of small molecules that selectively bind to such quadruplex sequences should allow for the specific inhibition of dicing of shRNAs that contain suitable G-rich elements. In an attempt to find compounds that protect against dicer processing, we have examined the effects of quadruplex-binding compounds on the dicer processing of shRNAs containing G-quadruplexes. Although a variety of small molecules that are known to bind to quadruplexes inhibited in vitro dicing of shRNAs, only two substance classes, namely certain porphyrazines and bisquinolinium compounds, showed selective inhibition of G-rich shRNAs compared to control sequences lacking guanine-rich elements. The G-rich shRNAs displayed a potent knockdown of gene expression in mammalian cell culture, but the effect was not influenced by addition of the respective quadruplex-binding compounds.