| 论文题目: | Genome-wide identification of endogenous RNA-directed DNA methylation loci associated with abundant 21-nucleotide siRNAs in Arabidopsis |
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| 作者: | Zhao, Jian-Hua Fang, Yuan-Yuan Duan, Cheng-Guo Fang, Rong-Xiang Ding, Shou-Wei Guo, Hui-Shan |
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| 刊物名称: | Sci Rep |
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| 年份: | 2016 |
| 影响因子: | 5.525 |
| 论文下载: | http://www.nature.com/articles/srep36247 |
| 摘要: | In Arabidopsis, the 24-nucleotide (nt) small interfering RNAs (siRNAs) mediates RNA-directed DNA methylation (RdDM) and transcriptional gene silencing (TGS) of transposable elements (TEs). In the present study, we examined genome-wide changes in DNA methylation and siRNA accumulation in Arabidopsis induced by expression of the Cucumber mosaic virus silencing suppressor protein 2b known to directly bind to both the 21/24-nt siRNAs as well as their associated Argonaute proteins. We demonstrated a genome-wide reduction of CHH and CHG methylation in the 2b-transgenic plants. We found that 2b suppressed RdDM not only at the previously annotated loci directed by 24-nt siRNAs but also a new set of loci associated with 21/22-nt siRNAs. Further analysis showed that the reduced methylation of TEs and coding genes targeted by 21/22-nt siRNAs was associated with sequestration of the duplex siRNAs by the 2b protein but not with changes in either siRNA production or transcription. Notably, we detected both the deletion and/or the transposition of multicopy TEs associated with 2b-induced hypomethylation, suggesting potential TE reactivation. We propose that the silencing of many TEs in Arabidopsis is controlled by the 24- and 21-nt endogenous siRNAs analogous to Drosophila TE silencing by PIWI-interacting RNAs and siRNAs. |
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