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| Subject Categories: Chromatin & Transcription | Plant Biology |
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| The EMBO Journal
(2007) 26, 1691–1701, doi:10.1038/sj.emboj.7601603 Published online 1 March 2007 |
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| Role of Arabidopsis AGO6 in siRNA accumulation, DNA methylation and transcriptional gene silencing |
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| Xianwu Zheng, Jianhua Zhu, Avnish Kapoor and Jian-Kang Zhu |
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Department of Botany and Plant Sciences, University of California, CA, USA To whom correspondence should be addressed Jian-Kang Zhu, Department of Botany and Plant Sciences, University of California, 2150 Batchelor Hall, University of California, Riverside, CA 92521, USA. Tel.: +1 951 827 7117; Fax: +1 951 827 4437; E-mail: jian-kang.zhu@ucr.edu Received 17 July 2006; Accepted 24 January 2007; Published online 1 March 2007. |
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| Abstract |
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| Argonautes (AGOs) are conserved proteins that contain an RNA-binding PAZ domain and an RNase H-like PIWI domain. In Arabidopsis, except for AGO1, AGO4 and AGO7, the roles of seven other AGOs in gene silencing are not known. We found that a mutation in AGO6 partially suppresses transcriptional gene silencing in the DNA demethylase mutant ros1-1. In ago6-1ros1-1 plants, RD29A promoter short interfering RNAs (siRNAs) are less abundant, and cytosine methylation at both transgenic and endogenous RD29A promoters is reduced, compared to that in ros1-1. Interestingly, the ago4-1 mutation has a stronger suppression of the transcriptional silencing phenotype of ros1-1 mutant. Analysis of cytosine methylation at the endogenous MEA-ISR, AtREP2 and SIMPLEHAT2 loci revealed that the CpNpG and asymmetric methylation levels are lower in either of the ago6-1 and ago4-1 single mutants than those in the wild type, and the levels are the lowest in the ago6-1ago4-1 double mutant. These results suggest that AGO6 is important for the accumulation of specific heterochromatin-related siRNAs, and for DNA methylation and transcriptional gene silencing, this function is partly redundant with AGO4. |
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| Keywords: Argonaute, RNA-directed DNA methylation, silencing, small RNA |
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Top of page MORE ARTICLES LIKE THISThese links to content published by NPG are automatically generated RESEARCHRole of Arabidopsis AGO6 in siRNA accumulation, DNA methylation and transcriptional gene silencing The EMBO Journal Article Distinct catalytic and non-catalytic roles of ARGONAUTE4 in RNA-directed DNA methylation Nature Letters to Editor (26 Oct 2006) Nature Genetics Letter (01 Jun 2006) The EMBO Journal Article (16 Dec 2002) |
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