Dataset Information

Specific but interdependent functions for Arabidopsis AGO4 and AGO6 in RNA-directed DNA methylation.

ABSTRACT: Argonaute (AGO) family proteins are conserved key components of small RNA-induced silencing pathways. In the RNA-directed DNA methylation (RdDM) pathway in Arabidopsis, AGO6 is generally considered to be redundant with AGO4. In this report, our comprehensive, genomewide analyses of AGO4- and AGO6-dependent DNA methylation revealed that redundancy is unexpectedly negligible in the genetic interactions between AGO4 and AGO6. Immunofluorescence revealed that AGO4 and AGO6 differ in their subnuclear co-localization with RNA polymerases required for RdDM. Pol II and AGO6 are absent from perinucleolar foci, where Pol V and AGO4 are co-localized. In the nucleoplasm, AGO4 displays a strong co-localization with Pol II, whereas AGO6 co-localizes with Pol V. These patterns suggest that RdDM is mediated by distinct, spatially regulated combinations of AGO proteins and RNA polymerases. Consistently, Pol II physically interacts with AGO4 but not AGO6, and the levels of Pol V-dependent scaffold RNAs and Pol V chromatin occupancy are strongly correlated with AGO6 but not AGO4. Our results suggest that AGO4 and AGO6 mainly act sequentially in mediating small RNA-directed DNA methylation.

SUBMITTER: Duan CG

PROVIDER: S-EPMC4365029 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature

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Specific but interdependent functions for Arabidopsis AGO4 and AGO6 in RNA-directed DNA methylation.

Duan Cheng-Guo CG Zhang Huiming H Tang Kai K Zhu Xiaohong X Qian Weiqiang W Hou Yueh-Ju YJ Wang Bangshing B Lang Zhaobo Z Zhao Yang Y Wang Xingang X Wang Pengcheng P Zhou Jianping J Liang Gaimei G Liu Na N Wang Chunguo C Zhu Jian-Kang JK

The EMBO journal 20141219 5

Argonaute (AGO) family proteins are conserved key components of small RNA-induced silencing pathways. In the RNA-directed DNA methylation (RdDM) pathway in Arabidopsis, AGO6 is generally considered to be redundant with AGO4. In this report, our comprehensive, genomewide analyses of AGO4- and AGO6-dependent DNA methylation revealed that redundancy is unexpectedly negligible in the genetic interactions between AGO4 and AGO6. Immunofluorescence revealed that AGO4 and AGO6 differ in their subnuclear ...[more]

PMID: 25527293

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Project description:RNA-directed DNA methylation (RdDM) is a biological process in which non-coding RNA molecules direct the addition of DNA methylation to specific DNA sequences. The RdDM pathway is unique to plants, although other mechanisms of RNA-directed chromatin modification have also been described in fungi and animals. To date, the RdDM pathway is best characterized within angiosperms (flowering plants), and particularly within the model plant Arabidopsis thaliana. However, conserved RdDM pathway components and associated small RNAs (sRNAs) have also been found in other groups of plants, such as gymnosperms and ferns. The RdDM pathway closely resembles other sRNA pathways, particularly the highly conserved RNAi pathway found in fungi, plants, and animals. Both the RdDM and RNAi pathways produce sRNAs and involve conserved Argonaute, Dicer and RNA-dependent RNA polymerase proteins. RdDM has been implicated in a number of regulatory processes in plants. The DNA methylation added by RdDM is generally associated with transcriptional repression of the genetic sequences targeted by the pathway. Since DNA methylation patterns in plants are heritable, these changes can often be stably transmitted to progeny. As a result, one prominent role of RdDM is the stable, transgenerational suppression of transposable element (TE) activity. RdDM has also been linked to pathogen defense, abiotic stress responses, and the regulation of several key developmental transitions. Although the RdDM pathway has a number of important functions, RdDM-defective mutants in Arabidopsis thaliana are viable and can reproduce, which has enabled detailed genetic studies of the pathway. However, RdDM mutants can have a range of defects in different plant species, including lethality, altered reproductive phenotypes, TE upregulation and genome instability, and increased pathogen sensitivity. Overall, RdDM is an important pathway in plants that regulates a number of processes by establishing and reinforcing specific DNA methylation patterns, which can lead to transgenerational epigenetic effects on gene expression and phenotype.

Dataset Information

Specific but interdependent functions for Arabidopsis AGO4 and AGO6 in RNA-directed DNA methylation.

Publications

Specific but interdependent functions for Arabidopsis AGO4 and AGO6 in RNA-directed DNA methylation.

Similar Datasets

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