51. Two Components of the RNA-Directed DNA Methylation Pathway Associate with MORC6 and Silence Loci Targeted by MORC6 in Arabidopsis
- Author
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Yong-Qiang Li, Huan-Wei Huang, Tao Cai, Chang-Rong Shao, Xin-Jian He, Jin-Xing Zhou, Lin Li, Zhang-Wei Liu, and She Chen
- Subjects
0301 basic medicine ,Cancer Research ,Transcription, Genetic ,Biochemistry ,Sequencing techniques ,Gene Expression Regulation, Plant ,Heterochromatin ,Arabidopsis ,Small interfering RNAs ,RNA-Directed DNA Methylation ,Genetics (clinical) ,Adenosine Triphosphatases ,Genetics ,DNA methylation ,biology ,Nucleotides ,Organic Compounds ,RNA-Binding Proteins ,RNA sequencing ,Chromatin ,Nucleic acids ,Chemistry ,Physical Sciences ,Epigenetics ,DNA modification ,Chromatin modification ,Research Article ,Chromosome biology ,Cell biology ,RNA-induced transcriptional silencing ,lcsh:QH426-470 ,DNA transcription ,Cytosine ,03 medical and health sciences ,Epigenetics of physical exercise ,Gene silencing ,Gene Silencing ,Non-coding RNA ,Molecular Biology ,Ecology, Evolution, Behavior and Systematics ,RNA, Double-Stranded ,Biology and life sciences ,Arabidopsis Proteins ,Organic Chemistry ,Chemical Compounds ,Histone-Lysine N-Methyltransferase ,Methyltransferases ,DNA ,Chromatin Assembly and Disassembly ,biology.organism_classification ,Gene regulation ,Research and analysis methods ,lcsh:Genetics ,Pyrimidines ,Molecular biology techniques ,030104 developmental biology ,Genetic Loci ,RNA ,Gene expression - Abstract
The SU(VAR)3-9 homolog SUVH9 and the double-stranded RNA-binding protein IDN2 were thought to be components of an RNA-directed DNA methylation (RdDM) pathway in Arabidopsis. We previously found that SUVH9 interacts with MORC6 but how the interaction contributes to transcriptional silencing remains elusive. Here, our genetic analysis indicates that SUVH2 and SUVH9 can either act in the same pathway as MORC6 or act synergistically with MORC6 to mediate transcriptional silencing. Moreover, we demonstrate that IDN2 interacts with MORC6 and mediates the silencing of a subset of MORC6 target loci. Like SUVH2, SUVH9, and IDN2, other RdDM components including Pol IV, Pol V, RDR2, and DRM2 are also required for transcriptional silencing at a subset of MORC6 target loci. MORC6 was previously shown to mediate transcriptional silencing through heterochromatin condensation. We demonstrate that the SWI/SNF chromatin-remodeling complex components SWI3B, SWI3C, and SWI3D interact with MORC6 as well as with SUVH9 and then mediate transcriptional silencing. These results suggest that the RdDM components are involved not only in DNA methylation but also in MORC6-mediated heterochromatin condensation. This study illustrates how DNA methylation is linked to heterochromatin condensation and thereby enhances transcriptional silencing at methylated genomic regions., Author Summary DNA methylation is a conserved epigenetic mark that is required for the silencing of transposons and introduced transgenes in eukaryotes. An RNA-directed DNA methylation pathway mediates de novo DNA methylation and thereby leads to transcriptional silencing in Arabidopsis. In this study, we find that two RNA-directed DNA methylation components interact with the microrchidia (MORC) protein MORC6 and lead to transcriptional silencing through a mechanism that is distinct from the RNA-directed DNA methylation pathway. MORC6 was previously thought to mediate transcriptional silencing through heterochromatin condensation. Our study suggests that the interaction of the RNA-directed DNA methylation components with MORC6 may mediate a link between DNA methylation and heterochromatin condensation.
- Published
- 2016