Publication Date:
2014-01-28
Description:
RNA-directed DNA methylation in Arabidopsis thaliana depends on the upstream synthesis of 24-nucleotide small interfering RNAs (siRNAs) by RNA POLYMERASE IV (Pol IV) and downstream synthesis of non-coding transcripts by Pol V. Pol V transcripts are thought to interact with siRNAs which then recruit DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2) to methylate DNA. The SU(VAR)3-9 homologues SUVH2 and SUVH9 act in this downstream step but the mechanism of their action is unknown. Here we show that genome-wide Pol V association with chromatin redundantly requires SUVH2 and SUVH9. Although SUVH2 and SUVH9 resemble histone methyltransferases, a crystal structure reveals that SUVH9 lacks a peptide-substrate binding cleft and lacks a properly formed S-adenosyl methionine (SAM)-binding pocket necessary for normal catalysis, consistent with a lack of methyltransferase activity for these proteins. SUVH2 and SUVH9 both contain SRA (SET- and RING-ASSOCIATED) domains capable of binding methylated DNA, suggesting that they function to recruit Pol V through DNA methylation. Consistent with this model, mutation of DNA METHYLTRANSFERASE 1 (MET1) causes loss of DNA methylation, a nearly complete loss of Pol V at its normal locations, and redistribution of Pol V to sites that become hypermethylated. Furthermore, tethering SUVH2 with a zinc finger to an unmethylated site is sufficient to recruit Pol V and establish DNA methylation and gene silencing. These results indicate that Pol V is recruited to DNA methylation through the methyl-DNA binding SUVH2 and SUVH9 proteins, and our mechanistic findings suggest a means for selectively targeting regions of plant genomes for epigenetic silencing.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3963826/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3963826/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Johnson, Lianna M -- Du, Jiamu -- Hale, Christopher J -- Bischof, Sylvain -- Feng, Suhua -- Chodavarapu, Ramakrishna K -- Zhong, Xuehua -- Marson, Giuseppe -- Pellegrini, Matteo -- Segal, David J -- Patel, Dinshaw J -- Jacobsen, Steven E -- F32GM096483-01/GM/NIGMS NIH HHS/ -- GM60398/GM/NIGMS NIH HHS/ -- P30 CA016042/CA/NCI NIH HHS/ -- R37 GM060398/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2014 Mar 6;507(7490):124-8. doi: 10.1038/nature12931. Epub 2014 Jan 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA [2]. ; 1] Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA [2]. ; Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA. ; 1] Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA [2] Howard Hughes Medical Institute, University of California at Los Angeles, Los Angeles, California 90095, USA. ; 1] Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA [2] Wisconsin Institute for Discovery, Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA. ; Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA. ; Genome Center and Department of Biochemistry and Molecular Medicine, University of California at Davis, Davis, California 95616, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24463519" target="_blank"〉PubMed〈/a〉
Keywords:
*Arabidopsis/enzymology/genetics
;
Arabidopsis Proteins/*chemistry/genetics/*metabolism
;
Binding Sites/genetics
;
Biocatalysis
;
Chromatin/chemistry/genetics/metabolism
;
Crystallography, X-Ray
;
DNA (Cytosine-5-)-Methyltransferase/genetics/metabolism
;
*DNA Methylation/genetics
;
DNA-Binding Proteins/chemistry/metabolism
;
DNA-Directed RNA Polymerases/*metabolism
;
Flowers/growth & development
;
Gene Expression Regulation, Plant
;
Gene Silencing
;
Genome, Plant/genetics
;
Histone-Lysine N-Methyltransferase/*chemistry/*metabolism
;
Models, Molecular
;
Mutation/genetics
;
Phenotype
;
Protein Structure, Tertiary
;
Protein Transport
;
RNA, Plant/biosynthesis/genetics/metabolism
;
RNA, Small Interfering/biosynthesis/genetics/metabolism
;
Transcription, Genetic
;
Zinc Fingers
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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