A structural-maintenance-of-chromosomes hinge domain-containing protein is required for RNA-directed DNA methylation.
RNA-directed DNA methylation (RdDM) is a process in which dicer-generated small RNAs guide de novo cytosine methylation at the homologous DNA region. To identify components of the RdDM machinery important for Arabidopsis thaliana development, we targeted an enhancer active in meristems for methylation, which resulted in silencing of a downstream GFP reporter gene. This silencing system also features secondary siRNAs, which trigger methylation that spreads beyond the targeted enhancer region. A screen for mutants defective in meristem silencing and enhancer methylation retrieved six dms complementation groups, which included the known factors DRD1 (ref. 3; a SNF2-like chromatin-remodeling protein) and Pol IVb subunits. Additionally, we identified a previously unknown gene DMS3 (At3g49250), encoding a protein similar to the hinge-domain region of structural maintenance of chromosomes (SMC) proteins. This finding implicates a putative chromosome architectural protein that can potentially link nucleic acids in facilitating an RNAi-mediated epigenetic modification involving secondary siRNAs and spreading of DNA methylation.
Kanno
Tatsuo
T
Gregor Mendel Institute for Molecular Plant Biology, Austrian Academy of Sciences, Dr. Bohrgasse 3, A-1030 Vienna, Austria.
Bucher
Etienne
E
Daxinger
Lucia
L
Huettel
Bruno
B
Böhmdorfer
Gudrun
G
Gregor
Wolfgang
W
Kreil
David P
DP
Matzke
Marjori
M
Matzke
Antonius J M
AJ
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation; D018744:DNA, Plant / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D044127:Epigenesis, Genetic; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D018519:Meristem / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D018749:RNA, Plant / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism*
D029681:Arabidopsis Proteins; D002868:Chromosomal Proteins, Non-Histone; C529025:DMS3 protein, Arabidopsis; D018744:DNA, Plant; D018749:RNA, Plant; D034741:RNA, Small Interfering; D049452:Green Fluorescent Proteins; C499181:RNA polymerase IV, Arabidopsis; D012321:DNA-Directed RNA Polymerases; C504888:DRD1 protein, Arabidopsis