title: ARGONAUTE4 control of locus-specific siRNA accumulation and DNA and histone methylation.
abstract: Proteins of the ARGONAUTE family are important in diverse posttranscriptional RNA-mediated gene-silencing systems as well as in transcriptional gene silencing in Drosophila and fission yeast and in programmed DNA elimination in Tetrahymena. We cloned ARGONAUTE4 (AGO4) from a screen for mutants that suppress silencing of the Arabidopsis SUPERMAN (SUP) gene. The ago4-1 mutant reactivated silent SUP alleles and decreased CpNpG and asymmetric DNA methylation as well as histone H3 lysine-9 methylation. In addition, ago4-1 blocked histone and DNA methylation and the accumulation of 25-nucleotide small interfering RNAs (siRNAs) that correspond to the retroelement AtSN1. These results suggest that AGO4 and long siRNAs direct chromatin modifications, including histone methylation and non-CpG DNA methylation.
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, Molecular Biology Institute, University of California, Los Angeles, CA 90095-1606.
authors.forename: Daniel
authors.initials: D
authors.lastname: Zilberman
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Cao
authors.forename: Steven E
authors.initials: SE
authors.lastname: Jacobsen
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D060565:Argonaute Proteins; D003001:Cloning, Molecular; D019175:DNA Methylation; D018744:DNA, Plant / Q000378:metabolism; D015257:DNA-Cytosine Methylases / Q000235:genetics / Q000378:metabolism; D015226:Dinucleoside Phosphates / Q000378:metabolism; D020868:Gene Silencing; D017343:Genes, Plant; D016153:Genes, Suppressor; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones / Q000378:metabolism*; D008745:Methylation; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D018749:RNA, Plant / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D018626:Retroelements; D013489:Suppression, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; D018744:DNA, Plant; D015257:DNA-Cytosine Methylases; D015226:Dinucleoside Phosphates; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones; D008780:Methyltransferases; D018749:RNA, Plant; D034741:RNA, Small Interfering; D018626:Retroelements; D014157:Transcription Factors; C471209:AGO4 protein, Arabidopsis; C096661:superman protein, Arabidopsis; C015772:CpG dinucleotide; C429766:CMT3 protein, Arabidopsis; C470731:DRM1 protein, Arabidopsis; C470732:DRM2 protein, Arabidopsis; C471228:SUVH4 protein, Arabidopsis