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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Alleles
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Arabidopsis / genetics
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Arabidopsis / metabolism*
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Arabidopsis Proteins / chemistry
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Arabidopsis Proteins / genetics*
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Arabidopsis Proteins / metabolism*
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Argonaute Proteins
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Cloning, Molecular
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DNA Methylation*
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DNA, Plant / metabolism
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DNA-Cytosine Methylases / genetics
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DNA-Cytosine Methylases / metabolism
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Dinucleoside Phosphates / metabolism
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Gene Silencing
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Genes, Plant
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Genes, Suppressor
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Histone-Lysine N-Methyltransferase
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Histones / metabolism*
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Methylation
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Methyltransferases / genetics
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Methyltransferases / metabolism
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Mutation
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RNA, Plant / metabolism
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RNA, Small Interfering / metabolism*
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Retroelements
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Suppression, Genetic
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Transcription Factors / genetics
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Transcription Factors / metabolism
Substances
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AGO4 protein, Arabidopsis
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Arabidopsis Proteins
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Argonaute Proteins
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DNA, Plant
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Dinucleoside Phosphates
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Histones
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RNA, Plant
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RNA, Small Interfering
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Retroelements
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Transcription Factors
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superman protein, Arabidopsis
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cytidylyl-3'-5'-guanosine
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DNA-Cytosine Methylases
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Methyltransferases
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CMT3 protein, Arabidopsis
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DRM1 protein, Arabidopsis
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DRM2 protein, Arabidopsis
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Histone-Lysine N-Methyltransferase
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SUVH4 protein, Arabidopsis