title: RNA polymerase IV directs silencing of endogenous DNA.
abstract: Plants encode subunits for a fourth RNA polymerase (Pol IV) in addition to the well-known DNA-dependent RNA polymerases I, II, and III. By mutation of the two largest subunits (NRPD1a and NRPD2), we show that Pol IV silences certain transposons and repetitive DNA in a short interfering RNA pathway involving RNA-dependent RNA polymerase 2 and Dicer-like 3. The existence of this distinct silencing polymerase may explain the paradoxical involvement of an RNA silencing pathway in maintenance of transcriptional silencing.
authors.affiliation: Sainsbury Laboratory, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Herr
authors.forename: M B
authors.initials: MB
authors.lastname: Jensen
authors.forename: T
authors.initials: T
authors.lastname: Dalmay
authors.forename: D C
authors.initials: DC
authors.lastname: Baulcombe
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002843:Chromatin / Q000378:metabolism; D019175:DNA Methylation; D004251:DNA Transposable Elements; D018744:DNA, Plant / Q000235:genetics* / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020868:Gene Silencing; D017343:Genes, Plant; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000201:enzymology / Q000235:genetics; D030821:Plants, Genetically Modified; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012319:RNA Polymerase II / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D019076:Transgenes
chemical_list: D029681:Arabidopsis Proteins; D002843:Chromatin; D004251:DNA Transposable Elements; D018744:DNA, Plant; D021122:Protein Subunits; D018749:RNA, Plant; D034741:RNA, Small Interfering; D049452:Green Fluorescent Proteins; D012319:RNA Polymerase II; C499181:RNA polymerase IV, Arabidopsis; D012321:DNA-Directed RNA Polymerases