title: RNA polymerase IV functions in paramutation in Zea mays.
abstract: Plants have distinct RNA polymerase complexes (Pol IV and Pol V) with largely unknown roles in maintaining small RNA-associated gene silencing. Curiously, the eudicot Arabidopsis thaliana is not affected when either function is lost. By use of mutation selection and positional cloning, we showed that the largest subunit of the presumed maize Pol IV is involved in paramutation, an inherited epigenetic change facilitated by an interaction between two alleles, as well as normal maize development. Bioinformatics analyses and nuclear run-on transcription assays indicate that Pol IV does not engage in the efficient RNA synthesis typical of the three major eukaryotic DNA-dependent RNA polymerases. These results indicate that Pol IV employs abnormal RNA polymerase activities to achieve genome-wide silencing and that its absence affects both maize development and heritable epigenetic changes.
authors.affiliation: Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, CA 94720-3102, USA.
authors.forename: Karl F
authors.initials: KF
authors.lastname: Erhard
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Stonaker
authors.forename: Susan E
authors.initials: SE
authors.lastname: Parkinson
authors.forename: Jana P
authors.initials: JP
authors.lastname: Lim
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Hale
authors.forename: Jay B
authors.initials: JB
authors.lastname: Hollick
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D019295:Computational Biology; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D044127:Epigenesis, Genetic; D020868:Gene Silencing; D017343:Genes, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development
chemical_list: D021122:Protein Subunits; D018749:RNA, Plant; D034741:RNA, Small Interfering; D012321:DNA-Directed RNA Polymerases