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Entry URI http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u15766525i
Entry name Onodera Yasuyuki et al. 2005 Mar. Cell 120(5):613-22.
Title Plant nuclear RNA polymerase IV mediates siRNA and DNA methylation-dependent heterochromatin formation.
Authors Costa Nunes Pedro|Haag Jeremy R|Onodera Yasuyuki|Pikaard Craig S|Pontes Olga|Ream Thomas
Abstract All eukaryotes have three nuclear DNA-dependent RNA polymerases, namely, Pol I, II, and III. Interestingly, plants have catalytic subunits for a fourth nuclear polymerase, Pol IV. Genetic and biochemical evidence indicates that Pol IV does not functionally overlap with Pol I, II, or III and is nonessential for viability. However, disruption of the Pol IV catalytic subunit genes NRPD1 or NRPD2 inhibits heterochromatin association into chromocenters, coincident with losses in cytosine methylation at pericentromeric 5S gene clusters and AtSN1 retroelements. Loss of CG, CNG, and CNN methylation in Pol IV mutants implicates a partnership between Pol IV and the methyltransferase responsible for RNA-directed de novo methylation. Consistent with this hypothesis, 5S gene and AtSN1 siRNAs are essentially eliminated in Pol IV mutants. The data suggest that Pol IV helps produce siRNAs that target de novo cytosine methylation events required for facultative heterochromatin formation and higher-order heterochromatin associations.
Pubmed ID 15766525
Journal Cell
Volume 120
Issue 5
Pages 613-22
Publication date 2005 Mar
Num of phenotype gene 0