The Arabidopsis Chromatin-Modifying Nuclear siRNA Pathway Involves a Nucleolar RNA Processing Center
Copyright policy )The Arabidopsis Chromatin-Modifying Nuclear siRNA Pathway Involves a Nucleolar RNA Processing Center
In Arabidopsis thaliana, small interfering RNAs (siRNAs) direct cytosine methylation at endogenous DNA repeats in a pathway involving two forms of nuclear RNA polymerase IV (Pol IVa and Pol IVb), RNA-DEPENDENT RNA POLYMERASE 2 (RDR2), DICER-LIKE 3 (DCL3), ARGONAUTE4 (AGO4), the chromatin remodeler DRD1, and the de novo cytosine methyltransferase DRM2. We show that RDR2, DCL3, AGO4, and NRPD1b (the largest subunit of Pol IVb) colocalize with siRNAs within the nucleolus. By contrast, Pol IVa and DRD1 are external to the nucleolus and colocalize with endogenous repeat loci. Mutation-induced loss of pathway proteins causes downstream proteins to mislocalize, revealing their order of action. Pol IVa acts first, and its localization is RNA dependent, suggesting an RNA template. We hypothesize that maintenance of the heterochromatic state involves locus-specific Pol IVa transcription followed by siRNA production and assembly of AGO4- and NRPD1b-containing silencing complexes within nucleolar processing centers.
- University of California, Los Angeles United States
- University of Mary United States
- Instituto Superior da Maia Portugal
- University of Washington United States
DNA, Plant, Biochemistry, Genetics and Molecular Biology(all), Arabidopsis Proteins, Macromolecular Substances, Arabidopsis, DNA-Directed RNA Polymerases, DNA Methylation, Plants, Genetically Modified, Chromatin, Protein Subunits, Gene Expression Regulation, Plant, Argonaute Proteins, Mutation, RNA, Gene Silencing, RNA, Small Interfering, Cell Nucleolus, Signal Transduction
DNA, Plant, Biochemistry, Genetics and Molecular Biology(all), Arabidopsis Proteins, Macromolecular Substances, Arabidopsis, DNA-Directed RNA Polymerases, DNA Methylation, Plants, Genetically Modified, Chromatin, Protein Subunits, Gene Expression Regulation, Plant, Argonaute Proteins, Mutation, RNA, Gene Silencing, RNA, Small Interfering, Cell Nucleolus, Signal Transduction
citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).392 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Top 1% influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Top 1% impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 0.1%
Citations provided by BIP!Popularity provided by BIP!