Project description:RNA-mediated transcriptional silencing prevents deleterious effects of transposon activity and controls the expression of protein-coding genes. It involves long non-coding RNAs (lncRNAs)1, which in Arabidopsis thaliana are produced by a specialized RNA Polymerase V (Pol V)2. lncRNAs guide Argonaute-siRNA complexes to specific genomic loci and mediate the establishment of DNA methylation3,4. The mechanism by which lncRNAs affect chromatin structure and mRNA production remains mostly unknown. Here we identify the SWI/SNF nucleosome remodeling complex as a component of the RNA-mediated transcriptional silencing pathway. We found that SWI3, an essential subunit of the SWI/SNF complex, physically interacts with a lncRNA-binding IDN2 protein5,6. RNA-mediated DNA methylation and transcriptional silencing was compromised in the swi3 mutant. Moreover, targets of SWI/SNF significantly overlapped with genes controlled by Pol V, which shows that the physical interaction reflects a functional relationship. We further found that non-coding transcription by Pol V affects nucleosome positioning on silenced regions. We propose that lncRNAs mediate transcriptional silencing by guiding the SWI/SNF complex and establishing positioned nucleosomes on specific genomic loci. We further propose that guiding ATP-dependent chromatin remodeling complexes may be a more general function of lncRNAs. H3 ChIP-seq of 2 samples (Col-0 and nrpe1) with 2 biological repeats.
Project description:RNA-mediated transcriptional silencing prevents deleterious effects of transposon activity and controls the expression of protein-coding genes. It involves long non-coding RNAs (lncRNAs)1, which in Arabidopsis thaliana are produced by a specialized RNA Polymerase V (Pol V)2. lncRNAs guide Argonaute-siRNA complexes to specific genomic loci and mediate the establishment of DNA methylation3,4. The mechanism by which lncRNAs affect chromatin structure and mRNA production remains mostly unknown. Here we identify the SWI/SNF nucleosome remodeling complex as a component of the RNA-mediated transcriptional silencing pathway. We found that SWI3, an essential subunit of the SWI/SNF complex, physically interacts with a lncRNA-binding IDN2 protein5,6. RNA-mediated DNA methylation and transcriptional silencing was compromised in the swi3 mutant. Moreover, targets of SWI/SNF significantly overlapped with genes controlled by Pol V, which shows that the physical interaction reflects a functional relationship. We further found that non-coding transcription by Pol V affects nucleosome positioning on silenced regions. We propose that lncRNAs mediate transcriptional silencing by guiding the SWI/SNF complex and establishing positioned nucleosomes on specific genomic loci. We further propose that guiding ATP-dependent chromatin remodeling complexes may be a more general function of lncRNAs. Mnase-seq of 2 samples (Col-0 and nrpe1).
Project description:RNA-mediated transcriptional silencing prevents deleterious effects of transposon activity and controls the expression of protein-coding genes. It involves long non-coding RNAs (lncRNAs)1, which in Arabidopsis thaliana are produced by a specialized RNA Polymerase V (Pol V)2. lncRNAs guide Argonaute-siRNA complexes to specific genomic loci and mediate the establishment of DNA methylation3,4. The mechanism by which lncRNAs affect chromatin structure and mRNA production remains mostly unknown. Here we identify the SWI/SNF nucleosome remodeling complex as a component of the RNA-mediated transcriptional silencing pathway. We found that SWI3, an essential subunit of the SWI/SNF complex, physically interacts with a lncRNA-binding IDN2 protein5,6. RNA-mediated DNA methylation and transcriptional silencing was compromised in the swi3 mutant. Moreover, targets of SWI/SNF significantly overlapped with genes controlled by Pol V, which shows that the physical interaction reflects a functional relationship. We further found that non-coding transcription by Pol V affects nucleosome positioning on silenced regions. We propose that lncRNAs mediate transcriptional silencing by guiding the SWI/SNF complex and establishing positioned nucleosomes on specific genomic loci. We further propose that guiding ATP-dependent chromatin remodeling complexes may be a more general function of lncRNAs. RNA-seq of 3 samples (Col-0, nrpe1 [a mutant defective in the largest subunit of Pol V and unable to produce lncRNA], swi3b, idn2) with 3 biological replicates.
Project description:RNA-mediated transcriptional silencing prevents deleterious effects of transposon activity and controls the expression of protein-coding genes. It involves long non-coding RNAs (lncRNAs)1, which in Arabidopsis thaliana are produced by a specialized RNA Polymerase V (Pol V)2. lncRNAs guide Argonaute-siRNA complexes to specific genomic loci and mediate the establishment of DNA methylation3,4. The mechanism by which lncRNAs affect chromatin structure and mRNA production remains mostly unknown. Here we identify the SWI/SNF nucleosome remodeling complex as a component of the RNA-mediated transcriptional silencing pathway. We found that SWI3, an essential subunit of the SWI/SNF complex, physically interacts with a lncRNA-binding IDN2 protein5,6. RNA-mediated DNA methylation and transcriptional silencing was compromised in the swi3 mutant. Moreover, targets of SWI/SNF significantly overlapped with genes controlled by Pol V, which shows that the physical interaction reflects a functional relationship. We further found that non-coding transcription by Pol V affects nucleosome positioning on silenced regions. We propose that lncRNAs mediate transcriptional silencing by guiding the SWI/SNF complex and establishing positioned nucleosomes on specific genomic loci. We further propose that guiding ATP-dependent chromatin remodeling complexes may be a more general function of lncRNAs.
Project description:RNA-mediated transcriptional silencing prevents deleterious effects of transposon activity and controls the expression of protein-coding genes. It involves long non-coding RNAs (lncRNAs)1, which in Arabidopsis thaliana are produced by a specialized RNA Polymerase V (Pol V)2. lncRNAs guide Argonaute-siRNA complexes to specific genomic loci and mediate the establishment of DNA methylation3,4. The mechanism by which lncRNAs affect chromatin structure and mRNA production remains mostly unknown. Here we identify the SWI/SNF nucleosome remodeling complex as a component of the RNA-mediated transcriptional silencing pathway. We found that SWI3, an essential subunit of the SWI/SNF complex, physically interacts with a lncRNA-binding IDN2 protein5,6. RNA-mediated DNA methylation and transcriptional silencing was compromised in the swi3 mutant. Moreover, targets of SWI/SNF significantly overlapped with genes controlled by Pol V, which shows that the physical interaction reflects a functional relationship. We further found that non-coding transcription by Pol V affects nucleosome positioning on silenced regions. We propose that lncRNAs mediate transcriptional silencing by guiding the SWI/SNF complex and establishing positioned nucleosomes on specific genomic loci. We further propose that guiding ATP-dependent chromatin remodeling complexes may be a more general function of lncRNAs.
Project description:RNA-mediated transcriptional silencing prevents deleterious effects of transposon activity and controls the expression of protein-coding genes. It involves long non-coding RNAs (lncRNAs)1, which in Arabidopsis thaliana are produced by a specialized RNA Polymerase V (Pol V)2. lncRNAs guide Argonaute-siRNA complexes to specific genomic loci and mediate the establishment of DNA methylation3,4. The mechanism by which lncRNAs affect chromatin structure and mRNA production remains mostly unknown. Here we identify the SWI/SNF nucleosome remodeling complex as a component of the RNA-mediated transcriptional silencing pathway. We found that SWI3, an essential subunit of the SWI/SNF complex, physically interacts with a lncRNA-binding IDN2 protein5,6. RNA-mediated DNA methylation and transcriptional silencing was compromised in the swi3 mutant. Moreover, targets of SWI/SNF significantly overlapped with genes controlled by Pol V, which shows that the physical interaction reflects a functional relationship. We further found that non-coding transcription by Pol V affects nucleosome positioning on silenced regions. We propose that lncRNAs mediate transcriptional silencing by guiding the SWI/SNF complex and establishing positioned nucleosomes on specific genomic loci. We further propose that guiding ATP-dependent chromatin remodeling complexes may be a more general function of lncRNAs.
Project description:The nucleosome remodeling complex RSC functions throughout the yeast genome to set the positions of -1 and +1 nucleosomes and thereby determines the widths of nucleosome-depleted regions (NDRs). The related complex SWI/SNF participates in nucleosome remodeling/eviction and promoter activation at certain yeast genes, including those activated by transcription factor Gcn4, but does not appear to function broadly in establishing NDRs. By analyzing the large cohort of Gcn4-induced genes in mutants lacking the catalytic subunits of SWI/SNF or RSC, we uncovered cooperation between these remodelers in evicting nucleosomes from different locations in the promoter and in repositioning the +1 nucleosome downstream to produce wider NDRs, highly depleted of nucleosomes, during transcriptional activation. SWI/SNF also functions on par with RSC at the most highly transcribed constitutively expressed genes, suggesting general cooperation by these remodelers for maximal transcription. SWI/SNF and RSC occupancies are greatest at the most highly expressed genes, consistent with their cooperative functions in nucleosome remodeling and transcriptional activation. Thus, SWI/SNF acts comparably to RSC in forming wide, nucleosome-free NDRs to achieve high-level transcription, but only at the most highly expressed genes exhibiting the greatest SWI/SNF occupancies.