The DDR complex facilitates the genome-wide association of RNA Polymerase V to promoters and evolutionarily young transposons
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE39247 | GEO | 2012/08/05
SECONDARY ACCESSION(S): PRJNA170665
REPOSITORIES: GEO
Similar Datasets
Project description:The plant-specific DNA-dependent RNA polymerase V (Pol V) evolved from Pol II to function in an RNA-directed DNA methylation pathway. Here, we have identified targets of Pol V in Arabidopsis thaliana on a genome-wide scale using ChIP-seq of NRPE1, the largest catalytic subunit of Pol V. We found that Pol V is enriched at promoters and evolutionarily recent transposons. This localization pattern is highly correlated with Pol V-dependent DNA methylation and small RNA accumulation. We also show that genome-wide association of Pol V with chromatin is dependent on all members of a putative chromatin-remodeling complex termed DDR. Our study presents the first genome-wide view of Pol V occupancy and sheds light on the mechanistic basis of Pol V localization. Furthermore, these findings suggest a role for Pol V and RNA-directed DNA methylation in genome surveillance and in responding to genome evolution. For wild type plants (ecotype Columbia) and nrpe1 mutants whole-genome small RNA (sRNA-seq) and bisulfite sequencing (BS-seq) was performed. In addition whole genome chromatin immunoprecipitation (ChIP-seq) was performed on wild type (ecotype Columbia) plants as a negative control with experimentals consiting of wild type plants carrying a C-terminally epitope tagged (2XFLAG) NRPE1, as well as the NRPE1-FLAG construct in drd1, dms3, and rdm1 mutant backgrounds.
2012-08-05 | E-GEOD-39247 | biostudies-arrayexpress
Project description:DNA methylation is a mechanism of epigenetic gene regulation and genome defense conserved in many eukaryotic organisms. In Arabidopsis, the DNA methyltransferase DRM2 controls RNA-directed DNA methylation in a pathway that also involves the plant specific RNA Polymerase V (Pol V). The Arabidopsis genome also encodes an evolutionarily conserved but catalytically inactive DNA methyltransferase DRM3. Here, we show that DRM3 has moderate effects on global RNA-directed DNA methylation and small RNA abundance throughout the genome, and DRM3 protein physically interacts with Pol V. In drm3 mutants, we observe a lower level of Pol V-dependent transcripts, even though Pol V chromatin occupancy is increased at many sites in the genome. These findings suggest that DRM3 acts to promote Pol V transcriptional elongation or assist in the stabilization of Pol V transcripts, and shed further light on the mechanism of RNA-directed DNA methylation. For wildtype plants as well as drm3, drm2, and nrpe1 mutants ChIP-seq was carried out using an endogenous NRPE1 antibody given to us by the Craig Pikaard lab. Two biological replicates of ChIP-seq were also carried out using anti-Flag resin on wildtype and drm3 plants carrying a Flag epitope tagged version of NRPE1. Small RNA sequencing was carried out on Col, drm3, drm2, and nrpe1 plants. Finally, whole-genome bisulfite sequencing analysis was carried out on previously published datasets (as detailed below) which were realigned using a newer genome version and mapping protocol. As such the updated processed files are part of this submission. Please note that the drm2, drm3, and nrpe1 mutant libraries used in this study were previously published (GSE39901), as were the 2 other Col replicates used (GSE36129) as below and thus duplicated sample records were created for the convenient retrieval of the complete raw data from SRA; Bisulfite_seq-Col_1 - GSM881756 Bisulfite_seq-Col_2 - GSM1193638 Bisulfite_seq-drm3 - GSM981017 Bisulfite_seq-drm2 - GSM981015 Bisulfite_seq-nrpe1- GSM981040
2015-02-01 | E-GEOD-61192 | biostudies-arrayexpress
Project description:DNA methylation is an important epigenetic mark in many eukaryotic organisms. De novo DNA methylation in plants can be achieved by the RNA-directed DNA methylation (RdDM) pathway, where the plant-specific DNA-dependent RNA polymerase Pol IV transcribes target sequences to initiate 24-nt siRNA production and action. The Arabidopsis DTF1/SHH1 has been shown to associate with Pol IV and is required for 24-nt siRNA accumulation and transcriptional silencing at several RdDM target loci. However, the extent and mechanism of DTF1 function in RdDM is unclear. We show here that DTF1 is necessary for the accumulation of the majority of Pol IV-dependent 24-nt siRNAs. It is also required for a large proportion of Pol IV-dependent de novo DNA methylation. Interestingly, there is a group of RdDM target loci where 24-nt siRNA accumulation but not DNA methylation is dependent on DTF1. Taken together, our results show that DTF1 is a core component of the RdDM pathway. Our results also suggest the involvement of DTF1 in an important negative feedback mechanism for DNA methylation at some RdDM target loci. Examination of whole-genome DNA methylation and small RNA in 12-day-old Col-0, dtf1-2, nrpd1-3 and nrpe1-11 seedlings
2013-06-03 | E-GEOD-44209 | biostudies-arrayexpress
Project description:In plants, the plant-specific RNA polymerase V (Pol V) transcripts non-coding RNA and provides a docking platform for the association of accessory proteins in the RNA-directed DNA methylation (RdDM) pathway. Various components were uncovered in the process of DNA methylation, but it is still not clear how the transcription of Pol V is regulated. Here, we found the conserved elongation factor, SPT6L, bound to thousands of intergenic regions in an RNA polymerase II (Pol II) independent manner. The intergenic enrichment of SPT6L, interestingly, co-occupied with the largest subunit of Pol V (NRPE1) and the mutation of SPT6L led to the reduction of DNA methylation but not Pol V enrichment. Furthermore, the association of SPT6L at Pol V loci was dependent on the Pol V associated factor, SPT5L, rather than the presence of Pol V, and the interaction between SPT6L and NRPE1 was compromised in spt5l. Finally, Pol V RIP-seq revealed that SPT6L is required to maintain the amount and length of Pol V transcripts. Our findings revealed the critical role of a Pol II conserved elongation factor in Pol V mediated DNA methylation and transcription, and shed light on the mutual regulation between Pol V and Pol II in plants.
2024-04-22 | GSE233781 | GEO
Project description:Silencing pathways prevent transposable element (TE) proliferation and help to maintain genome integrity through cell division. Silenced genomic regions can be classified as either euchromatic or heterochromatic, and are targeted by genetically separable epigenetic pathways. In plants, the RNA-directed DNA methylation (RdDM) pathway targets mostly euchromatic regions, while CMT methyltransferases are mainly associated with heterochromatin. However, many epigenetic features - including DNA methylation patterning - are largely indistinguishable between these regions, so how the functional separation is maintained is unclear. The linker histone H1 is preferentially localised to heterochromatin and has been proposed to restrict RdDM from encroachment. To test this hypothesis, we followed RdDM genomic localisation in an H1 mutant by performing ChIP-seq on the largest subunit, NRPE1, of the central RdDM polymerase (Pol V). Loss of H1 resulted in heterochromatic TE enrichment of NPRE1. Increased NRPE1 binding was associated with increased chromatin accessibility in h1, suggesting that H1 restricts NRPE1 occupancy by compacting chromatin. However, RdDM occupancy did not impact H1 localization, demonstrating that H1 hierarchically restricts RdDM positioning. H1 mutants experience major symmetric (CG and CHG) DNA methylation gains, and by generating an h1/nrpe1 double mutant, we demonstrate these gains are largely independent of RdDM. However, loss of NRPE1 occupancy from a subset of euchromatic regions in h1 experienced corresponding loss of methylation in all sequence contexts, while at ectopically bound heterochromatic loci, NRPE1 deposited methylation specifically in the CHH context. Additionally, we found that H1 restricts the occupancy of the methylation reader and activator complex component, SUVH1, indicating that H1’s regulatory control of methylation pathways is not limited to RdDM. Together, the results support a model whereby H1 helps maintain the exclusivity of heterochromatin by preventing encroachment from other competing pathways.
2023-09-12 | GSE225480 | GEO
Project description:RNA-directed DNA methylation (RdDM) in Arabidopsis thaliana depends on the synthesis of non-coding RNAs by nuclear RNA polymerase E (NRPE or Pol V) 1-3, but the mechanism by which Pol V is targeted is unknown. Here we show that genome-wide Pol V association with chromatin redundantly requires the SU(VAR)3-9 homologs, SUVH2 and SUVH9. These proteins resemble histone methyltransferases, however a crystal structure reveals that SUVH9 lacks a peptide-substrate binding cleft and lacks a properly formed S-Adenosyl methionine (SAM) binding pocket necessary for normal catalysis, consistent with a lack of methyltransferase activity for these proteins. SUVH2 and SUVH9 both contain SET- and RING-ASSOCIATED (SRA) domains capable of binding methylated DNA, suggesting that they function to recruit Pol V through DNA methylation. Consistent with this model, mutation of the DNA METHYLTRANSFERASE 1, MET1, causes losses of DNA methylation, a nearly complete loss of Pol V at its normal locations, and redistribution of Pol V to sites that become hypermethylated. By tethering SUVH2 with a zinc finger to an unmethylated epiallele of the homeodomain transcription factor FWA, we demonstrate that SUVH2 is sufficient to both recruit Pol V and establish DNA methylation and gene silencing. Our results suggest that Pol V is recruited to DNA methylation through the methyl-DNA binding SUVH2 and SUVH9 proteins, and our mechanistic findings suggest a means for selectively targeting regions of the plant genome for epigenetic silencing. For wild type plants (ecotype Columbia) and suvh2 suvh9 double mutants whole-genome small RNA (sRNA-seq) and bisulfite sequencing (BS-seq) was performed. For the small RNA sequencing nrpd1 and nrpe1 mutant plants were sequenced in parallel as controls. For the bisulfite sequencing data, the wildtype data and that of the suvh2 and suvh9 single mutants was previously published and is thus not submitted here. In addition, two replicates of whole genome chromatin immunoprecipitation (ChIP-seq) was performed on wild type (ecotype Columbia) plants as a negative control with experimentals consiting of wildtype and suvh2 suvh9 mutant plants carrying a C-terminally epitope tagged (3XFLAG) NRPE1. Whole genome ChIP seq was also performed using a gifted endogenous NRPE1 antibody in a wildtype and met1 mutant background. Whole-genome bisulfite sequencing was also performed on fwa-4 epiallele plants transformed with the wild-type SUVH2 protein-coding construct containing a tethering zinc finger targeted to repeats at the fwa gene. For these transgenic libraries a line carrying a FLAG and fwa targeting zinc-finger tagged KRYPTONITE methyltransferase was bisulfite sequenced as a control (“FLAG-ZF-KYP”).
2014-01-01 | E-GEOD-52041 | biostudies-arrayexpress
Project description:DNA methylation is a mechanism of epigenetic gene regulation and genome defense conserved in many eukaryotic organisms. In Arabidopsis, the DNA methyltransferase DRM2 controls RNA-directed DNA methylation in a pathway that also involves the plant specific RNA Polymerase V (Pol V). The Arabidopsis genome also encodes an evolutionarily conserved but catalytically inactive DNA methyltransferase DRM3. Here, we show that DRM3 has moderate effects on global RNA-directed DNA methylation and small RNA abundance throughout the genome, and DRM3 protein physically interacts with Pol V. In drm3 mutants, we observe a lower level of Pol V-dependent transcripts, even though Pol V chromatin occupancy is increased at many sites in the genome. These findings suggest that DRM3 acts to promote Pol V transcriptional elongation or assist in the stabilization of Pol V transcripts, and shed further light on the mechanism of RNA-directed DNA methylation.
2015-02-01 | GSE61192 | GEO
Project description:RNA polymerases IV and V (Pol IV and Pol V) are plant-specific polymerases required for the generation of noncoding RNAs in RNA-directed DNA methylation (RdDM) and transcriptional gene silencing. Their subunit compositions largely resemble that of Pol II. However, the mechanism and accessory factors involved in their assembly remain largely unknown. In this study, we performed a forward genetic screen and identified novel mutant alleles of MINIYO (IYO), QUATRE-QUART 2 (QQT2) and NUCLEAR RNA POLYMERASE B/D/E 11 (NRPB/D/E11) that are defective in RdDM. We found that Pol IV-dependent small interfering RNAs (siRNAs) and Pol V-dependent transcripts were greatly reduced in the mutants. NRPE1, the largest subunit of Pol V, dissociated from other Pol V subunits in the iyo and qqt2 mutants, suggesting the involvement of IYO and QQT2 in Pol V assembly. Furthermore, we found that IYO and QQT2 were mutually dependent for their binding to the NRPE3 subassembly to facilitate the assembly of Pol V holoenzyme. Our findings reveal IYO and QQT2 as cofactors for Pol V assembly and provide mechanistic insights into how RNA polymerases are assembled in Arabidopsis.
2018-04-09 | GSE103326 | GEO
Project description:24 nucleotide siRNAs are central players in RNA-directed DNA methylation (RdDM), a process that establishes DNA methylation at transposable elements to ensure genome stability. The plant-specific RNA polymerase IV (Pol IV) is required for siRNA biogenesis and is thought to transcribe RdDM loci to produce primary transcripts that serve as precursors to siRNAs. Yet, no such transcripts have ever been reported. Here, through RNA sequencing and double-stranded RNA sequencing in genotypes that compromise the dicing of siRNA precursors, we were able to identify Pol IV-dependent transcripts from tens of thousands of loci. We show that Pol IV-dependent transcripts correspond to both DNA strands, while the Pol II-dependent transcripts produced upon de-repression of the loci are derived from primarily one strand. We show that Pol IV-dependent transcripts have a 5â monophosphate, lack a polyA tail at the 3â end, and contain no introns; these features distinguish them from Pol II-dependent transcripts. Moreover, RDR2 is shown to play similar roles with Pol IV in both the abundance of siRNA precursors and siRNAs as well as the CHH DNA methylation. The decreased CHH methylation at dcl234 can inhibit the transcription of Pol IV at DRM2-target sites. Finally, the regulations of siRNA biogenesis were explored. To detect siRNA precursors transcribed by RNA polymerase IV, the genome wide profiling of RNA were carried out at dcl234 and dcl234 nrpd1. Different types of RNA (including Total RNA, polyA+ RNA, polyA- RNA, double stranded RNA) libraries were built to detect different transcripts. RDR2 is a RNA-dependent RNA polymerase in Pol IV complex, so the RNA-seq libraries with the mutation of RDR2 were also built. In addition, smRNA libraries with mutations blocking siRNA biogenesis were also built
2014-11-11 | E-GEOD-57215 | biostudies-arrayexpress
Project description:This study used the mutants nrpe1-11 and ros1-4 to assess the impact of RNA-directed DNA methylation (RdDM) and ROS1 on the Arabidopsis thaliana (ecotype Col-0) methylome.
2022-11-07 | GSE199625 | GEO