Co-targeting RNA Polymerases IV and V promotes efficient de novo DNA methylation in Arabidopsis [small RNA-seq]
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE124749 | GEO | 2019/02/07
REPOSITORIES: GEO
Similar Datasets
Project description:The RNA-directed DNA methylation (RdDM) pathway in plants controls gene expression via cytosine DNA methylation. The ability to manipulate RdDM would shed light on the mechanisms and applications of DNA methylation to control gene expression. Here, we identified diverse RdDM proteins that are capable of targeting methylation and silencing in Arabidopsis when tethered to an artificial zinc finger (ZF-RdDM). We studied their order of action within the RdDM pathway by testing their ability to target methylation in different mutants. We also evaluated ectopic siRNA biogenesis, RNA Polymerase V (Pol V) recruitment, targeted DNA methylation, and gene expression changes at thousands of ZF-RdDM targets. We found that co-targeting both arms of the RdDM pathway, siRNA biogenesis and Pol V recruitment, dramatically enhanced targeted methylation. This work defines how RdDM components establish DNA methylation, and enables new strategies for epigenetic gene regulation via targeted DNA methylation.
2019-02-07 | GSE124744 | GEO
Project description:The RNA-directed DNA methylation (RdDM) pathway in plants controls gene expression via cytosine DNA methylation. The ability to manipulate RdDM would shed light on the mechanisms and applications of DNA methylation to control gene expression. Here, we identified diverse RdDM proteins that are capable of targeting methylation and silencing in Arabidopsis when tethered to an artificial zinc finger (ZF-RdDM). We studied their order of action within the RdDM pathway by testing their ability to target methylation in different mutants. We also evaluated ectopic siRNA biogenesis, RNA Polymerase V (Pol V) recruitment, targeted DNA methylation, and gene expression changes at thousands of ZF-RdDM targets. We found that co-targeting both arms of the RdDM pathway, siRNA biogenesis and Pol V recruitment, dramatically enhanced targeted methylation. This work defines how RdDM components establish DNA methylation, and enables new strategies for epigenetic gene regulation via targeted DNA methylation.
2019-02-07 | GSE124546 | GEO
Project description:The RNA-directed DNA methylation (RdDM) pathway in plants controls gene expression via cytosine DNA methylation. The ability to manipulate RdDM would shed light on the mechanisms and applications of DNA methylation to control gene expression. Here, we identified diverse RdDM proteins that are capable of targeting methylation and silencing in Arabidopsis when tethered to an artificial zinc finger (ZF-RdDM). We studied their order of action within the RdDM pathway by testing their ability to target methylation in different mutants. We also evaluated ectopic siRNA biogenesis, RNA Polymerase V (Pol V) recruitment, targeted DNA methylation, and gene expression changes at thousands of ZF-RdDM targets. We found that co-targeting both arms of the RdDM pathway, siRNA biogenesis and Pol V recruitment, dramatically enhanced targeted methylation. This work defines how RdDM components establish DNA methylation, and enables new strategies for epigenetic gene regulation via targeted DNA methylation.
2019-02-07 | GSE124750 | GEO
Project description:The RNA-directed DNA methylation (RdDM) pathway in plants controls gene expression via cytosine DNA methylation. The ability to manipulate RdDM would shed light on the mechanisms and applications of DNA methylation to control gene expression. Here, we identified diverse RdDM proteins that are capable of targeting methylation and silencing in Arabidopsis when tethered to an artificial zinc finger (ZF-RdDM). We studied their order of action within the RdDM pathway by testing their ability to target methylation in different mutants. We also evaluated ectopic siRNA biogenesis, RNA Polymerase V (Pol V) recruitment, targeted DNA methylation, and gene expression changes at thousands of ZF-RdDM targets. We found that co-targeting both arms of the RdDM pathway, siRNA biogenesis and Pol V recruitment, dramatically enhanced targeted methylation. This work defines how RdDM components establish DNA methylation, and enables new strategies for epigenetic gene regulation via targeted DNA methylation.
2019-02-07 | GSE124747 | GEO
Project description:The RNA-directed DNA methylation (RdDM) pathway in plants controls gene expression via cytosine DNA methylation. The ability to manipulate RdDM would shed light on the mechanisms and applications of DNA methylation to control gene expression. Here, we identified diverse RdDM proteins that are capable of targeting methylation and silencing in Arabidopsis when tethered to an artificial zinc finger (ZF-RdDM). We studied their order of action within the RdDM pathway by testing their ability to target methylation in different mutants. We also evaluated ectopic siRNA biogenesis, RNA Polymerase V (Pol V) recruitment, targeted DNA methylation, and gene expression changes at thousands of ZF-RdDM targets. We found that co-targeting both arms of the RdDM pathway, siRNA biogenesis and Pol V recruitment, dramatically enhanced targeted methylation. This work defines how RdDM components establish DNA methylation, and enables new strategies for epigenetic gene regulation via targeted DNA methylation.
2019-02-07 | GSE124746 | GEO
Project description:DNA methylation is an epigenetic modification that plays critical roles in gene silencing, development, and the maintenance of genome integrity. In Arabidopsis, DNA methylation is established by DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2) and is targeted by 24 nt small interfering RNAs (siRNAs) through a pathway termed RNA-directed DNA methylation (RdDM)1. This pathway requires two plant-specific RNA polymerases: Pol-IV, which functions to initiate siRNA biogenesis and Pol-V, which functions in the downstream DNA methyltransferase targeting phase of the RdDM pathway to generate scaffold transcripts that recruit downstream RdDM factors1,2. To understand the mechanisms controlling Pol-IV targeting we investigated the function of SAWADEE HOMEODOMAIN HOMOLOG 1 (SHH1)3,4, a Pol-IV interacting protein3. Here we show that SHH1 acts upstream in the RdDM pathway to enable siRNA production from a large subset of the most active RdDM targets and that SHH1 is required for Pol-IV occupancy at these same loci. We also show that the SHH1 SAWADEE domain is a novel chromatin binding module that adopts a unique tandem Tudor-like fold and functions as a dual lysine reader, probing for both unmethylated K4 and methylated K9 modifications on the histone 3 (H3) tail. Finally, we show that key residues within both lysine binding pockets of SHH1 are required in vivo to maintain siRNA and DNA methylation levels as well as Pol-IV occupancy at RdDM targets, demonstrating a central role for methyl H3K9 binding in SHH1 function and providing the first insights into the mechanism of Pol-IV targeting. Given the parallels between methylation systems in plants and mammals1,5, a further understanding of this early targeting step may aid in our ability to control the expression of endogenous and newly introduced genes, which has broad implications for agriculture and gene therapy.
2013-05-13 | GSE45368 | GEO
Project description:In plants, heterochromatin is maintained by a small RNA-based gene silencing mechanism known as RNA-directed DNA methylation (RdDM). RdDM requires the non-redundant functions of two plant-specific DNA-dependent RNA polymerases (Pol) Pol IV and Pol V. Pol IV plays a major role in siRNA biogenesis, while Pol V may recruit DNA methylation machinery to target endogenous loci for silencing. Although small RNA-generating regions which are dependent on both Pol IV and Pol V have been identified previously, the genomic loci targeted Pol V for siRNA accumulation and silencing have not been described extensively. To characterize the Pol V-dependent, heterochromatic siRNA-generating regions in the Arabidopsis genome, we deeply sequenced the small RNA populations of wild-type and Pol V mutant plants. Furthermore, we characterized the siRNA-generating regions which were dependent on RdDM effectors and examined their dependency on Pol V. Small RNA libraries were generated and deeply sequenced from mutant alleles dms4-1, drd1-1, dms3-1, and rdm1-4, along with their control library (“Wt(T+S)”) which has been described previously (Kanno et al. 2004 Current Biology). More than 2,000 small RNA-generating loci were identified which were greatly suppressed in Pol V mutants. The Pol V-dependent, heterochromatic siRNA-generating regions were characterized in the Arabidopsis genome by deep sequencing the small RNA populations of wild-type and Pol V mutant plants. Deep SBS sequencing was used for small RNA profiling of immature inflorescence tissues from RNA polymerase V and RdDM mutants.
2012-06-11 | E-GEOD-36424 | biostudies-arrayexpress
Project description:DNA methylation is an epigenetic modification that plays critical roles in gene silencing, development, and the maintenance of genome integrity. In Arabidopsis, DNA methylation is established by DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2) and is targeted by 24 nt small interfering RNAs (siRNAs) through a pathway termed RNA-directed DNA methylation (RdDM)1. This pathway requires two plant-specific RNA polymerases: Pol-IV, which functions to initiate siRNA biogenesis and Pol-V, which functions in the downstream DNA methyltransferase targeting phase of the RdDM pathway to generate scaffold transcripts that recruit downstream RdDM factors1,2. To understand the mechanisms controlling Pol-IV targeting we investigated the function of SAWADEE HOMEODOMAIN HOMOLOG 1 (SHH1)3,4, a Pol-IV interacting protein3. Here we show that SHH1 acts upstream in the RdDM pathway to enable siRNA production from a large subset of the most active RdDM targets and that SHH1 is required for Pol-IV occupancy at these same loci. We also show that the SHH1 SAWADEE domain is a novel chromatin binding module that adopts a unique tandem Tudor-like fold and functions as a dual lysine reader, probing for both unmethylated K4 and methylated K9 modifications on the histone 3 (H3) tail. Finally, we show that key residues within both lysine binding pockets of SHH1 are required in vivo to maintain siRNA and DNA methylation levels as well as Pol-IV occupancy at RdDM targets, demonstrating a central role for methyl H3K9 binding in SHH1 function and providing the first insights into the mechanism of Pol-IV targeting. Given the parallels between methylation systems in plants and mammals1,5, a further understanding of this early targeting step may aid in our ability to control the expression of endogenous and newly introduced genes, which has broad implications for agriculture and gene therapy. For wild type plants (ecotype Columbia) and RdDM mutants whole-genome small RNA (sRNA-seq) and bisulfite sequencing (BS-seq) was performed. The Col and nrpe1 BS-seq libraries were previously reported (GSE39247) and so are not part of this submission. 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 nrpd1 mutant plants carrying a C-terminally epitope tagged (3XFLAG) NRPD1. Whole-genome bisulfite sequencing and small RNA sequencing was also performed on shh1 mutant plants transformed with the wild-type SHH1 protein-coding construct as well as multiple constructs containing point mutations. For these complementation libraries a separate shh1 mutant and Col control line were sequenced (“complementation replicates”).
2013-05-13 | E-GEOD-45368 | biostudies-arrayexpress
Project description:In plants, RNA polymerase II (Pol II) transcription of inverted DNA repeats produces hairpin RNAs that are processed by several DICER-LIKE enzymes into siRNAs that are 21-24-nt in length. When targeted to transcriptional regulatory regions, the 24-nt size class can induce RNA-directed DNA methylation (RdDM) and transcriptional gene silencing (TGS). In a forward genetic screen to identify mutants defective in RdDM of a target enhancer leading to TGS of a downstream GFP reporter gene in Arabidopsis thaliana, we recovered a structurally mutated silencer locus, named SM-NM-^T35S, in which the 35S promoter driving transcription of an inverted repeat of target enhancer sequences had been specifically deleted. Although Pol II-dependent, hairpin-derived 21-24-nt siRNAs were no longer generated at the newly created SM-NM-^T35S locus, the GFP reporter gene was nevertheless still partially silenced. Silencing was associated with methylation in a short tandem repeat in the upstream target enhancer and with low levels of 24-nt tandem repeat siRNAs. Introducing an nrpd1 mutation into the SM-NM-^T35S line fully released GFP silencing and eliminated both the tandem repeat methylation and associated 24-nt siRNAs, demonstrating their dependence on Pol IV. Deletion of the 35S promoter thus revealed a Pol IV-dependent pathway of 24-nt siRNA biogenesis that was previously inhibited or masked by the Pol II-dependent pathway in wild-type plants. Both Pol II- and Pol IV-dependent siRNAs accrued predominantly from cytosine (C)-containing segments of the tandem repeat monomer, suggesting that the local base composition influenced siRNA accumulation. Preferential accumulation of siRNAs at C-containing sequences was also observed at an endogenous tandem repeat comprising discrete C-rich and AT-rich sections. Our studies illuminate the potential complexity of siRNA generation at repeat-containing loci and show that Pol IV can act in siRNA biogenesis in the absence of a conventional Pol II promoter. Examination of whole-genome DNA methylation status in transgenic T+S Arabidopsis plant
2013-05-30 | E-GEOD-47453 | 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