Atypical DNA methylation of genes encoding cysteine-rich peptides in Arabidopsis thaliana
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE34207 | GEO | 2012/11/22
SECONDARY ACCESSION(S): PRJNA149671
REPOSITORIES: GEO
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Project description:In plants, transposons and non-protein-coding repeats are epigenetically silenced by CG and non-CG methylation. This pattern of methylation is mediated in part by small RNAs and two specialized RNA polymerases, Pol IV and Pol V, in a process called RNA-directed DNA methylation. By contrast, many protein-coding genes transcribed by Pol II contain in their gene bodies exclusively CG methylation that is independent of small RNAs and Pol IV/Pol V activities. It is unclear how the different methylation machineries distinguish between transposons and genes. Here we report on a group of atypical genes that display in their coding region a transposon-like methylation pattern, which is associated with gene silencing in sporophytic tissues. We performed a methylation-sensitive amplification polymorphism analysis to search for targets of RNA-directed DNA methylation in Arabidopsis thaliana and identified several members of a gene family encoding cysteine-rich peptides (CRPs). We also examined small RNA abundance at individual CRP genes in the wild type plant, nrpd1, and rdr2 mutant plants.
2012-11-22 | E-GEOD-34207 | biostudies-arrayexpress
Project description:To examine the relationship of reduced CG methylation and gene expression in Lsh KO MEFs, we computed mean CG methylation levels at promoter regions of protein-coding genes. About 60% of TSS regions of protein-coding genes display a difference of CG methylation values greater than 0.3 (WT CG methylation minus KO CG methylation) indicating that Lsh deletion has widespread effects at promoter regions. RNA-seq analysis detects similar transcript steady state levels in WT and KO samples. To determine the relationship of Pol II binding and CG methylation reduction in KO MEFs, Pol II Chip-seq was performed. Protein coding genes were ranked according their CG methylation differences between WT MEFs and KO MEFs. The greatest loss of CG methylation is found at promoter with low CG density. Pol II association is inversely related to the number of CpG sites within promoter regions. KO MEFs show less Pol II association at CG rich promoter regions. However, RNA-seq reads are indistinguishable comparing WT and KO samples, suggesting similar transcriptional efficiency in the absence of Lsh. To explore other molecular mechanisms that may preserve low transcription activity or repression at CG hypomethylated promoter regions, we examined H3K27me3 and H3K4me3 modifications by ChIP-seq. Genome wide computation of histone modifications at 5kb tiles shows no increase of H3K27me3 level in KO MEFs. When we ranked 5kb tiles based on CG methylation differences between WT and KO, we observed alterations in H3K27me3 distribution, while H3K4me3 modifications are unremarkable. Regions with moderate CG methylation reduction exhibit concomitant decreases in H3K27me3. mRNA profiles and Genome-wide maps of H3K27me3, H3K4me3 and Pol II in wildtype (WT) and Lsh KO primary MEFs.
2014-06-24 | E-GEOD-57419 | biostudies-arrayexpress
Project description:In plants, the maintenance of DNA methylation is controlled by several self-reinforcing loops involving histone methylation and non-coding RNAs. However, how methylation is initially patterned at specific genomic loci is largely unknown. Here, we describe four Arabidopsis REM transcription factors, VDD, VAL, REM12 and REM13, that recognize specific sequence regions, and together with the protein GENETICS DETERMINES EPIGENETICS1 (GDE1), recruit RNA polymerase IV transcription complexes. This targeted recruitment leads to the production of 24-nucleotide small interfering RNAs (24nt-siRNAs) that guide DNA methylation to specific genomic sites in plant female reproductive tissues. In the absence of GDE1, Pol IV transcription complexes are directed to loci bound by an alternative transcription factor, REM8, highlighting the role of REM transcription factors and GDE1 proteins as positional cues for epigenetic modulation. These findings establish a direct connection between sequence-specific transcription factors and the spatial regulation of siRNAs production and DNA methylation, offering refreshed insights into the genetic control of epigenetic patterning.
2025-04-14 | MSV000097625 | MassIVE
Project description:RNA-directed DNA methylation (RdDM) functions in de novo methylation in CG, CHG, and CHH contexts. Here, we performed map-based cloning of OsNRPE1, which encodes the largest subunit of Pol V, a key regulator of gene silencing and reproductive development in rice. We found that rice Pol V is required for CHH methylation on RdDM loci by transcribing long non-coding RNAs. Pol V influences the accumulation of 24-nt siRNAs in a locus-specific manner. Biosynthesis of 24-nt siRNAs on loci with high CHH methylation levels and low CG and CHG methylation levels tends to depend on Pol V. In contrast, low methylation levels in the CHH context and high methylation levels in CG and CHG contexts predisposes 24-nt siRNA accumulation to be independent of Pol V. H3K9me1 and H3K9me2 tend to be enriched on Pol V-independent 24-nt siRNA loci, whereas various active histone modifications are enriched on Pol V-dependent 24-nt siRNA loci. DNA methylation is required for 24-nt siRNAs biosynthesis on Pol V-dependent loci but not on Pol V-independent loci. Our results reveal the function of rice Pol V for long non-coding RNA production, DNA methylation, 24-nt siRNA accumulation, and reproductive development.
2021-07-07 | GSE158710 | GEO
Project description:RNA-directed DNA methylation (RdDM) functions in de novo methylation in CG, CHG, and CHH contexts. Here, we performed map-based cloning of OsNRPE1, which encodes the largest subunit of Pol V, a key regulator of gene silencing and reproductive development in rice. We found that rice Pol V is required for CHH methylation on RdDM loci by transcribing long non-coding RNAs. Pol V influences the accumulation of 24-nt siRNAs in a locus-specific manner. Biosynthesis of 24-nt siRNAs on loci with high CHH methylation levels and low CG and CHG methylation levels tends to depend on Pol V. In contrast, low methylation levels in the CHH context and high methylation levels in CG and CHG contexts predisposes 24-nt siRNA accumulation to be independent of Pol V. H3K9me1 and H3K9me2 tend to be enriched on Pol V-independent 24-nt siRNA loci, whereas various active histone modifications are enriched on Pol V-dependent 24-nt siRNA loci. DNA methylation is required for 24-nt siRNAs biosynthesis on Pol V-dependent loci but not on Pol V-independent loci. Our results reveal the function of rice Pol V for long non-coding RNA production, DNA methylation, 24-nt siRNA accumulation, and reproductive development.
2021-07-07 | GSE158709 | GEO
Project description:RNA-directed DNA methylation (RdDM) functions in de novo methylation in CG, CHG, and CHH contexts. Here, we performed map-based cloning of OsNRPE1, which encodes the largest subunit of Pol V, a key regulator of gene silencing and reproductive development in rice. We found that rice Pol V is required for CHH methylation on RdDM loci by transcribing long non-coding RNAs. Pol V influences the accumulation of 24-nt siRNAs in a locus-specific manner. Biosynthesis of 24-nt siRNAs on loci with high CHH methylation levels and low CG and CHG methylation levels tends to depend on Pol V. In contrast, low methylation levels in the CHH context and high methylation levels in CG and CHG contexts predisposes 24-nt siRNA accumulation to be independent of Pol V. H3K9me1 and H3K9me2 tend to be enriched on Pol V-independent 24-nt siRNA loci, whereas various active histone modifications are enriched on Pol V-dependent 24-nt siRNA loci. DNA methylation is required for 24-nt siRNAs biosynthesis on Pol V-dependent loci but not on Pol V-independent loci. Our results reveal the function of rice Pol V for long non-coding RNA production, DNA methylation, 24-nt siRNA accumulation, and reproductive development. This SuperSeries is composed of the SubSeries listed below.
2021-07-06 | GSE158711 | GEO
Project description:RNA polymerase IV (Pol IV) transcribes transposable elements (TEs) into precursors for small interfering RNAs (siRNAs) that guide DNA methylation to silence these potentially dangerious mobile elements in plants. Pol IV is recruited to TEs via SNF2-like CLASSY (CLSY) proteins. How Pol IV evolved to partner with the CLSYs is unknown. Using phylogenetics, we identified a conserved CYC-YPMF motif that is specific to Pol IV’s largest subunit. Modeling predicts that this motif coordinates a zinc ion and is exposed near Pol IV’s surface in a domain contacting downstream DNA. Via immunoprecipitation and mass spectrometry we found that this motif is essential for the association of all four CLSYs with Pol IV and hereby designate it as a CLSY-docking motif. Consistent with these biochemical results, mutations in the CLSY-docking motif or in neighboring sites of the Pol IV clamp domain, phenocopy pol iv null mutants and display a near-total loss of siRNA biogenesis, resulting in defects in DNA methylation and TE silencing. Together, our findings provide structural and functional insights into a critical protein feature that distinguishes Pol IV from other RNA polymerases, allowing Pol IV to target, transcribe and limit the expression of TE regions, thereby protecting genome integrity.
2024-11-28 | PXD047743 | Pride
Project description:Abstract: Cytosine DNA methylation plays crucial roles in gene regulation, transposon silencing, and diverse developmental processes. While methylation patterns are known to differ between cell-types, tissues, and disease states, how these differences arise remains poorly understood. In plants, DNA methylation is established via the RNA-directed DNA methylation pathway (RdDM), wherein 24-nucleotide small interfering RNAs (siRNAs) guide methylation at cognate genomic loci1. RNA POLYMERASE-IV (Pol-IV), a plant-specific polymerase, initiates the biogenesis of these methylation-targeting RNAs, thus understanding how Pol-IV is regulated is critical in determining how specific patterns of DNA methylation are generated. Here we show roles for four Pol-IV-associated factors, CLASSY (CLSY) 1-42,3, in both locus-specific and global regulation of Pol-IV function. Individually, each CLSY protein controls siRNA production and Pol-IV chromatin association at unique set of loci. This translates into locus-specific DNA methylation losses and the release of silencing. In addition to locus-specific effects, several layers of redundancy were identified: The clsy1,2 and clsy3,4 mutants act synergistically, regulating thousands more siRNA loci than the single mutants. Furthermore, the clsy1,2- and clsy3,4-dependent loci are mutually exclusive and geographically distinct, revealing a striking division of labor amongst the CLSY family. Finally, the clsy quadruple mutant causes global siRNA losses, demonstrating that Pol-IV is completely dependent on the CLSY family. Investigation into the mechanisms underlying the CLSY specificity revealed connections between clsy1,2- and clsy3,4-dependent loci and either SAWADEE HOMEODOMAIN HOMOLOG 1 or DNA METHYLTRANSFERASE 1, demonstrating a reliance on different chromatin modifications, H3K9 or CG DNA methylation, respectively4,5. Together, these findings not only shed light on Pol-IV function, but also reveal an additional layer of complexity to the RdDM pathway that enables the locus-specific control of DNA methylation patterns. Given the parallels between methylation systems in plants and mammals1, these findings will be informative for analogous processes in a broad range of organisms.
2018-04-14 | GSE99691 | GEO
Project description:Abstract: Cytosine DNA methylation plays crucial roles in gene regulation, transposon silencing, and diverse developmental processes. While methylation patterns are known to differ between cell-types, tissues, and disease states, how these differences arise remains poorly understood. In plants, DNA methylation is established via the RNA-directed DNA methylation pathway (RdDM), wherein 24-nucleotide small interfering RNAs (siRNAs) guide methylation at cognate genomic loci1. RNA POLYMERASE-IV (Pol-IV), a plant-specific polymerase, initiates the biogenesis of these methylation-targeting RNAs, thus understanding how Pol-IV is regulated is critical in determining how specific patterns of DNA methylation are generated. Here we show roles for four Pol-IV-associated factors, CLASSY (CLSY) 1-42,3, in both locus-specific and global regulation of Pol-IV function. Individually, each CLSY protein controls siRNA production and Pol-IV chromatin association at unique set of loci. This translates into locus-specific DNA methylation losses and the release of silencing. In addition to locus-specific effects, several layers of redundancy were identified: The clsy1,2 and clsy3,4 mutants act synergistically, regulating thousands more siRNA loci than the single mutants. Furthermore, the clsy1,2- and clsy3,4-dependent loci are mutually exclusive and geographically distinct, revealing a striking division of labor amongst the CLSY family. Finally, the clsy quadruple mutant causes global siRNA losses, demonstrating that Pol-IV is completely dependent on the CLSY family. Investigation into the mechanisms underlying the CLSY specificity revealed connections between clsy1,2- and clsy3,4-dependent loci and either SAWADEE HOMEODOMAIN HOMOLOG 1 or DNA METHYLTRANSFERASE 1, demonstrating a reliance on different chromatin modifications, H3K9 or CG DNA methylation, respectively4,5. Together, these findings not only shed light on Pol-IV function, but also reveal an additional layer of complexity to the RdDM pathway that enables the locus-specific control of DNA methylation patterns. Given the parallels between methylation systems in plants and mammals1, these findings will be informative for analogous processes in a broad range of organisms.
2018-04-14 | GSE99692 | GEO
Project description:Abstract: Cytosine DNA methylation plays crucial roles in gene regulation, transposon silencing, and diverse developmental processes. While methylation patterns are known to differ between cell-types, tissues, and disease states, how these differences arise remains poorly understood. In plants, DNA methylation is established via the RNA-directed DNA methylation pathway (RdDM), wherein 24-nucleotide small interfering RNAs (siRNAs) guide methylation at cognate genomic loci1. RNA POLYMERASE-IV (Pol-IV), a plant-specific polymerase, initiates the biogenesis of these methylation-targeting RNAs, thus understanding how Pol-IV is regulated is critical in determining how specific patterns of DNA methylation are generated. Here we show roles for four Pol-IV-associated factors, CLASSY (CLSY) 1-42,3, in both locus-specific and global regulation of Pol-IV function. Individually, each CLSY protein controls siRNA production and Pol-IV chromatin association at unique set of loci. This translates into locus-specific DNA methylation losses and the release of silencing. In addition to locus-specific effects, several layers of redundancy were identified: The clsy1,2 and clsy3,4 mutants act synergistically, regulating thousands more siRNA loci than the single mutants. Furthermore, the clsy1,2- and clsy3,4-dependent loci are mutually exclusive and geographically distinct, revealing a striking division of labor amongst the CLSY family. Finally, the clsy quadruple mutant causes global siRNA losses, demonstrating that Pol-IV is completely dependent on the CLSY family. Investigation into the mechanisms underlying the CLSY specificity revealed connections between clsy1,2- and clsy3,4-dependent loci and either SAWADEE HOMEODOMAIN HOMOLOG 1 or DNA METHYLTRANSFERASE 1, demonstrating a reliance on different chromatin modifications, H3K9 or CG DNA methylation, respectively4,5. Together, these findings not only shed light on Pol-IV function, but also reveal an additional layer of complexity to the RdDM pathway that enables the locus-specific control of DNA methylation patterns. Given the parallels between methylation systems in plants and mammals1, these findings will be informative for analogous processes in a broad range of organisms.
2018-04-14 | GSE99693 | GEO