Project description:The evolution of gene body methylation (gbM) and the underlying mechanism is poorly understood. By pairing the largest collection of CHROMOMETHYLTRANSFERASE (CMT) sequences (773) and methylomes (72) across land plants and green algae we provide novel insights into the evolution of gbM and its underlying mechanism. The angiosperm- and eudicot-specific whole genome duplication events gave rise to what are now referred to as CMT1, 2 and 3 lineages. CMTε, which includes the eudicot-specific CMT1 and 3, and orthologous angiosperm clades, is essential for the perpetuation of gbM in angiosperms, implying that gbM evolved at least 236 MYA. Independent losses of CMT1, 2 and 3 in eudicots, and CMT2 and CMTmonocot+magnoliid in monocots suggests overlapping or fluid functional evolution. The resulting gene family phylogeny of CMT transcripts from the most diverse sampling of plants to date redefines our understanding of CMT evolution and its evolutionary consequences on DNA methylation.
Project description:In mammals, it has long been hypothesized that DNA damage could induce DNA hypermethylation and contribute to carcinogenesis. However, the evidence that DNA damage is a cause of genome hypermethylation is still insufficient. Here, we demonstrated that, in plant, DNA damage can induce DNA hypermethylation in the context of symmetric CG, CHG as well as asymmetric CHH. Mechanically, DNA damage regulates the DREAM complex, to induce CG and CHG methylation. Moreover, DNA damage also utilizes the RdDM pathway to induce CHH hypermethylation. The hypermethylation sites of CG and CHG resulting from DNA damage tend to localize to gene body, and a large proportion of them are de nove generated. In contrast, the hypermethylation sites of CHH induced by DNA damage were mainly concentrated in the centromere and pre-centromere regions, and most of them are amplification of existing CHH methylation. Importantly, withdrawing the DNA damage or blocking the DNA damage response signal could fully abolish the CHH hypermethylation, partially rescue the CHG hypermethylation, but rarely recover the CG hypermethylation, indicating that DNA damage leaves symmetric DNA methylation as genetic imprinting. Collectively, our results suggest that DNA damage drives DNA methylation generation and evolution in plants.
Project description:In mammals, it has long been hypothesized that DNA damage could induce DNA hypermethylation and contribute to carcinogenesis. However, the evidence that DNA damage is a cause of genome hypermethylation is still insufficient. Here, we demonstrated that, in plant, DNA damage can induce DNA hypermethylation in the context of symmetric CG, CHG as well as asymmetric CHH. Mechanically, DNA damage regulates the DREAM complex, to induce CG and CHG methylation. Moreover, DNA damage also utilizes the RdDM pathway to induce CHH hypermethylation. The hypermethylation sites of CG and CHG resulting from DNA damage tend to localize to gene body, and a large proportion of them are de nove generated. In contrast, the hypermethylation sites of CHH induced by DNA damage were mainly concentrated in the centromere and pre-centromere regions, and most of them are amplification of existing CHH methylation. Importantly, withdrawing the DNA damage or blocking the DNA damage response signal could fully abolish the CHH hypermethylation, partially rescue the CHG hypermethylation, but rarely recover the CG hypermethylation, indicating that DNA damage leaves symmetric DNA methylation as genetic imprinting. Collectively, our results suggest that DNA damage drives DNA methylation generation and evolution in plants.
Project description:Background: Plants memorize previous pathogen attacks and are ‘primed’ to produce a faster and stronger defense response, which is critical for defense against pathogens. In plants, cytosines in transposons and gene bodies are reported to be frequently methylated. Demethylation of transposons can affect disease resistance by regulating the transcription of nearby genes during defense response, but the role of gene body methylation (GBM) in defense responses remains unclear. Results: Here, we find that loss of the chromatin remodeler decrease in DNA methylation 1 (ddm1) synergistically enhances resistance to a biotrophic pathogen under mild chemical priming. DDM1 mediates gene body methylation at a subset of stress-responsive genes with distinct chromatin properties from conventional gene body methylated genes. Decreased gene body methylation in loss of ddm1 mutant is associated with hyperactivation of these gene body methylated genes. Knockout of glyoxysomal protein kinase 1 (gpk1), a hypomethylated gene in ddm1 loss of function mutant, impairs priming of defense response to pathogen infection in Arabidopsis. We also find that DDM1-mediated gene body methylation is prone to epigenetic variation among natural Arabidopsis populations, and GPK1 expression is hyperactivated in natural variants with demethylated GPK1. Conclusions: Based on our collective results, we propose that DDM1-mediated GBM provides a possible regulatory axis for plants to modulate the inducibility of the immune response.
Project description:Gene bodies of vertebrates and flowering plants are occupied by histone variant H3.3 and DNA methylation. The origin and significance of these profiles remain largely unknown. The profiles of enrichments in DNA methylation and H3.3 over gene bodies are correlated and both depend similarly on gene transcription levels. This suggests a mechanistic link between H3.3 and gene body methylation. We engineered H3.3 knockdown in Arabidopsis and observed transcription reduction that predominantly affected genes responsive to environmental cues. When H3.3 levels were reduced, gene bodies showed a loss of DNA methylation correlated with transcription levels. To study the origin of changes in DNA methylation profiles when H3.3 levels are reduced, we examined genome wide distributions of several histone H3 marks, H2A.Z, linker histone H1 and nucleosome densities. We observed that in absence of H3.3, H1 distribution increased in gene bodies. This depends on levels of gene transcription. We propose that H3.3 prevents recruitment of H1, which in turn promotes chromatin folding and antagonizes access to DNA methyltransferases responsible for gene body methylation. Thus, gene body methylation is likely shaped by H3.3 dynamics in relation with transcriptional activity.
Project description:Gene bodies of vertebrates and flowering plants are occupied by histone variant H3.3 and DNA methylation. The origin and significance of these profiles remain largely unknown. The profiles of enrichments in DNA methylation and H3.3 over gene bodies are correlated and both depend similarly on gene transcription levels. This suggests a mechanistic link between H3.3 and gene body methylation. We engineered H3.3 knockdown in Arabidopsis and observed transcription reduction that predominantly affected genes responsive to environmental cues. When H3.3 levels were reduced, gene bodies showed a loss of DNA methylation correlated with transcription levels. To study the origin of changes in DNA methylation profiles when H3.3 levels are reduced, we examined genome wide distributions of several histone H3 marks, H2A.Z, linker histone H1 and nucleosome densities. We observed that in absence of H3.3, H1 distribution increased in gene bodies. This depends on levels of gene transcription.We propose that H3.3 prevents recruitment of H1, which in turn promotes chromatin folding and antagonizes access to DNA methyltransferases responsible for gene body methylation. Thus, gene body methylation is likely shaped by H3.3 dynamics in relation with transcriptional activity.
Project description:Gene bodies of vertebrates and flowering plants are occupied by histone variant H3.3 and DNA methylation. The origin and significance of these profiles remain largely unknown. The profiles of enrichments in DNA methylation and H3.3 over gene bodies are correlated and both depend similarly on gene transcription levels. This suggests a mechanistic link between H3.3 and gene body methylation. We engineered H3.3 knockdown in Arabidopsis and observed transcription reduction that predominantly affected genes responsive to environmental cues. When H3.3 levels were reduced, gene bodies showed a loss of DNA methylation correlated with transcription levels. To study the origin of changes in DNA methylation profiles when H3.3 levels are reduced, we examined genome-wide distributions of several histone H3 marks, H2A.Z, linker histone H1 and nucleosome densities. We observed that in absence of H3.3, H1 distribution increased in gene bodies. This depends on levels of gene transcription. We propose that H3.3 prevents recruitment of H1, which in turn promotes chromatin folding and antagonizes access to DNA methyltransferases responsible for gene body methylation. Thus, gene body methylation is likely shaped by H3.3 dynamics in relation with transcriptional activity.
Project description:Gene bodies of vertebrates and flowering plants are occupied by histone variant H3.3 and DNA methylation. The origin and significance of these profiles remain largely unknown. The profiles of enrichments in DNA methylation and H3.3 over gene bodies are correlated and both depend similarly on gene transcription levels. This suggests a mechanistic link between H3.3 and gene body methylation. We engineered H3.3 knockdown in Arabidopsis and observed transcription reduction that predominantly affected genes responsive to environmental cues. When H3.3 levels were reduced, gene bodies showed a loss of DNA methylation correlated with transcription levels. To study the origin of changes in DNA methylation profiles when H3.3 levels are reduced, we examined genome wide distributions of several histone H3 marks, H2A.Z, linker histone H1 and nucleosome densities. We observed that in absence of H3.3, H1 distribution increased in gene bodies. This depends on levels of gene transcription. We propose that H3.3 prevents recruitment of H1, which in turn promotes chromatin folding and antagonizes access to DNA methyltransferases responsible for gene body methylation. Thus, gene body methylation is likely shaped by H3.3 dynamics in relation with transcriptional activity.
Project description:This SuperSeries is composed of the following subset Series: GSE26018: Crosstalk between gene body DNA methylation, H3K9me3 and H3K36me3 chromatin marks and transcription [HuEx-1_0-st] GSE26019: Crosstalk between gene body DNA methylation, H3K9me3 and H3K36me3 chromatin marks and transcription [HuGene-1_0-st] GSE26038: Crosstalk between gene body DNA methylation, H3K9me3 and H3K36me3 chromatin marks and transcription [HuEx-1_0-st, transcript] GSE26040: Relationship between gene body DNA methylation and intragenic H3K9me3 and H3K36me3 chromatin marks Refer to individual Series
Project description:Genome-wide DNA methylation profiling was performed to identify novel markers for DNA methylation-based identification of forensically forensically relevant body flulids. CpGs specifically methylated or unmethylated in saliva, vaginal swabs, blood and semen were searched by comparing beta values of about 850000 CpGs of pooled samples of each body fluid.