Project description:DNA methylation is a key epigenetic mark that impacts gene expression and represses transposable elements (TEs) in eukaryotes. Numerous examples of cis-elements targeted by DNA methylation, particularly at CG sites (mCG), have been reported to be under selective pressure in animals and plants. By contrast, there is limited knowledge of trans-regulators of mCG leading to adaptation. Here, using genome-wide association studies, we identify CELL DIVISION CYCLE-ASSOCIATED PROTEIN 7 ALPHA (CDCA7α) as a trans-regulator of mCG in natural populations of Arabidopsis thaliana. CDCA7α and its paralog, CDCA7β, directly bind to the chromatin remodeler DECREASE IN DNA METHYLATION 1 (DDM1), which facilitates access of methyltransferases to DNA. CDCA7α/β selectively regulates mCG and minimally impacts other DDM1-dependent processes such as non-CG methylation and histone variant deposition. We identify the cis-regulatory sequence modulating CDCA7α expression in natural populations and determining the degree of mCG and TE silencing. The geographic distribution of CDCA7α alleles suggests that new alleles have repeatedly expanded to novel ecological niches, indicating a potential role in local adaptation. Altogether, our findings provide new insight into how changes in global DNA methylation levels through transcriptional regulation of the epigenetic machinery have the capacity to facilitate local adaptation.
Project description:DNA methylation is a key epigenetic mark that impacts gene expression and represses transposable elements (TEs) in eukaryotes. Numerous examples of cis-elements targeted by DNA methylation, particularly at CG sites (mCG), have been reported to be under selective pressure in animals and plants. By contrast, there is limited knowledge of trans-regulators of mCG leading to adaptation. Here, using genome-wide association studies, we identify CELL DIVISION CYCLE-ASSOCIATED PROTEIN 7 ALPHA (CDCA7α) as a trans-regulator of mCG in natural populations of Arabidopsis thaliana. CDCA7α and its paralog, CDCA7β, directly bind to the chromatin remodeler DECREASE IN DNA METHYLATION 1 (DDM1), which facilitates access of methyltransferases to DNA. CDCA7α/β selectively regulates mCG and minimally impacts other DDM1-dependent processes such as non-CG methylation and histone variant deposition. We identify the cis-regulatory sequence modulating CDCA7α expression in natural populations and determining the degree of mCG and TE silencing. The geographic distribution of CDCA7α alleles suggests that new alleles have repeatedly expanded to novel ecological niches, indicating a potential role in local adaptation. Altogether, our findings provide new insight into how changes in global DNA methylation levels through transcriptional regulation of the epigenetic machinery have the capacity to facilitate local adaptation.
Project description:DNA methylation is a key epigenetic mark that impacts gene expression and represses transposable elements (TEs) in eukaryotes. Numerous examples of cis-elements targeted by DNA methylation, particularly at CG sites (mCG), have been reported to be under selective pressure in animals and plants. By contrast, there is limited knowledge of trans-regulators of mCG leading to adaptation. Here, using genome-wide association studies, we identify CELL DIVISION CYCLE-ASSOCIATED PROTEIN 7 ALPHA (CDCA7α) as a trans-regulator of mCG in natural populations of Arabidopsis thaliana. CDCA7α and its paralog, CDCA7β, directly bind to the chromatin remodeler DECREASE IN DNA METHYLATION 1 (DDM1), which facilitates access of methyltransferases to DNA. CDCA7α/β selectively regulates mCG and minimally impacts other DDM1-dependent processes such as non-CG methylation and histone variant deposition. We identify the cis-regulatory sequence modulating CDCA7α expression in natural populations and determining the degree of mCG and TE silencing. The geographic distribution of CDCA7α alleles suggests that new alleles have repeatedly expanded to novel ecological niches, indicating a potential role in local adaptation. Altogether, our findings provide new insight into how changes in global DNA methylation levels through transcriptional regulation of the epigenetic machinery have the capacity to facilitate local adaptation.
Project description:DNA methylation is a key epigenetic mark that impacts gene expression and represses transposable elements (TEs) in eukaryotes. Numerous examples of cis-elements targeted by DNA methylation, particularly at CG sites (mCG), have been reported to be under selective pressure in animals and plants. By contrast, there is limited knowledge of trans-regulators of mCG leading to adaptation. Here, using genome-wide association studies, we identify CELL DIVISION CYCLE-ASSOCIATED PROTEIN 7 ALPHA (CDCA7α) as a trans-regulator of mCG in natural populations of Arabidopsis thaliana. CDCA7α and its paralog, CDCA7β, directly bind to the chromatin remodeler DECREASE IN DNA METHYLATION 1 (DDM1), which facilitates access of methyltransferases to DNA. CDCA7α/β selectively regulates mCG and minimally impacts other DDM1-dependent processes such as non-CG methylation and histone variant deposition. We identify the cis-regulatory sequence modulating CDCA7α expression in natural populations and determining the degree of mCG and TE silencing. The geographic distribution of CDCA7α alleles suggests that new alleles have repeatedly expanded to novel ecological niches, indicating a potential role in local adaptation. Altogether, our findings provide new insight into how changes in global DNA methylation levels through transcriptional regulation of the epigenetic machinery have the capacity to facilitate local adaptation.
Project description:DNA methylation occurs in both CG and non-CG sequence contexts. Non-CG methylation is abundant in plants, and is mediated by CHROMOMETHYLASE (CMT) and DOMAINS REARRANGED METHYLTRANSFERASE (DRM) proteins; however its roles remain poorly understood. Here we characterize the roles of non-CG methylation in Arabidopsis thaliana. We show that a poorly characterized methyltransferase, CMT2, is a functional methyltransferase in vitro and in vivo. CMT2 specifically binds histone H3 lysine 9 (H3K9) dimethylation and methylates non-CG cytosines at sites that are also regulated by H3K9 dimethylation. By generating different combinations of non-CG methylation mutants, we reveal the contributions and redundancies between each methyltransferase in DNA methylation patterning and in regulating transposable elements (TEs) and protein-coding genes. We also demonstrate extensive dependencies of small RNA accumulation and H3K9 methylation patterning on non-CG methylation, suggesting self-reinforcing mechanisms between these epigenetic factors. The results suggest that non-CG methylation patterns are critical in shaping the histone modification and small non-coding RNA landscapes.
Project description:DNA methylation occurs in both CG and non-CG sequence contexts. Non-CG methylation is abundant in plants, and is mediated by CHROMOMETHYLASE (CMT) and DOMAINS REARRANGED METHYLTRANSFERASE (DRM) proteins; however its roles remain poorly understood. Here we characterize the roles of non-CG methylation in Arabidopsis thaliana. We show that a poorly characterized methyltransferase, CMT2, is a functional methyltransferase in vitro and in vivo. CMT2 specifically binds histone H3 lysine 9 (H3K9) dimethylation and methylates non-CG cytosines at sites that are also regulated by H3K9 dimethylation. By generating different combinations of non-CG methylation mutants, we reveal the contributions and redundancies between each methyltransferase in DNA methylation patterning and in regulating transposable elements (TEs) and protein-coding genes. We also demonstrate extensive dependencies of small RNA accumulation and H3K9 methylation patterning on non-CG methylation, suggesting self-reinforcing mechanisms between these epigenetic factors. The results suggest that non-CG methylation patterns are critical in shaping the histone modification and small non-coding RNA landscapes. Eighteen mRNA-seq samples, five smRNA-seq samples, five bisulfite-seq samples, twenty ChIP-seq samples. Bisulfite-seq data for cmt2-7 single mutants, cmt3 single mutants, drm1/2 double mutants, drm1/2 cmt3 triple mutants are deposited in GSE39901. Processed wiggle format files for all datasets can be downloaded at http://genomes.mcdb.ucla.edu/AthBSseq/
Project description:CG Methylation of Col, Van and reciprocal hybrids using HpaII and MspI digestion followed by bioprime random labeling, and hybridization to AtTILE1 forward array. Study on constitutive and ploymorphic CG methylation between arabidopsis thaliana accessions Col-0 and Van-0. Study on the inheritance of CG methylation in reciprocal hybrids. Keywords: genomic hybridization