Project description:We report a distinctive gene-targeted RNA-directed DNA methylation (RdDM) activity in the Arabidopsis thaliana male sexual lineage that regulates gene expression in meiocytes. Loss of sexual-lineage-specific RdDM causes mis-splicing of the MPS1 gene (also known as PRD2), thereby disrupting meiosis. Our results establish a regulatory paradigm in which de novo methylation creates a cell-lineage-specific epigenetic signature that controls gene expression and contributes to cellular function in flowering plants.
Project description:DNA methylation is essential for silencing transposable elements and some genes in higher eukaryotes, implying that this modification must be tightly controlled. However, accidental changes in DNA methylation can be transmitted through mitosis, as in cancer, or meiosis, leading to epiallelic variation. Here, we demonstrate the existence of an efficient and faithful mechanism that protects against transgenerational loss of DNA methylation in the plant Arabidopsis. This process is specific to the subset of heavily methylated genomic repeats that are targeted by the RNAi machinery, and does not spread into flanking regions. Remethylation is often progressive over two to four sexual generations. This differential and incremental correction of epigenetic defects may preserve genome stability while increasing adaptive opportunities.
Project description:DNA methylation is essential for silencing transposable elements and some genes in higher eukaryotes, implying that this modification must be tightly controlled. However, accidental changes in DNA methylation can be transmitted through mitosis, as in cancer, or meiosis, leading to epiallelic variation. Here, we demonstrate the existence of an efficient and faithful mechanism that protects against transgenerational loss of DNA methylation in the plant Arabidopsis. This process is specific to the subset of heavily methylated genomic repeats that are targeted by the RNAi machinery, and does not spread into flanking regions. Remethylation is often progressive over two to four sexual generations. This differential and incremental correction of epigenetic defects may preserve genome stability while increasing adaptive opportunities. 2 samples examined: wild type, and ddm1 mutant.
Project description:Ecotype-specific differences in genome methylation were assayed in Arabidopsis Col and Ler variations using genomic tiling microarrays. Comparative genome hybridization was also performed so that the contribution of ecotype-specific amplifications and deletions could be estimated and integrated into the analysis of differential DNA methylation. Keywords: methylation analysis and comparative genome hybridization
