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Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Minireview cung cấp cho các bạn kiến thức về ngành y đề tài: Reprogramming the epigenome during germline and seed development. | X Genome Biology Minireview Reprogramming the epigenome during germline and seed development Mark A Johnson and Judith Bender Address Brown University Department of Molecular Biology Cell Biology and Biochemistry 185 Meeting St. Providence RI 02912 USA. Correspondence Judith Bender. Email judith_bender@brown.edu Abstract Gene silencing by DNA methylation and small RNAs is globally reconfigured during gametogenesis in Arabidopsis affecting transposon activity gene regulation and development. Epigenomics the comprehensive study of how a genome is marked by histone modifications and 5-methylcytosine DNA methylation to provide regulatory information is now in its heyday. Epigenomics has the power to uncover overall trends in chromatin dynamics as well as specific regulatory loci during development and disease progression. The reference plant Arabidopsis thaliana has led the way in developing epigenomics technologies because of its compact genome decorated with histone modifications and DNA methylation that serve similar gene-activating or gene-repressing functions as in mammalian genomes. For example in Arabidopsis transposons and repetitive sequences are targeted for DNA methylation and transcriptional gene silencing through a small-RNA-guided mechanism 1 analogous to the specialized Piwi-interacting RNA piRNA pathway in the mammalian germline 2 . Recent studies published in Science Nature and Cell have used Arabidopsis epigenomics to query patterns of DNA methylation transposable element expression and small RNA accumulation in reproductive cells 3 and during seed development 4-6 . The striking finding is that cells accompanying both the sperm and the embryo undergo genome-wide changes in DNA methylation that activate small RNA production from transposons and other repeats. This finding raises the intriguing possibility that the supporting cells are used as a source of small RNAs that can move into the germline and reconfigure the epigenome. Successful fertilization
