title: DNA methylation dynamics during sexual reproduction in Arabidopsis thaliana.
abstract: DNA methylation maintains genome stability and regulates gene expression [1]. In mammals, DNA methylation is reprogrammed in the germline from one generation to the next [2]. In plants, it was considered that patterns of DNA methylation are stably maintained through sexual reproduction [3-6]. However, a recent report showed discrete variations of DNA methylation profiles from mother to daughter plants [7]. The mechanisms that explain these variations have remained unknown. Here, we report that maintenance DNA methyltransferases are barely expressed during Arabidopsis female gametogenesis. In contrast, after fertilization both maintenance and de novo DNA methyltransferases are expressed strongly in the embryo. Embryogenesis is marked by increased de novo DNA methylation, reaching levels that are further maintained in the adult plant. The accumulation of these epigenetic marks after fertilization silences a methylation-sensitive fluorescent reporter. De novo DNA methylation in the embryo provides a mechanism that could account for the gradual remethylation of experimentally demethylated genomes [8, 9]. In conclusion, we uncover that DNA methylation activity fluctuates during sexual reproduction. This cycle likely explains variations of genome-wide patterns of DNA methylation across generations in Arabidopsis [7, 10] and enables a limited degree of reprogramming of the epigenome.
authors.affiliation: Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore 117604, Singapore. pjullien@ethz.ch
authors.forename: Pauline E
authors.initials: PE
authors.lastname: Jullien
authors.forename: Daichi
authors.initials: D
authors.lastname: Susaki
authors.forename: Ramesh
authors.initials: R
authors.lastname: Yelagandula
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Higashiyama
authors.forename: Frédéric
authors.initials: F
authors.lastname: Berger
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D015257:DNA-Cytosine Methylases / Q000235:genetics / Q000378:metabolism; D044127:Epigenesis, Genetic; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D012639:Seeds / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C117389:FIS2 protein, Arabidopsis; D014157:Transcription Factors; D015257:DNA-Cytosine Methylases; C499608:MET1 protein, Arabidopsis; D008780:Methyltransferases; C429766:CMT3 protein, Arabidopsis; D004248:DNA (Cytosine-5-)-Methyltransferases; C470732:DRM2 protein, Arabidopsis