title: Establishing epigenetic variation during genome reprogramming.
abstract: Transgenerational reprogramming of DNA methylation is important for transposon silencing and epigenetic inheritance. A stochastic regulation of methylation states in the germline may lead to epigenetic variation and the formation of epialleles that contribute to phenotypic variation. In Arabidopsis thaliana inbred lines, the frequency of single base variation of DNA methylation is much higher than genetic mutation and, interestingly, variable epialleles are pre-methylated in the male germline. However, these same alleles are targeted for demethylation in the pollen vegetative nucleus, by a mechanism that seems to contribute to the accumulation of small RNAs that reinforce transcriptional gene silencing in the gametes. These observations are paving the way toward understanding the extent of epigenetic reprogramming in higher plants, and the mechanisms regulating the stability of acquired epigenetic states across generations.
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA. fsborges@cshl.edu
authors.forename: Filipe
authors.initials: F
authors.lastname: Borges
authors.forename: Robert A
authors.initials: RA
authors.lastname: Martienssen
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D045647:DNA Glycosylases / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D004251:DNA Transposable Elements; D044127:Epigenesis, Genetic; D014644:Genetic Variation; D018745:Genome, Plant; D055993:Germ Cells, Plant / Q000254:growth & development; D011058:Pollen / Q000235:genetics* / Q000254:growth & development; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000737:chemistry / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D034741:RNA, Small Interfering; D045647:DNA Glycosylases
keywords: Arabidopsis; DNA methylation; epiallele; germline; small RNAs; transposable elements