title: Histone H1 affects gene imprinting and DNA methylation in Arabidopsis.
abstract: Imprinting, i.e. parent-of-origin expression of alleles, plays an important role in regulating development in mammals and plants. DNA methylation catalyzed by DNA methyltransferases plays a pivotal role in regulating imprinting by silencing parental alleles. DEMETER (DME), a DNA glycosylase functioning in the base-excision DNA repair pathway, can excise 5-methylcytosine from DNA and regulate genomic imprinting in Arabidopsis. DME demethylates the maternal MEDEA (MEA) promoter in endosperm, resulting in expression of the maternal MEA allele. However, it is not known whether DME interacts with other proteins in regulating gene imprinting. Here we report the identification of histone H1.2 as a DME-interacting protein in a yeast two-hybrid screen, and confirmation of their interaction by the in vitro pull-down assay. Genetic analysis of the loss-of-function histone h1 mutant showed that the maternal histone H1 allele is required for DME regulation of MEA, FWA and FIS2 imprinting in Arabidopsis endosperm but the paternal allele is dispensable. Furthermore, we show that mutations in histone H1 result in an increase of DNA methylation in the maternal MEA and FWA promoter in endosperm. Our results suggest that histone H1 is involved in DME-mediated DNA methylation and gene regulation at imprinted loci.
authors.affiliation: Department of Biology, Saint Louis University, 3507 Laclede Ave, St. Louis, MO 63103, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Rea
authors.forename: Wenguang
authors.initials: W
authors.lastname: Zheng
authors.forename: Ming
authors.initials: M
authors.lastname: Chen
authors.forename: Christopher
authors.initials: C
authors.lastname: Braud
authors.forename: Drutdaman
authors.initials: D
authors.lastname: Bhangu
authors.forename: Tara N
authors.initials: TN
authors.lastname: Rognan
authors.forename: Wenyan
authors.initials: W
authors.lastname: Xiao
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000378:metabolism*; D019175:DNA Methylation; D056625:Endosperm / Q000378:metabolism; D018392:Genomic Imprinting; D006657:Histones / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism; D005810:Multigene Family; D009154:Mutation; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; C117389:FIS2 protein, Arabidopsis; C416366:FWA protein, Arabidopsis; D006657:Histones; D018398:Homeodomain Proteins; C111712:MEA protein, Arabidopsis; D015534:Trans-Activators; D014157:Transcription Factors; C463261:DEMETER protein, Arabidopsis; D009699:N-Glycosyl Hydrolases