title: The PHD finger protein VRN5 functions in the epigenetic silencing of Arabidopsis FLC.
abstract: Vernalization, the acceleration of flowering by the prolonged cold of winter, ensures that plants flower in favorable spring conditions. During vernalization in Arabidopsis, cold temperatures repress FLOWERING LOCUS C (FLC) expression in a mechanism involving VERNALIZATION INSENSITIVE 3 (VIN3), and this repression is epigenetically maintained by a Polycomb-like chromatin regulation involving VERNALIZATION 2 (VRN2), a Su(z)12 homolog, VERNALIZATION 1 (VRN1), and LIKE-HETEROCHROMATIN PROTEIN 1. In order to further elaborate how cold repression triggers epigenetic silencing, we have targeted mutations that result in FLC misexpression both at the end of the prolonged cold and after subsequent development. This identified VERNALIZATION 5 (VRN5), a PHD finger protein and homolog of VIN3. Our results suggest that during the prolonged cold, VRN5 and VIN3 form a heterodimer necessary for establishing the vernalization-induced chromatin modifications, histone deacetylation, and H3 lysine 27 trimethylation required for the epigenetic silencing of FLC. Double mutant and FLC misexpression analyses reveal additional VRN5 functions, both FLC-dependent and -independent, and indicate a spatial complexity to FLC epigenetic silencing with VRN5 acting as a common component in multiple pathways.
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich, NR4 7UH, United Kingdom.
authors.forename: Thomas
authors.initials: T
authors.lastname: Greb
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Mylne
authors.forename: Pedro
authors.initials: P
authors.lastname: Crevillen
authors.forename: Nuno
authors.initials: N
authors.lastname: Geraldo
authors.forename: Hailong
authors.initials: H
authors.lastname: An
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Gendall
authors.forename: Caroline
authors.initials: C
authors.lastname: Dean
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000502:physiology*; D003080:Cold Temperature; D004268:DNA-Binding Proteins / Q000502:physiology; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing / Q000502:physiology*; D026161:MADS Domain Proteins / Q000502:physiology*; D009154:Mutation; D014157:Transcription Factors / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C418902:At5g10140 protein, Arabidopsis; D026161:MADS Domain Proteins; D014157:Transcription Factors; C480553:VIN3 protein, Arabidopsis; C518076:VRN5 protein, Arabidopsis