Quantitative modulation of polycomb silencing underlies natural variation in vernalization.
2012
COUSTHAM , Vincent (INRA , Nouzilly (France). UR 0083 Recherches Avicoles) | Li , Peijin (John Innes Centre, Norwich(Royaume Uni). Norwich Research Park) | Strange , Amy (John Innes Centre, Norwich(Royaume Uni). Norwich Research Park) | Lister , Clare (John Innes Centre, Norwich(Royaume Uni). Norwich Research Park) | Song , Jie (John Innes Centre, Norwich(Royaume Uni). Norwich Research Park) | Dean , Caroline(auteur de correspondance) (John Innes Centre, Norwich(Royaume Uni). Norwich Research Park)
Arabidopsis thaliana accessions have adapted to growth in a wide range of climates. Variation in flowering and alignment of vernalization response with winter length are central to this adaptation. Vernalization involves the epigenetic silencing of the floral repressor FLC via a conserved Polycomb (PRC2) mechanism involving trimethylation of Lys(27) on histone H3 (H3K27me3). We found that variation for response to winter length maps to cis polymorphism within FLC. A rare combination of four polymorphisms localized around the nucleation region of a PHD-Polycomb complex determines a need for longer cold. Chromatin immunoprecipitation experiments indicate that these polymorphisms influence the accumulation of H3K27me3 in Arabidopsis accession Lov-1, both at the nucleation site and over the gene body. Quantitative modulation of chromatin silencing through cis variation may be a general mechanism contributing to evolutionary change.
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