Vernalization-Mediated Epigenetic Silencing by a Long Intronic Noncoding RNA

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Science  02 Dec 2010:
DOI: 10.1126/science.1197349


Vernalization is an environmentally induced epigenetic switch in which winter cold triggers epigenetic silencing of floral repressors and thus provides competence to flower in spring. In Arabidopsis, winter cold triggers enrichment of tri-methylated Histone H3 Lys 27 at chromatin of the floral repressor, FLOWERING LOCUS C (FLC) and results in epigenetically stable repression of FLC. This epigenetic change is mediated by an evolutionarily conserved repressive complex, Polycomb Repressive Complex 2 (PRC2). Here, we show that a long intronic noncoding RNA (termed as COLDAIR) is required for the vernalization-mediated epigenetic repression of FLC. COLDAIR physically associates with a component of PRC2 and targets PRC2 to FLC. Our results show that COLDAIR is required for establishing stable repressive chromatin at FLC through its interaction with PRC2.