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Vernalization-Mediated Epigenetic Silencing by a Long Intronic Noncoding RNA

Jae Bok Heo and Sibum Sung

Science Vol. 331 no. 6013 pp. 76-79, 7 January 2011.
DOI: 10.1126/science.1197349

This week’s straight summary/analysis by Carla Klattenhoff:

In this paper the authors present exciting findings about the role of a novel long ncRNA, termed COLDAIR, in the process of vernalization in Arabidopsis. Vernalization is a system that allows plants to sense prolonged exposure to cold and acquire the ability to flower rapidly in the spring. Previous work has established that prolonged cold results in epigenetic silencing of the floral repressor FLC, mediated by the conserved repressive complex PRC2. COLDAIR is expressed from a cryptic promoter in an intronic region of FLC during exposure to cold and binds to PRC2. Knockdown of COLDAIR results in delayed flowering after vernalization and consistent increased expression of FLC. This increase in FLC expression is correlated with decreased recruitment of PRC2 and H3K27 tri-methylation at the FLC locus. The authors conclude that COLDAIR is required to recruit PRC2 to the FLC locus during vernalization to stably repress FLC expression.

I think the data presented in this paper is solid and support the conclusions drawn by the authors. My only criticism is that the discussion of the mechanism and implications of this finding seemed a little simplistic and superficial.