The Binding Specificity of the PHD-Finger Domain of VIN3 Moderates Vernalization Response.

Vernalization is a response to winter cold to initiate flowering in spring. VERNALIZATION INSENSITIVE3 (VIN3) is induced by winter cold and is essential to vernalization response in Arabidopsis (Arabidopsis thaliana). VIN3 encodes a PHD-finger domain that binds to modified histones in vitro. An alteration in the binding specificity of the PHD-finger domain of VIN3 results in a hypervernalization response. The hypervernalization response is achieved by increased enrichments of VIN3 and trimethylation of Histone H3 Lys 27 at the FLC locus without invoking the increased enrichment of Polycomb Repressive Complex 2. Our result shows that the binding specificity of the PHD-finger domain of VIN3 plays a role in mediating a proper vernalization response in Arabidopsis.