Phylogenetic tree and domain composition of HDA proteins. Maximum likelihood phylogenetic tree of HDA predicted proteins from Arabidopsis thaliana (At), Oryza sativa (Os), Solanum lycopersicon (Sl) and Zea mays (Zm). Bootstrap values higher than 50% are shown. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. Class I and Class II include the homologs of RPD3 and of HDA1 from yeast, respectively; Class III includes the homologs of human HDAC11. The hist_deacetyl domain (PF00850) is the conserved domain of HDA proteins.