Structure and mechanism of plant histone mark readers.

In eukaryotes, epigenetic-based mechanisms are involved in almost all the important biological processes. Amongst different epigenetic regulation pathways, the dynamic covalent modifications on histones are the most extensively investigated and characterized types. The covalent modifications on histone can be "read" by specific protein domains and then subsequently trigger downstream signaling events. Plants generally possess epigenetic regulation systems similar to animals and fungi, but also exhibit some plant-specific features. Similar to animals and fungi, plants require distinct protein domains to specifically "read" modified histones in both modification-specific and sequence-specific manners. In this review, we will focus on recent progress of the structural studies on the recognition of the epigenetic marks on histones by plant reader proteins, and further summarize the general and exceptional features of plant histone mark readers.