Chromatin dynamics and Polycomb regulation in Arabidopsis

Overview & Synopsis

In eukaryotes, cell-fate determination, differentiation and developmental programs require precise spatial and temporal control of gene expression. Balance between gene activation and repression as well as mechanisms of maintenance and erasure of expression patterns are required for a fine gene tuning. This is achieved by highly dynamic changes of the chromatin conformation based on DNA methylation, biochemical and biophysical properties of the nucleosomes (i.e. histone post-translational modifications, histones variants) and large chromatin-related protein complexes. For instance, Polycomb group (PcG) proteins and thithorax (Trx) proteins are key transcriptional regulators in these regulatory mechanisms, that establish silent and active chromatin states, respectively, and perpetuate epigenetic states through cell divisions. I will briefly review chromatin dynamics by using the epigenetic regulation of FLOWERING LOCUS C, a floral transcriptional regulator, as a model. Then, I will discuss Polycomb regulation in plants.