Abstract 1707 Characterization of the contribution of the Mediator complex subunit MED23 to H3K27me3 homeostasis

H3K27me3 is a repressive histone modification that marks the genes associated with differentiation and development in plants and animals. Characterization of the Mediator complex, which acts as a scaffold for RNA polymerase II and plays a key conserved role in eukaryotic transcription, revealed that a point mutation in a Mediator tail subunit, ref4-3, results in a modest decrease in enrichment of H3K27me3 in the model plant Arabidopsis. As ref4-3 has the potential to exhibit neomorphic properties, this phenotype may not reflect the wild-type role of Mediator in plants.