PRC1 (Polycomb repressive complex 1) contains the products of the PcG genes Polycomb, Posterior sex combs, polyhomeotic, Sex combs on midleg, and several other proteins. Preincubation of PRC1 with nucleosomal arrays blocks the ability of these arrays to be remodeled by SWI/SNF. PRC1 and SWI/SNF are likely compete with each other for the nucleosomal template. [ ]