known as Brahma-associated proteins (BAP). Subsequently, analysis of several other subunits of the BAP complex — SNR1 (Snf5-related protein 1; a homologue of mammalian BAF47 and yeast Snf5) and SAYP (supporter of activation of yellow protein; also known as E(Y)3; a homologue of mammalian BAF45-family members) — showed that they are also required for the antagonism of PcG proteins18,19. By light microscopy, PcG proteins and BAP complex proteins are mutually exclusive on salivary-gland polytene chromosomes20 and PcG proteins might directly counteract the chromatin-remodelling activity and recruitment of the BAP complex to chromatin21.
