PRC2 during vertebrate organogenesis: A complex in transition

► Polycomb factors function in chromatin-remodeling complexes to silence genes. ► PRC2 regulates developmental transitions during organogenesis. ► PRC2 functions are context-dependent and tissue-specific. ► H3K27me3 is dynamic and selective during tissue development. ► PRC2 subunit expression and function is likely regulated by tissue-specific factors.