Polycomb and trithorax opposition in development and disease

Early discoveries in chromatin biology and epigenetics heralded new insights into organismal development. From these studies, two mediators of cellular differentiation were discovered: the Polycomb group ( PcG ) of transcriptional repressors, and the trithorax group ( trxG ) of transcriptional activators. These protein families, while opposed in function, work together to coordinate the appropriate cellular developmental programs that allow for both embryonic stem cell self‐renewal and differentiation. Recently, both the PcG and trxG chromatin modulators have been observed to be deregulated in a wide spectrum diseases including developmental disorders and cancer. To understand the impact of these findings we outline the past, present, and future. WIREs Dev Biol 2016, 5:659–688. doi: 10.1002/wdev.244 This article is categorized under: Gene Expression and Transcriptional Hierarchies > Gene Networks and Genomics Gene Expression and Transcriptional Hierarchies > Cellular Differentiation Early Embryonic Development > Development to the Basic Body Plan