A15 - The role of histone H2A monoubiquitylation and deubiquitylation in Drosophila
PRC1 monoubiquitylates histone H2A and thereby forms H2Aub. Functional studies in Drosophila revealed that transcriptional repression of Polycomb target genes does not require the ubiquitylation of H2A but rather the deubiquitylation of H2Aub by PR-DUB. In this project, we combine genetic, genomic and biochemical approaches to investigate why H2Aub deubiquitylation is required for Polycomb repression. Analyses in Drosophila with truncation alleles in the PR-DUB subunit Asx will help us to understand the molecular basis of the Boring-Opitz and Bainbridge-Ropers syndromes in humans that are caused by equivalent mutations in ASXL1 and ASXL3, respectively.