Cyclin G: looking for the causes of developmental noise

International audienceDrosophila melanogaster Cyclin G (dCycG) controls transcription and regulates the cell cycle. We previously determined that dCycG shares many transcriptional targets with the Polycomb PRC1 and PR-DUB complexes1. Overexpression of a potentially more stable form of dCycG down-regulates genes involved in mitochondrial activity. Interestingly, it also induces a high developmental noise, as estimated by an increase of wing fluctuating asymmetry (FA) in adults2. Overexpression of dCycG in background mutants for the Polycomb complexes PRC1 or PR-DUB leads to a previously unseen FA1. We show here that dCycG directly interacts with dRing, the ubiquitine-ligase of PRC1 and Calypso, the deubiquitinase of PR-DUB. Our resullts suggest that dCycG undergoes a ubiquitination/deubiquitination cycle driven by these complexes and bookmarks its transcriptional targets during mitosis. We have produced a dCycG mutant by CRISPR/Cas9. This mutant displays a high FA. Although its amount of mitochondrial DNA does not vary, wing imaginal disc respiration unexpectedly increases. The next step will be to check the amount of Reactive Oxygen Species in these tissues and address whether an increase in ROS is causal to developmental noise