the enhancer of trithorax and polycomb corto interacts with cyclin g in drosophilatrithorax增强剂和polycomb corto与细胞周期蛋白g在果蝇.pdf

The Enhancer of Trithorax and Polycomb Corto Interacts with Cyclin G in Drosophila 1¤ 2 ` 1 ´ 1 2 Juliette Salvaing , Anja C. Nagel , Emmanuele Mouchel-Vielh , Sebastien Bloyer , Dieter Maier , Anette 2 ´ ´ 1 Preiss , Frederique Peronnet * ´ ´ 1 Laboratoire de Biologie du Developpement, UMR 7622, Centre National de la Recherche Scientifique (CNRS), Universite Pierre et Marie Curie-Paris 6, Paris, France, ¨ ¨ 2 Institut fur Genetik (240), Universitat Hohenheim, Stuttgart, Germany Abstract Background: Polycomb (PcG) and trithorax (trxG) genes encode proteins involved in the maintenance of gene expression patterns, notably Hox genes, throughout development. PcG proteins are required for long-term gene repression whereas TrxG proteins are positive regulators that counteract PcG action. PcG and TrxG proteins form large complexes that bind chromatin at overlapping sites called Polycomb and Trithorax Response Elements (PRE/TRE). A third class of proteins, so- called ‘‘Enhancers of Trithorax and Polycomb’’ (ETP), interacts with either complexes, behaving sometimes as repressors and sometimes as activators. The role of ETP proteins is largely unknown. Methodology/Principal Findings: In a two-hybrid screen, we identified Cyclin G (CycG) as a partner of the Drosophila ETP Corto. Inactivation of CycG by RNA interference highlights its essential role during development. We show here that Corto and CycG directly interact and bind to each other in embryos and S2 cells. Moreover, CycG is targeted to polytene