Identification of regulators of the three-dimensional polycomb organization by a microscopy-based genome-wide RNAi screen.
Polycomb group (PcG) proteins dynamically define cellular identities through epigenetic repression of key developmental genes. PcG target gene repression can be stabilized through the interaction in the nucleus at PcG foci. Here, we report the results of a high-resolution microscopy genome-wide RNAi screen that identifies 129 genes that regulate the nuclear organization of Pc foci. Candidate genes include PcG components and chromatin factors, as well as many protein-modifying enzymes, including components of the SUMOylation pathway. In the absence of SUMO, Pc foci coagulate into larger aggregates. Conversely, loss of function of the SUMO peptidase Velo disperses Pc foci. Moreover, SUMO and Velo colocalize with PcG proteins at PREs, and Pc SUMOylation affects its chromatin targeting, suggesting that the dynamic regulation of Pc SUMOylation regulates PcG-mediated silencing by modulating the kinetics of Pc binding to chromatin as well as its ability to form Polycomb foci.
Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France.
Inma
I
Gonzalez
Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France.
Julio
J
Mateos-Langerak
Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France.
Aubin
A
Thomas
Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France.
Thierry
T
Cheutin
Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France. Electronic address: giacomo.cavalli@igh.cnrs.fr.
Giacomo
G
Cavalli
D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D016000:Cluster Analysis; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D063990:Gene Ontology; D060227:Imaginal Discs / Q000166:cytology / Q000378:metabolism; D010641:Phenotype; D063146:Polycomb-Group Proteins / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D034622:RNA Interference; D058207:Sumoylation
D002843:Chromatin; D029721:Drosophila Proteins; D063146:Polycomb-Group Proteins