A novel screen to identify regulators of cell competition in Drosophila. Justin A. Bosch, Iswar Hariharan. Molecular and Cell Biology, University of California - Berkeley, Berkeley, CA.

   Cell competition is a phenomenon observed in Drosophila that results in the removal of cells from a developing tissue. The molecular mechanism of cell competition is not well understood and requires identifying novel molecules that allow cells to detect and respond to competitive ability. We have devised a novel genetic assay in Drosophila, named CoinFLP, to systematically screen for genes affecting cell competition by gene overexpression or RNAi knockdown. This system uses the Gal4/UAS system to misexpress a gene of interest in the Drosophila eye, and the FLP/FRT system to ensure this gene misexpression occurs only in a subset of the tissue. Two possible recombination events in the eye imaginal disc produce patches of cells that either express Gal4 or not. To facilitate easy scoring of cell competition phenotypes, Gal4 expressing cells are marked as white in the adult eye with UAS-whiteRNAi. Initial screening efforts have focused on genes encoding secreted or transmembrane proteins, since cell competition is thought to involve extracellular cell-cell communication.