EXPANDED - A GENE INVOLVED IN THE CONTROL OF CELL-PROLIFERATION IN IMAGINAL DISKS

The expanded gene was first identified by a spontaneous mutation that causes broad wings. We have identified an enhancer-trap insertion with in expanded and used it to generate additional mutations, including on e null allele. expanded is an essential gene, necessary for proper gro wth control of imaginal discs and, when mutant, causes either hyperpla sia or degeneration depending on the disc. Wing overgrowth in expanded hypermorphs is limited to specific regions along the anterior-posteri or and dorsal-ventral axis. expanded encodes a novel 1429 amino acid p rotein that is localized to the apical surface of disc cells and conta ins three potential SH3-binding sites. Together, these observations su ggest that the Expanded protein engages in protein-protein interaction s regulating cell proliferation in discs.