CELL-INTERACTIONS IN THE CONTROL OF SIZE IN DROSOPHILA WINGS

The vein locus (vn) includes lethal alleles (designated also defective dorsal discs) that prevent growth of dorsal discs and in viable genet ic combinations reduce the number of cells of the adult wing. Those ef fects are prominent in genetic mosaics. Cell proliferation is reduced in all regions of the wing blade in a local autonomous way. These effe cts are more extreme when mutant clones occupy full intervein regions bordering veins. Clones have, in addition, nonautonomous effects (acco mmodation) in the proliferation of wild-type cells of the same wing. T hese effects are more extreme in double mutant vn (ddd) and ve (rhombo id) allelic combinations. Developmental analysis shows that cell proli feration stops earlier in larval development the stronger the vn allel e considered. A model is discussed of how cell proliferation is contro lled by cellular interactions.