E(Dl)KP135 has been isolated previously as a recessive lethal Drosophila P element insertion line with a dominant enhancing effect on the phenotype of Delta, a gene encoding a surface membrane protein. We show here that this P insertion also enhances the wing phenotype of nd1, an allele of Notch encoding another transmembrane protein, the putative receptor of Delta, as well as that of if3, an allele of the integrin gene PS2 alpha. Moreover, we noticed that this P insertion causes a severe Minute phenotype. Molecular characterisation revealed that the P element disrupts the putative mRNA leader sequence of the ribosomal protein L19 gene. We tested further Minute genes and found that two of them, similarly to E(Dl)KP135, strongly enhance the nd1 wing phenotype. Our results suggest that the pleiotropic Minute syndrome can affect, probably indirectly, one or more steps of wing morphogenesis that involve surface adhesion of epithelial cells.