AUTOSOMAL MUTATIONS AFFECTING ADHESION BETWEEN WING SURFACES IN DROSOPHILA-MELANOGASTER

Integrins are evolutionarily conserved transmembrane alpha,beta hetero dimeric receptors involved in cell-to-matrix and cell-to-cell adhesion s. In Drosophila the position-specific (PS) integrins mediate the form ation and maintenance of junctions between muscle and epidermis and be tween the two epidermal wing surfaces. Besides integrins, other protei ns are implicated in integrin-dependent adhesion. In Drosophila, somat ic clones of mutations in PS integrin genes disrupt adhesion between w ing surfaces to produce wing blisters. To identify other genes whose p roducts function in adhesion between wing surfaces, we conducted a scr een for autosomal mutations that produce blisters in somatic wing clon es. We isolated 76 independent mutations in 25 complementation groups, 15 of which contain more than one allele. Chromosomal sites were dete rmined by deficiency mapping, and genetic interactions with mutations in the beta(PS) integrin gene myospheroid were investigated. Mutations in four known genes (blistered, Delta, dumpy and mastermind) were iso lated. Mutations were isolated in three new genes (piopio, rhea and st eamer duck) that affect myo-epidermal junctions or muscle function in embryos. Mutations in three other genes (kakapo, kiwi and moa) may als o affect cell adhesion or muscle function at hatching. These new mutan ts provide valuable material for the study of integrin-dependent cell- to-cell adhesion.