The Drosophila tissue polarity gene inturned acts cell autonomously and encodes a novel protein.

Mutations in the inturned (in) gene result in abnormal wing hair polarity and in many wing cells forming two or more hairs instead of the normal single hair. We have generated genetic mosaics in a number of different experiments and find that the in gene is required in all regions of the wing and that it functions in a cell autonomous fashion. We report the molecular cloning of the in gene, the molecular mapping of in mutations and the isolation and sequencing of an in cDNA clone. The in gene encodes a novel protein whose sequence suggests it will be membrane bound. The ability of an in cDNA, the expression of which is driven by the basal activity of the hsp70 promoter to rescue an in mutation suggests that patterned expression of in is unlikely to play a role in the function of the gene.