Transcriptomic Analysis of Phenotypic Non-Specificity in Drosophila melanogaster.

Phenotypic non-specificity is the redundant rescue of a transcription factor (TF) phenotype by multiple distinct TFs. The TF Apterous (AP), expressed in Drosophila melanogaster wing imaginal discs, is required for wing development. Expression of the AP (resident) TF, and three TFs not normally expressed in the same pattern as AP (non-resident TFs), from Upstream Activation Sequence (UAS) transgenes rescue the apnull phenotype. The female-specific DSX TF, DSXF, induces female-like abdominal pigmentation. Expression of DSXF and four non-resident TFs from UAS transgenes rescue female pigmentation. As all these TFs recognize distinct DNA-binding sites, I determined what genes were regulated by the resident and the non-resident TFs. RNA-seq analysis of dissected wing discs and abdomens was performed. Sets of regulated genes showed extensive coregulation for rescue of both phenotypes. Results determined the mechanism of TF function and gene regulation to explain phenotypic non-specificity which has broader implications for current gene expression models.