Structural and functional comparisons of the Drosophila virilis and Drosophila melanogaster rough genes.

We have isolated the homeobox gene rough (ro) from Drosophila virilis. Comparison of the predicted amino acid sequences of the D. melanogaster and D. virilis rough proteins reveals that domains of high conservation, including the homeodomain, are interspersed with highly diverged regions. Stretches of significant sequence conservation are also observed in the 5' promoter region and in the introns. The D. virilis rough gene rescues the rough mutant phenotype and is properly regulated when introduced into the D. melanogaster genome. Thus the rough protein as well as the cis-regulatory elements that ensure proper temporal and spatial regulation are functionally conserved between these Drosophila species.