Local transposition of a hobo element within the decapentaplegic locus of Drosophila

We have efficiently mobilized a phenotypically silent hobo transgene insert ed within the cis-regulatory heldout region of the decapentaplegic (dpp) lo cus in Drosophila melanogaster. The goal of our experiment was to identify germline transmission of a local transposition event within the dpp locus t hat meets two specific criteria. First, excision of the hobo construct does not generate an adult mutant phenotype, suggesting minimal alteration to t he original site of insertion. Second, we required a new insertion of the h obo transgene into the Haploinsufficient region of the locus similar to 25 kb away. Genetic and molecular criteria are used to evaluate candidate germ lines. In a pilot study, this local transposition event occurred independen tly in two individuals. Both of the transposition events appear to be new i nsertions into the dpp transcription unit. One insertion is between the two protein-coding exons, and the other is in the 3'-untranslated region of ex on three. Strains carrying these insertions are valuable new reagents for t he analysis of dpp function and molecular evolution. These results further support the use of the hobo system as an important tool in Drosophila genet ics.