A directed mutagenesis screen in Drosophila melanogaster reveals new mutants that influence hedgehog signaling

The Hedgehog signaling pathway has been recognized as essential for pattern ing processes in development of metazoan animal species. The signaling path way is, however, not entirely understood. To start to address this problem, we set out to isolate new mutations that influence Hedgehog signaling. We performed a mutagenesis screen for mutations that dominantly suppress Hedge hog overexpression phenotypes in the Drosophila,melanogaster wing. We isola ted four mutations that influence Hedgehog signaling. These were analyzed i n the amenable wing system using genetic and molecular techniques. One of t hese four mutations affects the stability of the Hedgehog expression domain boundary, also known as the organizer in the developing wing. Another muta tion affects a possible Hedgehog autoregulation mechanism, which stabilizes the same boundary.