Gene Regulation of BMP Ligands in Drosophila

Drosophila is a valuable system to study bone morphogenetic proteins (BMPs) due to the high functional conservation of the pathway and the molecular genetic tools available. Drosophila has three BMP ligands, decapentaplegic (BMP2/4), screw, and glass bottom boat (BMP5/6/7/8). Of these genes, the transcriptional regulation of decapentaplegic has been studied, and some of the enhancers directing its spatially specific gene expression have been described. These analyses have used many of the standard tools of molecular biology, but a valuable method of analysis often used in Drosophila is the creation of patches of mutant tissue at any stage and in any location by induced somatic recombination. The ability to create transgenic flies and manipulate the Drosophila genome with recombinases is well established. This method can be used to evaluate the requirements for specific transcription factors to act on enhancer elements in vivo, in stage- and tissue-specific manners. The yeast FLP/FRT recombination system facilitates experiments to interrogate loss- or gain-of-function for transcription factor activity on known enhancers. This chapter will outline the necessary steps to create the tools needed and conduct somatic cell recombination experiments to interrogate the function of transcription factors on BMP enhancers.