Expression and functional analysis of a novel Fusion Competent Myoblast specific GAL4 driver

In the Drosophila embryo, body wall muscles are formed by the fusion of two cell types, Founder Cells (FCs) and Fusion Competent Myoblasts (FCMs). Using an enhancer derived from the Dmef2 gene ([C/D]( *)), we report the first GAL4 driver specifically expressed in FCMs. We have determined that this GAL4 driver causes expression in a subset of FCMs and, upon fusion, in developing myotubes from stage 14 onwards. In addition, we have shown that using this Dmef2-5x[C/D]( *)-GAL4 driver to express dominant negative Rac in only FCMs causes a partial fusion block. This novel GAL4 driver will provide a useful reagent to study Drosophila myoblast fusion and muscle differentiation.