A genomic approach to myoblast fusion in Drosophila.

We have developed an integrated genetic, genomic, and computational approach to identify and characterize genes involved in myoblast fusion in Drosophila. We first used fluorescence-activated cell sorting to purify mesodermal cells both from wild-type embryos and from 12 variant genotypes in which muscle development is perturbed in known ways. Then, we obtained gene expression profiles for the purified cells by hybridizing isolated mesodermal RNA to Affymetrix GeneChip arrays. These data were subsequently compounded into a statistical metaanalysis that predicts myoblast subtype-specific gene expression signatures that were later validated by in situ hybridization experiments. Finally, we analyzed the myogenic functions of a subset of these myoblast genes using a double-stranded RNA interference assay in living embryos expressing green fluorescent protein under control of a muscle-specific promoter. This experimental strategy led to the identification of several previously uncharacterized genes required for myoblast fusion in Drosophila.