Skeletal muscles come in a variety of shapes and sizes important for functions like running or eye blinking; however, we do not yet understand the mechanisms that generate muscle fibers with discrete morphologies. To determine how muscles with distinct shapes and sizes are formed, we have focused on the transcription elongation factor and E3 ubiquitin-ligase complex member Elongin-B. Elo-B is conserved from yeast to humans, and was recently identified in a whole-genome screen for novel factors in Drosophila muscle development. Elo-B mutants display somatic muscle defects including muscle loss and misattachment. To learn more about the role of Elo-B in muscle development, we are examining the muscle pattern of Elo-B mutants, as well as mutants for proteins that interact with Elo-B. Taken together, these experiments are providing a clearer picture of the network of gene activity required for muscle development.