UASt regulatory sequences drive expression of an inverted repeat.
Flies expressing ballKK101994 under the control of Scer\GAL4Mef2.PU (at 29[o]C) eclose but are flightless. The myofibrils in indirect flight muscles are often thinner with shorter sarcomere length compared to wild-type, appear wavy and show a number of ultrastructural defects in the sarcomere (Z disc displacement and fragmentation, M-line disruption).