S. Desimone et al., ERECT WING, THE DROSOPHILA MEMBER OF A FAMILY OF DNA-BINDING PROTEINSIS REQUIRED IN IMAGINAL MYOBLASTS FOR FLIGHT-MUSCLE DEVELOPMENT, Development, 122(1), 1996, pp. 31-39
The erect wing locus of the fruit fly Drosophila melanogaster encodes
a protein, EWG, that shares extensive homology with the P3A2 DNA bindi
ng protein of sea urchin and a recently identified mammalian transcrip
tion factor. Loss-of-function erect wing alleles result in embryonic l
ethality. Viable alleles of erect wing cause severe abnormalities of t
he indirect flight muscles. We have analyzed the spatial pattern of er
ect wing expression in the developing indirect flight muscles during p
ostembryonic development. EWG is detected, 10 hours after puparium for
mation, in myoblasts that will form the indirect flight muscles. The e
arly events of muscle development are normal in ewg mutants. However,
a few hours after the onset of erect wing expression in myoblasts, def
ects are seen in the developing indirect flight muscles which subseque
ntly degenerate. We present results that show that the normal developm
ent of the indirect flight muscles requires erect wing expression in t
he progenitor myoblasts themselves. Finally, we examine the role of ta
rget muscles in the arborization of motor axons by studying the develo
ping innervation to the flight muscle in erect wing mutants. Our study
demonstrates, for the first time, a role for a regulatory gene expres
sed in imaginal myoblasts in Drosophila.