A-A" Staining of Drosophila indirect flight muscles at 25% pupal development with 22C10 antibody (myotube marker) and anti-Twist antibody (myoblast marker) indicates that in wild-type animals, indirect flight muscles are formed from 6 myotubes, and a large number of Twist+myoblasts are present.B-B" rumi79/79 mutants raised at 18C show no obvious defects in myoblast number or myotube morphology.C-D" rumi79/79 mutants exhibit decreased number of myoblasts at 25°-30°C and either an incomplete set of short myotubes when raised at 25C or aberrant morphology of myotubes when raised at 30C.E-E" rumi79/79 animals overexpressing FLAG-tagged POGLUT1WT in the muscle compartment using Mef2-GAL4 and raised at 25C during the pupal stage show a rescue of the rumi79/79 muscle phenotype.F-G" Overexpression of FLAG-tagged POGLUT1D233E only partially rescues the rumi79/79 muscle phenotype, with some variation in the myotube length and the number of restored Twist+cells (compare G and F). Note that the number of Twist+cells restored by POGLUT1D233E is much smaller than that restored by POGLUT1WT. Scale bar in A' is 50 µm and applies to A-G".H Quantification of myotube lengths in rumi79/79 mutants with or without POGLUT1 expression indicates a weak rescue of the phenotypes by POGLUT1D233E compared to POGLUT1WT. Mean ± standard deviation is shown. The differences in myotube lengths are statistically significant (n = 22-54). Mean ± standard deviation is shown; One-way Anova with Bonferroni´s multiple comparisons test. 