UASt regulatory sequences drive expression of the E(spl)m5-HLH coding region.
When expressed under the influence of Scer\GAL4da.G32, HLHm5Scer\UAS.cNa can cause central and peripheral neural hypoplasia. There are no obvious epidermal effects on these embryos. The severity of this phenotype depends on the site of insertion of the P{HLHm5-UAST} element. This effect is dramatically enhanced if the flies also carry P{UAS-E(spl).N}. When expressed under the influence of Scer\GAL4sca-537.4, HLHm5Scer\UAS.cNa can cause defects in the patterns of bristles. Pupal lethal lines from Scer\GAL4da.G32 or Scer\GAL4sca-537.4 lack almost all macro and microchaetae. Wing margin bristles are particularly affected in HLHm5Scer\UAS.cNa.
Expression under the influence of Scer\GAL4da.G32 attenuates the mutant phenotype of Df(3R)grob32.2, though to a lesser degree than for E(spl)Scer\UAS.cNa. Simultaneous expression of E(spl)Scer\UAS.cNa or HLHm5Scer\UAS.cNa with E(spl)1,bd-.Scer\UAS driven by Scer\GAL4da.G32 causes severe neural hypoplasia in embryos and adults, and reduces the level of neural hyperplasia in Df(3R)grob32.2.