UASt regulatory sequences drive expression of the C-terminal 123-179 residues of E(spl)m8-HLH. The phosphorylation sites in this sequence are retained and thus it should possess autoinhibitory activity.
Expression of E(spl)123-179.CtD.Scer\UAS in the proneural clusters, under the control of Scer\GAL4455.2 elicits ectopic macrochaeta on the scutellum of 62-78% of flies, with an average penetrance of approximately 70%.
Co-expression of E(spl)123-179.CtD.Scer\UAS under the control of Scer\GAL4sca-109-68 strongly rescues the reduced eye found upon expression of E(spl)SD.Scer\UAS in the developing eye morphogenetic furrow (Scer\GAL4sca-109-68) and significantly restores the aberrant ommatidial size and patterning.
Co-expression of E(spl)123-179.CtD.Scer\UAS restores 2-3 of the scutellar macrochaeta lost in a Scer\GAL4455.2>E(spl)Scer\UAS.cKa background. Often, socket cells and misshapen macrochaeta are found.