UASt regulatory sequences drive expression of a C-terminally truncated ttk69 protein.
photoreceptor cell R7, with Scer\GAL4hs.2sev
Expression of ttk69.ΔC500.Scer\UAS under the control of Scer\GAL4hs.2sev results in missing R7 cells in some ommatidia (the expressivity of the phenotype depends on the transgenic line used).