A genomic EcoRI fragment from within the regulatory regions of the spalt complex, within the first salr intron, is placed upstream of a weak P-element promoter followed by sequence encoding nuclear-localized lacZ.
Embryonic expression is detected in a subset of CNS cells where salm and salr are not normally expressed. Larval CNS and wing disc expression is also ectopic. In the larval eye imaginal disc, expression is detected in cone cells.