A 122bp enhancer located about 3.5kb upstream of the first exon of aop drives expression of a lacZ reporter.
EcollacZaop.O drives ubiquitous low level expression in the neuroepithelium of the developing optic lobe. Stronger expression is seen in a non-overlapping pattern to that of E(spl)mγ-HLHT:AvicGFP.