Expression is observed in a single photoreceptor cell per ommatidium, identified as R7, starting at row 8 behind the morphogenetic furrow in third instar larval eye discs. Expression continues throughout the whole imaginal disc mainly in one cell per ommatidium (R7). Expression continues in R7 cells in pupae but no expressio is observed in the adult retina. Some expression is seen in adults in a subset of laminar neurons.