aln is expressed in many neurons of

the lamina, medulla, other brain regions. It is also expressed in sensory neurons in appendages including wings and legs. In the retina, however, aln^Ty1-T2A-Gal4 driven expression was confined to mechanosensory bristle neurons (identified by their unique shape and position in the retina), but excluded from photoreceptors. Evidence suggests that aln expressed in the

lamina is secreted and taken up by photoreceptor cells.