In late third instar larva, pattern of expression differs in different discs, although there is differential expression in the proximal-distal axis in all. In wing and haltere discs expression is confined to a broad ring around the pouch that will make the distal appendage, expression does not extend into the distal-most region. In leg and antennal discs staining extends to the central (distal) tip of the disc. Strongest expression in pouch region of wing disc and in haltere disc. Weak expression throughout the CNS.

In adults, expressed in a distinct cell type in Malpighian tubules, described as "tiny cells".

Expressed in a class of tiny cells in the lower tubule (adjacent to the ureter) and posterior midgut.