Larval expression is observed in the proximal-most region of the presumptive notum in the wing disc.
During embryogenesis, expressed in the dorsalmost cells of the epidermis (at the amnioserosa/dorsal epidermis boundary) from just before germ band retraction (late stage 11) to hatching. Expressed exclusively in the row of elongated cells that define the dorsal edge of the epidermal sheet and that lead the dorsalward movement of the epidermal sheet during dorsal closure.