In insects that completely metamorphose, such as Drosophila, embryonically specified imaginal cells remain dormant until the larval stages when their coordinated proliferation and differentiation generates various adult organs. Now, on , Chrysoula Pitsouli and Norbert Perrimon describe how embryonic cells – spiracular branch (SB) tracheoblasts – remodel the Drosophila abdominal airways during metamorphosis. The adult fly tracheal system consists of branched tracheal tubes (which transport air into the insect's body) and spiracles (the external respiratory organs, which are surrounded by epidermal cells). The researchers show that embryonic SB tracheoblasts are multipotent cells that express the homeobox transcription factor Cut, which is necessary for their survival and normal development. SB tracheoblasts, they report, give rise to three distinct cell populations at the end of larval development, which generate the two components of the adult tracheal system and the surrounding epidermis. This dissection of the molecular events that underlie the formation of an adult tubular structure in Drosophila might shed light on mammalian tubular organ development, suggest the researchers.
