Fig. 7. Model for Fas2 and JH action in Drosophila organ looping. (A) Fas2 is specifically expressed and required in neurosecretory cells innervating the corpora allata, to control JH titers. JH is released into the circulating hemolymph and reaches the genital disc to control its rotation non-autonomously. (B) Parallels between the vertebrate and the Drosophila pathways controlling asymmetric organ looping. In vertebrates, two conserved pathways have been implicated in LR asymmetry, the retinoic acid (RA) and the nodal pathways. RA plays a dual role as it is also involved in organ looping. In Drosophila, mutants exist that can lead to a reversion of genitalia rotation (Milani, 1955; Milani, 1956) (G.Á. and S.N., unpublished), suggesting that they are involved in LR asymmetry (collectively represented by a question mark). The analysis of Fas2^spin shows a role for JH, a RA analog, in the control of organ looping and suggests an evolutionary conserved function of terpenoids in the control of asymmetric organ looping.

Return to article