Metamorphic changes of wild type and mutant Drosophila tissues induced by 20-hydroxy ecdysone in vitro

Abstract

Wild type (Oregon R) and non-pupariating as well as late-pupariating mutant larval tissues were cultured in vitro up to 5 weeks with and without 20-hydroxy ecdysone (1 μg/ml). The following responses were elicited by the hormone: in the case of wild type tissues detachment of the larval epidermis and muscles from the cuticle; puparial tanning and sclerotization of the larval cuticle; dissociation of the fat body into single cells; inhibition of the movement of the hind intestine. Most of these responses developed within 1 week of culturing. Of the 4 mutants tested, 3 behaved like the wild type. In cultures of ℓ(1) npr-1, however, puparial tanning, disc evagination, and inhibition of the movement of the hind intestine was abnormally weak and the dissociation of fat body was not observed at all. Detachment of the epidermis and muscles as well as formation of the pupal cuticle by disc tissue occurred normally. The results are discussed with respect to the ecdysteroid-induced metamorphosis of the tissues and the autonomy of mutant gene action.