The action of the geneprune (pn)inDrosophila melanogaster

Abstract

The genepnwas found to be active already in larvae 30 h old, long before eye-pteridines accumulated. At this developmental stagepninteracts with the geneK-pn. From studies with induced somatic recombination, gynandromorphs, and inducedpnmutations, in aK-pnbackground it was concluded that the interactionpn-K-pnis non-autonomous in the epidermis, but in some internal organs it is apparently autonomous and causes the death ofpn–K-pnflies. It is proposed thatpnmutants interfere with an early step of the conversion of guanosine to pteridine, so that a deficiency of drosopterines, but not of the competing sepiapterine and biopterine, is caused. The accumulated precursor is presumably the substrate for a poisonous reaction triggered byK-pn.