The regulation of expression of the genes coding for the yolk-proteins inDrosophila

Abstract

Summary The expression of the yolk protein genes has been investigated in male and female Drosophila melanogaster. The continued incorporation of radiolabeled ribonucleotides into yolk protein transcripts suggests that the genes are actively transcribed in the female fat body throughout the period of yolk protein production. In the male, the injection of high doses of 20-hydroxyecdysone transiently stimulates the production of yolk proteins. Investigation by HPLC and RIA of the fate of 20-hydroxyecdysone following its injection into male flies indicated a very rapid rate of metabolism to a group of compounds of higher polarity. Inhibition of yolk protein transcript accumulation by cycloheximide in both males and females suggested that the synthesis of other protein factors may be required for the initiation and maintenance of yolk protein gene transcription in Drosophila. A model suggesting how the yolk protein genes are regulated is presented.