Genetic and Hormonal Regulation of Vitellogenesis inDrosophila

Abstract

In Drosophila the female-specific yolk protein, or vitellogenin, is synthesized in the fat body. In D. melanogaster , vitellogenin, is first detected in the female hemolymph at the time of adult eclosion and in the ovaries 20 hours later, suggesting different regulatory mechanisms for the processes of synthesis and uptake. Transplantations of pupal or immature adult ovaries into D. melanogaster adult males induce vitellogenin synthesis, implicating an ovarian agent in the control of synthesis. Larval ovaries fail to stimulate synthesis. Female-sterile mutants with rudimentary or previtellogenic ovaries synthesize and accumulate large quantities of vitellogenin in the hemolymph, but not in the ovaries. Transplantation of these rudimentary ovaries into males induces vitellogenin synthesis, suggesting that the ovarian inducing agent does not originate from the germ cells. Treatment of the homozygous female-sterile mutants with juvenile hormone stimulates the uptake of vitellogenin by the ovary in some strains. This shows that juvenile hormone plays a role in vitellogenin uptake. The potential importance of Drosophila vitellogenesis for studies of gene regulation is discussed.