20-hydroxyecdysone stimulates tissue-specific yolk-protein gene transcription in both male and female Drosophila

J Embryol Exp Morphol. 1983 Dec;78:249-68.

Abstract

The yolk polypeptides of Drosophila are normally synthesized in the fat body and ovarian follicle cells of adult females. In response to 20-hydroxyecdysone males synthesize yolk polypeptides. The actual level of yolk polypeptides synthesized in males is not always a direct reflection of the YP-transcripts present. Initially YP-transcripts are efficiently translated into polypeptides whereas later they are not and the YP-transcripts can have a half-life of less than 8 h in males. We suggest that the expression of the genes coding for the yolk polypeptides in males may be regulated at transcriptional and translational levels. Treatment of females with 20-hydroxyecdysone leads to a transient increase in YP-transcript accumulation, but the response is difficult to assess in whole flies due to the high variability in transcript levels during normal development. Analysing the response to 20-hydroxyecdysone at the level of specific tissues shows that transcript accumulation is dramatically increased in body walls (fat-body cells, epidermis and oenocytes) of both males and females. Gut, Malpighian tubules, testis and ovaries are not affected. Treatment of females with 20-hydroxyecdysone followed by measuring YP-transcript accumulation over the next 24 h in ovaries and body walls separately, confirms that only body walls respond to the hormone. There is an increase in yolk-polypeptide synthesis during the period of increased YP-transcript accumulation in females. We conclude that the response of the YP-genes to 20-hydroxyecdysone is tissue-, but not sex-specific.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Drosophila / drug effects
  • Drosophila / genetics*
  • Drosophila / metabolism
  • Ecdysterone / pharmacology*
  • Female
  • Male
  • Peptide Biosynthesis
  • Peptides / genetics*
  • Protein Biosynthesis
  • RNA / analysis
  • Transcription, Genetic / drug effects*
  • Yolk Sac / metabolism

Substances

  • Peptides
  • Ecdysterone
  • RNA