Up- and downregulation of esr20, an ecdysteroid-regulated gene expressed in the tracheae of Manduca sexta

Melinda Mészáros, David B. Morton

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Investigations of ecdysteroid-regulated gene cascades in Drosophila have shown that characteristics of downstream genes in such cascades include their repression by high ecdysteroid levels, their expression at low hormone levels, and the dependence of their expression on protein synthesis. In an earlier study, we identified a gene, esr20, which is expressed in the tracheae of the tobacco hornworm, Manduca sexta, prior to larval and pupal ecdyses. Initial characterization of the expression of esr20 suggested that it had the above characteristics of a downstream gene in an ecdysteroid-regulated cascade. The present study shows that, unlike the downstream genes in Drosophila, the expression of esr20 in tracheae cannot be induced by changes in the ecdysteroid levels alone. We present evidence which suggests that a decline in ecdysteroid is necessary but not sufficient for expression. Soon after pupal ecdysis the level of the esr20 transcript drops fourfold, and by 24 h after ecdysis the transcript is undetectable. Evidence is presented which suggests that this decline in transcript levels requires protein synthesis and appears to result from a decline in the stability of the transcript.

Original languageEnglish (US)
Pages (from-to)159-174
Number of pages16
JournalArchives of insect biochemistry and physiology
Issue number2
StatePublished - 1997
Externally publishedYes


  • 20-hydroxyecdysone
  • Ecdysis
  • Ecdysteroid
  • Gene expression
  • Metamorphosis

ASJC Scopus subject areas

  • Physiology
  • Biochemistry
  • Insect Science


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