Hormonal regulation and patterning of the Broad-Complex in the epidermis and wing discs of the tobacco hornworm, Manduca sexta

Baohua Zhou, Lynn M. Riddiford

Research output: Contribution to journalArticlepeer-review

89 Scopus citations

Abstract

Expression of Manduca Broad-Complex (BR-C) mRNA in the larval epidermis is under the dual control of ecdysone and juvenile hormone (JH). Immunocytochemistry with antibodies that recognize the core, Z2, and Z4 domains of Manduca BR-C proteins showed that BR-C appearance not only temporally correlates with pupal commitment of the epidermis on day 3 of the fifth (final) larval instar, but also occurs in a strict spatial pattern within the abdominal segment similar to that seen for the loss of sensitivity to JH. Levels of Z2 and Z4 BR-C proteins shift with Z2 predominating at pupal commitment and Z4 dominant during early pupal cuticle synthesis. Both induction of BR-C mRNA in the epidermis by 20-hydroxyecdysone (20E) and its suppression by JH were shown to be independent of new protein synthesis. For suppression JH must be present during the initial exposure to 20E. When JH was given 6 h after 20E, suppression was only seen in those regions that had not yet expressed BR-C. In the wing discs BR-C was first detected earlier 1.5 days after ecdysis, coincident with the pupal commitment of the wing. Our findings suggest that BR-C expression is one of the first molecular events underlying pupal commitment of both epidermis and wing discs.

Original languageEnglish (US)
Pages (from-to)125-137
Number of pages13
JournalDevelopmental Biology
Volume231
Issue number1
DOIs
StatePublished - Mar 1 2001

Keywords

  • 20-hydroxyecdysone
  • Broad-Complex
  • Insect metamorphosis
  • Juvenile hormone
  • Manduca sexta

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology

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