Parallel molecular genetic pathways operate during CNS metamorphosis in Drosophila

Linda L. Restifo, Wanda Hauglum

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Insect metamorphosis provides a valuable model for studying mechanisms of steroid hormone action on the nervous system during a dynamic phase of functional remodeling. The Drosophila Broad Complex (BRC) holds a pivotal position in the gene expression cascade triggered by the molting hormone 20- hydroxyecdysone (20E) at the onset of metamorphosis. We previously demonstrated that the BRC, which encodes a family of zinc-finger transcription factors, is essential for transducing 20E signals into the morphogenetic movements and cellular assembly that alter the CNS from juvenile to adult form end function. We set out to examine the relationship of BRC to two other genes, IMP-E1 and Deformed (Dfd), involved in the metamorphic transition of the CNS. Representatives of the whole family of BRC transcript isoforms accumulate in the CNS during the larval-to-pupal transition and respond directly to 20E in vitro. IMP-E1 is also directly regulated by 20E, but its induction is independent of BRC, revealing that 20E works through at least two pathways in the CNS. DFD expression is also independent of BRC function. Surprisingly, BRC and DFD proteins are expressed in distinct, nonoverlapping subsets of neuronal nuclei of the subesophageal ganglion even though both are required for its migration into the head capsule. This suggests that the segment identity and ecdysone cascades operate in parallel to control region-specific reorganization during metamorphosis.

Original languageEnglish (US)
Pages (from-to)134-148
Number of pages15
JournalMolecular and Cellular Neurosciences
Volume11
Issue number3
DOIs
StatePublished - Jun 1998

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Keywords

  • Broad Complex
  • Deformed
  • Ecdysone
  • Gene expression
  • IMP- E1
  • In vitro culture
  • Neurogenetics
  • Steroid hormones
  • Transcription factors

ASJC Scopus subject areas

  • Molecular Biology
  • Cellular and Molecular Neuroscience
  • Cell Biology

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