Manduca sexta IRP1: Molecular characterization and in vivo response to iron

Dianzheng Zhang, Cara Ferris, Jürgen Gailer, Pete Kohlhepp, Joy J. Winzerling

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Manduca sexta IRP1 was cloned and sequenced. The deduced amino acid sequence of Manduca IRP1 shows high similarity to other IRP1 proteins. The Cys residues required as ligands for the iron sulfur cluster, as well as all residues necessary for aconitase activity are conserved in the insect protein. Purified recombinant Manduca IRP1 binds specifically to transcripts of the iron responsive element (IRE) of Manduca or human ferritin subunit mRNA. Binding activity of the recombinant protein was not influenced by the presence of β-mercaptoethanol. However, IRP/IRE binding activity of cytoplasmic extracts from fat body was decreased by reducing agents in a dose-responsive manner. Fat body IRP1/IRE binding activity was reduced for Manduca sexta larvae injected with low doses of iron, while IRP1 mRNA and protein levels remained stable. At higher iron doses, binding activity increased and stabilized. Hemolymph ferritin levels showed an inverse relationship to IRP1/IRE binding activity. These data suggest that the Manduca IRP1 is likely involved in translational control of ferritin synthesis in a manner similar to that found in vertebrates. However, factors other than iron can influence IRP/IRE interaction and hemolymph ferritin levels in insects.

Original languageEnglish (US)
Pages (from-to)85-96
Number of pages12
JournalInsect Biochemistry and Molecular Biology
Volume32
Issue number1
DOIs
StatePublished - Jan 1 2001

Keywords

  • Ferritin
  • IRE
  • IRP1
  • Iron
  • Manduca sexta
  • Translational control

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Insect Science

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