Synthesis of a homodimer neurohormone precursor of locust adipokinetic hormone studied by in vitro translation and cDNA cloning

Neuron. 1989 Apr;2(4):1369-73. doi: 10.1016/0896-6273(89)90075-5.

Abstract

The homodimer neurohormone precursor P1, consisting of 41 residue subunits or A-chains, is synthesized by the glandular neurosecretory cells of the corpora cardiaca (CC) of the locust Schistocerca gregaria. Processing of P1 generates two copies of a 10 amino acid peptide neurohormone (AKH I) and one copy of a homodimer peptide (APRP 1). Here we show that the P1 dimer is formed from two independent A-chain translation products. Translation of CC mRNA in vitro produces a prominent 6.4 kd protein, the synthesis of which can be blocked by oligonucleotides hybridizing to mRNA encoding the A-chain. Northern blot experiments suggest that the 6.4 kd protein is produced by an integral of 500 base mRNA. cDNA cloning reveals a pre-A-chain structure in which a single copy of the A-chain is preceded by a 22 amino acid signal peptide. This evidence indicates that the P1 dimer is synthesized by coupling of very small translational products rather than by folding and processing of a larger protein containing more than one copy of the A-chain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cell-Free System
  • DNA / genetics
  • DNA, Recombinant
  • Grasshoppers / genetics
  • Grasshoppers / metabolism*
  • Insect Hormones / biosynthesis*
  • Insect Hormones / genetics
  • Molecular Sequence Data
  • Neuropeptides / biosynthesis*
  • Neuropeptides / genetics
  • Poly A / genetics
  • Protein Biosynthesis
  • Protein Precursors / biosynthesis
  • Protein Precursors / genetics*
  • Protein Processing, Post-Translational
  • RNA, Messenger / genetics

Substances

  • DNA, Recombinant
  • Insect Hormones
  • Neuropeptides
  • Protein Precursors
  • RNA, Messenger
  • Poly A
  • adipokinetic hormone (locust)
  • DNA