Functional characterization of chemosensory proteins in the scarab beetle, Holotrichia oblita Faldermann (Coleoptera: Scarabaeida)

PLoS One. 2014 Sep 4;9(9):e107059. doi: 10.1371/journal.pone.0107059. eCollection 2014.

Abstract

Chemosensory proteins (CSPs) play important roles in chemical communication by insects, as they recognize and transport environmental chemical signals to receptors within sensilla. In this study, we identified HoblCSP1 and HoblCSP2 from a cDNA library of Holotrichia oblita antennae, successfully expressed them in E. coli and purified them by Ni ion affinity chromatography. We then measured the ligand-binding specificities of HoblCSP1 and HoblCSP2 to 50 selected ligands in a competitive binding assay. These results demonstrated that HoblCSP1 and HoblCSP2 have similar ligand-binding spectra. Both proteins displayed the highest affinity for β-ionone, α-ionone and cinnamaldehyde, indicating that they prefer binding to odorants other than sex pheromones. Additionally, immuno-localization revealed that HoblCSP1 is highly concentrated in sensilla basiconica, while HoblCSP2 is specifically localized to sensilla placodea. In conclusion, HoblCSP1 and HoblCSP2 are responsible for binding to general odorants with slightly different specificities due to their different in vivo environments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrolein / analogs & derivatives
  • Acrolein / chemistry
  • Acrolein / metabolism
  • Amino Acid Sequence
  • Animals
  • Arthropod Antennae / metabolism*
  • Arthropod Antennae / ultrastructure
  • Binding, Competitive
  • Coleoptera / classification
  • Coleoptera / genetics
  • Coleoptera / metabolism*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Female
  • Gene Expression
  • Insect Proteins / genetics
  • Insect Proteins / metabolism*
  • Ligands
  • Male
  • Molecular Sequence Data
  • Neurons, Afferent / cytology
  • Neurons, Afferent / metabolism
  • Norisoprenoids / chemistry
  • Norisoprenoids / metabolism
  • Odorants / analysis
  • Phylogeny
  • Protein Binding
  • Receptors, Odorant / genetics
  • Receptors, Odorant / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Sensilla / metabolism*
  • Sensilla / ultrastructure

Substances

  • Insect Proteins
  • Ligands
  • Norisoprenoids
  • Receptors, Odorant
  • Recombinant Proteins
  • Acrolein
  • beta-ionone
  • alpha-ionone
  • cinnamaldehyde

Grants and funding

This work was supported by the Special Fund for Agro-Scientific Research in the Public Interest (No. 201003025) and the National Natural Science Foundation of China (No. 31371997) to KL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.