Functional dissection of Odorant binding protein genes in Drosophila melanogaster

Abstract

Most organisms rely on olfaction for survival and reproduction. The olfactory system of Drosophila melanogaster is one of the best characterized chemosensory systems and serves as a prototype for understanding insect olfaction. Olfaction in Drosophila is mediated by multigene families of odorant receptors and odorant binding proteins (OBPs). Although molecular response profiles of odorant receptors have been well documented, the contributions of OBPs to olfactory behavior remain largely unknown. Here, we used RNAi-mediated suppression of Obp gene expression and measurements of behavioral responses to 16 ecologically relevant odorants to systematically dissect the functions of 17 OBPs. We quantified the effectiveness of RNAi-mediated suppression by quantitative real-time polymerase chain reaction and used a proteomic liquid chromatography and tandem mass spectrometry procedure to show target-specific suppression of OBPs expressed in the antennae. Flies in which expression of a specific OBP is suppressed often show altered behavioral responses to more than one, but not all, odorants, in a sex-dependent manner. Similarly, responses to a specific odorant are frequently affected by suppression of expression of multiple, but not all, OBPs. These results show that OBPs are essential for mediating olfactory behavioral responses and suggest that OBP-dependent odorant recognition is combinatorial.

Protein Baits, Volatile Compounds and Irradiation Influence the Expression Profiles of Odorantbinding Protein Genes in Bactrocera Dorsalis (Diptera: Tephritidae)

“…In our study, some OBPs showed the same response to MIX treatment and were highly expressed at all physiological stages. This result further supports the view that OBPs are not just simple, general solubilizers that act as transporters for odorants but also play a vital role in the perception of different kinds of chemicals in the environment (Pelosi et al, 2006;Swarup et al, 2011). An OBP in Hylamorpha elegans showed a high binding affinity to β-ionone (Venthur et al, 2016), a volatile compound derived from plant carotenoids (Simkin et al, 2004).…”

The Lepidoptera Odorant Binding Protein gene family: Gene gain and loss within the GOBP/PBP complex of moths and butterflies

“…Some studies have demonstrated that reduced expression or genetic alteration of an OBP can lower the sensitivity of a sensory neuron to its odor ligand and/or alter chemosensory behavioral phenotypes (e.g. Syed et al, 2006;Pelletier et al, 2010;Wang et al, 2010;Swarup et al, 2011); other studies have demonstrated promising methodologies that reduce OBP expression but have not characterized resulting physiological or behavioral phenotypes (e.g. Sengul and Tu, 2010).…”

Analysis of antennal transcriptome and odorant binding protein expression profiles of the recently identified parasitoid wasp, Sclerodermus sp.

“…The OBPs are believed to solubilize volatile hydrophobic molecules, enabling their delivery to odor receptors via the sensillum lymph (Sanchez-Gracia et al, 2009;Zhou, 2010;Swarup et al, 2011). The OBPs contain two or three disulfide bridges.…”