Odorant-binding proteins of the mosquito Culex quinquefasciatus (Diptera: Culicidae): Genome analysis and expression patterns

Insects Odorant-Binding Proteins (OBPs) constitute a multigenic family likely to be involved in the peripheral reception of odorants that occurs in specialized structures, the olfactory sensilla. Even if their exact function is still not completely understood, these proteins could act in the transport of odorant molecules through the sensillum lymph and their delivery to the odorant receptors (ORs) anchored in the dendritic membrane of olfactory receptor neurons (ORNs). By taking advantage of the recently released genome sequence of Culex quinquefasciatus, a vector of several diseases, we have identified 34 “classic” OBP genes in this species. Genomic organization confirms an expansion of this family by gene duplications. Expression patterns studied by RT-PCR reveal a heterogeneous distribution in olfactory (antennae, maxillary palps and proboscis) as well as non-olfactory tissues (legs, bodies). Next step of this work will focus on antennae-specific OBPs and their potential role in the recognition of physiologically relevant olfactory cues.