Transcriptional profiling and functional modeling of the chemosensory appendages of anopheles gambiae

Abstract

Mosquitoes are vectors of many human diseases. The vectorial capacity of mosquitoes is directly a consequence of olfactory driven, host seeking behaviors. Olfaction in mosquitoes is mediated by several gene families which encode the olfactory receptors present in the major chemosensory appendages (antenna and maxillary palp) of the adult mosquito. Here, we employ RNA-seq to elucidate the transcriptional profile of these appendages in the major Afrotropical vector mosquito Anopheles gambiae. By then integrating odorant receptor functional information with the quantitative transcriptional data, we construct a synthetic model of the chemoreceptive capacity of the entire mosquito antennae. This model is then assessed against known mosquito behaviors to add a phenotypic dimension to the models. In all we conclude that olfactory receptors in the peripheral olfactory system are subtly dynamic based upon the physiological state of the mosquito. Moreover, these subtle differences are also manifest when compared to a closely related sibling species, and the resulting model is in agreement with known phenotypic differences between the species. In all we have added further evidence to the generalizable notion that peripheral odor coding at the level of olfactory receptors is sufficient to explain many observable differences in olfactory-driven behaviors.