Dataset Information

Silent, generic and plant kairomone sensitive odorant receptors from the Southern house mosquito.

ABSTRACT: The Southern house mosquito Culex quinquefasciatus has the largest repertoire of odorant receptors (ORs) of all mosquitoes and dipteran species whose genomes have been sequenced to date. Previously, we have identified and de-orphanized two ORs expressed in female antennae, CquiOR2 and CquiOR10, which are sensitive to oviposition attractants. In view of a new nomenclature for the Culex genome (VectorBase) we renamed these ORs as CquiOR21 (formerly CquiOR10) and CquiOR121 (CquiOR2). In addition, we selected ORs from six different phylogenetic groups for deorphanization. We cloned four of them by using cDNA from female antennae as a template. Attempts to clone CquiOR87 and CquiOR110 were unsuccessful either because they are pseudogenes or are not expressed in adult female antennae, the main olfactory tissue. By contrast, CquiOR1, CquiOR44, CquiOR73, and CquiOR161 were highly expressed in female antennae. To de-orphanize these ORs, we employed the Xenopus oocyte recording system. CquiORx-CquiOrco-expressed oocytes were challenged with a panel of 90 compounds, including known oviposition attractants, human and vertebrate host odorants, plant kairomones, and naturally occurring repellents. While CquiOR161 did not respond to any test compound in two different laboratories, CquiOR1 showed the features of a generic OR, with strong responses to 1-octen-3-ol and other ligands. CquiOR44 and CquiOR73 showed preference to plant-derived terpenoids and phenolic compounds, respectively. While fenchone was the best ligand for the former, 3,5-dimethylphenol elicited the strongest responses in the latter. The newly de-orphanized ORs may be involved in reception of plant kairomones and/or natural repellents.

SUBMITTER: Xu P

PROVIDER: S-EPMC3800014 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature

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Silent, generic and plant kairomone sensitive odorant receptors from the Southern house mosquito.

Xu Pingxi P Choo Young-Moo YM Pelletier Julien J Sujimoto Fernando R FR Hughes David T DT Zhu Fen F Atungulu Elizabeth E Cornel Anthony J AJ Luetje Charles W CW Leal Walter S WS

Journal of insect physiology 20130719 9

The Southern house mosquito Culex quinquefasciatus has the largest repertoire of odorant receptors (ORs) of all mosquitoes and dipteran species whose genomes have been sequenced to date. Previously, we have identified and de-orphanized two ORs expressed in female antennae, CquiOR2 and CquiOR10, which are sensitive to oviposition attractants. In view of a new nomenclature for the Culex genome (VectorBase) we renamed these ORs as CquiOR21 (formerly CquiOR10) and CquiOR121 (CquiOR2). In addition, w ...[more]

PMID: 23876610

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Project description:Olfactory-based behaviors in mosquitoes are mediated by odorant-binding proteins (OBPs). They form a multigenic family involved in the peripheral events in insect olfaction, specifically the transport of odorants to membrane-bound odorant receptors. OBPs contribute to the remarkable sensitivity of the insect's olfactory system and may be involved in the selective transport of odorants.We have employed a combination of bioinformatics and molecular approaches to identify and characterize members of the "classic" OBP family in the Southern House mosquito Culex pipiens quinquefasciatus ( = Cx. quinquefasciatus), a vector of pathogens causing several human diseases. By taking advantage of the recently released genome sequences, we have identified fifty-three putative Cx. quinquefasciatus OBP genes by Blast searches. As a first step towards their molecular characterization, expression patterns by RT-PCR revealed thirteen genes that were detected exclusively and abundantly in chemosensory tissues. No clear differences were observed in the transcripts levels of olfactory-specific OBPs between antennae of both sexes using semi-quantitative RT-PCR. Phylogenetic and comparative analysis revealed orthologous of Cx. quinquefasciatus OBPs in Anopheles gambiae and Aedes aegypti. The identification of fifty-three putative OBP genes in Cx. quinquefasciatus highlights the diversity of this family. Tissue-specificity study suggests the existence of different functional classes within the mosquito OBP family. Most genes were detected in chemosensory as well as non chemosensory tissues indicating that they might be encapsulins, but not necessarily olfactory proteins. On the other hand, thirteen "true" OBP genes were detected exclusively in olfactory tissues and might be involved specifically in the detection of "key" semiochemicals. Interestingly, in Cx. quinquefasciatus olfactory-specific OBPs belong exclusively to four distinct phylogenetic groups which are particularly well conserved among three mosquito species.

Project description:The southern house mosquito, Culex quinquefasciatus, is one of the most prevalent vectors of lymphatic filariasis and flavivirus-induced encephalitis. Its vectorial capacity is directly affected by its reproductive feeding behaviors, such as host seeking, blood feeding, resting, and egg laying. In mosquitoes, these gonotrophic behaviors are odor-mediated and regulated following blood feeding. Immediately after a blood meal, female mosquitoes show reduced olfactory responsiveness and flight activity, as they enter a resting state. Insights into antennal chemosensory gene regulation at this time period can provide a foundation to identify targets involved in the state switch between host seeking and resting.This study used quantitative gene expression analyses to explore blood meal induced regulation of chemosensory gene families in the antennae of 6 days post-emergence C. quinquefasciatus females. Improved annotations for multiple chemosensory gene families, and a quantitative differential gene expression analysis between host seeking and 24 h post- blood fed females of the same age, allowed for the detection of transcripts that potentially play a role in the switch from host seeking to resting, in C. quinquefasciatus. The expression profiles of chemosensory genes varied significantly between the two treatments.Annotations for chemosensory gene repertoires in C. quinquefasciatus have been manually curated and corrected for 3' exon choice and transcript length, through sequence and transcriptome analyses. The gene expression analyses identified various molecular components of the peripheral olfactory system in C. quinquefasciatus, including odorant receptors, ionotropic receptors, odorant binding proteins and chemosensory proteins, that are regulated in response to blood feeding, and could be critical for the behavioral switch from host seeking to resting. Functional characterization of these proteins in the future can identify targets essential for the females' gonotrophic behaviors, and can be used to design novel vector control strategies.

Dataset Information

Silent, generic and plant kairomone sensitive odorant receptors from the Southern house mosquito.

Publications

Silent, generic and plant kairomone sensitive odorant receptors from the Southern house mosquito.

Similar Datasets

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