Antennal-expressed ammonium transporters in the malaria vector mosquito Anopheles gambiae

• Published in: PloS one Vol. 9; no. 10; p. e111858
• Main Authors: Pitts, R Jason, Derryberry, Jr, Stephen L, Pulous, Fadi E, Zwiebel, Laurence J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 31-10-2014; Public Library of Science (PLoS)
• Subjects: Alternative splicing; Ammonia; Ammonium; Ammonium transporter; Animals; Anopheles; Anopheles - genetics; Anopheles - metabolism; Anopheles gambiae; Antennae; Aquatic insects; Arthropod Antennae - metabolism; Bacteria; Biology and Life Sciences; Blood meals; Carboxylic acids; Cation Transport Proteins - chemistry; Cation Transport Proteins - genetics; Cation Transport Proteins - metabolism; Corynebacterium glutamicum; Females; Genes, Insect; Genetic Complementation Test; Health aspects; Health risks; Injections; Insect Proteins - chemistry; Insect Proteins - genetics; Insect Proteins - metabolism; Insect Vectors - genetics; Insect Vectors - metabolism; Insects; Ion Channel Gating; Kairomones; Lactic acid; Malaria; Malaria - parasitology; Mammals; Meals; Membranes; Mosquitoes; Mutation - genetics; Nitrogen; Odors; Olfaction; Oocytes; Oocytes - metabolism; Organic acids; Phylogeny; Protein Structure, Tertiary; Proteins; RNA, Messenger - genetics; RNA, Messenger - metabolism; Saccharomyces cerevisiae - metabolism; Signal transduction; Vector-borne diseases; Xenopus; Xenopus laevis; Yeast; United States > US; Tennessee; Nashville Tennessee
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0111858

The principal Afrotropical malaria vector mosquito, Anopheles gambiae remains a significant threat to human health. In this anthropophagic species, females detect and respond to a range of human-derived volatile kairomones such as ammonia, lactic acid, and other carboxylic acids in their quest for blood meals. While the molecular underpinnings of mosquito olfaction and host seeking are becoming better understood, many questions remain unanswered. In this study, we have identified and characterized two candidate ammonium transporter genes, AgAmt and AgRh50 that are expressed in the mosquito antenna and may contribute to physiological and behavioral responses to ammonia, which is an important host kairomone for vector mosquitoes. AgAmt transcripts are highly enhanced in female antennae while a splice variant of AgRh50 appears to be antennal-specific. Functional expression of AgAmt in Xenopus laevis oocytes facilitates inward currents in response to both ammonium and methylammonium, while AgRh50 is able to partially complement a yeast ammonium transporter mutant strain, validating their conserved roles as ammonium transporters. We present evidence to suggest that both AgAmt and AgRh50 are in vivo ammonium transporters that are important for ammonia sensitivity in An. gambiae antennae, either by clearing ammonia from the sensillar lymph or by facilitating sensory neuron responses to environmental exposure. Accordingly, AgAmt and AgRh50 represent new and potentially important targets for the development of novel vector control strategies.