title: Antennal-expressed ammonium transporters in the malaria vector mosquito Anopheles gambiae.
abstract: 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.
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America; Vanderbilt Institute for Global Health, Nashville, Tennessee, United States of America.
authors.forename: R Jason
authors.initials: RJ
authors.lastname: Pitts
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Derryberry
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Fadi E
authors.initials: FE
authors.lastname: Pulous
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America; Vanderbilt Institute for Global Health, Nashville, Tennessee, United States of America; Department of Pharmacology, Vanderbilt Brain Institute, Program in Developmental Biology and Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America.
authors.forename: Laurence J
authors.initials: LJ
authors.lastname: Zwiebel
mesh_terms: D000818:Animals; D000852:Anopheles / Q000235:genetics / Q000378:metabolism*; D057506:Arthropod Antennae / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017344:Genes, Insect; D005816:Genetic Complementation Test; D007267:Injections; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007303:Insect Vectors / Q000235:genetics / Q000378:metabolism*; D015640:Ion Channel Gating; D008288:Malaria / Q000469:parasitology*; D009154:Mutation / Q000235:genetics; D009865:Oocytes / Q000378:metabolism; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D014981:Xenopus
chemical_list: D027682:Cation Transport Proteins; D019476:Insect Proteins; D012333:RNA, Messenger