The sensitivity to volatile carbon dioxide (CO_{2}) produced by humans and other animals is a critical component in the host preference behaviors of the malaria vector mosquito Anopheles coluzzii. The molecular receptors responsible for the ability to sense CO_{2} are encoded by three putative gustatory receptor (Gr) genes (Gr22,23,24) which are expressed in a distinctive array of sensory neurons housed in maxillary palp capitate peg sensilla of An. coluzzii. Despite the identification of these components and subsequent studies, there is a paucity of understanding regarding the respective roles of these three GRs in the mosquito’s CO_{2} transduction process. To address this, we have used CRISPR/Cas9-based gene editing technique combined with in vivo electrophysiological recordings to directly examine the role of Gr22,23,24 in detecting CO_{2} in An. coluzzii. These studies reveal that both Gr23 and Gr24 are absolutely required to maintain in vivo CO_{2} sensitivity while, in contrast, Gr22 knock out mutants are still able to respond to CO_{2} stimuli albeit with significantly weaker sensitivity. Our data supports a model in which Gr22 plays a modulatory role to enhance the functionality of Gr23/24 complexes that are responsible for CO_{2} sensitivity of mosquitoes.
【저자키워드】 malaria, CRISPR/Cas9, CO(2), gustatory receptor, Anopheles coluzzii, Single sensillum recording,