Gene editing reveals obligate and modulatory components of the CO2 receptor complex in the malaria vector mosquito, Anopheles coluzzii

• DOI: 10.1016/j.ibmb.2020.103470
• Publication Date: 2020-09-20T14:30:40Z
• Authors: Feng Liu; Zi Ye; Adam Baker; Huahua Sun; Laurence J. Zwiebel
• Keywords: Transduction (biophysics); Obligate

AbstractThe sensitivity to volatile carbon dioxide (CO2) produced by humans and other animals is a critical component in the host preference behaviors of the malaria vector mosquitoAnopheles coluzzii. The molecular receptors responsible for the ability to sense CO2are 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 ofAn. 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 CO2transduction process. To address this, we have used CRISPR/Cas9-based gene editing techniques combined within vivoelectrophysiological recordings to directly examine the role ofGr22,23,24in detecting CO2inAn. coluzzii. These studies reveal that bothGr23andGr24are absolutely required to maintainin vivoCO2sensitivity while, in contrast,Gr22knock out mutants are still able to respond to CO2stimuli albeit with significantly weaker sensitivity. Our data supports a model in whichGr22plays a modulatory role to enhance the functionality ofGr23/24complexes that are responsible for CO2sensitivity of mosquitoes.