The 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 mosquito Anopheles coluzzii. The molecular receptors responsible for the ability to sense CO₂ 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 CO₂ 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 CO₂ in An. coluzzii. These studies reveal that both Gr23 and Gr24 are absolutely required to maintain in vivo CO₂ sensitivity while, in contrast, Gr22 knock out mutants are still able to respond to CO₂ 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 CO₂ sensitivity of mosquitoes.

对人类和其他动物产生的挥发性二氧化碳 (CO ₂ )的敏感性是疟疾病媒蚊按蚊的宿主偏好行为的关键组成部分。负责感知 CO ₂能力的分子受体由三个假定的味觉受体 ( Gr ) 基因 ( Gr22,23,24 )编码，这些基因在An 的上颌触须头状感受器中的一系列独特的感觉神经元中表达。coluzzii。尽管确定了这些成分并进行了后续研究，但对这三种遗传资源在蚊子 CO _{2 中}的各自作用仍缺乏了解转导过程。为了解决这个问题，我们使用基于 CRISPR/Cas9 的基因编辑技术结合体内电生理记录来直接检查Gr22、23、24在检测An 中的CO ₂中的作用。coluzzii。这些研究表明，Gr23和Gr24都绝对需要维持体内CO ₂敏感性，而相比之下，Gr22敲除突变体仍然能够响应 CO ₂刺激，尽管敏感性明显较弱。我们的数据支持一个模型，其中Gr22发挥调节作用来增强负责蚊子对 CO ₂敏感性的Gr23/24复合物。