G‐protein gamma subunit 1 is required for sugar reception in Drosophila

Though G‐proteins have been implicated in the primary step of taste signal transduction, no direct demonstration has been done in insects. We show here that a G‐protein gamma subunit, G γ 1 , is required for the signal transduction of sugar taste reception in Drosophila . The G γ 1 gene is expressed mainly in one of the gustatory receptor neurons. Behavioral responses of the flies to sucrose were reduced by the targeted suppression of neural functions of G γ 1 ‐expressing cells using neural modulator genes such as the modified Shaker K + channel (EKO), the tetanus toxin light chain or the shibire ( shi ts1 ) gene. RNA interference targeting to the G γ 1 gene reduced the amount of G γ 1 mRNA and suppressed electrophysiological response of the sugar receptor neuron. We also demonstrated that responses to sugars were lowered in G γ 1 null mutant, G γ 1 N159 . These results are consistent with the hypothesis that G γ 1 participates in the signal transduction of sugar taste reception.