Co-expression of Gr8aScer\UAS.cLa, Gr98bScer\UAS.cSa and Gr66aScer\UAS.cLa in sugar-activated gustatory receptor neurons in L-type sensilla under the control of Scer\GAL4Gr64f.9.7 confers robust L-canavanine responses to these sensilla. Expression of only two of the three constructs is insufficient to confer significant L-canavadine responsiveness, although in some cases, co-expression of Gr8aScer\UAS.cLa and Gr66aScer\UAS.cLa produces a small L-canavanine-evoked response in L-type sensilla.
Expressing Gr8aScer\UAS.cLa, Gr98bScer\UAS.cSa and Gr66aScer\UAS.cLa in low salt-sensing gustatory receptor neurons under the control of Scer\GAL4Ir76b.1.5 confers significant L-canavanine responsiveness to these neurons. They do not induce responsiveness to any bitter compounds.
Expression of Gr8aScer\UAS.cLa, Gr98bScer\UAS.cSa and Gr66aScer\UAS.cLa under the control of Scer\GAL4Gr64f.9.7 in sweet-sensing gustatory receptor neurons enhances the loss of preference for sucrose over sucrose laced with L-canavanine seen in Df(3L)ex83 mutant flies: the flies now exhibit a significant attraction to the L-canavanine-containing food. No enhancement is seen when any two of the three constructs is expressed.
Expression of Gr66aScer\UAS.cLa under the control of either Scer\GAL4Gr66a.PD or Scer\GAL4Gr8a.0.7 restores normal L-canavanine-induced action potentials in the S3, S5 and S10 taste sensilla of Df(3L)ex83 flies.