The preference for fructose in two-choice preference assays exhibited by wild type larvae is abolished in Gr43aGAL4 mutants. The preferences for glucose, melezitose and sorbitol are also lost. Preferences for casein peptone (an amino acid/peptide mixture) or sodium chloride are similar to controls.
Taste neurons in the forelegs of homozygous flies show significantly reduced Ca[2+] response to fructose compared to wild type, while responses to sucrose, glucose, trehalose, arabinose and maltose are unaffected.
In contrast to wild type, homozygous flies do not show a preference for 100mM sorbitol over water in a modified capillary feeding assay.
Homozygous flies show significantly increased consumption of the nutritious sugars sucrose and glucose compared to wild type in a modified capillary feeding assay. Consumption of fructose is slightly increased in this assay in the mutant flies, while trehalose consumption is not significantly different from normal. Consumption of the non-nutritious sugars arabinose, xylose and sucralose in a modified capillary feeding assay is normal in homozygous flies.
Homozygous flies show significantly increased consumption of a sorbitol and sucralose solution compared to wild type in a modified capillary feeding assay.
Gr43aGAL4 is an enhancer of abnormal proboscis extension reflex phenotype of Df(3L)ΔGr64, Gr61a1
The Ca[2+] response of taste neurons in the forelegs to fructose, sucrose, glucose, trehalose, arabinose or maltose is abolished in flies triply homozygous Gr43aGAL4 ; Gr61a1 Df(3L)ΔGr64.
Gr43aGAL4 ; Gr61a1 Df(3L)ΔGr64 triple mutant flies show completely lack a proboscis extension reflex to fructose and sucrose.
Gr43aGAL4 is rescued by Scer\GAL4Gr43a-GAL4/Gr43aUAS.cMa
Gr43aGAL4 is rescued by Scer\GAL4Gr43a-GAL4/Gr43aUAS.cMa
Gr43aGAL4 is partially rescued by Scer\GAL80ChAT.7.4P/Scer\GAL4Gr43a-GAL4/Gr43aUAS.cMa
Expression of Gr43aScer\UAS.cMa under the control of Scer\GAL4Gr43a-GAL4 rescues the loss of sugar preference in two-choice preference assays seen in Gr43aGAL4 mutant larvae. Preferences for fructose, glucose, melezitose and sorbitol are all restored.
Expression of Gr43aScer\UAS.cMa under the control of Scer\GAL4Gr43a-GAL4 (restricted to the brain using Scer\GAL80ChAT.7.4P) rescues the defects in glucose and sorbitol preference in two-choice preference assays seen in Gr43aGAL4 mutant larvae. The preference for fructose is not fully rescued and is still severely reduced.
Expression of Gr43aScer\UAS.cMa under the control of Scer\GAL4Gr43a-GAL4 rescues the reduced Ca[2+] response to fructose which is seen in taste neurons of the foreleg in Gr43aGAL4 homozygotes.
Expression of Gr43aScer\UAS.cMa under the control of Scer\GAL4Gr43a-GAL4 rescues a preference for 100mM sorbitol over water in a modified capillary feeding assay in Gr43aGAL4 homozygotes. This rescue is still seen in the presence of Scer\GAL80Cha.7.4P (which limits expression to the Scer\GAL4Gr43a-GAL4-expressing neurons in the brain).
Expression of Gr43aScer\UAS.cMa under the control of Scer\GAL4Gr43a-GAL4 rescues the over-consumption of sucrose, glucose and fructose seen in Gr43aGAL4 homozygotes in a modified capillary feeding assay.
Expression of Gr43aScer\UAS.cMa under the control of Scer\GAL4Gr43a-GAL4 in the presence of Scer\GAL80Cha.7.4P rescues the over-consumption of a sorbitol and sucralose solution seen in Gr43aGAL4 homozygotes in a modified capillary feeding assay.
