The Drosophila Gustatory Receptor Genes: the Molecular Basis of Taste Perception and Coding
Abstract
Discrimination between edible and contaminated foods is crucial for the survival of
animals. In Drosophila, a family of gustatory receptors (GRs) expressed in taste neurons
is thought to mediate the recognition of sugars and bitter compounds, thereby controlling
feeding behavior. Using the Gal4/UAS system, we have characterized the expression
of Gr genes in detail, and find that gene expression falls into two distinct groups.
The first group, which make up the majority of the genes analyzed, are co-expressed
with Gr66a, and functional ablation of taste neurons expressing these genes demonstrates
that these neurons mediate sensitivity to bitter substrates. A second, distinct group
of taste neurons, express Gr5a and mediate sensitivity to trehalose. We find that
these two sub-populations of taste neurons - attractive-type and avoidance-type -
project afferents to discrete areas of the primary taste center in the CNS. These
results demonstrate how bitter and sweet taste are coded for in the periphery and
indicates that information about different taste modalities is initially segregated
in the CNS. We have also used the Gal4/UAS system to thoroughly characterize the
expression profile of a cluster of six Grs - Gr28a and Gr28b.a-b.e. We find that these
receptors are expressed not only in taste neurons, but other sensory neurons, as well
as neurons in the CNS. RNA in situ hybridization confirms this unusual expression
pattern. In order to explore the function of these Grs, these genes have been deleted
using ends-out homologous recombination, to produce Gr28 mutant flies. Initial behavioral
experiments with Gr28 mutant flies suggest that these receptors may play a role in
detecting aversive substrates and/or modulate avoidance responses to these substrates.
Type
DissertationDepartment
Genetics and GenomicsPermalink
https://hdl.handle.net/10161/392Citation
Thorne, Natasha (2007). The Drosophila Gustatory Receptor Genes: the Molecular Basis of Taste Perception and
Coding. Dissertation, Duke University. Retrieved from https://hdl.handle.net/10161/392.Collections
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