GABA neurotransmitter transporters (GAT)-1A and GAT-1B, from the honeybee (Apis mellifera) : structure, phylogenetics, expression and function

Dutton, Paul James St. John (2005). GABA neurotransmitter transporters (GAT)-1A and GAT-1B, from the honeybee (Apis mellifera) : structure, phylogenetics, expression and function MPhil Thesis, School of Molecular and Microbial Sciences, The University of Queensland.

       
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Author Dutton, Paul James St. John
Thesis Title GABA neurotransmitter transporters (GAT)-1A and GAT-1B, from the honeybee (Apis mellifera) : structure, phylogenetics, expression and function
School, Centre or Institute School of Molecular and Microbial Sciences
Institution The University of Queensland
Publication date 2005
Thesis type MPhil Thesis
Supervisor Dr Paul R. Ebert
Total pages 121
Collection year 2005
Language eng
Subjects L
270201 Gene Expression
780105 Biological sciences
Formatted abstract

GABA is the most abundant inhibitory neurotransmitter in both mammalian and insect brains. GABA (Y-aminobutyric acid) transporters, members of the Na+ (and CI-) dependent neurotransmitter transporter superfamily, are responsible for the termination of GABAergic neurotransmission. Two GABA transporter-1 homologues (GAT-1 A & GAT-IB) have been identified in the honeybee (Apis mellifera) and protein expressed from the clones was confirmed to catalyse GABA uptake in a Xenopus laevis expression system. GAT-1 A and GAT-IB are both expressed in most neuropile regions of the brain, but also exhibit unique spatial and temporal regulation that suggests a role in age-dependent regulation of visual sensitivity.   

 

Southern hybridisation revealed only two homologous sequences in the bee genome. Sequence comparison and phylogenetic analysis indicates that these two sequences are more closely related to the mammalian GAT-1 gene than to the other known mammalian high affinity GABA transporters (GAT-2, GAT-3 and BGT-1). In fact, only GAT-1 orthologues have been cloned from insects and the complete Drosophila genome sequence also contains only GAT-1 orthologues. Complete sequence of three GAT-IB cDNA clones revealed two allelic variants that differed by four amino acid substitutions distributed throughout the deduced protein sequence. One of two non-conservative changes disrupted a putative phosphorylation site within a regulatory domain common to related transporters and may, therefore, be functionally significant. As well as allelic variants, alternatively spliced transcripts were identified from these genes, which may also give rise to functionally significant protein variants. 

Keyword GABA -- Analysis
Neurotransmitters
Honeybee -- Physiology

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
 
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Created: Fri, 24 Aug 2007, 18:43:46 EST