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Characterization of a GABAA receptor ß subunit in the abalone Haliotis asinina that is upregulated during larval development
Citation
Stewart, P and Williams, EA and Stewart, MJ and Soonklang, N and Degnan, SM and Cummins, SF and Hanna, PJ and Sobhon, P, Characterization of a GABAA receptor ß subunit in the abalone Haliotis asinina that is upregulated during larval development, Journal of Experimental Marine Biology and Ecology, 410 pp. 53-60. ISSN 0022-0981 (2011) [Refereed Article]
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DOI: doi:10.1016/j.jembe.2011.10.005
Abstract
In the tropical abalone Haliotis asinina, the neurotransmitter γ-aminobutyric acid (GABA) is a potent inducer
of larval settlement, a process beginning with the onset of a behavioral search for a suitable substratum and
ending with metamorphosis. In the natural environment, larvae can encounter GABA or GABA-like molecules
through association with conspecific foot mucus and crustose coralline algae. To understand the role of GABA
in the molecular process leading to settlement required identification and analysis of GABA's cognate receptor.
We now have isolated the first abalone full-length GABAA receptor (Has-GABAAR) β subunit gene, which
encodes a protein of 485 amino acids, from juvenile H. asinina neural tissue. Similar to other metazoan
GABAARs, the abalone GABAAR contains four transmembrane domains, a conserved cysteine loop in the Nterminal
extra-cellular domain, and highly conserved sequence motifs. The Has-GABAAR gene is expressed
at extremely low levels in unfertilized eggs, but increases significantly just prior to settlement, peaking at
120 h post fertilization (hpf). We further demonstrate that during the period of larval competence
(96144 hpf), gene transcripts and the encoded Has-GABAAR were localized in a cluster of cells along the dorsal
and lateral edges of the foot, as well as the posterior epithelium. In functional settlement assays using GABA
and 5-AVA, we found that there was significantly lower settlement of veligers pre-treated with antibodies to an
external domain of the Has-GABAAR than those treated with preimmune serum, or untreated veligers. We postulate
that this receptor may act as a highly sensitive chemical sensor, whose activation is necessary to trigger
chloride-mediated sensory neuron activation or inhibition, leading to the initiation of settlement and metamorphosis
events.
Item Details
Item Type: | Refereed Article |
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Keywords: | GABAA receptor Haliotis asinina Larvae Settlement |
Research Division: | Biological Sciences |
Research Group: | Zoology |
Research Field: | Invertebrate biology |
Objective Division: | Animal Production and Animal Primary Products |
Objective Group: | Fisheries - aquaculture |
Objective Field: | Aquaculture molluscs (excl. oysters) |
UTAS Author: | Stewart, MJ (Dr Michael Stewart) |
ID Code: | 76054 |
Year Published: | 2011 |
Web of Science® Times Cited: | 11 |
Deposited By: | Sustainable Marine Research Collaboration |
Deposited On: | 2012-02-24 |
Last Modified: | 2012-04-11 |
Downloads: | 0 |
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