Partial rescue of taste responses of α-gustducin null mice by transgenic expression of α-transducin

Wei He, Vicktoria Danilova, Shiying Zou, Göran Hellekant, Marianna Max, Robert F. Margolskee, Sami Damak

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

The transduction of responses to bitter and sweet compounds utilizes guanine nucleotide binding proteins (G proteins) and their coupled receptors. α-Gustducin, a transducin-like G protein α-subunit, and rod α-transducin are expressed in taste receptor cells. α-Gustducin knockout mice have profoundly diminished behavioral and electrophysiological responses to many bitter and sweet compounds, although these mice retain residual responses to these compounds. α-Gustducin and rod α-transducin are biochemically indistinguishable in their in vitro interactions with retinal phosphodiesterase, rhodopsin and G protein βγ-subunits. To determine if α-transducin can function in taste receptor cells and to compare the function of α-gustducin versus α-transducin in taste transduction in vivo, we generated transgenic mice that express α-transducin under the control of the gustducin promoter in the α-gustducin null background. Immunohistochemistry showed that the α-transducin transgene was expressed in about two-thirds of the α-gustducin lineage of taste receptor cells. Two-bottle preference tests showed that transgenic expression of rod a-transducin partly rescued responses to denatonium benzoate, sucrose and the artificial sweetener SC45647, but not to quinine sulfate. Gustatory nerve recordings showed a partial rescue by the transgene of the response to sucrose, SC45647 and quinine, but not to denatonium. These results demonstrate that α-transducin can function in taste receptor cells and transduce some taste cell responses. Our results also suggest that α-transducin and α-gustducin may differ, at least in part, in their function in these cells, although this conclusion must be qualified because of the limited fidelity of the transgene expression.

Original languageEnglish (US)
Pages (from-to)719-727
Number of pages9
JournalChemical Senses
Volume27
Issue number8
StatePublished - Oct 2002

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