This transgene contains a cDNA encoding a mutant human glycine receptor alpha 1 subunit in which the arginine at amino acid position 271 has been replaced by glutamine (R271Q); this mutation is associated with a dominant hereditary hyperekplexia (human startle disease). The human cDNA has replaced, in an expression vector, a segment of the mouse thymus antigen 1 gene whose deletion limits expression to neurons. Reverse transcription-polymerase chain reaction (RT-PCR) analysis using primers that amplify both mouse and human Glra1/GLRA1 cDNA demonstrates elevated mRNA expression in the spinal cord and forebrain of transgenic versus wild-type mice. In situ hybridization analysis confirms higher expression in transgenic brains and reveals sites of ectopic expression. Expression in mice of this line is significantly higher than (roughly two-fold) that in mice bearing Tg(Thy1-GLRA1*R271Q)382Wha. While competition between endogenous and transgene-derived alpha 1 receptor subunits for endogenous beta subunits confounds quantitative ligand-binding analysis, presence of complete receptors at sites of ectopic GLRA1 mRNA expression in transgenic, but not wild-type, brains is shown by competitive and non-competitive ligand binding to frozen brain sections. (J:76009)
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