The Production of a Stably Transformed Insect Cell Line Expressing An Invertebrate GABA A Receptor β-Subunit

We have produced a stable insect cell line derived from Spodoptera frugiperda (Sf9) cells expressing a cDNA encoding a β-subunit of the Lymnaea stagnalis GABAA receptor. The cDNA was randomly integrated into the insect cell genome under the control of a baculovirus immediate early gene (IE-1) promoter. Stable cell lines were established by transformation of Sf9 cells with the expression vector pIEK1.LGβ1 together with a plasmid encoding a selectable marker which confers neomycin (G418) resistance. Following growth in the presence of G418, neomycin resistant clones were selected, amplified and analysed for the presence of functional GABA-gated chloride channels. Electrophysiological analysis of one cell line showed the presence of a picrotoxin-sensitive chloride channel not present in control Sf9 cells. These channels were also sensitive to GABA, albeit at relatively high (mM) concentrations