SELECTION OF STABLY TRANSFECTED CELLS EXPRESSING A HIGH-LEVEL OF PETAL MUSCLE NICOTINIC RECEPTORS

We had earlier found that the numbers of mouse muscle nicotinic recept ors expressed on the surface of individual cells of a stably transfect ed clonal line of quail fibroblasts varied from cell to cell (Kopta an d Steinbach: J Neurosci 14:3922-3933, 1994). We have now used repeated selective passages of these clonal cells to produce a population of c ells which expresses a greater and more uniform number of surface rece ptors per cell. The increased level is stable over many cell divisions , and over many half-lives for the metabolic degradation of the surfac e receptors, Selection was performed by adhesion to a surface coated w ith a monoclonal antibody to a surface epitope on the muscle receptor, followed by expansion of the most tightly attached population of cell s, Studies of the selected cells show that the surface receptors conta in all four subunits of the muscle nicotinic receptor, and the functio nal properties of the receptors appear normal, The metabolic stability of the surface receptors is not altered, while the amount of mRNA for the subunits is increased in the selected population of cells, These observations indicate that the more likely reason for increased expres sion is a transcriptional effect, and that translational or posttransl ational changes are unlikely. (c) 1995 Wiley-Liss, Inc.