A NOVEL METHOD TO ISOLATE CELLS WITH CONDITIONAL GENE-EXPRESSION USING FLUORESCENCE-ACTIVATED CELL SORTING (FACS)

An inducible expression system using control elements of the tetracycl ine resistance operon has recently shown promise for conditional gene expression of any gene of interest. However, intensive screening of mu ltiple independent clones is often required to find cell lines with op timal induction characteristics. By coupling expression of the gene of interest with a fluorescent marker, we have developed a novel fluores cence activated cell sorting (FACS) based strategy to isolate cells wi th desirable expression characteristics, thus alleviating the laboriou s isolation and analysis of multiple independent clones.