Detection of hRluc-EGFP reporter expression in rBDNF-hRluc-EGFP cell lines. (A) Fluorescence microscopy images of rBDNF-hRluc-EGFP cell lines. (B) Percentage of EGFP positive cells in different rBDNF-hRluc-EGFP BAC cell lines counted by fluorescence-activated cell sorting (FACS). (C) Histograms showing the variability of reporter gene expression level within a cell population of different rBDNF-hRluc-EGFP cell lines counted by FACS. (D) Detection of Renilla luciferase enzymatic activity in rBDNF-hRluc-EGFP cell lines relative to the background signal measured in parental HeLa cells. Enduren luciferase live cell substrate was added with fresh culture medium to rBDNF-hRluc-EGFP cells and HeLa cells and Renilla luciferase luminescence was measured after 12 hour incubation. Results are normalised to cell viability assayed by cellular ATP levels after 12 hour incubation. Error bars indicate SD of three independent experiments.