Time-course of lentivirus-mediated pIN-KDEL expression in COS-7 cells. Sub-confluent COS-7 cells in culture, were treated with pIN-KDEL lentiviral particles, fixed, stained with DAPI and imaged at the post-transduction times indicated. Images were analysed using Image J, by first, making maxium intensity Z projections of the green (EGFP) channel, followed by subtraction of background fluorescence defined as that <3× the average. The integrated channel fluorescence within the field was then corrected for the number of cells (determined by counting DAPI stained nuclei in the blue channel) to yield an average fluorescence/cell. Data shown are the mean and standard error for at least 10 independent fields (>5 cells) of view/day. Inset: Example of LV-pIN-KDEL (green) transduced COS-7 cell; DAPI (blue), note similarity to image obtained by transfection (Fig 3, panel P). Scale bar 15 μm.