Asymmetrical signals with cytoplasmic GFP. The typical distribution of fluorescence intensity of cytoplasmic GFP in human cord blood–derived neutrophils along the axis shown of a polarizing cell (a) and a cell undergoing phagocytosis (b). (c) The dynamic nature of the fluorescence asymmetry of GFP during phagocytosis is shown in a time sequence of images of a cell undergoing phagocytosis. The position of the iC3b-opsonised zymosan particle (presented with a micropipette) is indicated in the phase-contrast image and the fluorescent images below at the times indicated. The complete time course is shown in Video 2 (available). (d) The effect of localized photobleaching (30 s) within the white square on the GFP signal from the leading pseudopodia and cell body is shown and (e) quantified for the leading pseudopodia (ps) and cell body (b). The ratio of mean intensities in the two locations is also shown as the dotted line (e). Bars: (a and b) 5 µm; (c) 10 µm; (d) 10 µm. Human neutrophils expressing GFP were generated from cord blood as described previously (Omidvar et al., 2006).