Figure 8.

Cellular localization of MDR1 by immunocytochemistry. UIC2/goat anti-mouse Alexa-Fluor 488 immunofluorescence (green) and propidium iodide fluorescence (red) visualized by laser-scanning confocal microscopy in control (0.1% DMSO) (a), rifampin (10 μM) (b) and 72-h digoxin-treated (1 μM) (c) T84 cell monolayers grown on permeable Transwell supports. (d) Occludin/goat anti-mouse Alexa-Fluor 488 immunofluorescence (green) and propidium iodide fluorescence (red). x–y images display horizontal confocal optical section at the level of the apical cell surface, whereas x–z images show vertical optical cross-sections of the epithelial monolayer. Arrows indicate the apical surface (upper) or basal cell/filter border (lower). Note the columnar morphology and prominent nuclei (propidium staining). Representative images from three experiments. Scale bars: (x–y, a–d)=20 μm; (x–z, a)=10 μm and (x–z, b–d)=20 μm.