Fig. 3. The effect of Rho GTPase inhibition on epithelial cell differentiation. (A) mTEC cultures treated with vehicle, mevasatin, or toxin B for 24 hours on ALI day 2 were harvested one day later and stained for actin (phalloidin, red) and basal bodies (-tubulin, green). Different fields are shown for each marker assayed. Bar, 10 µm. (B) Scanning electron micrograph of mTEC on ALI day 4 after treatment with mevastatin on ALI day 3 showing microvilli but absent cilia. (C) Transmission electron photomicrograph of mTEC treated with toxin B as in B. Vehicle treated cells show normal basal bodies docked at the apical membrane with ciliary axonemes (arrowheads). In toxin B treated cells, apical basal bodies are absent, but centrioles are present within the cytoplasm (magnification shown in the box). Microvilli are intact at the apical membrane (arrows) Bar, 1 µm in B,C.