Figure 3.

Tg737 and Polaris expression is associated with ciliated epithelia of the lung. (A) In whole mounts, Tg737 expression as revealed by β-galactosidase activity was prominently detected in the distal bronchioles and in the trachea. (B) In sections, not all cells lining the bronchioles were found to express Tg737. (C and D) Similar results were obtained when Polaris localization was determined using immunofluorescence where both expressing and nonexpressing cells were evident. Polaris (red) expression was only seen in cells that also express β-tubulin (green). Closer examination of the regions in C and D marked by the asterisks indicate that Polaris is most concentrated in a band in the apical cytoplasm of the epithelium (C) and in small projections that are also positive for β-tubulin (D).