Figure 1: Immunofluorescent staining of the TJ cytoplasmic plaque protein ZO-1 (green) of the NCI-H441 monolayer on day 12, performed as described in Section 2. NCI-h441 differentiated with 1 μM Dexamethasone after day 3 of culture were positively stained for ZO-1 at the cell-cell interface (a) confirming the formation of functional TJs while in cells without Dexamethasone treatment the ZO-1 staining clearly demonstrates the absence of TJs formation; (b) nuclei were stained with DAPI (blue), ZO-1 (green), and actin (red).