Figure 5

TTF-1 induced α ₅ transcription via interaction with putative TTF-1 response elements (TREs). A. Schematic of a wild type (WT) α₅ luciferase reporter containing the 0.85-kb mouse α₅ promoter sequence and reporters that contain a 0.85-kb α₅ promoter with each sequential TRE targeted by site-directed mutagenesis (Mutants A-E). B. TTF-1-mediated increases in α₅ transcription were significantly diminished in Beas2B cells when the second or fourth TREs were mutated. C. Each TRE was demonstrated to be significant in regulating TTF-1-mediated α₅ transcription in ATII-like A-549 cells. Significant decreases in TTF-1 induced luciferase activity resulting from each mutant reporter compared to WT + TTF-1 are noted at P ≤ 0.05 (*).