Reporter gene analysis of TGF-β₁ 5′UTR mutations.

<p><b>A</b>. Schematic diagram of the TGF-β₁ 5′UTR endogenous and mutant 167-nucleotide fragments as described in the methods. Open boxes indicate the stem loop secondary structure, filled boxes indicated the position of the adenine residue substitutions. <b>B</b>. Luminescence was measured by Dual Luciferase Reporter Assay Kit (Promega). Luciferase activity is expressed as normalised firefly luciferase activity relative to that of the pGL3-Control vector. Results shown represent mean (±SEM) of four experiments performed in triplicate. Statistical analysis was performed using an unpaired <i>t</i> test with Welch's correction (P<0.05**, P<0.005***).