Figure 5.

Degradation of the reporter mRNA containing pairwise combinations of the VEGF 5′UTR, coding region, and 3′UTR. Time courses of degradation of the f5′V-GH-3′V (A), f5′V-164–3′GH (B), and f164–3′V (C) mRNAs from cells incubated under normoxic conditions. The graphs show data as mean ± SEM for two independent experiments, normalized with respect to GAPDH. The levels of serum induction observed for each experiment were 6.4- and 5.5-fold for the f5′V-GH-3′V reporter gene, 5.7- and 6.3-fold for the f5′V-164–3′GH reporter gene, and 5.2- and 9.3-fold for the f164–3′V reporter gene. The maximal levels of induction (expressed as a ratio to the GAPDH level) were 0.22 and 0.25 for the f5′V-GH-3′V reporter gene, 0.17 and 0.20 for the f5′V-164–3′GH reporter gene, and 0.27 and 0.11 for the f164–3′V reporter gene. Decay kinetics of the mRNAs are also shown and were calculated from mean data with the background levels of mRNA from the unstimulated samples subtracted. Regression lines, calculated half-lives (t_1/2), and decay rates (k) are indicated.