FGF2 and ischemia: To investigate the impact of ischemia on FGF2 expression and IRES activity, cutaneous ischemia was induced, using a skin flap model, in RFL12 transgenic mice expressing a bicistronic mRNA encoding both Renilla luciferase (LucR) and Firefly luciferase (LucF) separated by the FGF2 IRES (Fig 1A, right) [18].