FIGURE 6.

Glutamine stimulates translation of igf2 mRNA mostly from the L2 leader sequence. A, schematic drawing of the translational reporter constructs containing the leader sequences subcloned upstream of the destabilized luciferase of the pGL4.24 vector. B, normalized luciferase activities were determined in lysates of transfected in MIN6 cells incubated for 3 h in the indicated incubation conditions. C, normalized luciferase activities were measured in cells exposed to glucose (Gluc) and glutamine as indicated and in the presence of DON or rapamycin. D, the Igf2 leader sequences were subcloned in a luciferase reporter lentivector, and the recombinant lentiviruses were used to co-infect dispersed mouse islets cells with a Renilla luciferase encoding lentivirus. Relative luciferase activity was measured after incubation for 3 h in the indicated conditions. The activities were expressed relative to the normalized luciferase measured in 5 mm glucose. The data are the means ± S.D. from three independent experiments. *, p < 0.05; **p < 0.01; ***, p < 0.001; RLU, relative light units; w.r.t., fold induction over basal activity.