Mutation of the ins-PRS leads to reporter CAT mRNA destabilization. Rat islets cells were transfected with four different constructs. The empty pCR™3-CAT vector, the pCR™3-CAT vector with wild-type, mutant 1, or mutant 2 ins-PRS inserted in the 3′-UTR of the vector. Two days after the transfection, the islets were incubated for 24 h in 2.8 mM glucose during normoxic (hatched bars = 21% O2) or hypoxic (black bars = 5% O2) conditions, without (A) or with (B) 5 µg/ml actinomycin D. RT-PCR was performed for CAT, β-actin, and GAPDH mRNA. Results are mean ±SEM for three to four experiments.