An RNA G-quadruplex in the 3′ UTR of the proto-oncogene PIM1 represses translation

We have identified a conserved G-quadruplex forming sequence in the 3' untranslated region (UTR) of the protooncogene PIM1. Circular dichroism and thermal denaturation studies revealed that the PIM1 mRNA guanine-rich sequence forms a highly stable intramolecular G-quadruplex structure. Reporter gene assay demonstrated that the PIM1 RNA G-quadruplex represses translation. It is the first experimental evidence of an RNA G-quadruplex structure located in the 3' UTR that may act as posttranscriptional regulator.