Fig 3.

Prediction of NF45-dependent IRES. (A) Determination of threshold AU content for NF45-dependent IRES. IRES activity data from Fig. 2A were transformed into log₂ space and plotted against the AU content of the 5′ UTRs tested. A constraint of >60% AU content was chosen based on the clustered activities of IRES that changed by more than 2-fold up or down in d5 versus c cells (shaded quadrant). (B) Conservation of NF45-IRES interactions allows prediction of NF45-dependent IRES in Canis lupus subsp. familiaris. The Scamper IRES (63% AU content) was cloned into a bicistronic vector as described in Materials and Methods and was tested for IRES activity as described for Fig. 2A (n = 3; mean ± SD).