To test for IRES-like function in JV, bi-cistronic constructs were made with a cap dependent 59 EGFP cistron and a 39 lacZ cistron under the translational control of either the JV 59GS (pEGFP-C1/ JV59GS/lacZ) or an authentic EMCV IRES (pEGFP-C1/IRES/ lacZ). CRFK cells were transfected with the bi-cistronic constructs and, following incubation, were assayed for EGFP and lacZ expression.