Figure 5.

Northern blot analysis of RNAs extracted from BHK-21 cells at 12 h after transfection with bicistronic constructs. A filled triangle, as opposed to an empty triangle, depicts RNA extracted from cells expressing T7 RNA polymerase. For each construct two lanes were loaded, containing in the right lane a double amount of RNA compared to the left lane. pBIC-3′NCR₁ or pBIC-3′NCR₂ corresponds to two independent transfections carried out with two plasmid samples of identical sequence. Below each lane is indicated whether or not co-transfection with pLb was performed. The blot was probed with a [α-³²P]UTP-labeled RNA fragment complementary to nucleotides 1–462 of the FMDV IRES. The positions of 28S and 18S rRNA have been marked as migration and loading controls. The mobility of the RNAs derived from the bicistronic plasmids is indicated with an arrow.