Figure 2.

Analysis of S. cerevisiae YAP1 leader sequence in the intercistronic region of a dicistronic reporter mRNA with Renilla and Photinus luciferase-coding sequences as cistrons. (A) Schematic representations of the RP, YAP1/RP, and CLN3/RP dicistronic mRNAs are indicated. Yeast were transformed with pMyr constructs that expressed these mRNAs. IRES activities were determined 3 h after galactose induction of dicistronic mRNA induction and are represented as ratios of Photinus luciferase activity to Renilla luciferase activity. Values represent activities that have been normalized to those of the RP vector. Horizontal bars indicate SEM. (B) Dicistronic constructs with a hairpin structure at the 5′ end of the mRNA. These experiments were performed as in A; however, the IRES activities were normalized to those of the parent RPh construct. (C) Northern blot of total RNA purified from cells transformed with the dicistronic constructs indicated, and probed as in Fig. 1. The positions of the 25S and 18S rRNAs are indicated.