Fig. 1. Sequences of the 5′ leader regions of GCN4–LUC genes used in this study. The sequence shown begins with the T7 RNA polymerase-binding site and ends within the LUC coding region. The 5′ and 3′ boundaries of the wild-type GCN4 sequence are boxed. GCN4 uORFs and the GCN4 ATGORF are shown in bold and mutations are indicated below the wild-type sequence. Horizontal arrows below the sequence indicate the sequences for which the reverse complements were synthesized and used as primers ZW4 and ZW18 for toeprint analysis.