Fig. 2. Map of the genomic 5' UTR of regA. Grey boxes symbolize exons, and the lines between them represent introns. The locations of the upstream ATGs (ATG1-ATG8) and of the functional start codon (ATG9) are indicated. The transcription start (+1) is marked by a bent arrow. The expanded portions below show the ATG1, ATG2 and ATG7 open reading frames (light grey boxes); the black bars indicate the potential bipartite take-off (E1.1 and E1.2) and landing (E3) sites, the location of the triple-hairpin structure (HPS, lower bar), the region deleted in the S18 construct, and the point where the artificial hairpin (hp) shown in Fig. 6 was inserted.