Figure 28-4: Organization of the immA region. (A) Map and transcription map of the immA locus (32). Coordinates on the kb scale given according to the phage map. Protein-encoding genes are shown by open boxes, cA, which encodes an RNA, by gray box across the main line. Bent arrows indicate transcription start points corresponding to promoters Pa and Pb (solid boxes). Positions of putative terminators T1, T2 and T3 are shown by solid triangles. The transcripts of the immA region are indicated by arrows. The CA RNA is represented by a closed bar. (B) Predicted secondary structure of N15 CA RNA.