FIG. 1.

Lysis-lysogeny switches of λ, 186, and P2. CI and C are immunity repressors, and Cro, Apl, and Cox are anti-immunity repressors. The diagrams are not to scale, but the relative distances between the repressor and anti-immunity repressor open reading frames for the three switches are accurate. Note the back-to-back arrangement of the lytic (p_R) and lysogenic (p_RM) promoters in λ, their face-to-face arrangement in 186 (p_R and p_L) and P2 (p_e and p_c), and the different locations of the binding sites for the immunity (rectangles) and anti-immunity (filled circles) repressors. p_RE and p_E are the CII-activated establishment promoters of λ and 186, respectively.