Figure 9.

cAMP-Crp is a positive regulator of IS insertion into bgl. (A) Effect of adding external cAMP on insertional Bgl⁺ mutations in wild type cells and ∆cyaA cells. cAMP was added to M9 + Salicin agar from 0 mM to 3 mM. (B,C) Effects of cpdA deletion and overexpression on total Bgl⁺ mutations (B) and insertional Bgl⁺ mutations (C). cpdA encodes a phosphodiesterase which degrades cAMP to 5’-AMP, and in its absence, cAMP levels increase. For overexpression, the strong constitutive tet promoter, Ptet, was used to drive cpdA on the plasmid pZA31. WT Rf = ●; ∆cpdA Rf = ▲; PK20 = ○.