FIG 7.

High levels of c-di-AMP inhibit expression of kdpA. Shown is the relative quantification (RQ) of transcript levels of kdpA measured by RT-qPCR for the wild-type S. aureus strain LAC* (WT) and an isogenic gdpP (ΔgdpP) mutant strain (with constitutively high levels of c-di-AMP), normalized to gyrB transcript levels. WT and mutant S. aureus strains were grown to an OD₆₀₀ of 0.7 in LB medium without salt (0 M NaCl) or containing 1 M NaCl, and RNA was extracted and used for RT-qPCR experiments as described in Materials and Methods. Three independent experiments with triplicates were performed, and a representative result is shown. The data from one representative experiment are plotted and were analyzed by using a two-tailed Student t test. A statistically significant difference between the values was observed, with a P value of <0.01, and this is indicated by asterisks.