Role of CC3252 on expression of CC2906, CC3255 and sigF genes . Results shown are from qRT-PCR performed with total RNA extracted from exponential growth phase cells under control conditions (no stress) or stressed with potassium dichromate (K2Cr2O7). We analyzed the parental strain NA1000 without expression plasmid pJS14, NA1000 with the empty plasmid pJS14 and NA1000 with pJS14 containing CC3252 gene (CC3252++). Values represent the fold increase of CC2906, CC3255 and CC3253 (sigF) expression in the corresponding strain, exposed or not to the stress condition, compared with the parental strain NA1000 without pJS14 growing under control conditions. Results were normalized using gene CC0088 as the endogenous control, which was constitutively expressed in the samples analyzed. Data are mean values of two independent experiments; bars represent the standard error. Statistical analysis is shown in Additional file 1: Table S4.