Influence of AmtR on target gene expression. Hybridization experiments were carried out with RNA isolated from nitrogen-supplied cells and after different intervals of nitrogen starvation and a probe specific for msmeg_2184 mRNA. (A) Comparison of wild-type SMR5 (WT) and amtR deletion strain YL1 (∆amtR). (B) Complementation of amtR deletion strain YL1 with plasmid pMN016-amtR (∆amtR/pMN016-amtR); wild-type and strain YL1 transformed with vector pMN016 (WT/pMN016 and ∆amtR/pMN016) were used as control. (C) Influence of a glnR/amtR double deletion (∆glnR∆amtR).