FIG 5.
MucR counteracts c-di-GMP- and CuxR-mediated activation of the uxs1 promoter. (A) cuxR and uxs1 promoter activities in different S. meliloti genetic backgrounds measured using promoter-egfp fusions on medium-copy-number plasmid pSRKGm-egfp. (B) uxs1 promoter activity in different S. meliloti genetic backgrounds with (pABC-Psyn-cuxR) or without (empty vector pABC-Psyn) constitutively expressed cuxR. (A and B) c-di-GMP0, Rm2011 ΔXVI unable to produce detectable levels of c-di-GMP (27), was used as a background strain. Error bars represent the standard deviations from four biological replicates. (C) Interaction of His6-MucR with DNA containing the cuxR-uxs1 intergenic region (cuxR-uxs1IR) or a 196-bp region upstream of uxs1 (Puxs1) assayed with EMSA. DNA containing either the upstream region of rpsB or that of mucR served as negative or positive control, respectively.