Two ResD-Controlled Promoters Regulate ctaA Expression in Bacillus subtilis

Abstract

The Bacillus subtilis ResDE two-component system plays a positive role in global regulation of genes involved in aerobic and anaerobic respiration. ctaA is one of the several genes involved in aerobic respiration that requires ResD for in vivo expression. The ctaAB-divergent promoter regulatory region has three ResD binding sites; A1, A2, and A3. The A2 site is essential for in vivo promoter activity, while binding sites A2 and A3 are required for full ctaA promoter activity. In this study, we demonstrate the role of ResDϳP in the activation of the ctaA promoter using an in vitro transcription system. The results indicate that the ctaA promoter (binding sites A2 and A3) has two transcriptional start sites. Binding site A2 was sufficient for weak transcription of the upstream promoter (Pv) by E The Bacillus subtilis two-component regulatory pair, designated ResD and ResE, has a positive role in global regulation of both aerobic and anaerobic respiration (18,23). The ResDE system is required for transcription of the following genes and operons involved in aerobic respiration; the resABCDE operon (23), encoding proteins similar to those involved in cytochrome c biogenesis (resABC) (6) and ResD-ResE (resDE) (23); the petCBD operon, encoding subunits of the cytochrome bf complex; the ctaBCDEF operon (12), encoding CtaB, which is required for the synthesis of heme O from heme B (ctaB) (25) and structural genes for cytochrome caa 3 (ctaCDEF) (22) and ctaA (23); and a gene required for heme A biogenesis (24, 25) and hence for the synthesis of the heme A-containing terminal cytochrome oxidases aa 3 and caa 3 . Recognition of phenotypic traits shared by resD and ctaA mutants (15) led to a study that revealed that ResD has an essential role in the activation of in vivo expression of the ctaA promoter (23). Phenotypic similarities shared by resD and ctaA mutants, among others, included a sporulation defect and the absence of the heme A-containing terminal oxidases aa 3 and caa 3 . A recent study has shown that either one of these two terminal oxidases is sufficient for sporulation since a qoxABCD (structural genes for aa 3 ) ctaCD (structural genes for caa 3 ) double mutant is sporulation deficient but a single mutant with either mutation is not (28). Thus, the sporulation defect in a resD mutant may be explained by the role of ResD in ctaA and/or ctaB regulation.A direct role for ResD in ctaA promoter activation was suggested in a recent study which showed that there are three ResD binding sites (A1, A2, and A3) in the intercistronic ctaAB promoter region to which either unphosphorylated or phosphorylated ResD binds (29). A1 and A2 are situated upstream of the Ϫ35 promoter region, and A3 is downstream of the Ϫ10 region of the ctaA promoter previously identified (15). Deletion experiments revealed that binding site A1 did not influence the in vivo expression of the ctaA gene (29), suggesting that site A1 may be involved in the regulation of the divergent ctaB promoter, which also requires ResD for expression (12). ctaA-lacZ...

The ResD Response Regulator, through Functional Interaction with NsrR and Fur, Plays Three Distinct Roles in Bacillus subtilis Transcriptional Control

“…ctaA and ctaB function in heme A and heme O biosynthesis, respectively, and the ctaCDEF genes code for subunits of cytochrome c oxidase. ResD-dependent activation of these genes was previously shown (29,30). ResD bound other genes involved in respiration, such as ctaO, whose product participates in heme O synthesis (31), and the yjlC-ndh (NADH dehydrogenase) operon (32).…”

Bacillus subtilis YdiH Is a Direct Negative Regulator of the cydABCD Operon

“…We have found that strains bearing the cmp mutation bypass the requirement for ResD for full alkaline phosphatase induction (Table 3). However, the cmp mutation does not compensate for the loss of resDE for anaerobic growth (19)(20)(21) or ctaA expression (23,38). Both ctaA and genes required for anaerobic growth require ResD as a transcription activator, suggesting that the nature of the cmp mutation is not to simply fill the role of ResD as a transcriptional regulator for Res regulon members.…”

“…ResD regulates the expression of fnr (21), hmp (21), nasDEF (21), hemN (12), hemZ (12), and the sbo-alb operon (20) under anaerobic conditions and has a role in the regulation of ctaA (23,38), ctaBCDEF (17), resABCDE (31), and petCBD (31) under aerobic conditions. Because ResDE is essential for expression of both ctaA and ctaB, which is required for heme A biosynthesis, ⌬resDE strains lack cytochromes aa 3 and caa 3 .…”

Genome-Wide Analysis of ResD, NsrR, and Fur Binding in Bacillus subtilis during Anaerobic Fermentative Growth by In Vivo Footprinting

“…As shown in Table 1, most of genes in group A, to which ResD binds both the promoter and coding regions, function in aerobic or anaerobic respiration and are controlled positively by ResD. These genes include hmp (8), nasD (19), narG (4), ctaA (heme A synthase gene) (20), ctaB (major heme O synthase gene) (21), qox (cytochrome aa 3 quinol oxidase gene) (22), and cydA (cytochrome bd ubiquinol oxidase gene) (23,24). Therefore, we speculated that ResD activates the transcription of all genes in this class.…”