PMID:17028278

Citation	Wiethaus, J, Wirsing, A, Narberhaus, F and Masepohl, B (2006) Overlapping and specialized functions of the molybdenum-dependent regulators MopA and MopB in Rhodobacter capsulatus. J. Bacteriol. 188:8441-51
Abstract	The phototrophic purple bacterium Rhodobacter capsulatus encodes two similar but functionally not identical molybdenum-dependent regulator proteins (MopA and MopB), which are known to replace each other in repression of the modABC genes (coding for an ABC-type high-affinity Mo transport system) and anfA (coding for the transcriptional activator of Fe-nitrogenase genes). We identified further Mo-regulated (mor) genes coding for a putative ABC-type transport system of unknown function (MorABC) and a putative Mo-binding protein (Mop). The genes coding for MopA and the ModABC transporter form part of a single transcriptional unit, mopA-modABCD, as shown by reverse transcriptase PCR. Immediately upstream of mopA and transcribed in the opposite direction is mopB. The genes coding for the putative MorABC transporter belong to two divergently transcribed operons, morAB and morC. Expression studies based on lacZ reporter gene fusions in mutant strains defective for either MopA, MopB, or both revealed that the regulators substitute for each other in Mo-dependent repression of morAB and morC. Specific Mo-dependent activation of the mop gene by MopA, but not MopB, was found to control the putative Mo-binding protein. Both MopA and MopB are thought to bind to conserved DNA sequences with dyad symmetry in the promoter regions of all target genes. The positions of these so-called Mo boxes relative to the transcription start sites (as determined by primer extension analyses) differed between Mo-repressed genes and the Mo-activated mop gene. DNA mobility shift assays showed that MopA and MopB require molybdenum to bind to their target sites with high affinity.
Links	PubMed PMC1698257 Online version:10.1128/JB.01188-06
Keywords	ATP-Binding Cassette Transporters/genetics; ATP-Binding Cassette Transporters/metabolism; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Base Sequence; Gene Expression Regulation, Bacterial; Molecular Sequence Data; Molybdenum/metabolism; Promoter Regions, Genetic; Rhodobacter capsulatus/genetics; Rhodobacter capsulatus/growth & development; Rhodobacter capsulatus/metabolism; Transcription, Genetic
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status

References

See Help:References for how to manage references in GONUTS.