Multiple regulators and their interactions in vivo and in vitro with the cbb regulons of Rhodobacter capsulatus.
The cbb(I) and cbb(II) operons encode structural genes which are important for carbon dioxide fixation via the Calvin-Benson-Bassham reductive pentose phosphate pathway in Rhodobacter capsulatus. Each operon is regulated by cognate LysR-type transcriptional activators, CbbR(I) and CbbR(II), with the product of the cbbR(I) gene, CbbR(I), able to control its own transcription under some growth conditions. Furthermore, CbbR(I) may at least partially regulate the cbb(II) operon, with significant, yet regulated transcription of the cbb(II) operon occurring in the absence of any CbbR. These results suggested the importance of additional regulators. Thus, in addition to the rather specific control exerted by CbbR, a more globally significant regulatory system, the RegA-RegB (PrrA-PrrB) two-component system, was found to contribute to transcriptional regulation of each cbb operon. The regA and regB mutant strains were found to contain constitutive levels of form I and form II RubisCO, the major proteins encoded by the cbb(I) and cbb(II) operons, respectively. In addition, DNaseI footprint analyses indicated that RegA*, a constitutively active mutant form of RegA, binds specifically to cbb(I) and cbb(II) promoter-operator regions. CbbR(I), CbbR(II), and RegA binding loci were localized relative to transcription start sites, leading to a coherent picture of how each of these regulators interacts with specific promoter-operator sequences of the cbb operons.
Vichivanives
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Department of Microbiology and Plant Biotechnology Center, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210-1292, USA.
Bird
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Bauer
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Robert Tabita
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D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D018983:DNA Footprinting; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D003850:Deoxyribonuclease I; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D000071677:Histidine Kinase; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D009875:Operator Regions, Genetic / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018085:Regulon / Q000235:genetics*; D016354:Rhodobacter capsulatus / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C085225:REGA protein, Rhodobacter sphaeroides; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; C072714:cfxR protein, bacteria; D011494:Protein Kinases; D000071677:Histidine Kinase; D003850:Deoxyribonuclease I; D012273:Ribulose-Bisphosphate Carboxylase