Mutational analysis of the Rhizobium meliloti nifA promoter
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چکیده
منابع مشابه
Mutational analysis of the Rhizobium meliloti nifA promoter.
The nifA gene of Rhizobium meliloti, the bacterial endosymbiont of alfalfa, is a regulatory nitrogen fixation gene required for the induction of several key nif and fix genes. Transcription of nifA is strongly induced in planta and under microaerobic conditions ex planta. Induction of nifA, in turn, is positively controlled by the fixL and fixJ genes of R. meliloti, the sensor and regulator, re...
متن کاملThe nifA gene of Rhizobium meliloti is oxygen regulated.
Experiments using plasmid-borne gene fusions and direct RNA measurements have revealed that expression from the nifA gene is induced in Rhizobium meliloti when the external oxygen concentration is reduced to microaerobic levels. Induction occurs in the absence of alfalfa and in the presence of fixed nitrogen and does not require ntrC. The production of functional nifA gene product (NifA) can be...
متن کاملThe central domain of Rhizobium meliloti NifA is sufficient to activate transcription from the R. meliloti nifH promoter.
The Rhizobium meliloti nifA product (NifA) shares extensive homology in its central region and at its C-terminal end with Rhizobium leguminosarum DctD and with NtrC from several species. All three proteins are transcriptional activators of NtrA (RpoN)-RNA polymerase-dependent promoters. Several large deletions of R. meliloti NifA were constructed to investigate the role of the conserved and div...
متن کاملRhizobium meliloti regulatory gene fixJ activates transcription of R. meliloti nifA and fixK genes in Escherichia coli.
When present in Escherichia coli on the multicopy expression vector pUC19, a Rhizobium meliloti regulatory gene, fixJ, belonging to a two-component regulatory system, activated the expression of two R. meliloti symbiotic genes, nifA and fixK. Primer extension by reverse transcription showed that FixJ stimulates nifA expression in E. coli by activating pnifA.
متن کاملOxygen-regulated in vitro transcription of Rhizobium meliloti nifA and fixK genes.
Oxygen concentration regulates the expression of nitrogen fixation genes in the symbiotic bacterium Rhizobium meliloti. We demonstrate that two proteins, FixL and FixJ, that belong to the two-component family of regulatory proteins are necessary and sufficient for oxygen-regulated in vitro transcription of the two key regulatory genes, nifA and fixK. We show directly that FixJ is a transcriptio...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1992
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.174.12.4120-4129.1992