Regulation of nitrogenase gene expression in anaerobic cultures of Anabaena variabilis
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چکیده
منابع مشابه
Regulation of nitrogenase gene expression by transcript stability in the cyanobacterium Anabaena variabilis.
The nitrogenase gene cluster in cyanobacteria has been thought to comprise multiple operons; however, in Anabaena variabilis, the promoter for the first gene in the cluster, nifB1, appeared to be the primary promoter for the entire nif cluster. The structural genes nifHDK1 were the most abundant transcripts; however, their abundance was not controlled by an independent nifH1 promoter, but rathe...
متن کاملRegulation of Three Nitrogenase Gene Clusters in the Cyanobacterium Anabaena variabilis ATCC 29413
The filamentous cyanobacterium Anabaena variabilis ATCC 29413 fixes nitrogen under aerobic conditions in specialized cells called heterocysts that form in response to an environmental deficiency in combined nitrogen. Nitrogen fixation is mediated by the enzyme nitrogenase, which is very sensitive to oxygen. Heterocysts are microxic cells that allow nitrogenase to function in a filament comprise...
متن کاملRNA processing of nitrogenase transcripts in the cyanobacterium Anabaena variabilis.
Little is known about the regulation of nitrogenase genes in cyanobacteria. Transcription of the nifH1 and vnfH genes, encoding dinitrogenase reductases for the heterocyst-specific Mo-nitrogenase and the alternative V-nitrogenase, respectively, was studied by using a lacZ reporter. Despite evidence for a transcription start site just upstream of nifH1 and vnfH, promoter fragments that included ...
متن کاملRegulation of V-nitrogenase genes in Anabaena variabilis by RNA processing and by dual repressors.
Anabaena variabilis ATCC 29413 fixes nitrogen in specialized cells called heterocysts using either a Mo-nitrogenase or a V-nitrogenase. V-nitrogenase structural genes, vnfDGK, as well as vnfEN form an operon with ava4025, located upstream of vnfDG that is repressed by fixed nitrogen and by Mo. The ava4025-vnfDGKEN operon is under the control of a Mo-repressible promoter located nearly 600 bp up...
متن کاملAlternative Nitrogenases in Anabaena variabilis: The Role of Molybdate and Vanadate in Nitrogenase Gene
Anabaena variabilis ATCC 29413 has two distinct nitrogenases that function in heterocysts, a conventional Mo-nitrogenase and an alternative V-nitrogenase. Synthesis of these two enzymes was repressed in cells growing with a source of fixed nitrogen, such as ammonium; however, the V-nitrogenase was also repressed by Mo. Expression of the V-nitrogenase which was not affected by V and expression o...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1988
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.170.2.552-557.1988