ISSN:
1574-6968
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Genetic analyses based on chromosomal lac fusions to nitrogen fixation (nif) genes demonstrated that NifA-dependent transcriptional activation of expression of Rhodobacter capsulatus nifH and nifB1 was negatively modulated by HvrA, whereas regulation of rpoN, nifA1, and nifA2 was independent of HvrA. Expression of hvrA itself was not influenced by a mutation in ntrC, which is absolutely essential for N2 fixation. Furthermore, HvrA accumulated to comparable levels in the presence and absence of ammonium, suggesting that the amount of HvrA in the cells does not differ under nitrogenase-repressing or -derepressing conditions. In addition, competitive gel retardation studies with HvrA-His6 purified from R. capsulatus were carried out, demonstrating preferential binding of HvrA to the nifH promoter region.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-6968.2002.tb11429.x
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