ISSN:
1573-5036
Keywords:
Klebsiella pneumoniae
;
nif transcription
;
Nitrogen-regulated promoters
;
Regulatory proteins
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary The nitrogen-fixing bacteriumKlebsiella pneumoniae has provided a model system for analysis of the organisation and regulation of nitrogen fixation (nif) genes in diazotrophs. Expression of the 17nif genes inKlebsiella is regulated in response to the nitrogen source by the products of the nitrogen control genesntrA, ntrB andntrC. Nif transcription is also specifically regulated in response to oxygen and low levels of fixed nitrogen by the products of thenifLA operon. Promoters subject to negative regulation by thentrBC products contain a homologous sequence with dyad symmetry, indicative of a repressor binding site.Ntr-activatable promoters do not show homology with typicalEscherichia coli promoters but have a characteristic primary structure. The model we propose for regulation ofnif transcription has important consequences for genetic manipulation of existing diazotrophs and for obtaining expression of theKlebsiella nif gene cluster in other ‘prokaryotic-like’ environments such as the chloroplast.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02277399
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