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Transcriptional regulation of the proton translocating NADH dehydrogenase (nuoA‐N) of Escherichia coli by electron acceptors, electron donors and gene regulators
Author(s) -
Bongaerts Johannes,
Zoske Sascha,
Weidner Uwe,
Linden Gottfried
Publication year - 1995
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1995.tb02416.x
Subject(s) - biology , operon , escherichia coli , nadh dehydrogenase , transcriptional regulation , gene , promoter , microbiology and biotechnology , repressor , regulation of gene expression , anaerobic respiration , gene expression , locus (genetics) , biochemistry , genetics , bacteria , protein subunit
Summary The promoter region and transcriptional regulation of the nuoA‐N gene locus encoding the proton‐translocating NADH:quinone oxidoreductase was analysed. A 560 bp intergenic region upstream of the nuo locus was followed by a gene (designated irhA for L ys R h omo‐logue A ) coding for a gene regulator similar to those of the LysR family. Disruption of irhA did not affect growth (respiratory or non‐respiratory) or expression of nuo significantly. Transcriptional regulation of nuo by electron acceptors, electron donors and the transcriptional regulators ArcA, FNR, NarL and NarP, and by IHF (integration host factor) was studied with protein and operon fusions containing the promoter region up to base pair ‐277 (‘nuo 277 ’) or up to base pair ‐899 (‘nuo 899 ’). The expression of the nuo 277 ‐lacZ fusions was subject to ArcA‐mediated anaerobic repression and NarL(+nitrate)‐mediated anaerobic activation. FNR and IHF acted as weak repressors under anaerobic conditions. Expression of nuo 899 ‐lacZ was stimulated during anaerobic fumarate respiration and aerobically by C 4 dicarboxylates. Therefore, expression of nuo is regulated by O 2 and nitrate via ArcA, NarL, FNR and IHF at sites within the ‐277 region, and by other factors including C 4 dicarboxylates at a site between ‐277 and ‐899. A physiological role for the transcriptional stimulation by O 2 and nitrate is suggested.