Open AccessActivation of Klebsiella pneumoniae and Rhizobium meliloti nitrogenase promoters by gln (ntr) regulatory proteins.
Author(s) -
Venkatesan Sundaresan,
David W. Ow,
Frederick M. Ausubel
Publication year - 1983
Publication title -
proceedings of the national academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.80.13.4030
Subject(s) - derepression , nitrogenase , biology , klebsiella pneumoniae , rhizobium , lac operon , regulator gene , gene , escherichia coli , promoter , gene product , fusion gene , microbiology and biotechnology , genetics , nitrogen fixation , regulation of gene expression , bacteria , gene expression , psychological repression
We have studied the expression, in different Escherichia coli gln (ntr) mutants, of fusions (constructed in vitro) of the nifHDK (nitrogenase) promoters from Klebsiella pneumoniae and Rhizobium meliloti to E. coli lacZ. Derepression of the K. pneumoniae nifH::lacZ fusion requires the glnF (ntrA) gene product in addition to the K. pneumoniae nifA gene product, indicating that regulation of the K. pneumoniae nif genes is more closely integrated with the overall nitrogen control system than previously demonstrated. Derepression of the R. meliloti nifH::lacZ fusion in E. coli by the K. pneumoniae nifA gene product (which we had previously shown) exhibits the same requirement for glnF. Derepression of the R. meliloti nifH::lacZ fusion, but not the K. pneumoniae nifH::lacZ fusion, can be mediated by the glnG (ntrC) gene product, suggesting that the gln regulatory genes might directly regulate the symbiotic nitrogen fixation genes in Rhizobium.
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