DNA binding activity of NtrC from Rhizobium grown on different nitrogen sources.
The DNA-binding activity of the NtrC protein can be demonstrated in gel retardation assays with concentrated protein extracts of Rhizobium etli. Using extracts from either the wild type or a ntrC mutant strain and an antiserum raised against the NtrC protein, we demonstrate specific binding of NtrC to the upstream regulatory region of the glnII gene, where two putative NtrC-binding sites are present. KNO3-grown bacteria contain less NtrC protein and more NtrC-binding activity than NH4Cl-grown bacteria, thus showing that with this protocol it is possible to detect changes in NtrC-binding activity. The advantages of this assay system in comparison with that using pure proteins is discussed.
International Institute of Genetics and Biophysics, CNR, Naples, Italy.
E J
EJ
Patriarca
A
A
Riccio
S
S
Colonna-Romano
R
R
Defez
M
M
Iaccarino
D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D005974:Glutamate-Ammonia Ligase / Q000235:genetics; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012231:Rhizobium / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D015534:Trans-Activators; C083573:ntrC protein, Rhizobium; C083818:glutamine synthetase 2; D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen