title: GlnB is specifically required for Azospirillum brasilense NifA activity in Escherichia coli.
abstract: The Azospirillum brasilense transcription regulator NifA and the nitrogen-status signaling proteins GlnB, GlnZ and GlnK were expressed in Escherichia coli and analyzed for their ability to activate nif gene expression. When expressed separately, none of the proteins were able to activate nifH promoter expression in any tested conditions; in contrast, nifH expression was observed in cells grown in the absence of ammonium and oxygen and when expressing simultaneously NifA and GlnB proteins, but not when expressing NifA and GlnZ or GlnK. Our results show that the GlnB protein is required for transcription activation by Azospirillum brasilense NifA and it cannot be replaced by GlnZ or GlnK.
authors.affiliation: Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, CP 19046, 81531-990 Curitiba, PR, Brazil.
authors.forename: Luiza M
authors.initials: LM
authors.lastname: Araújo
authors.forename: Rose A
authors.initials: RA
authors.lastname: Monteiro
authors.forename: Emanuel M
authors.initials: EM
authors.lastname: Souza
authors.forename: M Berenice R
authors.initials: MB
authors.lastname: Steffens
authors.forename: Liu U
authors.initials: LU
authors.lastname: Rigo
authors.forename: Fábio O
authors.initials: FO
authors.lastname: Pedrosa
authors.forename: Leda S
authors.initials: LS
authors.lastname: Chubatsu
mesh_terms: D015806:Azospirillum brasilense / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D009586:Nitrogen Fixation / Q000235:genetics / Q000502:physiology*; D051922:PII Nitrogen Regulatory Proteins; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C061338:NifA protein, Bacteria; D051922:PII Nitrogen Regulatory Proteins; D014157:Transcription Factors; C404143:PIID regulatory protein, Bacteria