title: The Streptomyces coelicolor GlnR regulon: identification of new GlnR targets and evidence for a central role of GlnR in nitrogen metabolism in actinomycetes.
abstract: Streptomyces coelicolor GlnR is a global regulator that controls genes involved in nitrogen metabolism. By genomic screening 10 new GlnR targets were identified, including enzymes for ammonium assimilation (glnII, gdhA), nitrite reduction (nirB), urea cleavage (ureA) and a number of biochemically uncharacterized proteins (SCO0255, SCO0888, SCO2195, SCO2400, SCO2404, SCO7155). For the GlnR regulon, a GlnR binding site which comprises the sequence gTnAc-n(6)-GaAAc-n(6)-GtnAC-n(6)-GAAAc-n(6) has been found. Reverse transcription analysis of S. coelicolor and the S. coelicolor glnR mutant revealed that GlnR activates or represses the expression of its target genes. Furthermore, glnR expression itself was shown to be nitrogen-dependent. Physiological studies of S. coelicolor and the S. coelicolor glnR mutant with ammonium and nitrate as the sole nitrogen source revealed that GlnR is not only involved in ammonium assimilation but also in ammonium supply. blast analysis demonstrated that GlnR-homologous proteins are present in different actinomycetes containing the glnA gene with the conserved GlnR binding site. By DNA binding studies, it was furthermore demonstrated that S. coelicolor GlnR is able to interact with these glnA upstream regions. We therefore suggest that GlnR-mediated regulation is not restricted to Streptomyces but constitutes a regulon conserved in many actinomycetes.
authors.affiliation: Mikrobiologie/Biotechnologie, Institut für Mikrobiologie, Fakultät für Biologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Tiffert
authors.forename: Petra
authors.initials: P
authors.lastname: Supra
authors.forename: Reinhild
authors.initials: R
authors.lastname: Wurm
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wohlleben
authors.forename: Rolf
authors.initials: R
authors.lastname: Wagner
authors.forename: Jens
authors.initials: J
authors.lastname: Reuther
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism*; D018085:Regulon / Q000235:genetics*; D048372:Streptomyces coelicolor / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C082451:GlnR protein, Streptomyces coelicolor; D015534:Trans-Activators; D009584:Nitrogen