title: StgR, a new Streptomyces alboniger member of the LysR family of transcriptional regulators.
abstract: A 3240-bp DNA fragment, located next to the puromycin biosynthetic gene cluster of Streptomyces alboniger, contains three complete ORFs in the order: stgA, stgU and stgR. The transcriptional orientation of stgA is opposite to that of stgU and stgR. Each gene is expressed from its own promoter, although stgU and stgR can be cotranscribed. The deduced amino acid sequences of their products present similarities to a variety of pyridoxal-phosphate-dependent aspartate aminotransferases (StgA), several proteins of unknown function (StgU), and the LysR-type of transcriptional regulators (StgR). In a delta stgR null mutant of S. alboniger, transcription of stgA and stgU is increased with respect to that in the wild type. In addition, in vivo experiments with promoter-probe plasmids indicated that in the delta stgR mutant, stgA- or stgU-promoter-dependent expression of the reporter gene was up to three-fold higher than in the wild type. Taken together, these results indicate that StgR is a LysR-type transcriptional repressor of both stgA and stgU.
authors.affiliation: Centro de Biologìa Molecular Severo Ochoa, CSIC/UAM, Universidad Autónoma de Madrid, Cantoblanco, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Tercero
authors.forename: J C
authors.initials: JC
authors.lastname: Espinosa
authors.forename: A
authors.initials: A
authors.lastname: Jiménez
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D000595:Amino Acid Sequence; D001219:Aspartate Aminotransferases / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001435:Bacteriophages; D001483:Base Sequence; D018387:Codon, Initiator; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D016366:Open Reading Frames / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D020121:5' Untranslated Regions; D001426:Bacterial Proteins; D018387:Codon, Initiator; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C115204:StgR protein, Streptomyces alboniger; C115205:StgU protein, Streptomyces lipmanii; D014157:Transcription Factors; C073470:LysR protein, Bacteria; D001219:Aspartate Aminotransferases