title: Mechanism for regulation of the putrescine utilization pathway by the transcription factor PuuR in Escherichia coli K-12.
abstract: In Escherichia coli, putrescine is metabolized to succinate for use as a carbon and nitrogen source by the putrescine utilization pathway (Puu pathway). One gene in the puu gene cluster encodes a transcription factor, PuuR, which has a helix-turn-helix DNA-binding motif. DNA microarray analysis of an E. coli puuR mutant, in which three amino acid residues in the helix-turn-helix DNA binding motif of PuuR were mutated to alanine to eliminate DNA binding of PuuR, suggested that PuuR is a negative regulator of puu genes. Results of gel shift and DNase I footprint analyses suggested that PuuR binds to the promoter regions of puuA and puuD. The binding of wild-type PuuR to a DNA probe containing PuuR recognition sites was diminished with increasing putrescine concentrations in vitro. These results suggest that PuuR regulates the intracellular putrescine concentration by the transcriptional regulation of genes in the Puu pathway, including puuR itself. The puu gene cluster is found in E. coli and closely related enterobacteria, but this gene cluster is uncommon in other bacterial groups. E. coli and related enterobacteria may have gained the Puu pathway as an adaptation for survival in the mammalian intestine, an environment in which polyamines exist at relatively high concentrations.
authors.affiliation: Division of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Nemoto
authors.forename: Shin
authors.initials: S
authors.lastname: Kurihara
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Kitahara
authors.forename: Kei
authors.initials: K
authors.lastname: Asada
authors.forename: Kenji
authors.initials: K
authors.lastname: Kato
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D001665:Binding Sites; D018983:DNA Footprinting; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D048168:Escherichia coli K12 / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D019077:Helix-Turn-Helix Motifs / Q000235:genetics; D005810:Multigene Family; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D011700:Putrescine / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D014157:Transcription Factors; D011700:Putrescine