title: GntR-type transcriptional regulator PckR negatively regulates the expression of phosphoenolpyruvate carboxykinase in Corynebacterium glutamicum.
abstract: The pck (cg3169) gene of Corynebacterium glutamicum encodes a phosphoenolpyruvate carboxykinase (PEPCK). Here, a candidate transcriptional regulator that binds to the promoter region of pck was detected using a DNA affinity purification approach. An isolated protein was identified to be PckR (Cg0196), a GntR family transcriptional regulator which consists of 253 amino acids with a mass of 27 kDa as measured by peptide mass fingerprinting. The results of electrophoretic mobility shift assays verified that PckR specifically binds to the pck promoter. The putative regulator binding region extended from position -44 to -27 (an 18-bp sequence) relative to the transcriptional start point of the pck gene. We measured the expression of pck in a pckR deletion mutant by using quantitative real-time reverse transcription-PCR. The expression level of pck in the pckR mutant was 7.6 times higher than that in wild-type cells grown in glucose. Comparative DNA microarray hybridizations and bioinformatic searches revealed the gene composition of the transcriptional regulon of C. glutamicum. Based on these results, PckR seemed to play an important role in the regulation of PEPCK in C. glutamicum grown in glucose. In particular, these assays revealed that PckR acts as a repressor of pck expression during glucose metabolism.
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors.forename: Jeong Eun
authors.initials: JE
authors.lastname: Hyeon
authors.forename: Dae Hee
authors.initials: DH
authors.lastname: Kang
authors.forename: Young In
authors.initials: YI
authors.lastname: Kim
authors.forename: Seung Kyou
authors.initials: SK
authors.lastname: You
authors.forename: Sung Ok
authors.initials: SO
authors.lastname: Han
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D048230:Corynebacterium glutamicum / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D016680:Genome, Bacterial; D020411:Oligonucleotide Array Sequence Analysis; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D024363:Transcription Initiation Site
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D010729:Phosphoenolpyruvate Carboxykinase (GTP)