title: Transcriptome sequencing revealed the transcriptional organization at ribosome-mediated attenuation sites in Corynebacterium glutamicum and identified a novel attenuator involved in aromatic amino acid biosynthesis.
abstract: The Gram-positive bacterium Corynebacterium glutamicum belongs to the order Corynebacteriales and is used as a producer of amino acids at industrial scales. Due to its economic importance, gene expression and particularly the regulation of amino acid biosynthesis has been investigated extensively. Applying the high-resolution technique of transcriptome sequencing (RNA-seq), recently a vast amount of data has been generated that was used to comprehensively analyze the C. glutamicum transcriptome. By analyzing RNA-seq data from a small RNA cDNA library of C. glutamicum, short transcripts in the known transcriptional attenuators sites of the trp operon, the ilvBNC operon and the leuA gene were verified. Furthermore, whole transcriptome RNA-seq data were used to elucidate the transcriptional organization of these three amino acid biosynthesis operons. In addition, we discovered and analyzed the novel attenuator aroR, located upstream of the aroF gene (cg1129). The DAHP synthase encoded by aroF catalyzes the first step in aromatic amino acid synthesis. The AroR leader peptide contains the amino acid sequence motif F-Y-F, indicating a regulatory effect by phenylalanine and tyrosine. Analysis by real-time RT-PCR suggests that the attenuator regulates the transcription of aroF in dependence of the cellular amount of tRNA loaded with phenylalanine when comparing a phenylalanine-auxotrophic C. glutamicum mutant fed with limiting and excess amounts of a phenylalanine-containing dipeptide. Additionally, the very interesting finding was made that all analyzed attenuators are leaderless transcripts.
authors.affiliation: Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Universitätsstraße 27, 33615 Bielefeld, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Neshat
authors.affiliation: Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Universitätsstraße 27, 33615 Bielefeld, Germany.
authors.forename: Almut
authors.initials: A
authors.lastname: Mentz
authors.affiliation: Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Universitätsstraße 27, 33615 Bielefeld, Germany; Technology Platform Genomics, Center for Biotechnology, Bielefeld University, Universitätsstraße 27, 33615 Bielefeld, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Rückert
authors.affiliation: Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Universitätsstraße 27, 33615 Bielefeld, Germany; Technology Platform Genomics, Center for Biotechnology, Bielefeld University, Universitätsstraße 27, 33615 Bielefeld, Germany. Electronic address: joern.kalinowski@cebitec.uni-bielefeld.de.
authors.forename: Jörn
authors.initials: J
authors.lastname: Kalinowski
mesh_terms: D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000235:genetics; D024322:Amino Acids, Aromatic / Q000096:biosynthesis* / Q000235:genetics; D048230:Corynebacterium glutamicum / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D015723:Gene Library; D009876:Operon / Q000235:genetics; D012313:RNA / Q000737:chemistry; D012270:Ribosomes / Q000378:metabolism*; D017423:Sequence Analysis, RNA; D014158:Transcription, Genetic / Q000235:genetics*; D059467:Transcriptome / Q000235:genetics*
chemical_list: D024322:Amino Acids, Aromatic; D012313:RNA; D010723:3-Deoxy-7-Phosphoheptulonate Synthase
keywords: Amino acid biosynthesis; Corynebacterium glutamicum; RNA-sequencing; Small RNAs; Transcriptional attenuation