title: Two enzymes, TilS and HprT, can form a complex to function as a transcriptional activator for the cell division protease gene ftsH in Bacillus subtilis.
abstract: The FtsH protein is an ATP-dependent cytoplasmic membrane protease involved in the control of membrane protein quality, cell division and heat shock response in Bacillus subtilis and many other bacteria. TilS, the tRNA(Ile2) lysidine synthetase, is a tRNA-binding protein that can modify pre-tRNA(Ile2). HprT, the hypoxanthine-guanine phosphoribosyltransferase, is implicated in purine salvage. Both tilS and hprT are essential for cell viability of B. subtilis. In this report, by co-purification experiments and gel filtration analyses, we show that there is complex formation between co-expressed TilS and HprT. Electrophoretic mobility shift assays and in vitro transcription analyses demonstrated that the TilS/HprT complex functions as a specific DNA-binding protein that can stimulate ftsH transcription in vitro. Two regions located upstream of the ftsH promoter have been identified as the TilS/HprT-binding sites and shown to be required for TilS/HprT-dependent ftsH transcription in vitro and in vivo. Results from gel supershift assays support the notion that the TilS/HprT complex likely employs its distinct segments for interaction with these two distinct TilS/HprT-binding sites, respectively. In conclusion, we present the first evidence that bi-functional TilS and HprT can form a complex to function as a transcriptional activator to stimulate ftsH transcription.
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei 112, Taiwan, People's Republic of China.
authors.forename: Ta-Hui
authors.initials: TH
authors.lastname: Lin
authors.forename: Yi-Nei
authors.initials: YN
authors.lastname: Hu
authors.forename: Gwo-Chyuan
authors.initials: GC
authors.lastname: Shaw
mesh_terms: D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics / Q000502:physiology*; D001412:Bacillus subtilis / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D002455:Cell Division; D002850:Chromatography, Gel; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D015534:Trans-Activators / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D015534:Trans-Activators; D010447:Peptide Hydrolases; C478461:tRNA(Ile)-lysidine synthetase, Bacillus subtilis; D000604:Amino Acyl-tRNA Synthetases
keywords: Bacillus subtilis; HprT; TilS; ftsH; transcriptional activator