title: Regulation of a modified CaMV 35S promoter by the Tn10-encoded Tet repressor in transgenic tobacco.
abstract: We have investigated the use of the Tn10-encoded tet repressor-operator system to regulate the expression of a suitably engineered cauliflower mosaic virus (CaMV) 35S promoter in transgenic tobacco plants. First, a transgenic plant was generated which constitutively synthesizes 600,000 Tet repressor monomers per cell. In a second transformation step, the beta-glucuronidase (gus) gene under the control of a modified CaMV 35S promoter, containing two tet operators, was stably integrated into the plant genome of a tetR+ plant. Expression of the gus gene is repressed 5-fold, if the operators are located flanking the TATA box, and 50- to 80-fold when both operators are positioned downstream of the TATA box. This indicates that Tet repressor-operator complexes can form on plant chromosomes and interfere with transcription. Maximal induction is achieved after 0.5 h upon application of only 0.1 mg/l tetracycline. This fast and efficient induction makes the system useful for specifically inducing expression of transferred genes at different stages of plant development.
authors.affiliation: Institut für Genbiologische Forschung, GmbH, Berlin, FRG.
authors.forename: C
authors.initials: C
authors.lastname: Gatz
authors.forename: A
authors.initials: A
authors.lastname: Kaiser
authors.forename: R
authors.initials: R
authors.lastname: Wendenburg
mesh_terms: D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D004274:DNA, Recombinant / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D005966:Glucuronidase / Q000096:biosynthesis / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data; D009029:Mosaic Viruses / Q000235:genetics*; D009875:Operator Regions, Genetic / Q000235:genetics*; D010947:Plants, Toxic; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011523:Protoplasts / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics*; D016385:TATA Box; D013752:Tetracycline / Q000494:pharmacology; D014026:Nicotiana / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects; D014170:Transformation, Genetic
chemical_list: D004274:DNA, Recombinant; D012333:RNA, Messenger; D012097:Repressor Proteins; C034811:tetracycline resistance-encoding transposon repressor protein; D005966:Glucuronidase; D013752:Tetracycline