title: A ROS repressor-mediated binary regulation system for control of gene expression in transgenic plants.
abstract: We describe a novel binary system to control transgene expression in plants. The system is based on the prokaryotic repressor, ROS, from Agrobacterium tumefaciens, optimized for plant codon usage and for nuclear targeting (synROS). The ROS protein bound in vitro to double stranded DNA comprising the ROS operator sequence, as well as to single stranded ROS operator DNA sequences, in an orientation-independent manner. A synROS-GUS fusion protein was localized to the nucleus, whereas wtROS-GUS fusion remained in the cytoplasm. The ability of synROS to repress transgene expression was validated in transgenic Arabidopsis thaliana and Brassica napus. When expressed constitutively under the actin2 promoter, synROS repressed the expression of the reporter gene gusA linked to a modified CaMV35S promoter containing ROS operator sequences in the vicinity of the TATA box and downstream of the transcription initiation signal. Repression ranged from 32 to 87% in A. thaliana, and from 23 to 76% in B. napus. These results are discussed in relation to the potential application of synROS in controlling the expression of transgenes and endogenous genes in plants and other organisms.
authors.affiliation: Molecular Genetics Section, Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, Sask., Canada S7N 0X2.
authors.forename: Ulrike A
authors.initials: UA
authors.lastname: Schäfer
authors.forename: Dwayne D
authors.initials: DD
authors.lastname: Hegedus
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Bate
authors.forename: Abdelali
authors.initials: A
authors.lastname: Hannoufa
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D002467:Cell Nucleus / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D005966:Glucuronidase / Q000032:analysis; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D014026:Nicotiana / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D005966:Glucuronidase