Localization of OccR-activated and TraR-activated promoters that express two ABC-type permeases and the traR gene of Ti plasmid pTiR10.
Conjugation of Agrobacterium tumefaciens wide-host-range octopine-type Ti plasmids is regulated by the LuxR-type transcriptional activator TraR in conjunction with an acylated homoserine lactone designated AAI. Expression of traR in octopine-type Ti plasmids is stimulated by OccR in response to octopine, an opine released from crown gall tumours, and is also positively autoregulated by TraR and AAI. Genetic and physical mapping of these promoters indicates that the OccR-activated promoter lies 14.5 kb upstream of traR, while the TraR-activated promoter lies 6 kb upstream. The upstream portion of the 14.5 kb operon contains seven previously characterized genes that direct the uptake and catabolism of octopine. The TraR-activated promoter lies just downstream from the octopine catabolic genes, and transcribes six genes in addition to traR, including five genes (ophABCDE) that show strong homology to oligo-peptide permeases of Salmonella typhimurium and Bacillus subtilis. Several TraR-regulated promoters overlap with 18 bp inverted repeats called tra boxes. In contrast, the traR autoregulatory promoter is not associated with a consensus tra box.
Fuqua
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Department of Biology, Trinity University, San Antonio, Texas 78212, USA. cfuqua@trinity.edu
Winans
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D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000483:Alleles; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D017123:Bacteriophage T7; D001483:Base Sequence; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D026901:Membrane Transport Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D026901:Membrane Transport Proteins; C080512:TraR protein, Agrobacterium tumefaciens; D015534:Trans-Activators; D014157:Transcription Factors; C073469:OccR protein, Bacteria; C005394:octopine; C037230:oligopeptide permease, Bacteria; D001120:Arginine