Abstract
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.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
