Please use this identifier to cite or link to this item:
|Title:||Genetic control of quorum-sensing signal turnover in Agrobacterium tumefaciens|
|Citation:||Zhang, H.-B., Wang, L.-H., Zhang, L.-H. (2002-04-02). Genetic control of quorum-sensing signal turnover in Agrobacterium tumefaciens. Proceedings of the National Academy of Sciences of the United States of America 99 (7) : 4638-4643. ScholarBank@NUS Repository. https://doi.org/10.1073/pnas.022056699|
|Abstract:||A signal turnover system is an essential component of many genetic regulatory mechanisms. The best-known example is the ubiquitin-dependent protein degradation system that exists in many organisms. We found that Agrobacterium tumefaciens adopts a unique signal turnover system to control exiting from a quorum-sensing mode. A. tumefaciens regulates Ti plasmid conjugal transfer by a quorum-sensing signal, N-3-oxo-octanoyl homoserine lactone (3OC8HSL), also known as Agrobacterium autoinducer. By using Tn5 mutagenesis and a functional cloning approach, we identified two genes that are involved in switching from a conjugal quorum-sensing mode to a nonconjugal mode at the onset of stationary phase. First, we located attJ, which codes for an IcIR-type suppressor that regulates the second gene attM. The latter encodes a homologue of N-acylhomoserine lactone (AHL)-lactonase. Mass spectrometry analysis shows that the enzyme encoded by attM is an AHL-lactonase that hydrolyzes the lactone ring of 3OC8HSL. In wild-type A. tumefaciens, attM expression is initially suppressed by AttJ but significantly elevated at the stationary phase accompanied a sharp decline in 3OC8HSL. DNA gel retardation analysis shows that AttJ specifically binds to the promoter that controls AHL-lactonase expression. Mutation of attJ resulted in constitutive production of AHL-lactonase that abolishes 3OC8HSL accumulation and Ti plasmid transfer. These data suggest that A. tumefaciens has a sophisticated multicomponent quorum-sensing signal turnover system, allowing the cell to sense a change in growth and adjust cellular activities accordingly.|
|Source Title:||Proceedings of the National Academy of Sciences of the United States of America|
|Appears in Collections:||Staff Publications|
Show full item record
Files in This Item:
There are no files associated with this item.
checked on Jul 16, 2018
WEB OF SCIENCETM
checked on Jun 26, 2018
checked on May 18, 2018
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.