D101 is critical for the function of AttJ, a repressor of quorum quenching system in Agrobacterium tumefaciens

다국어 초록 (Multilingual Abstract)

The quorum quenching system of Agrobacterium tumefaciens is specifically activated upon entering the stationary phase. Evidence has shown that this system includes two key components: the IclR-type transcriptional factor AttJ (also named as BlcR) and the AHL-lactonase AttM (also named as BlcC). At exponential phase, AttJ binds to the promoter region of attM and thus suppresses the expression of attM.
At stationary phase, however, the small molecule SSA directly binds to AttJ and relieves its inhibition of AttJ and thereby triggers the expression of attM. While the regulation of AttM has been extensively investigated, little is known about the regulation of AttJ. In this study, we demonstrated the D101 amino acid of AttJ is essential for the AttJ function. In vitro, the variant protein of AttJD101H appeared to be readily aggregated.
In vivo, the D101H mutation in AttJ entirely abolished the inhibitory activity of AttJ and overexpressed attM in A.
tumefaciens A6. In addition, D101H mutation led to an overexpression of attJ, indicating an auto-regulatory mechanism for the attJ regulation. Put together, these findings demonstrate that D101 is an important amino acid for the transcription activity of AttJ and the transcription of attJ is regulated by a negative feedback loop. These results expand previous biochemical characterization of AttJ and provide new mechanistic insights into the regulation of quorum quenching in A. tumefaciens.

참고문헌 (Reference)

1 Zhang, H.B., "The quormone degradation system of Agrobacterium tumefaciens is regulated by starvation signal and stress alarmone (p)ppGpp" 52 : 1389-1401, 2004

2 Carlier, A., "The assimilation of gamma-butyrolactone in Agrobacterium tumefaciens C58 interferes with the accumulation of the N-acyl-homoserine lactone signal" 17 : 951-957, 2004

3 Krell, T., "The IclR family of transcriptional activators and repressors can be defined by a single profile" 15 : 1207-1213, 2006

4 Pan, Y., "The Agrobacterium tumefaciens transcription factor BlcR is regulated via oligomerization" 286 : 20431-20440, 2011

5 Wang, C., "Succinic semialdehyde couples stress response to quorum-sensing signal decay in Agrobacterium tumefaciens" 62 : 45-56, 2006

6 Bertani, I., "Regulation of the phydroxybenzoic acid hydroxylase gene (pobA) in plant-growthpromoting Pseudomonas putida WCS358" 147 : 1611-1620, 2001

7 Sunnarborg, A., "Regulation of the glyoxylate bypass operon: Cloning and characterization of iclR" 172 : 2642-2649, 1990

8 Gui, L., "Regulated expression of a repressor protein: FadR activates iclR" 178 : 4704-4709, 1996

9 Chai, Y., "Reconstitution of the biochemical activities of the AttJ repressor and the AttK, AttL, and AttM catabolic enzymes of Agrobacterium tumefaciens" 189 : 3674-3679, 2007

10 Waters, C.M., "Quorum sensing: Cell-to-cell communication in bacteria" 21 : 319-346, 2005

11 Haudecoeur, E., "Proline antagonizes GABA-induced quenching of quorum-sensing in Agrobacterium tumefaciens" 106 : 14587-14592, 2009

12 Staskawicz, B., "Molecular characterization of cloned avirulence genes from race 0and race 1 of Pseudomonas syringae pv. glycinea" 169 : 5789-5794, 1987

13 Molina-Henares, A.J., "Members of the IclR family of bacterial transcriptional regulators function as activators and/or repressors" 30 : 157-186, 2006

14 Pan, Y., "In vivo analysis of DNA binding and ligand interaction of BlcR, an IclR-type repressor from Agrobacterium tumefaciens" 159 : 814-822, 2013

15 DiMarco, A.A., "Identification of the transcriptional activator pobR and characterization of its role in the expression of pobA, the structural gene for p-hydroxybenzoate hydroxylase in Acinetobacter calcoaceticus" 175 : 4499-4506, 1993

16 Wang, C., "Identification and characterization of a second quorum-sensing system in Agrobacterium tumefaciens A6" 196 : 1403-1411, 2014

17 Grainger, D.C., "Genomic studies with Escherichia coli MelR protein: Applications of chromatin immunoprecipitation and microarrays" 186 : 6938-6943, 2004

18 Bell, K.S., "Genome sequence of the enterobacterial phytopathogen Erwinia carotovora subsp. atroseptica and characterization of virulence factors" 101 : 11105-11110, 2004

19 Zhang, H.B., "Genetic control of quorum-sensing signal turnover in Agrobacterium tumefaciens" 99 : 4638-4643, 2002

20 Larsen, R.A., "Genetic analysis of pigment biosynthesis in Xanthobacter autotrophicus Py2 using a new, highly efficient transposon mutagenesis system that is functional in a wide variety of bacteria" 178 : 193-201, 2002

21 Chevrot, R., "Gaba controls the level of quorum-sensing signal in Agrobacterium tumefaciens" 103 : 7460-7464, 2006

22 Wang, C., "Dual control of quorum sensing by two tram-type antiactivators in Agrobacterium tumefaciens octopine strain A6" 188 : 2435-2445, 2006

23 Haudecoeur, E., "Different regulation and roles of lactonases AiiB and AttM in Agrobacterium tumefaciens C58" 22 : 529-537, 2009

24 Zhang, R.G., "Crystal structure of Thermotoga maritima 0065, a member of the IclR transcriptional factor family" 277 : 19183-19190, 2002

25 Piper, K.R., "Conjugation factor of Agrobacterium tumefaciens regulates Ti plasmid transfer by autoinduction" 362 : 448-450, 1993

26 Molina, M.L., "Clustering and coupled gating modulate the activity in KcsA, a potassium channel model" 281 : 18837-18848, 2006

27 White, C.E., "Cell-cell communication in the plant pathogen Agrobacterium tumefaciens" 362 : 1135-1148, 2007

28 Wang, C., "BswR controls bacterial motility and biofilm formation in Pseudomonas aeruginosa through modulation of the small RNA rsmZ" 42 : 4563-4576, 2014

29 Rutherford, S.T., "Bacterial quorum sensing:Its role in virulence and possibilities for its control" 2 : a012427-, 2012

30 Gui, L., "Autoregulation of iclR, the gene encoding the repressor of the glyoxylate bypass operon" 178 : 321-324, 1996

31 Dong, Y.H., "AiiA, an enzyme that inactivates the acylhomoserine lactone quorum-sensing signal and attenuates the virulence of Erwinia carotovora" 97 : 3526-3531, 2000

32 Subramoni, S., "Agrobacterium tumefaciens responses to plant-derived signaling molecules" 5 : 322-, 2014

33 Zhang, L., "Agrobacterium conjugation and gene regulation by N-acyl-L-homoserine lactones" 362 : 446-448, 1993

34 Wang, C., "ARF-TSS:An alternative method for identification of transcription start site in bacteria" 2012 : 1-3, 2012

35 McCormac, A.C., "A simple method for the production of highly competent cells of Agrobacterium for transformation via electroporation" 9 : 155-159, 1998

36 Matthysse, A.G., "A region of the Agrobacterium tumefaciens chromosome containing genes required for virulence and attachment to host cells" 1490 : 208-212, 2000

37 Haudecoeur, E., "A fine control of quorum-sensing communication in Agrobacterium tumefaciens" 3 : 84-88, 2010

38 Zhang, L.H., "A diffusible compound can enhance conjugal transfer of the TI plasmid in Agrobacterium tumefaciens" 173 : 1867-1872, 1991

39 Simon, R., "A broad host range mobilization system for in vivo genetic engineering: Transposon mutagenesis in Gram-negative bacteria" 1 : 784-791, 1983

40 Stachel, S.E., "A Tn3 lacZ transposon for the random generation of beta-galactosidase gene fusions: Application to the analysis of gene expression in Agrobacterium" 4 : 891-898, 1985

41 Pappas, K.M., "A LuxR-type regulator from Agrobacterium tumefaciens elevates Ti plasmid copy number by activating transcription of plasmid replication genes" 48 : 1059-1073, 2003