Imperial College London
Alternate

Professor Martin Buck FRS

Faculty of Natural Sciences, Department of Life Sciences

Senior Research Investigator
 
 
 
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Contact

 

+44 (0)20 7594 5442m.buck

 
 
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Location

 

448Sir Alexander Fleming BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Waite:2017:10.1128/mBio.02273-16,
author = {Waite, CJ and Schumacher, J and Jovanovic, M and Bennett, M and Buck, M},
doi = {10.1128/mBio.02273-16},
journal = {mBio},
title = {Negative autogenous control of the master type III secretion system regulator HrpL in Pseudomonas syringae},
url = {http://dx.doi.org/10.1128/mBio.02273-16},
volume = {8},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The type III secretion system (T3SS) is a principal virulence determi-nant of the model bacterial plant pathogenPseudomonas syringae. T3SS effectorproteins inhibit plant defense signaling pathways in susceptible hosts and elicitevolved immunity in resistant plants. The extracytoplasmic function sigma factorHrpL coordinates the expression of most T3SS genes. Transcription ofhrpLis depen-dent on sigma-54 and the codependent enhancer binding proteins HrpR and HrpSforhrpLpromoter activation.hrpLis oriented adjacently to and divergently from theHrpL-dependent genehrpJ, sharing an intergenic upstream regulatory region. Weshow that association of the RNA polymerase (RNAP)-HrpL complex with thehrpJpromoter element imposes negative autogenous control onhrpLtranscription inP. syringaepv.tomatoDC3000. ThehrpLpromoter was upregulated in a ΔhrpLmu-tant and was repressed by plasmid-bornehrpL. In a minimalEscherichia coliback-ground, the activity of HrpL was sufficient to achieve repression of reconstitutedhrpLtranscription. This repression was relieved if both the HrpL DNA-binding func-tion and thehrp-box sequence of thehrpJpromoter were compromised, implyingdependence upon thehrpJpromoter. DNA-bound RNAP-HrpL entirely occluded theHrpRS and partially occluded the integration host factor (IHF) recognition elementsof thehrpLpromoterin vitro, implicating inhibition of DNA binding by these factorsas a cause of negative autogenous control. A modest increase in the HrpL concen-tration caused hypersecretion of the HrpA1 pilus protein but intracellular accumula-tion of later T3SS substrates. We argue that negative feedback on HrpL activity fine-tunes expression of the T3SS regulon to minimize the elicitation of plant defenses.
AU  - Waite,CJ
AU  - Schumacher,J
AU  - Jovanovic,M
AU  - Bennett,M
AU  - Buck,M
DO  - 10.1128/mBio.02273-16
PY  - 2017///
SN  - 2150-7511
TI  - Negative autogenous control of the master type III secretion system regulator HrpL in Pseudomonas syringae
T2  - mBio
UR  - http://dx.doi.org/10.1128/mBio.02273-16
UR  - http://hdl.handle.net/10044/1/43576
VL  - 8
ER  -
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