BBSRC SWBio DTP PhD studentship: Characterizing the regulators and effectors of heavy metal resistance in the environmental organism and opportunistic pathogen, Burkholderia cepacia complex

Main Supervisor: Dr Alan Brown, Biosciences (University of Exeter)
Second Supervisor: Dr Steve Porter

Location:

University of Exeter, Streatham Campus, Exeter

Project Description:

Background. The Burkholderia cepacia complex (BCC) is a versatile group of closely-related bacterial species which occupy diverse environmental and clinical niches. They are frequently isolated from sources in which heavy metals are elevated, including heavy metal-contaminated soils and the sputum of cystic fibrosis patients. Consequently, BCC have robust heavy metal resistance mechanisms. This project will focus on defining the regulators and effectors of this resistance, and how they contribute to BCC’s success in diverse niches.

We have characterized the CzcRS two-component system (TCS) of BCC, which confers zinc and cadmium resistance by regulating the CzcCBA efflux pump and a separate gene cluster encoding a novel putative heavy metal resistance determinant. Strikingly, CzcRS also plays a role in virulence and intracellular survival, and has been implicated in antibiotic resistance, highlighting the importance of this single metal-responsive TCS in both natural and clinical environments. Clinical relevance is heightened by the increasing incorporation of zinc (and other metals) into medical devices (e.g. catheters), which may result in the activation of CzcRS-related TCSs during infection. We have also identified two other putative heavy metal-responsive TCSs that we predict form a novel multi-kinase network with CzcRS and may enable cells to modulate their responses to certain metals depending on the other stressors present.

Research Programme. Through a multidisciplinary programme of research combining biochemistry, molecular bacteriology and genomics, the student will:

• define the role of individual CzcRS-regulated genes;
• define the hierarchy and interconnectedness of the heavy metal-responsive TCSs;
• identify & characterize the resistance determinants controlled by each TCS.

The first year will comprise two rotation projects. The first (with Dr Steve Porter) will use bioinformatics to predict metal-responsive multi-kinase networks in BCC, and perform experimental validation on selected systems using phosphorylation assays. The second (with Dr Alan Brown) will investigate the putative novel heavy metal resistance determinant referred to above through targeted gene deletion and phenotyping of resulting mutants.

Thereafter (years 2-4), the student will (a) apply genomics (ChIP-seq) to define the regulon of each TCS; (b) perform targeted mutagenesis and phenotypic characterization of relevant regulators and effectors of resistance; (c) use fluorescent-reporter strains to assess the responsiveness of each TCS and their interdependence on each other; (d) biochemically investigate direct interactions within the putative multi-kinase network.

Conclusion. The project, which offers outstanding training opportunities in diverse methodologies, will reveal the complex regulatory networks and downstream effectors of heavy metal resistance in clinically- and environmentally-important BCC.
This project is one of a number that are in competition for funding from the South West Biosciences Doctoral Training Partnership (SWBio DTP). The SWBio DTP is a BBSRC-funded PhD training programme in the biosciences, delivered by a consortium comprising the Universities of Bristol (lead), Bath, Cardiff and Exeter and Rothamsted Research. The SWBio DTP projects are designed to provide outstanding interdisciplinary training in a range of topics in Agriculture & Food Security and World-Class Bioscience, underpinned by training in mathematics and complexity science. Each project will be supervised by an interdisciplinary team of academic staff and will follow a structured training 4 year PhD model.

The studentship will cover a stipend (currently £14,057pa), research costs and tuition fees at the UK/EU rate for students who meet the residency requirements outlined by the BBSRC. Students from EU countries who do not meet the residency requirements may still be eligible for a fees-only award. Applicants who are classed as International for tuition fee purposes are not eligible for funding. Duration of award: 4 years.

You will need a 2:1 (or a 2:2 plus Masters) and a minimum grade B in A-level Maths.
For further information and details of how to apply:
http://www.exeter.ac.uk/studying/funding/award/?id=1973