Jarvis Lab

Vacancies

 
 
Postdoc Positions  
 
We have space and projects available in our laboratory for researchers able to bring their own funding. We have core funding to cover the bulk of laboratory costs, but applicants must obtain funding to cover their living expenses. Some examples of the postdoctoral fellowships that are available are shown below, and we are happy to support all competitive applications. If you would like to apply, please contact Professor Jarvis in the first instance.
 
 
  Newton International Fellowships: http://www.newtonfellowships.org/  
  European Molecular Biology Organization (EMBO) Long-Term Fellowships: http://www.embo.org/fellowships/long_term.html  
  Human Frontier Science Program (HFSP) Long-Term Fellowships: http://www.hfsp.org/how/appl_forms_LTF.php  
  Marie Curie Fellowships: http://ec.europa.eu/research/mariecurieactions/  
  Japan Society for the Promotion of Science (JSPS) Study Abroad Fellowships: http://www.jsps.go.jp/j-ab/index.html  
   
PhD (DPhil) Studentships  
 
The following projects are available for 2014. Application procedures are described here, but candidates should in the first instance contact Professor Jarvis by e-mail.

These projects would suit candidates with a strong background in one or more of the following areas: molecular biology, cell biology, biochemistry, genetics.
 

 
Project 1 Characterization of new genes involved in chloroplast development identified through genetic suppressor analysis  
  Background:  Chloroplasts belong to a diverse family of plant organelles termed plastids. Chloroplasts are responsible for photosynthesis and many biosynthetic functions. As photosynthesis is the only significant mechanism of energy-input into the biosphere, chloroplasts are extremely important, not just to plants but to animals and mankind alike. Development of chloroplasts (and other plastids) depends on the import of thousands of nucleus-encoded proteins from the cytosol. Such protein import is mediated by multiprotein complexes in the plastid envelope membranes termed TOC and TIC (for Translocon at the Outer/Inner envelope membrane of Chloroplasts).

Project Description:
  The main components of the TOC/TIC complexes have been identified, but regulation of the machinery is poorly understood. To identify new components or regulators of the system, we conducted a large forward-genetic screen for extragenic suppressors of the Arabidopsis ppi1 mutation (which causes the loss of an important TOC component). This screen identified >200 suppressor of ppi1 (sp) mutants that are now awaiting analysis. Selected sp mutants will be characterized at the molecular level (including identification of the affected gene) to elucidate the mechanism of suppression. This approach recently revealed how chloroplasts are directly regulated by the ubiquitin-proteasome system.

Relevant Publications:

Ling, Q., Huang, W., Baldwin, A. and Jarvis, P. (2012) Chloroplast biogenesis is regulated by direct action of the ubiquitin-proteasome system. Science 338: 655-659.
Jarvis, P., Chen, L.-J., Li, H.-m., Peto, C., Fankhauser, C. and Chory, J. (1998) An Arabidopsis mutant defective in the chloroplast general protein import apparatus. Science 282: 100-103.
Jarvis, P. and López-Juez, E. (2013) Biogenesis and homeostasis of chloroplasts and other plastids. Nat. Rev. Mol. Cell Biol. 14: 787-802.
Jarvis, P. (2008) Targeting of nucleus-encoded proteins to chloroplasts in plants (Tansley Review). New Phytol. 179: 257-285.
 
 
Project 2 Elucidating the functions of STIC1 and STIC2 in chloroplast protein transport  
  Background:  As for Project 1 above.

Project Description:
  With the aim of identifying new factors involved in chloroplast protein transport, we conducted a forward-genetic screen for extragenic suppressors of the Arabidopsis tic40 mutation (which causes the loss of an important TIC component). In this way, the SUPPRESSOR OF TIC40 LOCUS 1 (STIC1) and STIC2 genes were identified. These genes are important for chloroplast protein transport, but they encode proteins of unknown function. To elucidate their roles, we used Affymetrix arrays to analyse the transcriptomes of the corresponding mutants (stic1 and stic2). Overall, the stic transcriptomes are very similar to that of wild type, but one gene is strongly up-regulated (>20-fold) in both mutants, relative to wild type. The function of this up-regulated gene, and its encoded protein, will be studied in detail, which in turn should elucidate STIC functions and chloroplast protein transport mechanisms.

Relevant Publications:
Bédard, J., Kubis, S., Bimanadham, S. and Jarvis, P. (2007) Functional similarity between the chloroplast translocon component, Tic40, and the human co-chaperone, Hip. J. Biol. Chem. 282: 21404-21414.
Kovacheva, S., Bédard, J., Patel, R., Dudley, P., Twell, D., Ríos, G., Koncz, C. and Jarvis, P. (2005) In vivo studies on the roles of Tic110, Tic40 and Hsp93 during chloroplast protein import. Plant J. 41: 412-428.
Jarvis, P. and López-Juez, E. (2013) Biogenesis and homeostasis of chloroplasts and other plastids. Nat. Rev. Mol. Cell Biol. 14: 787-802.
Jarvis, P. (2008) Targeting of nucleus-encoded proteins to chloroplasts in plants (Tansley Review). New Phytol. 179: 257-285.
 
 
Project 3 Analysis of the role of the BamA/Omp85-related protein OEP80 in chloroplast β-barrel biogenesis  
  Background:  As for Project 1 above.

Project Description:  The outer membrane of chloroplasts (like those of mitochondria and bacteria) contains β-barrel channel proteins. One of these proteins, Toc75, forms the main translocation pore of the TOC complex. Recent work in mitochondria and bacteria identified BamA/Omp85-type proteins as important mediators of the assembly of β-barrel proteins. However, little is known about the corresponding mechanisms in chloroplasts: a BamA/Omp85-related protein called OEP80 is proposed to be involved, but there is little evidence to support this. To address this hypothesis in an in vivo context, Arabidopsis plants that are OEP80-deficient will be characterized in detail. The aim will be to determine whether loss of OEP80 directly affects assembly of Toc75 and other β-barrels.

Relevant Publications:
Huang, W., Ling, Q., Bédard, J., Lilley, K. and Jarvis, P. (2011) In vivo analyses of the roles of essential Omp85-related proteins in the chloroplast outer envelope membrane. Plant Physiol. 157: 147-159.
Patel, R., Hsu, S., Bédard, J., Inoue, K. and Jarvis, P. (2008) The Omp85-related chloroplast outer envelope protein, OEP80, is essential for viability in Arabidopsis. Plant Physiol. 148: 235-245.
Jarvis, P. and López-Juez, E. (2013) Biogenesis and homeostasis of chloroplasts and other plastids. Nat. Rev. Mol. Cell Biol. 14: 787-802.
Jarvis, P. (2008) Targeting of nucleus-encoded proteins to chloroplasts in plants (Tansley Review). New Phytol. 179: 257-285.
 
 
Project 4 The control of plastid development by the ubiquitin-proteasome system in crop plants  
  Chloroplasts are members of a diverse group of organelles, the plastids, found ubiquitously in plants. They are responsible for photosynthesis and many important biosynthetic functions. Because photosynthesis is the only significant mechanism of energy-input into the biosphere, chloroplasts are of inestimable importance, not just to plants but to animals and mankind alike. Amyloplasts are another plastid type: they accumulate starch and act in energy storage (e.g., in grain, roots and tubers) and gravitropism. Different plastid types interconvert during specific phases of development, and these transitions are critical for plant growth.
     Development of plastids depends on the import of thousands of nucleus-encoded proteins from the cytosol. Protein import is initiated by TOC complexes in the plastid outer membrane. These incorporate multiple, client-specific receptors, and their reorganization is thought to control the plastid’s proteome, developmental fate, and functions. This reorganization is controlled by SP1, a RING-type ubiquitin E3 ligase in the plastid outer membrane (Ling et al., 2012, Science). It mediates ubiquitination of TOC components, promoting their degradation by the ubiquitin-proteasome system (UPS). Plants lacking SP1 perform developmental transitions that involve plastid proteome changes inefficiently.
     Thus, manipulation of SP1 may enable improvements in crop yield or quality, by allowing control of plastid changes (e.g., amyloplast development in grain). This project will involve:
     (1) Assessment of SP1 function in Brachypodium distachyon, a close relative of cereal crops and an ideal model for functional genomic studies in grasses (leading to crop improvement). The student will generate and study transgenic plants with altered SP1 expression (knockdown or overexpression), and assess parameters relevant to yield.
     (2) In a manner informed by the Brachypodium results, the work will be transferred to an agriculturally-important crop: rice. Rice is chosen because its transformation is straightforward, similar to Brachypodium. Analyses of the rice transgenics will be similar to those conducted using Brachypodium, and will include assessments of yield, grain quality, etc.

Relevant Publications:
Ling, Q., Huang, W., Baldwin, A. and Jarvis, P. (2012) Chloroplast biogenesis is regulated by direct action of the ubiquitin-proteasome system. Science 338: 655-659.
Ling, Q. and Jarvis, P. (2013) Dynamic regulation of endosymbiotic organelles by ubiquitination. Trends Cell Biol. 23: 399-408.
Jarvis, P. and López-Juez, E. (2013) Biogenesis and homeostasis of chloroplasts and other plastids. Nat. Rev. Mol. Cell Biol. 14: 787-802.
Huang, W., Ling., Q and Jarvis, P. (2013) The ubiquitin-proteasome system regulates chloroplast biogenesis. Commun. Integr. Biol. 6: e23001.
Kessler, F. (2012) Chloroplast delivery by UPS (Perspective). Science 338: 622-623.
 

 
 
 
  Self-Funded Students  
  Funded studentships are available within the University (and may be applied for as described above), but we also encourage applications from students able to bring their own funding: we have core funding to cover the bulk of laboratory costs, but candidates should obtain scholarship funding to cover: (a) their own living expenses; (b) fees charged by the University of Oxford.
 
 
  Web Links  
  Graduate Study in the Department of Plant Sciences: http://www.plants.ox.ac.uk/plants/students/postgraduates/default.aspx  
  The British Council: http://www.britishcouncil.org/home  
  Commonwealth Scholarship Commission (CSC): http://cscuk.dfid.gov.uk/  
   
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Last updated: Dec 2013
Paul Jarvis