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C2 Functional analysis of the interaction between host chaperones and viral transport proteins

Principal investigator
Uwe Sonnewald

Mentor
Manfred Marschall

PhD exam: 19.06.2015


Analysis of the macromolecule transport in plants and molecular analysis of a viral movement protein

In higher plants the symplastic communication between neighbouring cells occurs through so called plasmodesmata (Pds). Pds are membrane-lined channels that traverse the cell walls and facilitate the specific trafficking of small metabolites as well as of large RNA and protein macromolecules involved in local and systemic signalling. This system is also used by different plant viruses, which spread from cell to cell by encoding for specialized movement proteins (MPs). Several investigations could confirm the localization of these MPs to PDs, where they lead to an increase in the basal size exclusion limit (SEL). Furthermore the ability of MPs to bind viral nucleic acids enables both the intercellular and the intracellular transport of ribonucleocomplexes.
The centre of our research is the 17 kDa MP (MP17) of the potato leaf roll virus (PLRV). MP17 localizes to secondary plasmodesmata in source tissues but not to primary plasmodesmata of sink tissues, where it is degraded by the 26S proteasome. Furthermore, the constitutive expression of MP17 fused to the green fluorescent protein (GFP) in Arabidopsis thaliana results in a decrease of sucrose export and accumulation of carbohydrates in source leaves which phenotypically manifests in growth retardation and the development of chlorosis.
Attempts to identify host proteins involved in these processes failed so far. Therefore, we attempt to determine crucial amino acids for plasmodesmal targeting and protein degradation by the creation of deletion and mutant variants of the MP17 protein. Identified domains will be used in interaction screens to isolate possible binding partners and for bioinformatic prediction of plasmodesmal targeting sequences.

 

Figure: Epidermal cells of transgenic Arabidopsis thaliana expressing MP17:GFP under the control of the CaMV. Propidium iodide fluorescence of stained cell walls is shown in red.

 

Publications

Thran, M., Link, K. and Sonnewald, U. (2012). The Arabidopsis DCP2 gene is required for proper mRNA turnover and prevents transgene silencing in Arabidopsis. Plant J 72(3), 368-377.

Jungkunz, I., Link, K., Vogel, F., Voll, L. M., Sonnewald, S. and Sonnewald, U. (2011). AtHsp70-15-deficient Arabidopsis plants are characterized by reduced growth, a constitutive cytosolic protein response and enhanced resistance to TuMV. Plant J. 66(6), 983-995.

Link, K., Vogel, F. and Sonnewald, U. (2011). PD Trafficking of Potato Leaf Roll Virus Movement Protein in Arabidopsis Depends on Site-specific Protein Phosphorylation. Front Plant Sci 2:18.

 

 

Presentations

July 2013 5th Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
Molecular Analysis of MP17 and its Putative Interaction Partners
Talk
     
July 2012 4th Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
How can a putative choline transporter influence the plasmodesmal localization of MP17
Talk
     
October 2011 First International SFB 796 Conference: Mechanisms of viral host cell manipulations: from plants to humans, Bamberg, Germany
Insights into plasmodesmal transport - the PLRV MP17
Poster
     
July 2011 3rd Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
Insights into plasmodesmal transport – the PLRV MP17
Talk and Poster
     
February 2011 24. Tagung Molekularbiologie der Pflanzen, Dabringhausen, Germany
PD trafficking ofthe PLRV movement protein in Arabidopsis depends on site–specific protein phosphorylation
Poster
     
September 2010 2nd Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
Insights into plasmodesmal transport – the PLRV MP17
Talk
     
March 2010 Plasmodesmata 2010 Conference, Sidney, Australia
Insights into plasmodesmal transport – the PLRV MP17
Talk
     
September 2009 First Annual Retreat, Erlangen School of Molecular Communication, Schloss Atzelsberg, Atzelsberg, Germany
Analysis of the macromolecule transport in plants and molecular analysis of a viral movement protein
Talk
     

 

Awards

Best Talk Award
5th Annual Retreat, Erlangen School of Molecular Communication
Kloster Banz, Bad Staffelstein, Germany, July 2013
Molecular Analysis of MP17 and its Putative Interaction Partners