Max Kraner


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

Principal investigator
Uwe Sonnewald

Armin Ensser

Molecular and proteomic analysis of host factors involved in viral transport

Plasmodesmata (PD) are microscopic pores which traverse cell walls of plant cells and enable cell-to-cell transport and communication. Currently, little is known about the molecular mechanisms regulating PD formation, structure and distribution. To uncover components relevant for PD development we made use of the 17 kDa movement protein (MP17) of the Potato leafroll virus (PLRV). The protein is required for cell-to-cell movement of the virus and localizes to branched PD in source tissues. By forward genetic screening for Arabidopsis mutants with altered PD binding of MP17-GFP, several mutants were found. Map-based cloning of one of these mutants revealed a point mutation in one of the choline transporter-like (CHER1) family proteins (cher1-5). Turnip mosaic virus infection of the T-DNA insertion mutant cher1-4 indicatesa significant reduction of viral spread in Arabidopsis. Closer inspection of CHER1 mutants by transmission electron micrographs shows that the PD frequency decreases during leaf development while maturation of complex PD is diminished. Hence, this mutant serves as a promising source to elucidate the composition of complex plasmodesmata by comparative quantitative proteomics. Identification and characterization of so far undiscovered components will give further insights into the regulation of symplastic cell-to-cell communication and viral spread.

Figure: a,b: TEM images of plasmodesmata in fully extended cher1 leaves revealed strong reduction in PD number and complexity compared to Col-0. Scale bar. 200nm. Subsequently, cell wall enriched fractions containing embedded PD proteins are quantitatively analyzed by mass spectrometry.





October 2016 8th Annual Retreat, Erlangen School of Molecular Communication, Schloss Schney, Lichtenfels, Germany
“Insights into plant cell-to-cell connections”
July 2014 6th Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
“BioID -  Method to investigate cellular protein-protein interactions in plants”
July 2013 5th Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
Novel Methods to investigate cellular protein-protein Interactions