tanwir, fariha .
Comparison between different expression systems for AbMV movement proteins in host and non host plants to study protein interactions.
Abutilon mosaic geminivirus has a bipartite genome consisting of DNA A and DNA B. DNA A encode replication and encapsidation associated proteins whereas DNA B encodes movement associated proteins. Three proteins are responsible for mediating the transport of AbMV in host plant, coat protein (CP), nuclear shuttle protein (NSP) and movement protein (MP). Movement protein (also called as BCI) is essential for the long distance transport of virus where as the function of defective nuclear shuttle protein (BVI) can be complemented by coat protein (AVI). Previous studies showed the change in localization of BVI to the cytoplasmic side of the plasma membrane and to the adjacent cells during the co-expression studies in yeast and plant respectively and gives some hints about protein interactions. A demonstration of direct interaction between AbMV BV1 and BC1 in plants during the natural infection process is still impeded. During natural infection in plants BC1 and BV1 are rare proteins. Moreover AbMV is phloem-limited therefore the number of cells in a leaf expressing the proteins is low. The main focus of this study was to express viral movement proteins in host (N.benthamiana) and non-host (Arabidopsis thaliana) to study interactions between these proteins and localization of protein complexes. A prerequisite for this analysis is to express them in sufficient amounts in plants. Therefore we tried to express intron disrupted tagged proteins under the control of constitutive as well as estradiol induced promoter system. Protein level was monitored by co-cultivation of Agrobacterium in cell suspension, transient analysis and stable/transgenic plants. Our results showed that constitutive expression of viral movement proteins under 2x35S promoter in transgenic plants of N. benthamiana and Arabidopsis as well as in Arabidopsis cell suspension did not express any protein in contrast to GUS control, although the expression cassette was confirmed by PCR and selection marker in transgenic plants. Whereas the transient analysis of these proteins in N .benthamiana under the inducible system showed increased level of proteins until 24 hours after induction and subsequent reduction in protein level. Expressed proteins were confirmed by using the monoclonal antibodies against epitope and also against specific proteins to avoid any artefacts. Antibodies against epitope can only detect the plant expressed protein. Transgenic plants expressing viral proteins under inducible system are in progress. In-short possibility of over-expressing movement associated viral protein in the host plant under inducible vector system has opened up new horizons for analysing the complex process of virus movement in plants.
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1 - University of stuttgart, dept. of plant molecular biology and virology, Biological institute,, pfaffenwaldring 57, stuttgart, badenwürtemberg, 70569, Germany
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM