Crosby, Kevin C. , Winkel, Brenda S. J. .
Analysis of the sub-cellular localization and dynamics of the flavonoid multi-enzyme complex in Arabidopsis thaliana.
A key aspect of cellular metabolism is the assembly of biosynthetic enzymes into macromolecular complexes localized to specific intracellular sites. Our lab utilizes the flavonoid biosynthetic pathway in the plant Arabidopsis thaliana as a model for understanding the structural and functional aspects of this organization. Immunofluorescence microscopy has revealed that two of these enzymes, chalcone synthase and chalcone isomerase, co-localize both at the endoplasmic reticulum and in the nucleus. Our current research centers on understanding the architecture and dynamics of this flavonoid multienzyme complex and evaluating how these may be relevant to physiological function. Efforts are now being directed towards addressing the following questions: 1) what is the complete architecture of the putative flavonoid multienzyme complex?; 2) how is the subcellular localization of this complex regulated and is this localization functionally relevant?; and 3) does localization of the flavonoid enzymes change dynamically in response to external stimuli? We have begun to determine whether the localization of flavonoid enzymes is regulated in response to external stimuli. Flavonoid gene expression and the accumulation of flavonoid metabolites have been shown to be induced by wounding. In experiments where Arabidopsis roots were wounded by light crushing, we have seen evidence for changes in the sub-cellular localization and abundance of CHS and CHI. We also have preliminary evidence that the asymmetrical localization of CHS is independent of the endocytic pathway. We are using epitope tagging and immunofluorescent microscopy to expand this analysis to a number of additional enzymes in the flavonoid biosynthetic pathway.
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1 - Virginia Polytechnic Institute and State University, Biological Sciences, 428 Latham Hall, Blacskburg, VA, 24061, United States
2 - Virginia Polytechnic Institute and State University, Biological Sciences
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM