Functional analysis of Arabidopsis transporters for nucleobases and derivatives
Final Report Abstract
Nucleobases and derivatives play essential roles in the cells of all living organisms. Since the site of their synthesis frequently differs from the site of use, transport is required in multicellular organisms. In plants, crucial transport processes involving nucleobases or derivatives are not well understood at the molecular level. This includes the uptake of purines and pyrimidines into the cell for salvaging, the long distance transport of purine degradation products, with the ureides as prominent compounds in tropical legumes, and the allocation of cytokinins. The aim of this project was to evaluate the role of the members of two different protein families of Arabidopsis, which are potentially involved in these processes. The Ureide Permeases of Arabidopsis (AtUPS) were characterized to point out (i) their subcellular localization, (ii) the functional role of AtUPS1 and AtUPS4 in the utilization of pyrimidines during germination, (ii) and the role of AtUPS5 in the allocation of allantoin, uric acid and xanthine during stress. In addition, two A. thaliana members belonging to a novel protein family, which are potentially involved in cytokinin transport (designated as AtAzg1 and AtAzg2 for Arabidopsis thaliana Azaguanine resistant), were characterized with respect to their transport properties, gene expression and subcellular localization. Knockout and overexpressor plants were obtained and characterized.
Publications
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(2006) Comparative studies on Ureide Permeases in Arabidopsis thaliana and analysis of two alternative splice variants of AtUPS5. Planta 224:1329-1340
Schmidt A, Baumann N, Schwarzkopf A, Frommer WB, Desimone M
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(2006) Heterologous expression of a plant uracil transporter in yeast: Improvement of plasma membrane targeting in mutants of the Rsp5p ubiquitin protein ligase. Biotech J 1: 308-320
Froissard M, Belgareh-Touzé N, Buisson N, Desimone M, Frommer WB, Haguenauer- Tsapis R
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(2006) Transcription analysis of Arabidopsis membrane transporters and hormone pathways during developmental and induced leaf senescence. Plant Physiol 141:776-92
van der Graaff E, Schwacke R, Schneider A, Desimone M, Flügge UI, Kunze R
