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Title: IMMUNOCHEMICAL LOCALIZATION ON THE TONOPLAST AND EXPRESSION IN TRANSGENIC YEAST AND TOBACCO OF A PUTATIVE SUGAR TRANSPORTER FROM SUGAR BEET

Author
item CHIOU, TZYY-JEN - UNIV OF ILLINOIS, URB
item BUSH, DANIEL

Submitted to: Proceedings of International Plant Membrane Transports
Publication Type: Abstract Only
Publication Acceptance Date: 8/11/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Sugar transport within cells and between organs is a fundamental activity in all multicellular organisms. Recently, several plant genes have been cloned that are members of the sugar transporter subgroup of the major facilitator superfamily of transporters. In the results presented here, we report on the expression and surprising membrane localization of one of these porters found in sugar beet. Antibodies directed against small peptides repre- senting the N- and C-terminal domains of the expressed protein of our clone, cDNA1, were produced as tools to study this low abundance membrane protein. In transgenic yeast, an additional 40 kDa polypeptide was observed in western blot analysis of the microsomal membrane fraction of cDNA-1 transformed cells versus the non-transformed controls. This band was diffuse and smaller than that predicted from the deduced molecular weight, but was very similar to the in vitro translation product. Moreover, antibodies directed against either the N- or C-terminal domains recognized the same protein. This transporter was also examined in sugar beet and transgenic tobacco. Western analysis identified the cDNA1 protein in light membrane fractions containing golgi, ER, and tonoplast membranes. Detailed analysis of this transporter's distribution across linear sucrose gradients and flotation centrifugations showed that it comigrated with tonoplast membrane markers. We concluded that this carrier is located on the tonoplast membrane.