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Title: CLONING AND FUNCTIONAL EXPRESSION IN OOCYTES OF THE SUGAR BEET PROTON-SUCROSE SYMPORTER

Author
item LU, MEI-YEH - PLANT BIOLOGY UOFI URBANA
item CHEN, CHIEN-CHANG - MOLEC INTEGRATIVE PHY UI
item BEST, PHIL - MOLEC INTEGRATIVE PHY UI
item BUSH, DANIEL

Submitted to: Plant Physiology Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 8/6/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Sucrose transporters are important components of the assimilate partitioning pathway in many plants. In sugar beet, a key sucrose carrier in partitioning is the proton-sucrose symporter that mediates phloem loading. Our lab has described the transport properties of this carrier using purified plasma membranes vesicles and imposed proton electrochemcial potential differences. More recently, we have cloned a putative transporter from sugar beet using RT-PCR and sequence information derived from conserved regions of previously cloned symporters. A full-length clone was isolated from a sugar beet cDNA library that was generated with mRNA isolated from mature leaf tissue. The cDNA contains 1939 nt with an ORF that encodes a protein consisting of 539 amino acids. Northern analyses showed that the gene is primarily expressed in leaves, petioles, and hypocotyls, although low levels of message were detectable in roots. Direct proof that this is a sucrose transporter was achieved by functional expression. cRNA of this clone was micro injected into xenopus oocytes and sucrose accumulation was observed after seven days. We are currently using this system to explore the transport properties of this transporter in more detail.